1
|
Unveiling the mechanism for selective cleavage of C-C bonds in sugar reactions on tungsten trioxide-based catalysts. Proc Natl Acad Sci U S A 2022; 119:e2206399119. [PMID: 35984900 PMCID: PMC9407445 DOI: 10.1073/pnas.2206399119] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Conversion of naturally occurring sugars, the most abundant biomass resources on Earth, to fuels and chemicals provides a sustainable and carbon-neutral alternative to the current fossil resource-based processes. Tungsten-based catalysts (e.g., WO3) are efficient for selectively cleaving C-C bonds of sugars to C2,3 oxygenate intermediates (e.g., glycolaldehyde) that can serve as platform molecules with high viability and versatility in the synthesis of various chemicals. Such C-C bond cleavage follows a mechanism distinct from the classical retro-aldol condensation. Kinetic, isotope 13C-labeling, and spectroscopic studies and theoretical calculations, reveal that the reaction proceeds via a surface tridentate complex as the critical intermediate on WO3, formed by chelating both α- and β-hydroxyls of sugars, together with the carbonyl group, with two adjacent tungsten atoms (W-O-W) contributing to the β-C-C bond cleavage. This mechanism provides insights into sugar chemistry and enables the rational design of catalytic sites and reaction pathways toward the efficient utilization of sugar-based feedstocks.
Collapse
|
2
|
Borowski D, Maichle-Mössmer C, Ziegler T. Synthetic Adventures with 2- C
-Branched Carbohydrates: 4- C
-Formyl Branched Octoses with Structural Analogy to Bradyrhizose. European J Org Chem 2019. [DOI: 10.1002/ejoc.201900204] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Daniel Borowski
- Institute of Organic Chemistry; University of Tuebingen; Auf der Morgenstelle 18 72076 Tuebingen Germany
| | - Cäcilia Maichle-Mössmer
- Institute of Inorganic Chemistry; University of Tuebingen; Auf der Morgenstelle 18 72076 Tuebingen Germany
| | - Thomas Ziegler
- Institute of Organic Chemistry; University of Tuebingen; Auf der Morgenstelle 18 72076 Tuebingen Germany
| |
Collapse
|
3
|
Choi H, Engene N, Byrum T, Hwang S, Oh DC, Gerwick WH. Dragocins A−D, Structurally Intriguing Cytotoxic Metabolites from a Panamanian Marine Cyanobacterium. Org Lett 2018; 21:266-270. [DOI: 10.1021/acs.orglett.8b03712] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Hyukjae Choi
- College of Pharmacy, Yeungnam University, 280 Daehak-ro, Gyeongsan, Gyeongsangbukdo 38541, Republic of Korea
| | - Niclas Engene
- Department of Biological Sciences, Florida International University, Miami, Florida 33199, United States
| | - Tara Byrum
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
| | - Sunghoon Hwang
- Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - Dong-Chan Oh
- Natural Products Research Institute, College of Pharmacy, Seoul National University, 1 Gwanak-ro, Gwanak-gu, Seoul 08826, Republic of Korea
| | - William H. Gerwick
- Center for Marine Biotechnology and Biomedicine, Scripps Institution of Oceanography, University of California San Diego, La Jolla, California 92093, United States
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| |
Collapse
|
4
|
|
5
|
Hansen SU, Baráth M, Salameh BAB, Pritchard RG, Stimpson WT, Gardiner JM, Jayson GC. Scalable synthesis of L-iduronic acid derivatives via stereocontrolled cyanohydrin reaction for synthesis of heparin-related disaccharides. Org Lett 2009; 11:4528-31. [PMID: 19764712 DOI: 10.1021/ol901723m] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
L-ido cyanohydrin 3 was prepared from diacetone-D-glucose in four steps and 76% overall yield and 90% de via cyanohydrin reaction of aldehyde 2. This process can be scaled to provide >1 mol of pure L-ido cyanohydrin 3. Cyanohydrin 3 was elaborated to 1,2-isopropylidine-protected L-ido nitrile (8), iduronic amide 9, and known carboxy ester 10. Coupling of 8 and 9 with glucosamine donors leads to new types (6-cyano and 6-carboxamide) of heparin-related disaccharides.
Collapse
Affiliation(s)
- Steen Uldall Hansen
- School of Chemistry and Manchester Interdisciplinary Biocentre, The University of Manchester, 131 Princess Street, Manchester M1 7DN, UK.
| | | | | | | | | | | | | |
Collapse
|
6
|
Ogi T, Margiastuti P, Teruya T, Taira J, Suenaga K, Ueda K. Isolation of C11 cyclopentenones from two didemnid species, Lissoclinum sp. and Diplosoma sp. Mar Drugs 2009; 7:816-32. [PMID: 20098612 PMCID: PMC2810228 DOI: 10.3390/md7040816] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2009] [Revised: 12/14/2009] [Accepted: 12/16/2009] [Indexed: 11/16/2022] Open
Abstract
A series of new C(11) cyclopentenones 1-7 was isolated, together with four known metabolites 9/10, 12 and 13, from the extract of the didemnid ascidian Lissoclinum sp. The other didemnid ascidian Diplosoma sp. contained didemnenones 1, 2 and 5, and five known metabolites 8-12. The structures of 1-7 were elucidated by spectroscopic analyses. Cytotoxicity of the isolated compounds was evaluated against three human cancer cell lines (HCT116, A431 and A549).
Collapse
Affiliation(s)
- Takayuki Ogi
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; E-Mail:
(T.O.)
