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Yurchenko DV, Lytvynenko AS, Abdullayev EN, Peregon NV, Gavrilenko KS, Gorlova AO, Ryabukhin SV, Volochnyuk DM, Kolotilov SV. Catalytic Oxidation of Benzoins by Hydrogen Peroxide on Nanosized HKUST-1: Influence of Substituents on the Reaction Rates and DFT Modeling of the Reaction Path. Molecules 2023; 28:molecules28020747. [PMID: 36677805 PMCID: PMC9861975 DOI: 10.3390/molecules28020747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/15/2022] [Revised: 12/30/2022] [Accepted: 01/04/2023] [Indexed: 01/15/2023]
Abstract
In this research, the oxidation of a series of benzoins, R-C(=O)-CH(OH)-R, where R = phenyl, 4-methoxyphenyl, 4-bromophenyl, and 2-naphthyl, by hydrogen peroxide in the presence of nanostructured HKUST-1 (suspension in acetonitrile/water mixture) was studied. The respective benzoic acids were the only products of the reactions. The initial average reaction rates were experimentally determined at different concentrations of benzoin, H2O2 and an effective concentration of HKUST-1. The sorption of the isotherms of benzoin, dimethoxybenzoin and benzoic acid on HKUST-1, as well as their sorption kinetic curves, were measured. The increase in H2O2 concentration expectedly led to an acceleration of the reaction. The dependencies of the benzoin oxidation rates on the concentrations of both benzoin and HKUST-1 passed through the maxima. This finding could be explained by a counterplay between the increasing reaction rate and increasing benzoin sorption on the catalyst with the increase in the concentration. The electronic effect of the substituent in benzoin had a significant influence on the reaction rate, while no relation between the size of the substrate molecule and the rate of its oxidation was found. It was confirmed by DFT modeling that the reaction could pass through the Baeyer-Villiger mechanism, involving an attack by the HOO- anion on the C atom of the activated C=O group.
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Affiliation(s)
- Darya V. Yurchenko
- L.V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prosp. Nauky 31, 03028 Kyiv, Ukraine
| | - Anton S. Lytvynenko
- L.V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prosp. Nauky 31, 03028 Kyiv, Ukraine
- Department of Analytical Chemistry, Faculty of Science, Charles University, Albertov 6, 12800 Prague, Czech Republic
| | - Emir N. Abdullayev
- L.V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prosp. Nauky 31, 03028 Kyiv, Ukraine
- Enamine Ltd., 78 Chervonotkatska Str., 02094 Kyiv, Ukraine
| | - Nina V. Peregon
- L.V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prosp. Nauky 31, 03028 Kyiv, Ukraine
| | - Konstantin S. Gavrilenko
- Enamine Ltd., 78 Chervonotkatska Str., 02094 Kyiv, Ukraine
- Institute of High Technologies, National Taras Shevchenko University of Kyiv, 60 Volodymyrska Str., 01033 Kyiv, Ukraine
| | - Alina O. Gorlova
- Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, 5 Murmanska Str., 02094 Kyiv, Ukraine
| | - Sergey V. Ryabukhin
- Enamine Ltd., 78 Chervonotkatska Str., 02094 Kyiv, Ukraine
- Institute of High Technologies, National Taras Shevchenko University of Kyiv, 60 Volodymyrska Str., 01033 Kyiv, Ukraine
- Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, 5 Murmanska Str., 02094 Kyiv, Ukraine
| | - Dmitriy M. Volochnyuk
- Enamine Ltd., 78 Chervonotkatska Str., 02094 Kyiv, Ukraine
- Institute of High Technologies, National Taras Shevchenko University of Kyiv, 60 Volodymyrska Str., 01033 Kyiv, Ukraine
- Institute of Organic Chemistry of the National Academy of Sciences of Ukraine, 5 Murmanska Str., 02094 Kyiv, Ukraine
| | - Sergey V. Kolotilov
- L.V. Pisarzhevskii Institute of Physical Chemistry of the National Academy of Sciences of Ukraine, Prosp. Nauky 31, 03028 Kyiv, Ukraine
- Institute of High Technologies, National Taras Shevchenko University of Kyiv, 60 Volodymyrska Str., 01033 Kyiv, Ukraine
- Correspondence:
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Li Y, Zhang X, Yan Z, Du L, Tang W, Phillips DL. Photochemical α-Cleavage Reaction of 3',5'-Dimethoxybenzoin: A Combined Time-Resolved Spectroscopy and Computational Chemistry Study. Molecules 2020; 25:molecules25153548. [PMID: 32756525 PMCID: PMC7435414 DOI: 10.3390/molecules25153548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 07/30/2020] [Accepted: 07/31/2020] [Indexed: 11/16/2022] Open
Abstract
Benzoin is one of the most commonly used photoinitiators to induce free radical polymerization. Here, improved benzoin properties could be accomplished by the introduction of two methoxy substituents, leading to the formation of 3',5'-dimethoxybenzoin (DMB) which has a higher photo-cleavage quantum yield (0.54) than benzoin (0.35). To elucidate the underlying reaction mechanisms of DMB and obtain direct information of the transient species involved, femtosecond transient absorption (fs-TA) and nanosecond transient absorption (ns-TA) spectroscopic experiments in conjunction with density functional theory/time-dependent density functional theory (DFT/TD-DFT) calculations were performed. It was found that the photo-induced α-cleavage (Norrish Type I reaction) of DMB occurred from the nπ* triplet state after a rapid intersystem crossing (ISC) process (7.6 ps), leading to the generation of phenyl radicals on the picosecond time scale. Compared with Benzoin, DMB possesses two methoxy groups which are able to stabilize the alcohol radical and thus result in a stronger driving force for cleavage and a higher quantum yield of photodissociation. Two stable conformations (cis-DMB and trans-DMB) at ground state were found via DFT calculations. The influence of the intramolecular hydrogen bond on the α-cleavage of DMB was elaborated.
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Affiliation(s)
- Yuanchun Li
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China; (Y.L.); (X.Z.); (Z.Y.)
| | - Xiting Zhang
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China; (Y.L.); (X.Z.); (Z.Y.)
| | - Zhiping Yan
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China; (Y.L.); (X.Z.); (Z.Y.)
- Key Laboratory of Flexible Electronics & Institute of Advanced Materials, Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, Nanjing 211816, China
| | - Lili Du
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China; (Y.L.); (X.Z.); (Z.Y.)
- School of Life Sciences, Jiangsu University, Zhenjiang 212013, China
- Correspondence: (L.D.); (W.T.); (D.L.P.); Tel.: +852-6761-4757 (L.D.); +86-137-2109-1768 (W.T.); +852-2859-2160 (D.L.P.)
| | - Wenjian Tang
- School of Pharmacy, Anhui Medical University, Hefei 230032, China
- Correspondence: (L.D.); (W.T.); (D.L.P.); Tel.: +852-6761-4757 (L.D.); +86-137-2109-1768 (W.T.); +852-2859-2160 (D.L.P.)
| | - David Lee Phillips
- Department of Chemistry, The University of Hong Kong, Hong Kong 999077, China; (Y.L.); (X.Z.); (Z.Y.)
- Correspondence: (L.D.); (W.T.); (D.L.P.); Tel.: +852-6761-4757 (L.D.); +86-137-2109-1768 (W.T.); +852-2859-2160 (D.L.P.)
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Yao Y, Chen Y, Liu Y, Zhu Y, Liu Y, Zhang S. Facile Transfer of Reverse Micelles from the Organic to the Aqueous Phase for Mimicking Enzyme Catalysis and Imaging-Guided Cancer Therapy. Langmuir 2019; 35:5871-5877. [PMID: 30955338 DOI: 10.1021/acs.langmuir.9b00607] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Reverse micelles (RMs) with confined water pools have been applied in many fields. However, the water insolubility of RMs seriously limits the scope of their application, especially those needed to operate in aqueous environments. Here, we report the first successful transfer of RMs from the organic phase to water phase without disturbing their confined water pools and hydrophobic alkyl region. This transfer was achieved by virtue of a mild host-guest interaction between the hydrophobic tails of interfacial cross-linked reverse micelles (ICRMs) and the hydrophobic cavity of (2-hydroxypropyl)-β-cyclodextrin (HP-β-CD). Benefitting from the maintained confined water pools and the hydrophobic scaffold, the obtained water-soluble ICRMs served as multifunctional nanoplatforms for enzyme-mimicking catalysis and image-guided cancer therapy, which were impossible for normal RMs lacking water solubility or confined pool-buried water-soluble nanoparticles without a hydrophobic alkyl chain. This mild transfer approach thus surmounts the application obstacle of RMs and opens up new avenues for their application in aqueous environments.
