1
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Lin HS, Pan YZ, Tian YH, Pan YM, Wang X. Palladium‐Catalyzed Tandem Cyclization of 2‐(2 Ethynylphenyl)acetonitriles and Isocyanides: Access to Indeno[2,1‐b]pyrroles. Adv Synth Catal 2022. [DOI: 10.1002/adsc.202101311] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Hui-Shu Lin
- Guangxi University of Science and Technology CHINA
| | | | - Yu-Hong Tian
- Guangxi University of Science and Technology CHINA
| | - Ying-ming Pan
- State Key Laboratory for Chemistry and Molecular Engineering of Medicinal Resources CHINA
| | - Xu Wang
- Guangxi University of Science and Technology CHINA
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2
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Chavan SP, Kawale SA, Pisal MM, Kadam AL, Gonnade RG. Formal Synthesis of (-)-Quinagolide: Diastereoselective Ring Expansion via a Bicyclic Aziridinium Ion Strategy to Access the Octahydrobenzo[ g]quinoline Architecture. J Org Chem 2021; 86:9344-9352. [PMID: 34228439 DOI: 10.1021/acs.joc.1c00603] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The diastereoselective formal synthesis of (-)-quinagolide, a D2 receptor agonist, has been achieved. The synthesis started from l-pyroglutamic acid and relied on utilization of (a) a stereospecific catalytic hydrogenation and diastereoselective Horner-Emmons-Michael cascade to obtain functionalized prolinate, (b) a Lewis acid mediated Pummerer cyclization to construct a tricyclic fused ring system, and (c) a diastereoselective ring expansion via a bicyclic aziridinium intermediate to access the required 3-substituted piperidine scaffold.
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Affiliation(s)
- Subhash P Chavan
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sanket A Kawale
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Mahesh M Pisal
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Appasaheb L Kadam
- Division of Organic Chemistry, CSIR-National Chemical Laboratory, Pune 411008, India.,Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Rajesh G Gonnade
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India.,Physical and Materials Chemistry Division, CSIR-National Chemical Laboratory, Pune 411008, India
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3
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Gein VL, Nosova NV, Yankin AN, Bazhina AY, Dmitriev MV. An Eco-Friendly Stereoselective Synthesis of Novel Derivatives of Indeno[1,2- b]Pyrrole and Indeno[1,2- c]Pyridazine. Polycycl Aromat Compd 2021. [DOI: 10.1080/10406638.2019.1602061] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
| | | | - Andrei N. Yankin
- St. Petersburg State University, St. Petersburg, Russian Federation
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4
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Teng F, Peng Y, Wang X, Hu W, Hu H, He Y, Luo S, Zhu Q. Pd-Catalyzed Domino Imidoylation/Heck/C(sp2)–H Cyclization: Isocyanide Relay Strategy toward Tricyclic-Fused Heterocycles Containing an All-Carbon Quaternary Center. Org Lett 2020; 22:8188-8192. [DOI: 10.1021/acs.orglett.0c02503] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Fan Teng
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Yan Peng
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Xilong Wang
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Weiming Hu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Huaanzi Hu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Yimiao He
- Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, College of Chemistry and Materials, Nanning Normal University, Nanning 530001, China
| | - Shuang Luo
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
| | - Qiang Zhu
- State Key Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine and Health, Chinese Academy of Sciences, 190 Kaiyuan Avenue, Guangzhou 510530, China
- University of Chinese Academy of Sciences, No. 19(A) Yuquan Road, Shijingshan District, Beijing 100049, China
- Guangxi Key Laboratory of Natural Polymer Chemistry and Physics, College of Chemistry and Materials, Nanning Normal University, Nanning 530001, China
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5
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Verma K, Tailor YK, Khandelwal S, Rushell E, Agarwal M, Kumar M. Efficient and environmentally sustainable domino protocol for the synthesis of diversified spiroheterocycles with privileged heterocyclic substructures using bio-organic catalyst in aqueous medium. Mol Divers 2019; 24:1355-1365. [PMID: 31598819 DOI: 10.1007/s11030-019-09999-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 09/30/2019] [Indexed: 11/26/2022]
Abstract
An efficient and environmentally sustainable synthetic protocol has been presented to synthesize structurally diverse spiroxindoles spiroannulated with indenopyrroloimidazoles, pyranopyrroloimidazoles, chromenopyrroloimidazoles, and imidazopyrrolopyrimidines involving three-component reaction of isatins, hydantoin, and β-diketones in the presence of green and sustainable bio-organic catalyst, β-amino acid, 2-aminoethanesulfonic acid (taurine), in aqueous media. The synthetic efficiency, operational simplicity, and reusability of catalyst make the present synthetic protocol cost effective, time efficient, and eco-friendly to synthesize molecules with structural diversity and molecular complexity and expected to contribute significantly not only to drug discovery research but also to pharmaceutical and medicinal chemistry.