- Okinawa Industrial Technology Center, 12-2 Suzaki, Uruma, Okinawa 904-2234, Japan
| | - Palupi Margiastuti
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; E-Mail:
(T.O.)
| | - Toshiaki Teruya
- Faculty of Education, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; E-Mail:
(T.T.)
| | - Junsei Taira
- Department of Bioresources Engineering, Okinawa National College of Technology, 905 Henoko, Nago, Okinawa 905-2192, Japan; E-Mail:
(J.T.)
| | - Kiyotake Suenaga
- Department of Chemistry, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama, Kanagawa 223-8522, Japan; E-Mail:
(K.S.)
| | - Katsuhiro Ueda
- Department of Chemistry, Biology and Marine Science, University of the Ryukyus, 1 Senbaru, Nishihara, Okinawa 903-0213, Japan; E-Mail:
(T.O.)
- Author to whom correspondence should be addressed; E-Mail:
; Tel.: +81-98-895-8894; Fax: +81-98-895-8565
| |
Collapse
|
7
|
Hricovíniová Z. The influence of microwave irradiation on stereospecific Mo(VI)-catalyzed transformation of deoxysugars. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.tetasy.2009.05.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
8
|
Margiastuti P, Ogi T, Teruya T, Taira J, Suenaga K, Ueda K. An Unusual Iodinated 5′-Deoxyxylofuranosyl Nucleoside from an Okinawan Ascidian,Diplosomasp. CHEM LETT 2008. [DOI: 10.1246/cl.2008.448] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
|
9
|
Nakano K, Kotsuki H, Ichikawa Y. SYNTHESIS OF CONAGENIN AND α-METHYLSERINE. A REVIEW. ORG PREP PROCED INT 2008. [DOI: 10.1080/00304940809356641] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
|
10
|
Smellie IA, Bhakta S, Sim E, Fairbanks AJ. Synthesis of putative chain terminators of mycobacterial arabinan biosynthesis. Org Biomol Chem 2007; 5:2257-66. [PMID: 17609757 DOI: 10.1039/b704788f] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The synthesis of a variety of arabinose derivatives that have been modified at C-5 was achieved from d-arabinose. The 5-fluoro and 5-methoxy compounds were converted into the corresponding farnesyl phosphodiesters as putative chain terminators of mycobacterial arabinan biosynthesis. Biological testing of these materials revealed no effective anti-mycobacterial activity.
Collapse
Affiliation(s)
- Iain A Smellie
- Chemistry Research Laboratory, Oxford University, Mansfield Road, Oxford, UK OX1 3TA
| | | | | | | |
Collapse
|
11
|
|
12
|
Chandrasekhar S, Saritha B, Jagadeshwar V, Prakash SJ. Practical and highly stereoselective approaches to the total synthesis of (−)-codonopsinine. ACTA ACUST UNITED AC 2006. [DOI: 10.1016/j.tetasy.2006.05.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
13
|
Zhu Y, Pan Q, Thibaudeau C, Zhao S, Carmichael I, Serianni AS. [13C,15N]2-Acetamido-2-deoxy-d-aldohexoses and Their Methyl Glycosides: Synthesis and NMR Investigations of J-Couplings Involving 1H, 13C, and 15N. J Org Chem 2005; 71:466-79. [PMID: 16408953 DOI: 10.1021/jo051510k] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[reaction: see text] A series of 2-amino-2-deoxy-D-[1-13C]aldohexoses and their methyl glycosides was prepared with use of a simplified cyanohydrin reduction route. Four d-aldopentosylamines (arabino, lyxo, ribo, xylo) were prepared from the corresponding D-aldopentoses by reaction with NH3(g) in MeOH solvent, isolated in solid form, and characterized by 13C and 1H NMR. Hydrolysis of beta-D-xylopyranosylamine was studied using 13C-labeled substrates to establish optimal solution conditions for cyanohydrin formation. Major hydrolytic intermediates were observed and identified by time-lapse 1D and 2D NMR analyses of reaction mixtures. The aldopentosylamines were subsequently employed in cyanohydrin reduction reactions with K13CN to yield C2-epimeric [1-13C]2-aminosugars, which were separated by chromatography on ion-exchange columns. N-Acetylation and methyl glycosidation followed by chromatography gave pure 2-acetamido-2-deoxy-D-[1-13C]aldohexopyranosides. J(CH) and J(CC) spin-spin coupling constants involving the labeled anomeric carbon were measured and compared to those observed previously in methyl D-[1-13C]aldohexopyranosides. In parallel studies, theoretical J-couplings were calculated in model N-acetylated aldopyranosides using density functional theory (DFT) to predict the effect of OH vs NHCOCH(3) substitution at C2 on J(CH) and J(CC) values in aldopyranosyl rings. The synthetic method was also modified to accommodate (15)N- and (13)C-labeling within the N-acetyl side-chain, and some J-couplings involving 1H, 13C, and 15N atoms in 2-[1,2-13C2;15N]acetamido-2-deoxy-D-[1-13C]glucose were measured and interpreted.