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Affiliation(s)
| | | | - Yong Liu
- Collaborative Innovation Centre of Tissue Repair Material of Sichuan Province , China West Normal University , Nanchong 637009 , China
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Zhou T, Vallooran JJ, Mezzenga R. Supramolecular chirality and crystallization from biocatalytic self-assembly in lipidic cubic mesophases. Nanoscale 2019; 11:5891-5895. [PMID: 30874704 DOI: 10.1039/c8nr09671f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Biocatalytic self-assembly in a nanoconfined environment is widely used in nature to construct complex structures that endow special characteristics to life. There is tremendous interest in mimicking such bottom-up processes to fabricate functional materials. In this study, we have investigated a novel biomimetic scaffold based on lipidic cubic mesophases (LCMs), which provide a special nanoconfined environment for biocatalytic self-assembly and subsequent formation of organic crystals. (R)-Benzoin generated in situ from benzaldehyde in a reaction catalyzed by the enzyme benzaldehyde lyase (BAL) exhibits - when confined within LCMs - enhanced chirality compared to (R)-benzoin in solution or (R)-benzoin-doped LCMs. We infer that a metastable state is formed under kinetic control that displays enhanced supramolecular chirality. As they age, these metastable structures can further grow into thermodynamically stable crystals. The biomimetic, nanoconfined environment provided by the LCMs plays a key role in the development of supramolecular chirality and subsequent crystallization.
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Affiliation(s)
- Tao Zhou
- Department of Health Science and Technology, ETH Zurich, Schmelzbergstrasse 9, 8092 Zürich, Switzerland.
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Alamgir M, Khuhawar MY, Memon SQ, Hayat A, Zounr RA. Spectrofluorimetric analysis of famotidine in pharmaceutical preparations and biological fluids by derivatization with benzoin. Spectrochim Acta A Mol Biomol Spectrosc 2015; 134:449-452. [PMID: 25033237 DOI: 10.1016/j.saa.2014.06.118] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 06/06/2014] [Accepted: 06/19/2014] [Indexed: 06/03/2023]
Abstract
A sensitive and simple spectrofluorimetric method has been developed for the analysis of famotidine, from pharmaceutical preparations and biological fluids after derivatization with benzoin. The reaction was carried out in alkaline medium with measurement of fluorescence intensity at 446 nm with excitation wavelength at 286 nm. Linear calibration was obtained with 0.5-15 μg/ml with coefficient of determination (r(2)) 0.997. The factors affecting the fluorescence intensity were optimized. The pharmaceutical additives and amino acid did not interfere in the determination. The mean percentage recovery (n=4) calculated by standard addition from pharmaceutical preparation was 94.8-98.2% with relative standard deviation (RSD) 1.56-3.34% and recovery from deproteinized spiked serum and urine of healthy volunteers was 98.6-98.9% and 98.0-98.4% with RSD 0.34-0.84% and 0.29-0.87% respectively.
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Affiliation(s)
- Malik Alamgir
- Institute of Advance Research Studies in Chemical Sciences, University of Sindh, Jamshoro, Pakistan.
| | - Muhammad Yar Khuhawar
- Institute of Advance Research Studies in Chemical Sciences, University of Sindh, Jamshoro, Pakistan
| | - Saima Q Memon
- M.A. Kazi Institute of Chemistry, University of Sindh, Jamshoro, Pakistan
| | - Amir Hayat
- Institute of Advance Research Studies in Chemical Sciences, University of Sindh, Jamshoro, Pakistan
| | - Rizwan Ali Zounr
- Institute of Advance Research Studies in Chemical Sciences, University of Sindh, Jamshoro, Pakistan
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Carneiro L, Silva AR, Shuttleworth PS, Budarin V, Clark JH. Synthesis, immobilization and catalytic activity of a copper(II) complex with a chiral bis(oxazoline). Molecules 2014; 19:11988-98. [PMID: 25116806 PMCID: PMC6271255 DOI: 10.3390/molecules190811988] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2014] [Revised: 07/30/2014] [Accepted: 07/30/2014] [Indexed: 11/16/2022] Open
Abstract
A chiral bis(oxazoline) bearing CH2OH groups was synthesized from a commercial bis(oxazoline) and characterized by 1H- and 13C-NMR, high resolution ESI-mass spectrometry and FTIR. The corresponding copper(II) complex was immobilized onto the surface of a mesoporous carbonaceous material (Starbon® 700) in which the double bonds had been activated via conventional bromination. The materials were characterized by elemental analysis, ICP-OES, XPS, thermogravimetry and nitrogen adsorption at 77 K. The new copper(II) bis(oxazoline) was tested both in the homogeneous phase and once immobilized onto a carbonaceous support for the kinetic resolution of hydrobenzoin. Both were active, enantioselective and selective in the mono-benzoylation of hydrobenzoin, but better enantioselectivities were obtained in the homogeneous phase. The heterogeneous catalyst could be separated from the reaction media at the end of the reaction and reused in another catalytic cycle, but with loss of product yield and enantioselectivity.
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Affiliation(s)
- Liliana Carneiro
- Department of Chemistry, CICECO, University of Aveiro, Aveiro 3810-193, Portugal
| | - Ana R Silva
- Department of Chemistry, CICECO, University of Aveiro, Aveiro 3810-193, Portugal.
| | - Peter S Shuttleworth
- Departamento de Física de Polímeros, Elastámeros y Applicaciones Energéticas, Instituto de Ciencia e Tecnología de Polímeros, CSIC, Madrid 28006, Spain
| | - Vitaly Budarin
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, York YO10 5DD, UK
| | - James H Clark
- Green Chemistry Centre of Excellence, Department of Chemistry, University of York, York YO10 5DD, UK
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Hu QF, Zhou B, Ye YQ, Jiang ZY, Huang XZ, Li YK, Du G, Yang GY, Gao XM. Cytotoxic deoxybenzoins and diphenylethylenes from Arundina graminifolia. J Nat Prod 2013; 76:1854-1859. [PMID: 24063582 DOI: 10.1021/np400379u] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Eight new C-4-alkylated deoxybenzoins (1-8), three new diphenylethylenes (9-11), and five known diphenylethylenes were isolated from Arundina graminifolia. The structures of 1-11 were elucidated by spectroscopic methods including extensive 1D and 2D NMR techniques. Compounds 9-11 are the first naturally occurring diphenylethylenes possessing a hydroxyethyl unit. Compounds 1-11 were evaluated for cytotoxicity against five human tumor cell lines. Compounds 4, 5, and 9-11 showed significant cytotoxicity against five cancer cell lines, with IC50 values ranging from 1.8 to 8.7 μM.
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Affiliation(s)
- Qiu-Fen Hu
- Key Laboratory of Chemistry in Ethnic Medicinal Resources, State Ethnic Affairs Commission and Ministry of Education, Yunnan University of Nationalities , Kunming 650031, Yunnan, People's Republic of China
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8
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El-Shahawi MS, Al-Jahdali MS, Bashammakh AS, Al-Sibaai AA, Nassef HM. Spectroscopic and electrochemical characterization of some Schiff base metal complexes containing benzoin moiety. Spectrochim Acta A Mol Biomol Spectrosc 2013; 113:459-465. [PMID: 23792194 DOI: 10.1016/j.saa.2013.04.090] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 04/16/2013] [Accepted: 04/24/2013] [Indexed: 06/02/2023]
Abstract
The ligation behavior of bis-benzoin ethylenediamine (B2ED) and benzoin thiosemicarbazone (BTS) Schiff bases towards Ru(3+), Rh(3+), Pd(2+), Ni(2+) and Cu(2+) were determined. The bond length of M-N and spectrochemical parameters (10Dq, β, B and LFSE) of the complexes were evaluated. The redox characteristics of selected complexes were explored by cyclic voltammetry (CV) at Pt working electrode in non aqueous solvents. Au mesh (100 w/in.) optically transparent thin layer electrode (OTTLE) was also used for recording thin layer CV for selected Ru complex. Oxidation of some complexes occurs in a consecutive chemical reaction of an EC type mechanism. The characteristics of electron transfer process of the couples M(2+)/M(3+) and M(3+)/M(4+) (M=Ru(3+), Rh(3+)) and the stability of the complexes towards oxidation and/or reduction were assigned. The nature of the electroactive species and reduction mechanism of selected electrode couples were assigned.
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Affiliation(s)
- M S El-Shahawi
- Department of Chemistry, Faculty of Science, King Abdulaziz University, P.O. Box 80203, Jeddah 21589, Saudi Arabia.