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Affiliation(s)
- Kanchan Verma
- Department of Chemistry, University of Rajasthan, Jaipur, India
| | | | | | - Esha Rushell
- Department of Chemistry, University of Rajasthan, Jaipur, India
| | - Monu Agarwal
- Department of Chemistry, University of Rajasthan, Jaipur, India
| | - Mahendra Kumar
- Department of Chemistry, University of Rajasthan, Jaipur, India.
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6
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Mal K, Naskar B, Mondal A, Goswami S, Prodhan C, Chaudhuri K, Mukhopadhyay C. Dihydroindeno[1,2-b]pyrroles: new Al3+selective off–on chemosensors for bio-imaging in living HepG2 cells. Org Biomol Chem 2018; 16:5920-5931. [DOI: 10.1039/c8ob01411f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
An approach for the expeditious synthesis of a new Al3+-selective turn-on dihydroindeno[1,2-b]pyrrole probe under environmentally benevolent conditions and its bio-imaging studies on HepG2 cell.
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Affiliation(s)
- Kajal Mal
- Department of Chemistry
- University of Calcutta
- Kolkata-700009
- India
| | - Barnali Naskar
- Department of Chemistry
- University of Calcutta
- Kolkata-700009
- India
| | - Animesh Mondal
- Department of Chemistry
- University of Calcutta
- Kolkata-700009
- India
| | - Sanchita Goswami
- Department of Chemistry
- University of Calcutta
- Kolkata-700009
- India
| | - Chandraday Prodhan
- Molecular & Human Genetics Division
- CSIR–Indian Institute of Chemical Biology
- Kolkata–700032
- India
| | - Keya Chaudhuri
- Molecular & Human Genetics Division
- CSIR–Indian Institute of Chemical Biology
- Kolkata–700032
- India
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7
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Stereo-selective green protocol for the synthesis of highly substituted 1-phenyl-tetrahydro indeno [1, 2-b]pyrroles. RESEARCH ON CHEMICAL INTERMEDIATES 2017. [DOI: 10.1007/s11164-017-2893-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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8
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Li J, Lin N, Yu L, Zhang Y. Synthesis of β -prolinols via [3+2] cycloaddition and one-pot programmed reduction: Valuable building blocks for polyheterocycles. Tetrahedron Lett 2016. [DOI: 10.1016/j.tetlet.2016.11.035] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
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9
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Ibarra-Rivera TR, Rentería-Gómez MA, Nieto-Sepúlveda E, Gámez-Montaño R, Rivas Galindo VM, Hernandez-Fernandez E. Synthesis of novel tetrahydroindeno[1,2-b]pyrrolidines via Ugi multicomponent and palladium-catalyzed aerobic oxidative cyclization. SYNTHETIC COMMUN 2016. [DOI: 10.1080/00397911.2016.1152372] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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10
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Jeyachandran V, Muthu M, Ranjith Kumar R. Efficient Green Protocol for the Synthesis of Novel Dihydroindeno[1,2-b]pyrroles. SYNTHETIC COMMUN 2015. [DOI: 10.1080/00397911.2015.1005631] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Affiliation(s)
- Veerappan Jeyachandran
- Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Muthumani Muthu
- Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu, India
| | - Raju Ranjith Kumar
- Department of Organic Chemistry, School of Chemistry, Madurai Kamaraj University, Madurai, Tamil Nadu, India
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11
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Belov DS, Ratmanova NK, Andreev IA, Kurkin AV. Synthesis of bicyclic proline derivatives by the aza-Cope-Mannich reaction: formal synthesis of (±)-acetylaranotin. Chemistry 2015; 21:4141-7. [PMID: 25631763 DOI: 10.1002/chem.201405811] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Indexed: 11/11/2022]
Abstract
Herein we suggest an approach to oxygenated bicyclic amino acids based on an aza-Cope-Mannich rearrangement. Seven distinct amino acid scaffolds analogous to the natural products were prepared on a gram scale with precise control of stereochemistry. Successful implementation of our strategy resulted in the formal synthesis of acetylaranotin.