Collapse
Affiliation(s)
- Yuping Zhu
- Department of Chemistry and Biochemistry and the Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556-5670, USA
| | | | | | | | | | | |
Collapse
|
14
|
Chandrasekhar S, Jagadeshwar V, Prakash SJ. Total synthesis of the alkaloid (−)-codonopsinine from l-xylose. Tetrahedron Lett 2005. [DOI: 10.1016/j.tetlet.2005.02.140] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
15
|
Xiang TX, Niemi R, Bummer P, Anderson BD. Epimer interconversion, isomerization, and hydrolysis of tetrahydrouridine: Implications for cytidine deaminase inhibition. J Pharm Sci 2003; 92:2027-39. [PMID: 14502542 DOI: 10.1002/jps.10447] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Tetrahydrouridine (THU) is an inhibitor of cytidine deaminase (CDA), the enzyme responsible for the deactivation of ara-C and other cytidine analogues in vivo, and therefore is capable of improving the therapeutic efficacy of these antitumor agents. In aqueous solution formulations, THU exists as a mixture of epimers differing in stereochemistry of the 4-OH substituent. The aims of this study were to investigate the interconversion kinetics of the epimers of THU, the CDA inhibitory effects of these epimers, and the stability and degradation mechanisms of THU epimer mixtures in aqueous solution with the ultimate goal of developing optimal conditions for a parenteral formulation of THU. A stability indicating HPLC assay utilizing a derivatized beta-cyclodextrin column was developed to separate the two epimers of THU and to monitor their reversible isomerization to their beta-ribopyranosyl counterparts and their hydrolysis to form N-glycosidic bond cleavage products. MS and one- and two-dimensional (1)H- and (13)C-NMR measurements were conducted to identify THU epimers and degradation products and to quantitatively model the degradation kinetics. The interconversion reaction between the two THU epimers is acid catalyzed with a first-order rate constant for conversion of epimer 1(1) to epimer 1(2) of (7.4 +/- 0.3) x 10(-3) h(-1) and an equilibrium constant ([1(2)]/[1(1)] of 1.7 +/- 0.1 at pH 7.4 and 25 degrees C. Epimer interconversion was therefore sufficiently slow at pH 7.4 to allow the isolation of each and evaluation of their CDA inhibitory activities utilizing 1% (w/v) mouse kidney homogenates as a source for cytidine deaminase and cytidine as a substrate. Inhibition constants for the two THU epimers (1(1) and 1(2)) were determined to be 8 +/- 1 x 10(-7) M and 6.2 +/- 0.2 x 10(-8) M, respectively. Studies at elevated temperature suggested that THU degradation from epimer mixtures is biphasic with the initial rate of disappearance being acid catalyzed and first order in initial THU concentration, thus ruling out dimerization as a potential reaction mechanism. NMR/MS analyses revealed that the major degradation products included the beta-ribopyranosyl THU isomers (two epimers), the reduced pyrimidinone base (tetrahydrouracil), and various anomers of D-ribose formed through N-glycosidic bond cleavage, and the products of subsequent reactions of the base. Kinetic modeling of the data obtained from both HPLC and NMR measurements indicated that in an acidic solution THU beta-ribofuranosyl --> beta-ribopyranosyl isomerization is a rapid equilibrium reaction, which proceeds through an intermediate observable in 1H-NMR, and is followed by slower N-glycosidic bond hydrolysis. All the reactions between THU, its ribopyranosyl isomers, the intermediate, and the base are acid catalyzed and appear to proceed through the same sugar ring-opened intermediate (carbinolamine), consistent with previous literature.
Collapse
Affiliation(s)
- Tian-Xiang Xiang
- Division of Pharmaceutical Sciences, College of Pharmacy, University of Kentucky, Lexington, Kentucky 40536, USA
| | | | | | | |
Collapse
|
16
|
Cloran F, Carmichael I, Serianni AS. 2-Deoxy-beta-D-erythro-pentofuranose: hydroxymethyl group conformation and substituent effects on molecular structure, ring geometry, and NMR spin-spin coupling constants from quantum chemical calculations. J Am Chem Soc 2001; 123:4781-91. [PMID: 11457288 DOI: 10.1021/ja002525x] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The effect of hydroxymethyl conformation (gg, gt, and tg rotamers about the C4-C5 bond) on the conformational energies and structural parameters (bond lengths, bond angles, bond torsions) of the 10 envelope forms of the biologically relevant aldopentofuranose, 2-deoxy-beta-D-erythro-pentofuranose (2-deoxy-D-ribofuranose) 2, has been investigated by ab initio molecular orbital calculations at the HF/6-31G level of theory. C4-C5 bond rotation induces significant changes in the conformational energy profile of 2 (2gt and 2tg exhibit one global energy minimum, whereas 2gg exhibits two nearly equivalent energy minima), and structural changes, especially those in bond lengths, are consistent with predictions based on previously reported vicinal, 1,3- and 1,4-oxygen lone pair effects. HF/6-31G-optimized envelope geometries of 2gg were re-optimized using density functional theory (DFT, B3LYP/6-31G), and the resulting structures were used in DFT calculations of NMR spin-spin coupling constants involving 13C (i.e., J(CH) and J(CC) over one, two, and three bonds) in 2gg according to methods described previously. The computed J-couplings were compared to those reported previously in 2gt to assess the effect of C4-C5 bond rotation on scalar couplings within the furanose ring and hydroxymethyl side chain. The results confirm prior predictions of correlations between 2J(CH), 3J(CH), 2J(CC) and 3J(CC), and ring conformation, and verify the usefulness of a concerted application of these couplings (both their magnitudes and signs) in assigning preferred ring and C4-C5 bond conformations in aldopentofuranosyl rings. The new calculated J-couplings in 2gg have particular relevance to related J-couplings in DNA (and RNA indirectly), where the gg rotamer, rather than the gt rotamer, is observed in most native structures. The effects of two additional structural perturbations on 2 were also studied, namely, deoxygenation at C5 (yielding 2,5-dideoxy-beta-D-erythro-pentofuranose 4) and methyl glycosidation at O1 (yielding methyl 2-deoxy-beta-D-erythro-pentofuranoside 5) at the HF/6-31G level. The conformational energy profile of 4 resembles that found for 2gt, not 2gg, indicating that 4 is an inappropriate structural mimic of the furanose ring in DNA. Glycosidation failed to induce differential stabilization of ring conformations containing an axial C1-O1 bond (anomeric effect), contrary to experimental data. The latter discrepancy indicates that either the magnitude of this differential stabilization depends on ring configuration or that solvent effects, which are neglected in these calculations, play a role in promoting this stabilization.