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Abstract
Deoxybenzoins (1-(2,4-dihydroxyphenyl)-2-(4-hydroxyphenyl)ethanone) are possible precursors or metabolites of isoflavanones which may have xenoestrogenic potential on estrogen receptor (ER). In this study we evaluated three 2'-substituted deoxybenzoin derivatives for their estrogenic effect based upon their ability to affect the proliferation of ERα(+) MCF7 cells, ERβ(+) PC3 cells and Hep2 cells stably transfected and expressing either ERα or ERβ. These compounds designated as CMPD3, CMPD6 and CMPD9 had -COOH, -(CH(2))(4)-CH(3) and -CH(3) substitutions, respectively on the 2'-position of the 2,4-dihydroxyphenyl ring of deoxybenzoin. We found that all three compounds increased the proliferation of ERα(+) MCF7 cells (EC(50)~1-12 μM) and ERα(+) Hep2 cells, while causing apoptosis in ERβ(+) PC3 cells (IC(50)~1-5 μM) and ERβ(+) Hep2 cells. The compounds also up-regulated the expression of estrogen sensitive genes, trefoil factor 1 (TFF1, previously known as pS2) and cathepsin-D (CTSD), in these cells. We performed in vitro ER transcription activation assays using Hep2 cells transiently co-transfected with estrogen response element driven luciferase and either ERα or ERβ vectors to ascertain the mechanism of action of these compounds through the 'classical' genomic pathway of estrogenic activity and to determine their ER subtype selectivity. Molecular docking of the compounds with the Ligand Binding Domain of ERα and ERβ showed similar docking scores (Glidescores of -6.5 to -8.5 kcal/mol) indicating that these compounds were ligands of both ERα and ERβ with similar affinity.
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Izquierdo J, Hutson GE, Cohen DT, Scheidt KA. A continuum of progress: applications of N-hetereocyclic carbene catalysis in total synthesis. Angew Chem Int Ed Engl 2012; 51:11686-98. [PMID: 23074146 PMCID: PMC3756610 DOI: 10.1002/anie.201203704] [Citation(s) in RCA: 464] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Indexed: 11/08/2022]
Abstract
N-Heterocyclic carbene (NHC) catalyzed transformations have emerged as powerful tactics for the construction of complex molecules. Since Stetter's report in 1975 of the total synthesis of cis-jasmon and dihydrojasmon by using carbene catalysis, the use of NHCs in total synthesis has grown rapidly, particularly over the last decade. This renaissance is undoubtedly due to the recent developments in NHC-catalyzed reactions, including new benzoin, Stetter, homoenolate, and aroylation processes. These transformations employ typical as well as Umpolung types of bond disconnections and have served as the key step in several new total syntheses. This Minireview highlights these reports and captures the excitement and emerging synthetic utility of carbene catalysis in total synthesis.
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Affiliation(s)
- Javier Izquierdo
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Silverman Hall, Northwestern University, Evanston, IL 60208 (USA)
| | - Gerri E. Hutson
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Silverman Hall, Northwestern University, Evanston, IL 60208 (USA)
| | - Daniel T. Cohen
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Silverman Hall, Northwestern University, Evanston, IL 60208 (USA)
| | - Karl A. Scheidt
- Department of Chemistry, Center for Molecular Innovation and Drug Discovery, Chemistry of Life Processes Institute, Silverman Hall, Northwestern University, Evanston, IL 60208 (USA)
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Thanuja B, Nithya G, Kanagam CC. Ultrasonic studies of intermolecular interactions in binary mixtures of 4-methoxy benzoin with various solvents: Excess molar functions of ultrasonic parameters at different concentrations and in different solvents. Ultrason Sonochem 2012; 19:1213-1220. [PMID: 22498277 DOI: 10.1016/j.ultsonch.2012.03.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 02/17/2012] [Accepted: 03/13/2012] [Indexed: 05/31/2023]
Abstract
Density (ρ), ultrasonic velocity (U), for the binary mixtures of 4-methoxy benzoin (4MB) with ethanol, chloroform, acetonitrile, benzene, and di-oxane were measured at 298K. The solute-solvent interactions and the effect of the polarity of the solvent on the type of intermolecular interactions are discussed here. From the above data, adiabatic compressibility (β), intermolecular free length (L(f)), acoustic impedance (Z), apparent molar volume (Ø), relative association (RA) have been calculated. Other useful parameters such as excess density, excess velocity and excess adiabatic compressibility have also been calculated. These parameters were used to study the nature and extent of intermolecular interactions between component molecules in the binary mixtures.
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Affiliation(s)
- B Thanuja
- Dept. of Chemistry, Vels University, School of Engineering, Pallavaram, Chennai 600 117, Tamil Nadu, India.
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12
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Lu TM, Kuo DH, Ko HH, Ng LT. Synthesis and structure-activity relationship study of deoxybenzoins on relaxing effects of porcine coronary artery. J Agric Food Chem 2010; 58:10027-10032. [PMID: 20799703 DOI: 10.1021/jf1023643] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Deoxybenzoins are potent antioxidants and tyrosinase inhibitors with potential to be developed as food preservatives and cosmetic ingredients. To explore the potential in cardiovascular protection, 25 polyphenolic deoxybenzoins were synthesized and evaluated for inhibitory effects on KCl-induced porcine coronary arterial contraction. The results revealed deoxybenzoins are significant inhibitors of KCl-induced arterial contraction. Among those synthesized, two-thirds of the deoxybenzoins exhibited moderate to good efficacy on relaxing contracted artery including 2,4-dihydroxydeoxybenzoin with EC50=3.30 μM (Emax=100%, n=7) and 2,4-dihydroxy-4'-methoxydeoxybenzoin EC50=3.70 μM (Emax=100%, n=5). Deoxybenzoins displayed an endothelium-dependent relaxing manner on the contracted artery; the contractile responses of neither endothelium denuded nor L-NAME deactivated rings were inhibited. The structure-activity relationships of deoxybenzoin on arterial relaxing effects concluded that the 2,4-dihydroxylated deoxybenzoins presented a potential vascular relaxing pharmacophore, with favoring substitution on ring B in the order of H≥p-OMe>p-OH>o-OMe>m,p-diOMe≥m-OMe.
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Affiliation(s)
- Tzy-Ming Lu
- Department of Pharmacy, Tajen University, Pingtung 907, Taiwan.
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Pawełka Z, Czarnik-Matusewicz B, Zeegers-Huyskens T. Influence of solvents on the conformation of benzoin. Spectrochim Acta A Mol Biomol Spectrosc 2010; 75:48-53. [PMID: 19914860 DOI: 10.1016/j.saa.2009.09.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2009] [Revised: 09/18/2009] [Accepted: 09/24/2009] [Indexed: 05/28/2023]
Abstract
The conformation of benzoin in several organic solvents is investigated by infrared spectrometry and dipolometry. The frequencies, intensities, and band shapes of the nu(OH), nu(C=O), and aromatic ring vibrations indicate that in solvents of low proton acceptor ability, the cis conformer with intramolecular OH...O hydrogen bonding is preserved. In solvents of large proton acceptor ability there is equilibrium between the cis and trans conformers. The dipole moments are less sensitive to conformational changes, but indicate the same trends. The results are discussed as a function of the specific solvation of the O atoms or OH groups of benzoin.
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Affiliation(s)
- Z Pawełka
- Faculty of Chemistry, University of Wrocław, Wrocław, Poland.
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Li JT, Liu XR, Wang WF. An efficient oxidation of benzoins to benzils by ACC/silica gel under ultrasound irradiation. Ultrason Sonochem 2009; 16:331-333. [PMID: 19014896 DOI: 10.1016/j.ultsonch.2008.10.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/08/2008] [Revised: 10/04/2008] [Accepted: 10/06/2008] [Indexed: 05/27/2023]
Abstract
The oxidation of benzoins to the corresponding benzils was carried out in CH2Cl2 by ACC/silica gel in excellent yields within short time under ultrasound irradiation.
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Affiliation(s)
- Ji-Tai Li
- College of Chemistry and Environmental Science, Hebei University, Key Laboratory of Analytical Science and Technology of Hebei Province, Baoding 071002, PR China.