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Affiliation(s)
- Dmitry S Belov
- Lomonosov Moscow State University, Department of Chemistry, 1/3 Leninskie Gory, Moscow, 119991 (Russia) www.chem.msu.ru; EDASA Scientific srls., Via Stingi, 37, 66050 San Salvo (CH) (Italy) www.edasascientific.com.
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12
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Sardella R, Ianni F, Lisanti A, Scorzoni S, Marini F, Sternativo S, Natalini B. Direct chromatographic enantioresolution of fully constrained β-amino acids: exploring the use of high-molecular weight chiral selectors. Amino Acids 2014; 46:1235-42. [PMID: 24500113 DOI: 10.1007/s00726-014-1683-5] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Accepted: 01/23/2014] [Indexed: 11/25/2022]
Abstract
To the best of our knowledge enantioselective chromatographic protocols on β-amino acids with polysaccharide-based chiral stationary phases (CSPs) have not yet appeared in the literature. Therefore, the primary objective of this work was the development of chromatographic methods based on the use of an amylose derivative CSP (Lux Amylose-2), enabling the direct normal-phase (NP) enantioresolution of four fully constrained β-amino acids. Also, the results obtained with the glycopeptide-type Chirobiotic T column employed in the usual polar-ionic (PI) mode of elution are compared with those achieved with the polysaccharide-based phase. The Lux Amylose-2 column, in combination with alkyl sulfonic acid containing NP eluent systems, prevailed over the Chirobiotic T one, when used under the PI mode of elution, and hence can be considered as the elective choice for the enantioseparation of this class of rigid β-amino acids. Moreover, the extraordinarily high α (up to 4.60) and R S (up to 10.60) values provided by the polysaccharidic polymer, especially when used with camphor sulfonic acid containing eluent systems, make it also suitable for preparative-scale enantioisolations.
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Affiliation(s)
- Roccaldo Sardella
- Dipartimento di Scienze Farmaceutiche, Università degli Studi di Perugia, Via Fabretti 48, 06123, Perugia, Italy
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13
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Organocatalytic Michael addition of indanone carboxylates to vinyl selenone for the asymmetric synthesis of polycyclic pyrrolidines. Tetrahedron 2012. [DOI: 10.1016/j.tet.2012.08.077] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Hanessian S, Auzzas L. The practice of ring constraint in peptidomimetics using bicyclic and polycyclic amino acids. Acc Chem Res 2008; 41:1241-51. [PMID: 18646869 DOI: 10.1021/ar8000052] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Medicinal chemistry has witnessed major advances with the discovery of small synthetic molecules that mimic natural peptidic substrates. These small synthetic mimics do not undergo proteolytic degradation, an advantage they hold over their natural counterparts. Small synthetic molecules make up a number of life-saving marketed drugs that inhibit certain physiologically relevant proteases. The advent of sophisticated instrumental methods, such as X-ray crystallography and high-field NMR, has played a pivotal role in the design of structure-based enzyme inhibitors. Highly stereocontrolled methods of synthesis have led to a variety of functionally diverse molecules that function as peptidomimetics because they have isosteric subunits not affected by proteolytic enzymes. Further studies to optimize biological activity and achieve desirable pharmacokinetic profiles can eventually lead to drug substances. The practice of constraining natural amino acids like their conformationally rigid counterparts has been highly successful in the design and synthesis of peptidomimetic molecules. With some notable exceptions, structural information gathered from protein X-ray crystallography of therapeutically relevant target enzymes, alone or in complex forms with inhibitor molecules, has been instrumental in the design of peptidomimetics. For example, a significant number