Collapse
Affiliation(s)
- F Cloran
- Department of Chemistry and Biochemistry, and the Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, USA
| | | | | |
Collapse
|
17
|
Hayes MP, Hatala PJ, Sherer BA, Tong X, Zanatta N, Borer PN, Kallmerten J. Regioselective synthesis of 13C1-labeled 2-deoxyribonolactones. Tetrahedron 2001. [DOI: 10.1016/s0040-4020(00)01148-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
|
18
|
Glomb MA, Rösch D, Nagaraj RH. N(delta)-(5-hydroxy-4,6-dimethylpyrimidine-2-yl)-l-ornithine, a novel methylglyoxal-arginine modification in beer. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2001; 49:366-372. [PMID: 11170600 DOI: 10.1021/jf000493r] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
N(delta)-(5-Hydroxy-4,6-dimethylpyrimidine-2-yl)-L-ornithine, or Argpyrimidine, was identified and quantified in beer by high-performance liquid chromatography (HPLC) and coupled gas chromatography-mass spectrometry (HRGC-MS). This novel fluorescent arginine Maillard modification represents the first amino acid modification reported in beer retaining the full backbone of the original amino acid. Two mechanisms of formation could be verified: the major pathway via methylglyoxal and the minor pathway via 5-deoxypentoses. Argpyrimidine concentrations, determined in 35 lager-type beer varieties, reached up to 27 nmol/L and could be positively correlated to beer color and wort content. Within this context, 5-deoxy-D-ribose was identified as a novel intermediate of the Maillard reaction of maltose by HRGC-MS and independent synthesis.
Collapse
Affiliation(s)
- M A Glomb
- Institute of Food Chemistry, Technical University of Berlin, Gustav-Meyer-Allee 25, TIB4/3-1, 13355 Berlin, Germany.
| | | | | |
Collapse
|
19
|
Ugarkar BG, DaRe JM, Kopcho JJ, Browne CE, Schanzer JM, Wiesner JB, Erion MD. Adenosine kinase inhibitors. 1. Synthesis, enzyme inhibition, and antiseizure activity of 5-iodotubercidin analogues. J Med Chem 2000; 43:2883-93. [PMID: 10956196 DOI: 10.1021/jm000024g] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Adenosine receptor agonists produce a wide variety of therapeutically useful pharmacologies. However, to date they have failed to undergo successful clinical development due to dose-limiting side effects. Adenosine kinase inhibitors (AKIs) represent an alternative strategy, since AKIs may raise local adenosine levels in a more site- and event-specific manner and thereby elicit the desired pharmacology with a greater therapeutic window. Starting with 5-iodotubercidin (IC50 = 0.026 microM) and 5'-amino-5'-deoxyadenosine (IC50 = 0.17 microM) as lead inhibitors of the isolated human AK, a variety of pyrrolo[2,3-d]pyrimidine nucleoside analogues were designed and prepared by coupling 5-substituted-4-chloropyrrolo[2,3-d]pyrimidine bases with ribose analogues using the sodium salt-mediated glycosylation procedure. 5'-Amino-5'-deoxy analogues of 5-bromo- and 5-iodotubercidins were found to be the most potent AKIs reported to date (IC50S < 0.001 microM). Several potent AKIs were shown to exhibit anticonvulsant activity in the rat maximal electric shock (MES) induced seizure assay.
Collapse
Affiliation(s)
- B G Ugarkar
- Metabasis Therapeutics Inc, San Diego, California 92121, USA.
| | | | | | | | | | | | | |
Collapse
|
20
|
D'Souza FW, Ayers JD, McCarren PR, Lowary TL. Arabinofuranosyl Oligosaccharides from Mycobacteria: Synthesis and Effect of Glycosylation on Ring Conformation and Hydroxymethyl Group Rotamer Populations. J Am Chem Soc 2000. [DOI: 10.1021/ja993543l] [Citation(s) in RCA: 84] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Francis W. D'Souza
- Contribution from the Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Joseph D. Ayers
- Contribution from the Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Patrick R. McCarren
- Contribution from the Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| | - Todd L. Lowary
- Contribution from the Department of Chemistry, The Ohio State University, 100 West 18th Avenue, Columbus, Ohio 43210
| |
Collapse
|
21
|
Shull BK, Spielvogel DE, Head G, Gopalaswamy R, Sankar S, Devito K. Studies on the Structure of the Complex of the Boron Neutron Capture Therapy Drug, L‐p‐Boronophenylalanine, with Fructose and Related Carbohydrates: Chemical and 13C NMR evidence for the β‐D‐Fructofuranose 2,3,6‐(p‐Phenylalanylorthoboronate) Structure. J Pharm Sci 2000. [DOI: 10.1002/(sici)1520-6017(200002)89:2%3c215::aid-jps8%3e3.0.co%3b2-p] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
22
|
Shull BK, Spielvogel DE, Head G, Gopalaswamy R, Sankar S, Devito K. Studies on the structure of the complex of the boron neutron capture therapy drug, L-p-boronophenylalanine, with fructose and related carbohydrates: chemical and 13C NMR evidence for the beta-D-fructofuranose 2,3,6-(p-phenylalanylorthoboronate) structure. J Pharm Sci 2000; 89:215-22. [PMID: 10688750 DOI: 10.1002/(sici)1520-6017(200002)89:2<215::aid-jps8>3.0.co;2-p] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
The complex of L-L-boronophenylalanine (L-p-BPA) with fructose has been used for the past 5 years in clinical trials of boron neutron capture therapy to treat both melanoma and glioblastoma multiforme. However, the structure of this complex in water buffered at physiologic pH has not been established. In the (1)H NMR spectra (D(2)O buffered at pD 7.4) of the complex of L-p-BPA with various carbohydrates, the upfield chemical shifts of the aromatic protons of L-p-BPA confirm that the boron atom is negatively charged and tetrahedral. In the (13)C NMR spectrum of the complex of L-p-BPA with U-(13)C labeled fructose, the chemical shifts and (1)J(CC) coupling constants are consistent with fructose adopting the beta-D-fructofuranose form. In addition, the (1)J(CC) coupling constants along with the binding constants measured for L-p-BPA with a series of monosaccharides and disaccharides seem to suggest that the beta-D-fructofuranose 2,3,6-(p-phenylalanylorthoboronate) structure strongly predominates, with free L-p-BPA and fructose the only other species detected.