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Onikura N, Kishi K, Nakamura A, Takeuchi S. A screening method for toxicity identification evaluation on an industrial effluent using Chelex-100 resin and chelators for specific metals. Environ Toxicol Chem 2008; 27:266-271. [PMID: 18348643 DOI: 10.1897/07-327r.1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2007] [Accepted: 07/30/2007] [Indexed: 05/26/2023]
Abstract
Toxicity of an industrial effluent was characterized using a toxicity identification method established at our research institute. Toxicity was evaluated using the Ceriodaphnia dubia survival test. The industrial effluent chosen in the present study had toxic effects on C. dubia before treatment. The effluent was first filtered to remove suspended solids (F-treatment). Activated charcoal was then added to the effluent to adsorb organic substances (AC-treatment), followed by treatment of the supernatant with Chelex-100 resin to remove di- and trivalent cations, including transition metals (C100-treatment). The effluent exhibited a toxic effect on C. dubia even after the AC-treatment, but it was no longer toxic after the C100-treatment, indicating that the effluent contained cations that affect C. dubia survival. To further identify the metals responsible for the toxicity, benzoin-alpha-oxime or dimethylglyoxime was added to the effluent to chelate specific cations. The toxicity of the effluent was eliminated by addition of dimethylglyoxime but not significantly so by addition of benzoin-alpha-oxime, suggesting that the toxicants in the effluent strongly formed complexes with dimethylglyoxime. These results combined with those of metal analysis strongly suggest that nickel might be the noxious agent. The toxicity identification method described in this paper is effective for the identification of metal toxicants in industrial effluents. The method using insoluble chelating resins and chelators for specific metals would serve as a useful addition to the standard toxicity identification evaluation procedure.
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Affiliation(s)
- Norio Onikura
- Japan Pulp and Paper Research Institute, Tsukuba, Ibaraki, Japan
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16
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Borissova M, Gorbatsova J, Ebber A, Kaljurand M, Koel M, Vaher M. Nonaqueous CE using contactless conductivity detection and ionic liquids as BGEs in ACN. Electrophoresis 2007; 28:3600-5. [PMID: 17893951 DOI: 10.1002/elps.200700067] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
N,N'-Alkylmethylimidazolium cations have been separated in NACE when one of the N,N'-dialkylimidazolium salts (ionic liquids (ILs)) was used as an electrolyte additive to the organic solvent separation medium. The separated species were 1-methyl-, 1-ethyl-, 1-butyl-, 1-octyl-, 1-decyl-3-methylimidazolium and N-butyl-3-methylpyridinium cations and BGE composed of 1-ethyl-3-methylimidazolium ethylsulfate or 1-butyl-3-methylimidazolium trifluoroacetate [BMIm][FAcO] (A6; B2) diluted in ACN. It was demonstrated that contactless conductivity detection (CCD) may be applied to monitoring the separation process in nonaqueous separation media, allowing to use the UV light-absorbing imidazolium-based electrolyte additives. There could be marked three concentration regions of added ILs; at first ionic strength of BGE below 1-2 mM, and then the actual electrophoretic mobility of analytes rises from 0. At concentrations above 1-2 mM, the added IL facilitated separation. In concentration region of 1-20 mM, the actual electrophoretic mobility of analyzed imidazolium cations was increasing with decrease in separation medium ionic strength. At higher concentrations of BGE (above 30 mM), the conductivity of the separation media became too high for this detector. Some organic dyes were also successfully separated and detected by contactless conductivity detector in a 20 mM A6 separation electrolyte in ACN.
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Affiliation(s)
- Maria Borissova
- Department of Chemistry, Tallinn University of Technology, Tallinn, Estonia
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17
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Papoutsi Z, Kassi E, Fokialakis N, Mitakou S, Lambrinidis G, Mikros E, Moutsatsou P. Deoxybenzoins are novel potent selective estrogen receptor modulators. Steroids 2007; 72:693-704. [PMID: 17659312 DOI: 10.1016/j.steroids.2007.05.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2006] [Revised: 03/28/2007] [Accepted: 05/29/2007] [Indexed: 02/07/2023]
Abstract
Deoxybenzoins are plant compounds with similar structure to isoflavones. In this study, we evaluated the ability of two synthesized deoxybenzoins (compound 1 and compound 2) (a) to influence the activity of the estrogen receptor subtypes ERalpha and ERbeta in HeLa cells co-transfected with an estrogen response element-driven luciferase reporter gene and ERalpha- or ERbeta-expression vectors, (b) to modulate the IGFBP-3 and pS2 protein in MCF-7 breast cancer cells, (c) to induce mineralization of KS483 osteoblasts and (d) to affect the cell viability of endometrial (Ishikawa) and breast (MCF-7, MDA-MB-231) cancer cells. Docking and binding energy calculations were performed using the mixed Monte Carlo/Low Mode search method (Macromodel 6.5). Compound 1 displayed significant estrogenic activity via ERbeta but no activity via ERalpha. Compound 2 was an estrogen-agonist via ERalpha and antagonist via ERbeta. Both compounds increased, like the pure antiestrogen ICI182780, the IGFBP-3 levels. Compound 2 induced, like 17beta-estradiol, significant mineralization in osteoblasts. The cell viability of Ishikawa cells was unchanged in the presence of either compound. Compound 1 increased MCF-7 cell viability consistently with an increase in pS2 levels, whereas compound 2 inhibited the cell viability. Molecular modeling confirmed the agonistic or antagonistic behaviour of compound 2 via ER subtypes. Compound 2, being an agonist in osteoblasts, an antagonist in breast cancer cells, with no estrogenic effects in endometrial cancer cells, makes it a potential selective estrogen receptor modulator and a choice for hormone replacement therapy.
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Affiliation(s)
- Zoi Papoutsi
- Department of Biological Chemistry, Medical School, University of Athens, 75 Mikras Asias Street, Goudi 11527, Athens, Greece
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18
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Affiliation(s)
- Colin P McCoy
- School of Pharmacy, Queen's University Belfast, Belfast BT9 7BL, U.K.
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19
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Narin I, Surme Y, Bercin E, Soylak M. SP70-alpha-benzoin oxime chelating resin for preconcentration-separation of Pb(II), Cd(II), Co(II) and Cr(III) in environmental samples. J Hazard Mater 2007; 145:113-9. [PMID: 17145131 DOI: 10.1016/j.jhazmat.2006.11.001] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/28/2006] [Revised: 11/01/2006] [Accepted: 11/01/2006] [Indexed: 05/12/2023]
Abstract
In the presented work, alpha-benzoin oxime immobilized SP70 chelating resin was synthesized for separation and preconcentration of Pb(II), Cd(II), Co(II) and Cr(III). The optimization procedure for analytical parameters including pH, eluent type, flow rate, etc. was examined in order to gain quantitative recoveries of analyte ions. The effects of foreign ions on the recoveries of studied metal ions were also investigated. The detection limits (3sigma) were found to be 16.0, 4.2, 1.3, 2.4microgL(-1) for Pb, Cd, Co and Cr, respectively. The preconcentration factor was 75 for Pb, 100 for Cd, Co and Cr. The optimized method was validated with certified reference materials and successfully applied to the waters, crops and pharmaceutical samples with good results (recoveries greater than 95%, R.S.D. lower than 10%).
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Affiliation(s)
- Ibrahim Narin
- Erciyes University, Faculty of Pharmacy, Kayseri 38039, Turkey.
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20
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Takikawa H, Suzuki K. Modified Chiral Triazolium Salts for Enantioselective Benzoin Cyclization of Enolizable Keto-Aldehydes: Synthesis of (+)-Sappanone B. Org Lett 2007; 9:2713-6. [PMID: 17559218 DOI: 10.1021/ol070929p] [Citation(s) in RCA: 119] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Asymmetric synthesis of (+)-sappanone B (1), a natural product with a 3-hydroxy chromanone structure, was achieved via enantioselective benzoin cyclization by using a modified Rovis catalyst and triethylamine. This catalyst enabled the successful benzoin cyclization of readily enolizable keto-aldehydes.
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Affiliation(s)
- Hiroshi Takikawa
- Department of Chemistry, Tokyo Institute of Technology, SORST-JST Agency, 2-12-1 O-okayama, Meguro-ku, Tokyo 152-8551, Japan
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21
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Li HQ, Xue JY, Shi L, Gui SY, Zhu HL. Synthesis, crystal structure and antimicrobial activity of deoxybenzoin derivatives from genistein. Eur J Med Chem 2007; 43:662-7. [PMID: 17624635 DOI: 10.1016/j.ejmech.2007.05.013] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2007] [Revised: 05/11/2007] [Accepted: 05/24/2007] [Indexed: 11/28/2022]
Abstract
A series of deoxybenzoin derivatives from genistein were synthesized and their structures were elucidated by (1)H NMR, mass spectral data and micro analyses. The structures of 2, 7 and 10 were determined by single-crystal X-ray analysis. These obtained compounds were evaluated for their assayed antibacterial (Bacillus subtilis, Escherichia coli, Pseudomonas fluorescence and Staphylococcus aureus) and antifungal (Aspergillus niger, Candida albicans and Trichophyton rubrum) activities by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) method. Most compounds have displayed comparable antibacterial activity against bacterial. On the basis of the biological results, structure-activity relationships are discussed.
