- Improved Synthesis of 6-Deoxy-1,2-O-isopropylidene-β-L-talofuranose and 6-Deoxy-1,2-O-isopropylidene-β-L-idofuranose
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The key step in the preparation of 6-deoxy-1,2-O-isopropylidene-β-L-talofuranose (7) and 6-deoxy-1,2-O-isopropylidene-β-L-idofuranose (13) is the selective exchange of the 6-O-mesyl rest of 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene-α-D-allofuranose (4) and 3-O-acetyl-5,6-O-dimesyl-1,2-O-isopropylidene-α-D-glucofuranose (10) by acetate group (potassium actate/18-crown-6).
- Hiebl, Johann,Zbiral, Erich
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- Synthesis of 6-deoxy-L-idose and L-acovenose from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose
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A practical route toward the synthesis of 6-deoxy-L-idose and L-acovenose from 1,2:5,6-di-O-isopropylidene-α-D-glucofuranose is described. Key steps include the stereoselective hydrogenation of 6-deoxy-1,2:3,5-di-O-isopropylidene-α-D-xylo-hex-5-enofuranose, regioselective protection of 6-deoxy-1,2-O-isopropylidene-β-L-idofuranose at O-5, and epimerisation of 6-deoxy-5-O-tert-butyldimethylsilyl-1,2-O-isopropylidene-β-L-idofuranose at C-3.
- Hung, Shang-Cheng,Thopate, Shankar R.,Puranik, Ramachandra
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- Biologically potent L-hexoses and 6-deoxy-L-hexoses: Their syntheses and applications
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This account describes our recent work in the development of new methodologies to prepare rare and biologically potent L-hexoses and 6-deoxy-L-hexoses, from cheapest D-glucose, via L-hexofuranoses and 1,6-anhydro-β-L-hexopyranoses as key building blocks. Their applications in the syntheses of heparin oligosaccharides, the carbohydrate moiety of bleomycin A2, and L-acovenose are also summarized here.
- Kulkarni, Suvarn S.,Chi, Fa-Chen,Hung, Shang-Cheng
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p. 1193 - 1200
(2007/10/03)
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- Conformational analysis of cyclic phosphates derived from 5-C′ substituted 1,2-O-isopropylidene-α-D-xylofuranose derivatives
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Twelve 2-phenoxy-2-oxo-1,3,2-dioxaphosphorinanes fused with a 1,2-O-isopropylidene-α-D-xylofuranose moiety in cis orientation and substituted at the C′5 position were prepared in two steps from commercially available diacetone-α-D-glucose. Their conformations, and configurations were determined by 1H and 31P NMR and X-ray crystallographic techniques. Both, chair-twisted-chair and chair-boat equilibria were observed in solution. We observed that the strong anisotropic shielding effect of the benzene ring in the phenoxy group generates an upfield shift of the H1 hydrogen atom, when the cyclic phosphates adopt a boat conformation. This is due to a relative cis-orientation of the P-phenoxy group and the H1 proton of the 1,2-O-isopropylidene-α-D-xylofuranose moiety. Therefore, the configuration of the phosphorus center (SP or RP) can be determined by 1H NMR spectroscopy. Interestingly, the crystal structure of one of the cyclic phosphates exhibits two independent molecules in the asymmetric unit, one with a chair and the other one with a boat conformation.
- Sartillo-Piscil, Fernando,Cruz, Silvano,Sánchez, Mario,H?pfl, Herbert,De Parrodi, Cecilia Anaya,Quintero, Leticia
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p. 4077 - 4083
(2007/10/03)
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- Chemical modification of azasugars, inhibitors of N-glycoprotein-processing glycosidases and of HIV-I infection. Review and structure-activity relationships
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The synthesis of a series of analogues of the α-glucosidase inhibitor 1-deoxynojirimycin (dNM, 1) and of the α-mannosidase inhibitor 1-deoxymannojirimycin (dMM, 3) is described.The ability of dNM, dMM and a series of N-alkylated dNM and dMM derivatives to
- Broek, L. A. G. M. van den,Vermaas, D. J.,Heskamp, B. M.,Boeckel, C. A. A. van,Tan, M. C. A. A.,et al.
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