Collapse
Affiliation(s)
- B K Shull
- Glycosyn Pharmaceuticals, Inc., Cary, North Carolina 27513, USA.
| | | | | | | | | | | |
Collapse
|
23
|
Ravagli A, Boschin G, Scaglioni L, Arnoldi A. Reinvestigation of the reaction between 2-furancarboxaldehyde and 4-hydroxy-5-methyl-3(2H)-furanone. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 1999; 47:4962-4969. [PMID: 10606559 DOI: 10.1021/jf990523u] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The reaction between 2-furancarboxaldehyde and 4-hydroxy-5-methyl-3(2H)-furanone was reinvestigated as a part of a systematic study on low molecular weight colored compounds from the Maillard reaction. In acetic acid/piperidine, besides 2-(2-furanylmethylene)-4-hydroxy-5-methyl-3(2H)-furanone (1) and 5-[2-(2-furanyl)ethenyl]-2-(2-furanylmethylene)-4-hydroxy-5-methyl -3( 2H)-furanone (2), four novel compounds, 15a, 15b, 16a, and 16b, were isolated and characterized. These compounds are produced from two molecules of furanone 1 and one molecule of 2-furancarboxaldehyde, and a mechanism is proposed for their formation. Compounds 1, 15a, 15b, 16a, and 16b are formed also by reacting 2-furancarboxaldehyde and 4-hydroxy-5-methyl-3(2H)-furanone in water at pH 3 and 2, whereas 2 was never detected. The formation of these compounds was studied also in xylose/lysine and xylose/glycine model systems.
Collapse
Affiliation(s)
- A Ravagli
- Dipartimento di Scienze Molecolari Agroalimentari, Sezione di Chimica, Università di Milano, via Celoria 2, I-20133 Milano, Italy
| | | | | | | |
Collapse
|
24
|
|
25
|
Hadwiger P, Stütz AE. Ni(Ii)-Catalysed Reactions of Free D-Fructose Derivatives Modified at Positions C-5 and/or C-6. J Carbohydr Chem 1998. [DOI: 10.1080/07328309808001898] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
|
26
|
Bose B, Zhao S, Stenutz R, Cloran F, Bondo PB, Bondo G, Hertz B, Carmichael I, Serianni AS. Three-Bond C−O−C−C Spin-Coupling Constants in Carbohydrates: Development of a Karplus Relationship. J Am Chem Soc 1998. [DOI: 10.1021/ja981127f] [Citation(s) in RCA: 113] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Bidisha Bose
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Shikai Zhao
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Roland Stenutz
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Francis Cloran
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Paul B. Bondo
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Gail Bondo
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Brian Hertz
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Ian Carmichael
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| | - Anthony S. Serianni
- Contribution from the Department of Chemistry and Biochemistry, and Radiation Laboratory, University of Notre Dame, Notre Dame, Indiana 46556, and Omicron Biochemicals, Inc., 1347 N. Ironwood Drive, South Bend, Indiana 46615
| |
Collapse
|
27
|
Migawa MT, Girardet JL, Walker JA, Koszalka GW, Chamberlain SD, Drach JC, Townsend LB. Design, synthesis, and antiviral activity of alpha-nucleosides: D- and L-isomers of lyxofuranosyl- and (5-deoxylyxofuranosyl)benzimidazoles. J Med Chem 1998; 41:1242-51. [PMID: 9575044 DOI: 10.1021/jm970545c] [Citation(s) in RCA: 161] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Several 2-substituted alpha-D- and alpha-L-lyxofuranosyl and 5-deoxylyxofuranosyl derivatives of 5,6-dicholro-2-(isopropylamino)-1-(beta-L-ribofuranosyl) benzimidazole (1263W94) and 2,5,6-trichloro-1(beta-D-ribofuranosyl)benzimidazole (TCRB) were synthesized and evaluated for activity against two herpesviruses (HSV-1 and HCMV) and for their cytotoxicity against HFF and KB cells. Condensation of 1,2,3,5-tetra-O-acetyl-L-lyxofuranose (2a) with 2,5,6-trichlorobenzimidazole (1) yielded the alpha-nucleoside 3a. The 2-bromo derivative and 2-methylamino derivative were prepared by treatment of 3a with HBr followed by deprotection or from methylamine, respectively. Compound 3a was deprotected and the resultant nucleoside used to prepare the 2-cyclopropylamino and 2-isopropylamino derivatives. The 2-alkylthio nucleosides were prepared by condensing 2a with 5,6-dichlorobenzimidazole-2-thione followed by deprotection. Alkylation of this adduct gave the 2-methylthio and 2-benzylthio derivatives. Condensation of 5-deoxy-1,2,3-tri-O-acetyl-L-lyxofuranosyl, prepared from L-lyxose, with 1 or 2-bromo-5,6-dichlorobenzimidazole (15), followed by deprotection, gave the 2-chloro or 2-bromo-5'-deoxylyxo-furanosyl derivative, respectively. The cyclopropylamino derivative was prepared from the 2-chloro derivative. All D-isomers were prepared in an analogous fashion from D-lyxose. Either compounds were inactive against HSV-1 or weak activity was poorly separated from cytotoxicity. In contrast, the 2-halogen derivatives in both the alpha-lyxose and 5-deoxy-alpha-lyxose series were active against the Towne strain of HCMV. The 5-deoxy alpha-L analogues were the most active, IC50's = 0.2-0.4 microM, plaque assay; IC90's = 0.2-2 microM, yield reduction assay. All of the 2-isopropylamino or 2-cyclopropylamino derivatives were less active (IC50's = 60-100 microM, plaque assay; IC90's = 17-100 microM, yield reduction assay) and were not cytotoxic. The methylamino, thio, and methylthio derivatives were neither active nor cytotoxic. The benzylthio derivatives were weakly active, but this activity was poorly separated from cytotoxicity. The alpha-lyxose L-isomers were more active in a plaque assay against the AD169 strain of HCMV compared to the Towne strain, thereby providing additional evidence of antiviral specificity.