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Affiliation(s)
- Huan-Qiu Li
- Institute of Functional Biomolecules, State Key Laboratory of Pharmaceutical Biotechnology, Nanjing University, Nanjing 210093, People's Republic of China
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22
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Hagu H, Salmar S, Tuulmets A. Impact of ultrasound on hydrophobic interactions in solutions: ultrasonic retardation of benzoin condensation. Ultrason Sonochem 2007; 14:445-9. [PMID: 17207651 DOI: 10.1016/j.ultsonch.2006.09.012] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2006] [Accepted: 09/01/2006] [Indexed: 05/13/2023]
Abstract
Kinetics of the benzoin condensation of benzaldehyde in presence of KCN as the catalyst in water and in ethanol-water binary solutions were investigated without sonication and under ultrasound at 22 kHz. A statistically significant 20% decrease of the rate was observed in water. The retardation effect of ultrasound gradually decreases up to 45 wt% ethanol content. We report an evidence of ultrasonic retardation of reactions and thereby a direct evidence for sonochemical processes in the bulk solution. Ultrasound can disturb solvation of the species in the solution. If breaking down the stabilization of the encounter complexes between the reagents, sonication hinders the reaction while perturbation of the solvent-stabilization of the reagents accelerates the reaction.
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Affiliation(s)
- Hannes Hagu
- Institute of Organic and Bioorganic Chemistry, University of Tartu, 2 Jakobi Street, 51014 Tartu, Estonia
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23
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Boudebous H, Kosmrlj B, Sket B, Wirz J. Primary Photoreactions of the 3‘,5‘-Dimethoxybenzoin Cage and Determination of the Release Rate in Polar Media. J Phys Chem A 2007; 111:2811-3. [PMID: 17388582 DOI: 10.1021/jp071350b] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
3',5'-dimethoxybenzoin (DMB) is an important photoremovable protecting group. The primary photoreactions of DMB acetate and fluoride following photoexcitation by a subpicosecond laser flash were investigated by pump-probe spectroscopy. The primary photoproduct is identified as a preoxetane biradical intermediate that decays by different pathways depending on solvent polarity. In polar solvents (acetonitrile, water), the biradical decays by releasing acetate or fluoride with a lifetime of about 2 ns. Thus, DMB is an excellent protecting group for the investigation of fast processes such as protein folding.
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Affiliation(s)
- Hassen Boudebous
- Departement Chemie, Universität Basel, Klingelbergstrasse 80, CH-4056 Basel, Switzerland
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24
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Tuulmets A, Hagu H, Salmar S, Cravotto G, Järv J. Ultrasonic Evidence of Hydrophobic Interactions. Effect of Ultrasound on Benzoin Condensation and Some Other Reactions in Aqueous Ethanol. J Phys Chem B 2007; 111:3133-8. [PMID: 17388456 DOI: 10.1021/jp0682199] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The kinetics of KCN-catalyzed benzoin condensation of benzaldehyde in water and ethanol-water binary mixtures was investigated both under ultrasound at 22 kHz and without sonication. Thermodynamic activation parameters were calculated from kinetic data obtained at 35, 50, and 65 degrees C. Evidence that ultrasound can retard reactions is reported and hence a direct proof that sonochemical processes occur in the bulk solution. Former results and literature data for ester hydrolyses and tert-butyl chloride solvolysis are involved in the discussion. A quantitative relationship between sonication effects and the hydrophobicity of reagents is presented for the first time. Ultrasound affects hydrophobic interactions with the solvent, which are not manifested in conventional kinetics. When it suppresses the stabilization of the encounter complexes between reagents, sonication hinders the reaction but accelerates it when it perturbs the hydrophobic stabilization of the ground state of a reagent.
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Affiliation(s)
- Ants Tuulmets
- Institute of Organic and Bioorganic Chemistry, University of Tartu, Jakobi 2, 51014 Tartu, Estonia.
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25
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Affiliation(s)
- Pei-Chen Chiang
- Department of Chemistry and Biochemistry, University of California at Santa Barbara, Santa Barbara, California 93106-9510, USA
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26
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Sajonz P, Schafer W, Gong X, Shultz S, Rosner T, Welch CJ. Multiparallel microfluidic high-performance liquid chromatography for high-throughput normal-phase chiral analysis. J Chromatogr A 2007; 1145:149-54. [PMID: 17300788 DOI: 10.1016/j.chroma.2007.01.067] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2006] [Revised: 01/13/2007] [Accepted: 01/18/2007] [Indexed: 11/22/2022]
Abstract
The suitability of the Eksigent Express 800 microfluidic eight-channel HPLC instrument for multiparallel normal-phase chiral analysis in support of high-throughput pharmaceutical process research was investigated. Analysis of test mixtures containing the two enantiomers of benzoin and the closely related (R,S)-dihydrobenzoin, was carried out in a 96-well microplate, affording rapid (<2 h) and accurate assessment of enantiopurity. In a second example, use of the instrument to support high-throughput catalyst screening of the asymmetric hydrogenation of a prochiral unsaturated ester is presented, in which method development (gradient screening of four columns and two eluents, followed by optimization to afford a fast analytical method) and analysis of a 96-well microplate was carried out within a single working day. This represents a considerable improvement over conventional analysis techniques that usually take several days to complete.
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Affiliation(s)
- Peter Sajonz
- Separation & Analysis Technologies, Merck and Co., Inc., Rahway, NJ 07065, USA.
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27
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Jirapongphan SS, Warzywoda J, Budil DE, Sacco A. Enantioseparation of phenylglycinol in chiral-modified zeolite HY: A molecular simulation study. Chirality 2007; 19:514-7. [PMID: 17437262 DOI: 10.1002/chir.20407] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
A mechanism has been proposed for the separation of valinol enantiomers using a chiral-modified zeolite HY (i.e., zeolite HY containing (+)-(1R;2R)-hydrobenzoin) Molecular modeling of chiral-modified zeolite HY employed in enantioselective separation. Jirapongphan SS, Warzywoda J, Budil DE, Sacco A Jr. Chirality 2007; in press, which accurately predicted the experimentally measured enantioseparation. This methodology has been applied to predict the separation of an enantiomeric pair of phenylglycinol molecules (a precursor in the synthesis of HIV-1 protease inhibitors) using the modified zeolite HY as a CSP. Phenylglycinol and valinol molecules are similar in terms of the presence of polar (i.e., amine and hydroxyl) groups. These functional groups are important in the proposed chiral discrimination. Supercage-based docking simulations yielded an enantioselectivity of 1.3 with (+)-(S)-phenylglycinol molecule better retained in the zeolite. Also, the simulations predicted two binding modes that were the same as those in the valinol system. This suggests that specific structural features (i.e., number and type of polar groups), which generate the hypothesized binding modes, are required in an enantioseparation utilizing the chiral-modified zeolite HY.
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Affiliation(s)
- Siricharn S Jirapongphan
- Department of Chemical Engineering, Center for Advanced Microgravity Materials Processing, Northeastern University, Boston, Massachusetts 02115, USA
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28
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Abstract
Cross-coupling of aromatic aldehydes or benzoins with unactivated imines catalyzed by an N-heterocyclic carbene (NHC) affords alpha-amino ketones smoothly.
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Affiliation(s)
- Gong-Qiang Li
- State Key Laboratory of Organometallic Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 354 Fenglin Lu, Shanghai 200032, P. R. China
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29
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Aĭtmambetov A, Tlegenov RT, Tokhtybaeva AM. [A convenient method of isoflavonone synthesis]. Bioorg Khim 2006; 32:444-5. [PMID: 16909869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Reaction of 2-hydroxydeoxybenzoins with bis(dimethylamino)methane in ethanol results in isoflavonones.
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30
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Billiot FH, Billiot EJ, Ng YK, Warner IM. Chiral separation of norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, and three benzoin derivatives using amino acid based molecular micelles. J Chromatogr Sci 2006; 44:64-9. [PMID: 16620496 DOI: 10.1093/chromsci/44.2.64] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
In this study, 18 polymeric single amino acid and dipeptide surfactants are examined, and their performances, in terms of enantioselectivity, are compared for norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, benzoin, benzoin methyl, and benzoin ethyl enantiomers. Several aspects of amino acid-based polymeric surfactants including comparison of single amino acid versus dipeptide, amino acid order, steric effect, and effect of the position of the chiral center of dipeptide surfactants on the chiral selectivity of these optically active compounds are discussed.
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Affiliation(s)
- Fereshteh H Billiot
- Department of Physical and Life Sciences, Texas A and M University-Corpus Christi, Corpus Christi, TX 78412, USA
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31
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Affiliation(s)
- Dieter Enders
- Institute of Organic Chemistry, RWTH Aachen University, Landoltweg 1, 52074 Aachen, Germany.