have become marketed drugs as antihypertensives and antivirals. Natural products have also been a source of inspiration for the design and synthesis of truncated analogues with the intention of maintaining, or even improving, their biological activities. However, lower molecular weight peptides are not suitable as therapeutic agents because they are subject to rapid amide proteolysis. They are poorly transported to the brain and rapidly excreted through the liver and kidney. Thus, lower molecular weight peptides are eliminated as potential drug substances in clinical practice. A synthetic peptidomimetic is needed that is resistant to cleavage but maintains its biological activity. Conformationally constrained monocyclic and bicyclic unnatural amino acids can be directly incorporated in a potential inhibitor molecule as part of the design element. In this Account, we describe our efforts in the synthesis of constrained azacycles that contain proline or pipecolic acid as an integral part of bicyclic and polycyclic amino acids. We devised syntheses of conformationally biased monocyclic, bicyclic, and polycyclic amino acid analogues, into which pharmacologically or structurally relevant functional groups were incorporated. Stereocontrolled reactions for C-C, C-N, and C-O bond formation had to be implemented on appropriately protected amino acid frameworks. A number of these frameworks provided access to functionally diverse scaffolds for further use as core subunits in more elaborated structures. Specific applications as peptidomimetics of natural substrates for relevant enzymes, such as thrombin, were also pursued, resulting in highly active inhibitors in vitro.
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Affiliation(s)
- Stephen Hanessian
- Department of Chemistry, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, Québec H3C 3J7, Canada
| | - Luciana Auzzas
- Department of Chemistry, Université de Montréal, P.O. Box 6128, Station Centre-ville, Montréal, Québec H3C 3J7, Canada
- Istituto di Chimica Biomolecolare, Consiglio Nazionale delle Ricerche, Traversa La Crucca 3, I-07040 Sassari, Italy
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15
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Chatterjee B, Saha I, Raghothama S, Aravinda S, Rai R, Shamala N, Balaram P. Designed peptides with homochiral and heterochiral diproline templates as conformational constraints. Chemistry 2008; 14:6192-204. [PMID: 18491347 DOI: 10.1002/chem.200702029] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Diproline segments have been advanced as templates for nucleation of folded structure in designed peptides. The conformational space available to homochiral and heterochiral diproline segments has been probed by crystallographic and NMR studies on model peptides containing L-Pro-L-Pro and D-Pro-L-Pro units. Four distinct classes of model peptides have been investigated: a) isolated D-Pro-L-Pro segments which form type II' beta-turn; b) D-Pro-L-Pro-L-Xxx sequences which form type II'-I (betaII'-I, consecutive beta-turns) turns; c) D-Pro-L-Pro-D-Xxx sequences; d) L-Pro-L-Pro-L-Xxx sequences. A total of 17 peptide crystal structures containing diproline segments are reported. Peptides of the type Piv-D-Pro-L-Pro-L-Xxx-NHMe are conformationally homogeneous, adopting consecutive beta-turn conformations. Peptides in the series Piv-D-Pro-L-Pro-D-Xxx-NHMe and Piv-L-Pro-L-Pro-L-Xxx-NHMe, display a heterogeneity of structures in crystals. A type VIa beta-turn conformation is characterized in Piv-L-Pro-L-Pro-L-Phe-OMe (18), while an example of a 5-->1 hydrogen bonded alpha-turn is observed in crystals of Piv-D-Pro-L-Pro-D-Ala-NHMe (11). An analysis of pyrrolidine conformations suggests a preferred proline puckering geometry is favored only in the case of heterochiral diproline segments. Solution NMR studies, reveal a strong conformational influence of the C-terminal Xxx residues on the structures of diproline segments. In L-Pro-L-Pro-L-Xxx sequences, the Xxx residues strongly determine the population of Pro-Pro cis conformers, with an overwhelming population of the trans form in L-Xxx=L-Ala (19).