Collapse
Affiliation(s)
- M T Migawa
- Department of Chemistry, College of Literature, Science and Arts, University of Michigan, Ann Arbor, Michigan 48109-1065, USA
| | | | | | | | | | | | | |
Collapse
|
28
|
Kovács-Kulyassa Á, Herczegh P, Sztaricskai F. Synthesis of conagenin analogs modified at 3′-carbon atom. Tetrahedron 1997. [DOI: 10.1016/s0040-4020(97)00877-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
|
29
|
Sulfoquinovose and its aldonic acid: their preparation and oxidation to 2-sulfoacetaldehyde by periodate. Carbohydr Res 1997. [DOI: 10.1016/s0008-6215(97)00112-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
30
|
Kovács-Kulyassa Á, Herczegh P, Sztaricskai FJ. First synthesis of conagenin diastereoisomers. Tetrahedron Lett 1996. [DOI: 10.1016/0040-4039(96)00303-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
31
|
|
32
|
Cros S, Imberty A, Bouchemal N, Du Penhoat CH, Perez S. Modeling of arabinofuranose and arabinan, II. Nmr and Conformational analysis of arabinobiose and arabinan. Biopolymers 1994. [DOI: 10.1002/bip.360341014] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
|
33
|
|
34
|
Wu J, Serianni AS, Bondo PB. Multiply 13C-substituted monosaccharides: synthesis of D-(1,5,6-13C3)glucose and D-(2,5,6-13C3)glucose. Carbohydr Res 1992; 226:261-9. [PMID: 1617689 DOI: 10.1016/0008-6215(92)84074-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
D-(1,5,6-13C3)Glucose (7) has been synthesized by a six-step chemical method. D-(1,2-13C2)Mannose (1) was converted to methyl D-(1,2-13C2)mannopyranosides (2), and 2 was oxidized with Pt-C and O2 to give methyl D-(1,2-13C2)mannopyranuronides (3). After purification by anion-exchange chromatography, 3 was hydrolyzed to give D-(1,2-13C2)mannuronic acid (4), and 4 was converted to D-(5,6-13C2)mannonic acid (5) with NaBH4. Ruff degradation of 5 gave D-(4,5-13C2)arabinose (6), and 6 was converted to D-(1,5,6-13C3)glucose (7) and D-(1,5,6-13C3)mannose (8) by cyanohydrin reduction. D-(2,5,6-13C3)Glucose (9) was prepared from 8 by molybdate-catalyzed epimerization.
Collapse
Affiliation(s)
- J Wu
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556
| | | | | |
Collapse
|
35
|
Wu JA, Serianni AS. D-Penturonic acids: solution studies of stable-isotopically enriched compounds by 1H- and 13C-n.m.r. spectroscopy. Carbohydr Res 1991; 210:51-70. [PMID: 1652354 DOI: 10.1016/0008-6215(91)80112-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Methyl D-pentofuranosides were prepared by Fischer glycosidation of the aldopentoses D-arabinose, D-lyxose, D-ribose, D-xylose, and 2-deoxy-D-erythro-pentose, and oxidized with O2 over a platinum oxide catalyst to give the corresponding methyl D-pentofuranosiduronic acids. After purification by anion-exchange chromatography, these glycosides were hydrolyzed to give the corresponding D-penturonic acids [D-arabinuronic acid (1), D-lyxuronic acid (2), D-riburonic acid (3), D-xyluronic acid (4), and 2-deoxy-D-erythro-penturonic acid (5)] in 80% yield based on the starting pentofuranoside. 1-13C-Substituted D-aldopentoses were used to prepare D-(1-13C)penturonic acids. Aqueous solutions of the 1-13C-substituted penturonic acids, studied over a range of pH values by 13C-n.m.r. spectroscopy, were found to contain alpha- and beta-furanoses, acyclic aldehyde and hydrate, and/or hydrated 2,5-lactone. The ratio of D-riburonic acid anomers was most sensitive to solution pH (alpha/beta = 0.49 and 1.2 at pH 1.9 and 4.9, respectively). The values of the 1H and 13C chemical shifts, and 1H-1H. 13C-1H, and 13C-13C spin-coupling constants, were determined by 1H-(300, 500, and 620 MHz) and 13C-(75 MHz) n.m.r. spectroscopy with the aid of 2-D 13C-1H chemical shift correlation maps, 2-D 1H-1H COSY data, and 13C substitution, and were compared to those determined previously for structurally-related furanose rings. Isomerization of the penturonic acids at pH 5.0 and 50 degrees gave the corresponding 4-pentulosonic acids.