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32
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Dinçer M, Ozdemir N, Cukurovali A, Yilmaz I, Büyükgüngör O. Benzoin 4-ethylthiosemicarbazone. Acta Crystallogr C 2006; 62:o13-5. [PMID: 16397328 DOI: 10.1107/s0108270105037728] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2005] [Accepted: 11/16/2005] [Indexed: 11/10/2022] Open
Abstract
In the title compound, 2-hydroxy-1,2-diphenylethanone 4-ethylthiosemicarbazone, C17H19N3OS, the thiosemicarbazone moiety is planar and has an E configuration. The planar phenyl rings make dihedral angles of 82.34 (8) and 8.07 (17) degrees with the plane of the thiosemicarbazone moiety. The crystal structure contains two intramolecular (N-H...O and N-H...N) and one intermolecular interaction (O-H...S), as well as two C-H...pi(benzene) interactions. Molecules are stacked in columns running along the a axis. Molecules in each column are connected to each other by means of linear O-H...S hydrogen bonds and C-H...pi interactions. In addition, there are also C-H...pi(benzene) interactions between the columns.
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Affiliation(s)
- Muharrem Dinçer
- Department of Physics, Arts and Sciences Faculty, Ondokuz Mayis University, 55139 Samsun, Turkey
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33
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Abstract
The Eksigent Express 800 8-channel microfluidic HPLC system was investigated for carrying out multiparallel screening and development of fast normal phase chiral separations. In contrast to the familiar automated sequential chiral method development approaches that often afford a next day result, the multiparallel approach offers the exciting possibility of near "real time" method development, often affording an optimized method in less than 1 h. In this study, four column types (300 microm i.d.) with two different mobile phases are screened using a universal standard gradient approach. Interestingly, parallel method optimization following initial screening was shown to sometimes lead to surprising and unanticipated outcomes, emphasizing the value of the multiparallel screening approach. A variety of standard test racemates were analyzed, with optimized separation methods for most in the 1- to 2-min range. These results compare favorably with results obtained on a single channel conventional HPLC system using 4.6-mm i.d. columns. In addition, isocratic methods developed on the microbore columns are readily translated to the larger column format.
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Affiliation(s)
- Peter Sajonz
- Separation & Analysis Technologies, Process Research, Merck & Co. Inc., Rahway, New Jersey 07065, USA.
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34
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Ghaedi M, Asadpour E, Vafaie A. Sensitized spectrophotometric determination of Cr(III) ion for speciation of chromium ion in surfactant media using alpha-benzoin oxime. Spectrochim Acta A Mol Biomol Spectrosc 2006; 63:182-8. [PMID: 16344251 DOI: 10.1016/j.saa.2005.04.049] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2005] [Accepted: 04/22/2005] [Indexed: 05/05/2023]
Abstract
A simple and accurate micellanized spectrophotometric method for determination of trace amounts of Cr(III) ion in tab and top water and a synthetic mixture has been described. The micellar method is based on effect of organized molecular assemblies such as micelles in spectrophotometric measurement due to their effect on the systems of interest. The ability of micellar system in solubilizing of sparingly soluble ligand or complexes has been used for increasing figures of merit of an analytical method. Due to solubility increasing in aqueous media requirement for a primary extraction can be eliminated. Using the alpha-benzoin oxime (alpha-BO) spectrophotometric determination of Cr(III) ion has been performed and results are compared. The spectrophotometric determination of Cr(III) ion using alpha-BO in the presence of non-ionic surfactant Triton X-100 has been performed. The influence of type and amount of surfactant, pH, complexation time and amount of ligand were examined. Finally, the repeatability, accuracy and the effect of interfering ions on the determination of Cr(III) ion was evaluated. The proposed methods successfully with recovery yield of almost 100% have been applied to the rapid and simple determination of Cr(III) ion in the real samples. There is a good agreement between methods and atomic absorption spectrometry. The Beers law is obeyed over the concentration range of 0.1-13.7 microg mL(-1) for micellar media. The detection limit is 0.8 ng mL(-1). The molar absorptivity of complex is 5350 L mol(-1) cm(-1).
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Affiliation(s)
- Mehrorang Ghaedi
- Chemistry Department, Yasouj University, Yasouj 75914-353, Iran.
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35
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Abstract
Several mechanistic alternatives proposed for the photochemical deprotection of dimethoxybenzoin esters are presented. Both experimental and theoretical evidence suggest the mechanism is heterolysis of the singlet excited state to form a carboxylate and the alpha-ketocation. The alpha-ketocation has been observed by transient spectroscopy. We propose the alpha-ketocation undergoes electrocyclization to an intermediate with extended conjugation, whose deprotonation gives the observed benzofuran product. A Brønsted study of the rates of benzofuran formation with dimethoxybenzoin esters derived from acids of varying pKa shows the rate is independent of the basicity of the leaving group. In this multistep reaction, benzofuran formation by a final deprotonation is slower than alpha-ketocation generation.
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Affiliation(s)
- Michael C Pirrung
- Department of Chemistry, University of California, Riverside, CA 92521-0403 USA.
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36
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Hatanaka M, Takahashi K, Nakamura S, Mashino T. Preparation and antioxidant activity of α-pyridoin and its derivatives. Bioorg Med Chem 2005; 13:6763-70. [PMID: 16125390 DOI: 10.1016/j.bmc.2005.07.065] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2005] [Revised: 07/20/2005] [Accepted: 07/21/2005] [Indexed: 11/26/2022]
Abstract
Focusing on alpha-pyridoin (1, 1,2-di(2-pyridyl)-1,2-ethenediol) as the lead compound of the novel antioxidative enediol, we synthesized 5,5'- or 6,6'-bis-substituted derivatives of 1 from disubstituted pyridines. The antioxidant activity of 1 and its synthetic derivatives 2-7 was evaluated by DPPH (1,1-diphenyl-2-picrylhydrazyl radical) scavenging assay and inhibition of lipid peroxidation. In the DPPH assay, 1 exhibited an activity stronger than that of ascorbic acid, and 5,5'-dimethyl-(5) or 5,5'-dimethoxy-substituted derivatives (6) exhibited more potent activity than 1. The DPPH scavenging activities of alpha-pyridoins were correlated with their oxidation potential and thus the electron density of enediol. 5 and 6 effectively inhibited lipid peroxidation in the rat liver microsome/tert-butyl hydroperoxide system. Therefore, 5 and 6 serve as good candidates for a pharmacologically useful enediol antioxidant.
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Affiliation(s)
- Masashi Hatanaka
- Kyoritsu University of Pharmacy, Shibakoen 1-5-30, Minato-ku, Tokyo 105-8512, Japan
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Noroozi-Pesyan N, Dabbagh AH. Alumina and silica oxides as catalysts for the oxidation of benzoins to benzils under solvent-free conditions. Molecules 2005; 10:1364-8. [PMID: 18007531 PMCID: PMC6147609 DOI: 10.3390/10111364] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2005] [Accepted: 03/05/2005] [Indexed: 11/16/2022] Open
Abstract
Alumina or silica gel are used as catalysts for a solvent-free oxidation of benzoins to the corresponding benzils. These catalysts are easily recovered after completion of the reactions, which are carried out either by heating in a sand bath or using microwave irradiation. Comparison of the results obtained with both catalysts indicates that all the reactants examined were oxidized faster on alumina than on silica under these conditions.
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Affiliation(s)
- N Noroozi-Pesyan
- Department of Chemistry, Faculty of Science, Urmia University, 57159, Urmia, Iran.
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38
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Lin CE, Lin SL, Cheng HT, Fang IJ, Kuo CM, Liu YC. Migration behavior and enantioseparation of hydrobenzoin and structurally related compounds in capillary zone electrophoresis with a dual cyclodextrin system consisting of heptakis-(2,3-dihydroxy-6-O-sulfo)-β-cyclodextrin and β-cyclodextrin. Electrophoresis 2005; 26:4187-96. [PMID: 16252333 DOI: 10.1002/elps.200500294] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Migration behavior and enantioseparation of racemic hydrobenzoin and structurally related compounds, including benzoin and benzoin methyl ether, in CZE with a dual CD system consisting of heptakis-(2,3-dihydroxy-6-O-sulfo)-beta-CD (SI-S-beta-CD) and beta-CD as chiral selectors in the presence and absence of borate complexation at pH 9.0 were investigated. The results indicate that enantioseparation of hydrobenzoin is mainly governed by CD complexation of hydrobenzoin-borate complexes with SI-S-beta-CD when SI-S-beta-CD concentration is relatively high. Whereas CD complexation of hydrobenzoin-borate complexes with beta-CD plays a significant role in enantioseparation when SI-S-beta-CD concentration is comparatively low. The (S,S)-enantiomer of the hydrobenzoin-borate complex was found to interact more strongly than the corresponding (R,R)-enantiomer with both SI-S-beta-CD and beta-CD. These two types of CD show the same chiral recognition pattern, but they exhibit opposite effects on the mobility of the enantiomers of hydrobenzoin-borate complexes. Enantiomer migration reversal of hydrobenzoin occurred in the presence of borate complexation when varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. Binding constants of the enantiomers of benzoin-related compounds to beta-CD and those of hydrobenzoin-borate complexes to SI-beta-CD were evaluated; the mobility contributions of all complex species to the effective mobility of the enantiomers of hydrobenzoin as a function of beta-CD concentration in a borate buffer were analyzed. In addition, comparative studies on the enantioseparation of benzoin-related compounds with SI-S-beta-CD and with randomly sulfate-substituted beta-CD were made.