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Affiliation(s)
- Bhaswati Chatterjee
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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16
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Complementary routes to both enantiomers of pipecolic acid and 4,5-dihydroxypipecolic acid derivatives. Tetrahedron Lett 2008. [DOI: 10.1016/j.tetlet.2007.12.097] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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17
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Bolognesi ML, Andrisano V, Bartolini M, Cavalli A, Minarini A, Recanatini M, Rosini M, Tumiatti V, Melchiorre C. Heterocyclic inhibitors of AChE acylation and peripheral sites. ACTA ACUST UNITED AC 2005; 60:465-73. [PMID: 15878569 DOI: 10.1016/j.farmac.2005.03.010] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2004] [Accepted: 03/30/2005] [Indexed: 10/25/2022]
Abstract
Notwithstanding the criticism to the so called " cholinergic hypothesis", the therapeutic strategies for the treatment of Alzheimer's disease (AD) have been mainly centered on the restoration of cholinergic functionality and, until the last year, the only drugs licensed for the management of AD were the acetycholinesterase (AChE) inhibitors. Target enzyme AChE consists of a narrow gorge with two separate ligand binding sites: an acylation site at the bottom of the gorge containing the catalytic triad and a peripheral site located at the gorge rim, which encompasses binding sites for allosteric ligands. The aim of this short review is to update the knowledge on heterocyclic AChE inhibitors able to interact with the two sites of enzymes, structurally related to the well known inhibitors physostigmine, rivastigmine and propidium. The therapeutic potential of the dual site inhibithors in inhibiting amyloid-beta aggregatrion and deposition is also briefly summarised.
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18
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Hanessian S, Tremblay M. Tandem Functionalization of Nonactivated Alkenes and Alkynes in Intramolecular N-Acyloxyiminium Ion Carbocyclization. Synthesis of 6-Substituted Hydroindole 2-Carboxylic Acids. Org Lett 2004; 6:4683-6. [PMID: 15575660 DOI: 10.1021/ol040053b] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
[reaction: see text] Five-membered N-Boc acyliminium ions derived from L-pyroglutamic acid harboring 4-butenyl and 4-butynyl tethers undergo Lewis acid-mediated halo and tandem Friedel-Crafts carbocyclization within minutes at -78 degrees C to give stereodefined 6-substituted octahydroindole and hexahydroindole 2-carboxylic acid methyl esters, respectively. The cyclic vinyl bromides are excellent substrates for Pd-catalyzed Suzuki-Miyaura, Heck, and Stille couplings. The method also provides access to enantiopure sp2- and sp3-arylated azabicyclics that are novel and versatile scaffolds for chemical diversification.
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Affiliation(s)
- Stephen Hanessian
- Department of Chemistry, Université de Montréal, C.P. 6128, Station Centre-ville, Montréal, PQ, H3C 3J7 Canada.
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19
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Hanessian S, Papeo G, Fettis K, Therrien E, Viet MTP. Synthesis of 310-Helix-Inducing Constrained Analogues of l-Proline. J Org Chem 2004; 69:4891-9. [PMID: 15255713 DOI: 10.1021/jo0401422] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A bicyclic indolizidinone carboxylic acid and a tricyclic constrained analogue of l-proline were synthesized and evaluated for their ability to induce helix formation as l-Ala tetrapeptides. Variable-temperature NMR, DMSO titration, CD spectra, and X-ray structure analyses, in conjunction with molecular modeling, confirmed the existence of 3(10)-helical motifs with di- and tetrapeptides of l-Ala.
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Affiliation(s)
- Stephen Hanessian
- Department of Chemistry, Université de Montréal, C. P. 6128, Succ. Centre-Ville, Montréal, Quebec, Canada H3C 3J7.
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