Collapse
Affiliation(s)
- J A Wu
- Department of Chemistry and Biochemistry, University of Notre Dame, Indiana 46556
| | | |
Collapse
|
36
|
Snyder JR, Serianni AS. Deoxygenated and alkylated furanoses: Thorpe-Ingold effects on tautomeric equilibria and rates of anomerization. Carbohydr Res 1991; 210:21-38. [PMID: 1878878 DOI: 10.1016/0008-6215(91)80110-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
2-Deoxy-D-glycero-tetrose, 3-deoxy-DL-glycero-tetrose, 3-deoxy-3,3-di-C-methyl-DL-glycero-tetrose, 3-C-methyl-DL-erythrose, 3-C-methyl-DL-threose, 2-deoxy-5-O-methyl-D-erythro-pentose and 3-deoxy-5-O-methyl-D-erythro-pentose have been prepared, in some cases with 13C-substitution at the anomeric carbon, and characterized by 1H-(300 and 620 MHz) and 13C-n.m.r. (75 MHz) spectroscopy. The proportions of cyclic (alpha and beta furanoses) and acyclic (aldehyde and hydrate) forms were determined in aqueous (2H2O) solution, and ring-opening (kopen) and ring-closing (kclose) rate constants were measured by 1H and 13C saturation-transfer n.m.r. spectroscopy at p2H 5.0 (acetate buffer) and 60 degrees. The degree of furanose ring substitution was found to significantly affect both the thermodynamics and kinetics of furanose anomerization. Increased substitution enhances the proportion of cyclic forms in solution by stimulating furanose kclose. In contrast, furanose kopen was less affected by the degree of substitution; however, kinetic studies of 2-deoxyfuranose anomerization implicate furanose ring conformation as a potential determinant of kopen.
Collapse
Affiliation(s)
- J R Snyder
- Department of Chemistry and Biochemistry, University of Notre Dame, IN 46556
| | | |
Collapse
|
37
|
Vuorinen T, Serianni AS. Synthesis of D-erythro-2-pentulose and D-threo-2-pentulose and analysis of the 13C- and 1H-n.m.r. spectra of the 1-13C- and 2-13C-substituted sugars. Carbohydr Res 1991; 209:13-31. [PMID: 1828004 DOI: 10.1016/0008-6215(91)80142-a] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The pentuloses D-erythro-2-pentulose (1) and D-threo-2-pentulose (2) and their 1-13C- and 2-13C-substituted derivatives were prepared by hydrogenating the corresponding isotopically normal and 13C-substituted D-pentos-2-uloses with a Pd-carbon catalyst. The threo isomer and its labeled derivatives were alternatively prepared from isotopically normal and 13C-substituted D-xyloses with immobilized D-xylose (D-glucose) isomerase (E.C.5.3.1.5). The equilibrium compositions of 1 and 2 (furanose anomers and acyclic keto forms) in 2H2O were determined from 13C-n.m.r. spectra (75 MHz) of the 2-13C-labeled derivatives. The conformational properties of the cyclic and acyclic forms in 2H2O were assessed with the use of 1H-1H, 13C-1H, and 13C-13C spin-coupling constants obtained from 1H-n.m.r. (620 MHz) and 13C-n.m.r. (75 MHz) spectra. Compared with the structurally related aldotetrofuranoses the 2-pentulofuranoses more strongly prefer conformations in which the anomeric hydroxyl group is oriented quasi-axially. The strongly dipolarized carbonyl group in the acyclic keto forms of 1 and 2 appears to stabilize chain conformations having O-1 and O-3 eclipsed with the carbonyl oxygen.
Collapse
Affiliation(s)
- T Vuorinen
- Laboratory of Wood Chemistry, Helsinki University of Technology, Finland
| | | |
Collapse
|
38
|
|
39
|
Vuorinen T, Serianni AS. 13C-substituted pentos-2-uloses: synthesis and analysis by 1H- and 13C-n.m.r. spectroscopy. Carbohydr Res 1990; 207:185-210. [PMID: 2076516 DOI: 10.1016/0008-6215(90)84048-y] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
D-erythro-Pentos-2-ulose and D-threo-pentos-2-ulose and their 1-13C- and 2-13C-substituted derivatives have been prepared by oxidizing the corresponding natural and 13C-substituted D-aldopentoses (D-arabinose, D-xylose) with cupric acetate, and purifying the products by chromatography on a cation-exchange resin in the calcium or barium form. The equilibrium compositions of the pentos-2-uloses in 2H2O were determined by 13C-n.m.r. spectroscopy (75 MHz) at 25 degrees and 80 degrees. Among the eighteen possible monomeric acyclic, cyclic, and bicyclic forms, the anomeric pairs of the unhydrated aldopyranoses, aldopyranose endocyclic hydrates, aldofuranose endocyclic hydrates, and ketofuranose exocyclic hydrates were identified on the basis of 13C chemical shifts and 13C-1H and 13C-13C spin-coupling constants. 1H-N.m.r. (300, 500, and 620 MHz) and 13C-n.m.r. (75 MHz) spectroscopic data in one and two dimensions (DQF-COSY, homonuclear 2D-J) were used to evaluate the conformational properties of the cyclic structures. The unhydrated pyranoses are highly conformationally homogeneous; the erythro and threo isomers prefer 1C4 and 4C1 conformations, respectively. D-threo-Pentos-2-ulopyranose hydrate prefers the 4C1 conformation whereas the erythro isomers exists in both the 4C1 and 1C4 conformations. The furanoid forms favor structures having quasi-axial anomeric hydroxyl groups and quasi-equatorial exocyclic hydroxymethyl or dihydroxymethyl groups.