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Affiliation(s)
- Ching-Erh Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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39
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Hyatt JL, Stacy V, Wadkins RM, Yoon KJP, Wierdl M, Edwards CC, Zeller M, Hunter AD, Danks MK, Crundwell G, Potter PM. Inhibition of carboxylesterases by benzil (diphenylethane-1,2-dione) and heterocyclic analogues is dependent upon the aromaticity of the ring and the flexibility of the dione moiety. J Med Chem 2005; 48:5543-50. [PMID: 16107154 DOI: 10.1021/jm0504196] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Benzil has been identified as a potent selective inhibitor of carboxylesterases (CEs). Essential components of the molecule required for inhibitory activity include the dione moiety and the benzene rings, and substitution within the rings affords increased selectivity toward CEs from different species. Replacement of the benzene rings with heterocyclic substituents increased the K(i) values for the compounds toward three mammalian CEs when using o-nitrophenyl acetate as a substrate. Logarithmic plots of the K(i) values versus the empirical resonance energy, the heat of union of formation energy, or the aromatic stabilization energy determined from molecular orbital calculations for the ring structures yielded linear relationships that allowed prediction of the efficacy of the diones toward CE inhibition. Using these data, we predicted that 2,2'-naphthil would be an excellent inhibitor of mammalian CEs. This was demonstrated to be correct with a K(i) value of 1 nM being observed for a rabbit liver CE. In addition, molecular simulations of the movement of the ring structures around the dione dihedral indicated that the ability of the compounds to inhibit CEs was due, in part, to rotational constraints enforced by the dione moiety. Overall, these studies identify subdomains within the aromatic ethane-1,2-diones, that are responsible for CE inhibition.
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Affiliation(s)
- Janice L Hyatt
- Department of Molecular Pharmacology, St. Jude Children's Research Hospital, 332 N. Lauderdale, Memphis, Tennessee 38105, USA
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40
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Kneen MM, Pogozheva ID, Kenyon GL, McLeish MJ. Exploring the active site of benzaldehyde lyase by modeling and mutagenesis. Biochim Biophys Acta 2005; 1753:263-71. [PMID: 16226928 DOI: 10.1016/j.bbapap.2005.08.025] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/08/2005] [Revised: 08/15/2005] [Accepted: 08/24/2005] [Indexed: 10/25/2022]
Abstract
Benzaldehyde lyase (BAL) is a thiamin diphosphate-dependent enzyme, which catalyzes the breakdown of (R)-benzoin to benzaldehyde. In essence, this is the reverse of the carboligation reaction catalyzed by benzoylformate decarboxylase (BFD). Here, we describe the first steps towards understanding the factors influencing BFD to form a CC bond under conditions wherein BAL will cleave the same bond. What are the similarities and differences between these two enzymes that result in the different catalytic activities? The X-ray structures of BFD and pyruvate decarboxylase (PDC) were used as templates for modeling benzaldehyde lyase. The model shows that a glutamine residue, Gln113, replaces the active site histidines of BFD and PDC. Replacement of the Gln113 by alanine or histidine reduced the value of k(cat) for lyase activity by more than 200-fold. The residues in BFD interacting with the phenyl ring of benzoylformate have similarly positioned counterparts in BAL but Ser26, the residue known to interact with the carboxylate group of benzoylformate, has been replaced by an alanine (Ala28). The BAL A28S variant exhibited 7% of WT activity in the BAL assay but, in the most intriguing result, this variant was able to catalyze the decarboxylation of benzoylformate. Conversely, the BFD S26A variant was unable to cleave benzoin.
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Affiliation(s)
- Malea M Kneen
- College of Pharmacy, University of Michigan, Ann Arbor, MI 48109, USA
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41
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Ye W, Cai G, Zhuang Z, Jia X, Zhai H. One-Step Assembly of Functionalized γ-Butyrolactones from Benzoins or Benzaldehydes via an N-Heterocyclic Carbene-Mediated Tandem Reaction. Org Lett 2005; 7:3769-71. [PMID: 16092871 DOI: 10.1021/ol051422m] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We describe here a direct, efficient, one-step construction of gamma,gamma-difunctionalized gamma-butyrolactones from benzoins or benzaldehydes via a tandem reaction promoted by 1,3-dimethyl imidazolin-2-ylidene, an N-heterocyclic carbene (NHC). [reaction: see text]
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Affiliation(s)
- Wei Ye
- Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, Shanghai, China 200032
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42
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Abstract
In this work, cross silyl benzoin addition reactions between acylsilanes (1) and aldehydes (2) catalyzed by metal cyanides are described. Unsymmetrical aryl-, heteroaryl-, and alkyl-substituted benzoin adducts can be generated in moderate to excellent yields with complete regiocontrol using potassium cyanide and a phase transfer catalyst. From a screen of transition metal cyanide complexes, lanthanum tricyanide was identified as an improved second-generation catalyst for the cross silyl benzoin reaction. A study of the influence of water on the KCN-catalyzed cross silyl benzoin addition revealed more practical reaction conditions using unpurified solvent under ambient conditions. A sequential silyl benzoin addition/cyanation/O-acylation reaction that resulted in two new C-C bonds was achieved in excellent yield. The mechanism of cross silyl benzoin addition is proposed in detail and is supported by crossover studies and a number of unambiguous experiments designed to ascertain the reversibility of key steps. No productive chemistry arises from cyanation of the more electrophilic aldehyde component. Formation of the carbon-carbon bond is shown to be the last irreversible step in the reaction.
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Affiliation(s)
- Xin Linghu
- Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599-3290, USA
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43
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Yasuike S, Kishi Y, Kawara SI, Kurita J. Catalytic Action of Triarylstibanes: Oxidation of Benzoins into Benzyls Using Triarylstibanes Under an Aerobic Condition. Chem Pharm Bull (Tokyo) 2005; 53:425-7. [PMID: 15802844 DOI: 10.1248/cpb.53.425] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Benzoins are simply oxidized to benzils in excellent yields with a catalytic amount of triarylstibanes under an aerobic condition. This catalytic oxidation is heteroatom-specific in the antimony compound and no reaction take place with other group 15 reagents such as triphenylphosphane, -arsane and -bismuthane. The reaction should involve an oxidation-reduction cycle between stibane Sb(III) and stiborane Sb(V) under air.
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Affiliation(s)
- Shuji Yasuike
- Faculty of Pharmaceutical Sciences, Hokuriku University, Kanazawa
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44
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Abstract
Thiazolylalanine, in appropriately functionalized form, has been found to function as an enantioselective catalyst for an intramolecular Stetter reaction. Incorporation of the residue in a number of environments has resulted in a family of catalysts that promote the cyclization of a test substrate with up to 81% enantiomeric excess.
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Affiliation(s)
- Steven M Mennen
- Department of Chemistry, Merkert Chemistry Center, Boston College, Chestnut Hill, MA 02467, USA
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45
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Lin SL, Lin CE. Comparative studies on the enantioseparation of hydrobenzoin and structurally related compounds by capillary zone electrophoresis with sulfated beta-cyclodextrin as the chiral selector in the presence and absence of borate complexation. J Chromatogr A 2004; 1032:213-8. [PMID: 15065798 DOI: 10.1016/j.chroma.2003.11.100] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Comparative studies on the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary zone electrophoresis using sulfated beta-cyclodextrin (S-beta-CD) as a chiral selector in the presence and absence of borate complexation were investigated. The influences of S-beta-CD concentration on the enantioseparation of benzoins in a borate buffer and a phosphate background electrolyte and the influences of the concentration and the pH of borate buffer containing S-beta-CD on the enantioseparation of hydrobenzoin were examined. The results indicate that, depending on the degree of strong borate complexation and comparatively weak CD complexation, the selectivity of the enantiomers of hydrobenzoin can be greatly reduced in a buffer system containing borate ions. Enantioseparation of hydrobenzoin is mainly governed by the interaction between hydrobenzoin-borate complexes and S-beta-CD in a borate buffer, whereas enantioseparation of benzoins is primarily determined by CD complexation in a phosphate background electrolyte. Effective enantioseparations of benzoins were simultaneously achieved with addition of S-beta-CD at a concentration greater than 3.0% (w/v) in a borate buffer and at a concentration greater than 2.5% (w/v) in a phosphate background electrolyte at pH 9.0.