Collapse
Affiliation(s)
- T Vuorinen
- Laboratory of Wood Chemistry, Helsinki University of Technology, Espoo, Finland
| | | |
Collapse
|
40
|
|
41
|
Snyder JR, Serianni AS. Furanose ring anomerization: a kinetic study of the 5-deoxypentoses and 5-O-methylpentoses. Carbohydr Res 1988; 184:13-25. [PMID: 3242808 DOI: 10.1016/0008-6215(88)80002-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
The anomerization of 5-deoxy-L-pentoses (1-4) and 5-O-methyl-D-pentoses (5-8) in aqueous solution has been studied by 13C saturation-transfer n.m.r. (s.t.-n.m.r.) spectroscopy, using compounds substituted with 13C at the anomeric carbon atom. Unidirectional rate-constants of ring-opening (k open) and ring-closing (k close) have been obtained for these compounds under identical solution conditions (50mM acetate buffer, pH 4.0 at 60 degrees), and have been compared to those measured for the D-tetroses (9 and 10) and the four D-pentose 5-phosphates (11-14). Based on these comparisons, several correlations between furanose structure and reactivity have been revealed, and models have been proposed to explain the observed kinetic behavior of compounds (1-10). The effect of exocyclic structure on acid-catalyzed rate-constants was also examined by comparing the behavior of 5-deoxy-L-(1-13C)-lyxose and 5-O-methyl-D-(1-13C)lyxose. Some consideration has been given to identifying the factors (enthalpic and entropic) that may play roles in determining the effect of structure on anomerization reactivity.
Collapse
Affiliation(s)
- J R Snyder
- Department of Chemistry, University of Notre Dame, IN 46556
| | | |
Collapse
|
42
|
King-Morris MJ, Bondo PB, Mrowca RA, Serianni AS. Stable, isotopically substituted carbohydrates: an improved synthesis of (6-13C)aldohexoses. Carbohydr Res 1988; 175:49-58. [PMID: 3378241 DOI: 10.1016/0008-6215(88)80155-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
1,2-O-Isopropylidene-alpha-D-xylo-pentodialdo-1,4-furanose (1) has been used as the parent aldose in the preparation of D-(6-13C)glucose and L-6-13C)idose via cyanohydrin reduction. The addition of K13CN (pH 6.8, 5 min) to 1 yields D-gluco and L-ido cyanohydrins that are readily reduced with H2 and Pd-BaSO4, to give 1,2-O-isopropylidene-alpha-D-gluco-hexodialdo-1,4-furanose (2; approximately 65%) and 1,2-O-isopropylidene-beta-L-ido-hexodialdo-1,4-furanose (3; 35%). Aldehydes 2 and 3 are reduced in situ with NaBH4, the resulting alcohols are deprotected with aqueous acid, and the aldoses are chromatographed on Dowex 50 X-8 (Ca2+) ion-exchange resin (200-400 mesh), to yield D-(6-13C)glucose (6) and L-(6-13C)idose (7). Molybdate epimerization of 6 and 7 yields D-(6-13C)mannose and L-(6-13C)gulose, respectively. A similar reaction scheme may be applied to methyl 2,3-O-isopropylidene-beta-D-ribo-pentodialdo-1,4-furanoside to generate the remaining four (6-13C)aldohexoses. This route is considerably simpler than the traditional Kiliani-Fischer route, and higher yields are obtained.
Collapse
|
43
|
Snyder JR, Serianni AS. DL-apiose substituted with stable isotopes: synthesis, n.m.r.-spectral analysis, and furanose anomerization. Carbohydr Res 1987; 166:85-99. [PMID: 3308088 DOI: 10.1016/0008-6215(87)80046-0] [Citation(s) in RCA: 54] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The branched-chain pentose DL-apiose has been synthesized in good yield by a new and simple chemical method that can be adapted to prepare (1-13C)-, (2-13C)-, (1-2H)- and/or (2-2H)-enriched derivatives. N.m.r. spectra (1H- and 13C-) have been interpreted with the aid of selective (13C)- and (2H)-enrichment, and 2D and 13C[13C]-n.m.r. spectra. The solution composition of DL-(1-13C)apiose in 2H2O, determined by 13C-n.m.r. spectroscopy, has been found to differ from that determined previously by 1H-n.m.r. spectroscopy. Several 13C-1H and 13C-13C couplings have been measured and interpreted in terms of apiofuranose ring conformation. Ring-opening rate-constants of the four apiofuranoses [3-C-(hydroxymethyl)-alpha- and -beta-D-erythrofuranose, and 3-C-(hydroxymethyl)-alpha- and -beta-L-threofuranose] have been determined by 13C-saturation-transfer n.m.r. spectroscopy, and compared to those obtained previously for the structurally related tetrofuranoses.
Collapse
Affiliation(s)
- J R Snyder
- Department of Chemistry, University of Notre Dame, Indiana 46556
| | | |
Collapse
|