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Affiliation(s)
- Sheng-Li Lin
- Department of Chemistry, National Taiwan University, Taipei 10674, Taiwan
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46
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Shaginian A, Patel M, Li MH, Flickinger ST, Kim C, Cerrina F, Belshaw PJ. Light-Directed Radial Combinatorial Chemistry: Orthogonal Safety-Catch Protecting Groups for the Synthesis of Small Molecule Microarrays. J Am Chem Soc 2004; 126:16704-5. [PMID: 15612691 DOI: 10.1021/ja044702q] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We describe the development of photolabile protecting groups based on the 3,4,5-trimethoxyphenacyl group (TMP). Orthogonal safety-catches were created by introducing an acid-activatible dimethyl ketal (AA-TMP) and an oxidatively activatible 1,3-dithiane (OA-TMP) into the photolabile TMP group. We demonstrate the application of these protecting groups in light-directed synthesis of small molecule microarrays with diversity elements radially attached to a hydroxyproline scaffold.
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Affiliation(s)
- Alex Shaginian
- Department of Chemistry, Center for Nanotechnology, University of Wisconsin, Madison, WI 53706, USA
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47
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Sklute G, Oizerowich R, Shulman H, Keinan E. Antibody-catalyzed benzoin oxidation as a mechanistic probe for nucleophilic catalysis by an active site lysine. Chemistry 2004; 10:2159-65. [PMID: 15112204 DOI: 10.1002/chem.200305034] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Aldolase antibody 24H6, which was obtained by reactive immunization against a 1,3-diketone hapten, is shown to catalyze additional reactions, including H/D exchange and oxidation reactions. Comparison of the H/D exchange reaction at the alpha-position of a wide range of aldehydes and ketones by 24H6 and by other aldolase antibodies, such as 38C2, pointed at the significantly larger size of the 24H6 active site. This property allowed for the catalysis of the oxidation of substituted benzoins to benzils by potassium ferricyanide. This reaction was used as a mechanistic probe to learn about the initial steps of the 24H6-catalyzed aldol condensation reaction. The Hammett correlation (rho=4.7) of log(k(cat)) versus the substituent constant, sigma, revealed that the reaction involves rapid formation of a Schiff base intermediate from the ketone and an active site lysine residue. The rate-limiting step in this oxidation reaction is the conversion of the Schiff base to an enamine intermediate. In addition, linear correlation (rho=3.13) was found between log(K(M)) and sigma, indicating that electronic rather than steric factors are dominant in the antibody-substrate binding phenomenon and confirming that the reversible formation of a Schiff base intermediate comprises part of the substrate-binding mechanism.
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Affiliation(s)
- Genia Sklute
- Department of Chemistry and Institute of Catalysis Science and Technology, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel
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48
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Qin F, Chen X, Liu Y, Kong L, Zou H. [Preparation of covalently bonded cellulose tris (4-methylbenzoate) derivative chiral stationary phases through a polymerization reaction]. Se Pu 2004; 22:569-74. [PMID: 15807104] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Cellulose tris (4-methylbenzoate) derivatives (CTMB) having methacryloyl groups were synthesized with regio-selective or nonselective procedures, and were immobilized on gamma-methacrylatepropylated silica (gamma-MAPS) through a polymerization reaction. The obtained chiral stationary phases ( CSPs) were evaluated by high performance liquid chromatographic (HPLC) resolution of 9 racemates (3-butyl-phthalide, ketoprofen, trans-stilbene oxide, benzoin, benzoin analogue, Tröger' s base, warfarin, 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy-biphenyl-2,2'-dicarboxylate and 4,4'-dimethoxy-5,6,5',6'-dimethylenedioxy-biphenyl-2-methylcarboxylate-2'-ethylcarboxylate). For regio-nonselective procedure, increasing the content of vinyl group on CTMB would lead to higher immobilization efficiency and enantio-selectivity. CSPs prepared by regio-selective procedure possessed slightly higher enantioselectivities than those prepared by regio-nonselective procedure, while the latter showed some advantages for rapid and facile preparation. CSPs prepared with silica gel II (Fuji, 5 microm, 30 nm, ca. 150 m2/g) showed higher enantioselectivities than those prepared with silica gel I (Kromasil, 5 microm, 20 nm, ca. 240 m2/g). The prepared CSPs could keep stable under different eluents, even with 40% of tetrahydrofuran (THF) in mobile phases.
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Affiliation(s)
- Feng Qin
- National Chromatographic R. & A. Center, Dalian Institute of Chemical Physics, The Chinese Academy of Sciences, Dalian 116011, China
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49
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Lin CE, Lin SL, Fang IJ, Liao WS, Chen CC. Enantioseparations of hydrobenzoin and structurally related compounds in capillary zone electrophoresis using heptakis(2,3-dihydroxy-6-O-sulfo)-β-cyclodextrin as chiral selector and enantiomer migration reversal of hydrobenzoin with a dual cyclodextrin system in the presence of borate complexation. Electrophoresis 2004; 25:2786-94. [PMID: 15352010 DOI: 10.1002/elps.200405968] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We investigated the enantioseparations of racemic hydrobenzoin, together with benzoin and benzoin methyl ether, in capillary electrophoresis (CE) using the single-isomer heptakis(2,3-dihydroxy-6-O-sulfo)-beta-cyclodextrin (SI-S-beta-CD) as a chiral selector in the presence and absence of borate complexation and enantiomer migration reversal of hydrobenzoin with a dual CD system consisting of SI-S-beta-CD and beta-CD in the presence of borate complexation at pH 9.0 in a borate buffer. The enantioselectivity of hydrobenzoin increased remarkably with increasing SI-S-beta-CD concentration and the enantioseparation depended on CD complexation between hydrobenzoin-borate and SI-S-beta-CD. The (S,S)-enantiomer of hydrobenzoin-borate complexes interacted more strongly than the (R,R)-enantiomer with SI-S-beta-CD. The enantiomers of hydrobenzoin could be baseline-resolved in the presence of SI-S-beta-CD at a concentration as low as 0.1% w/v, whereas the three test analytes were simultaneously enantioseparated with addition of 0.3% w/v SI-S-beta-CD or at concentrations >2.0% w/v in a borate buffer and 0.5% w/v in a phosphate background electrolyte at pH 9.0. Compared with the results obtained previously using randomly sulfated beta-CD (MI-S-beta-CD) in a borate buffer, enantioseparation of these three benzoin compounds is more advantageously aided by SI-S-beta-CD as the chiral selector. The enantioselectivity of hydrobenzoin depended greatly on the degree of substitution of sulfated beta-CD. Moreover, binding constants of the enantiomers of benzoin compounds to SI-S-beta-CD and those of hydrobenzoin-borate complexes to SI-S-beta-CD were evaluated for a better understanding of the role of CD complexation in the enantioseparation and chiral recognition. Enantiomer migration reversal of hydrobenzoin could be observed by varying the concentration of beta-CD, while keeping SI-S-beta-CD at a relatively low concentration. SI-S-beta-CD and beta-CD showed the same chiral recognition pattern but they exhibited opposite effects on the mobility of the enantiomers.
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Affiliation(s)
- Ching-Erh Lin
- Department of Chemistry, National Taiwan University, Taipei, Taiwan.
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50
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Saito T, Maruyama R, Ono S, Yasukawa N, Kodaira KI, Nishizawa M, Ito S, Inoue M. Asymmetric reduction of benzil to (S)-benzoin with whole cells of Bacillus cereus. Appl Biochem Biotechnol 2004; 111:185-90. [PMID: 14665737 DOI: 10.1385/abab:111:3:185] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2002] [Revised: 05/01/2003] [Accepted: 05/01/2003] [Indexed: 11/11/2022]
Abstract
Benzil (1) was selectively reduced to (S)-benzoin (2) in the presence of a wild-type Bacillus cereus Tim-r01. A 92% yield of 2 with 94% enantiomeric excess ratio was attained in phosphate-buffered saline (PBS) (pH 7.5) by using glucose as a nutrient at 37 degrees C for 12 h. Compound 2 was not reduced further to hydrobenzoin (3) at all. The reduction activity differed greatly depending on the strain of B. cereus. Under these conditions the B. cereus strains IFO3001, IFO15305, IAM1110, IAM1229, IAM1656, and IAM1729 gave 2 in yields ranging from 23 to 46% and the configuration of 2 was (S)-form (7 to 86% ee).
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Affiliation(s)
- Tomoya Saito
- Department of System Engineering of Materials and Life Sciences, Faculty of Engineering, Toyama University, Gofuku 3190, Toyama 930-8555, Japan
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