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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

C-glycoside syntheses: Part I. Dendritic syntheses of hexose and aminohexose C-pyranosides from 2,6-anhydro-5,7-O-benzylidene-1-deoxy-1-nitro-D-guloheptitol (82). Part II. Henry condensation of nitroethane and nitropropane with 4,6-O-benzylidene-D-glucopyranose (81)

Wang, Xiaojing 01 January 1993 (has links)
The di-O-acetyl derivative of 4,6-O-benzylidene-1-deoxy-1-nitromethyl-β-D-glucopyranose was reduced by a mixture of elemental iron and nickel in aqueous tetrahydrofuran under CO2, with concurrent O → N acetyl migration to 1-acetamido-4-O-acetyl-2,6-anhydro-5,7-O-benzylidene-1-deoxy-D-glycero-D-guloheptitol. Its 2-O-mesyl derivative was converted by base into the D-manno-2,3-epoxide. The epoxide ring was opened by NH3 to give the 3-amino-β-D-altropyranose derivative, which was subsequently N-benzoylated to 1-acetamido-2,6-anhydro-4-benzoylamino-5,7-O-benzylidene-1,4-dideoxy-D-glycero-D-glucoheptitol. Attempts to prepare 1-acetamido-2,6-anhydro-4-benzoylamino-5,7-O-benzylidene-1,4-dideoxy-3-methanesulfonyl-Dglycero-D-glucoheptitol gave spontaneously the D-allo-oxazoline derivative. However, a 3-O-mesyl derivative could be obtained by mesylation of 1,4-di-acetamido-2,6-anhydro-5,7-0-benzylidene-I,4-dideoxy-D-glycero-D-glucoheptitol. 2,6-Anhydro-5,7-O-benzylidene-1-deoxy-1-nitro-D-glycero-D-guloheptitol was reduced and N-acetylated to the acetamidomethyl derivative. 3,4-Di-O-mesylation of 1-acetamido-2,6-anhydro-5,7-O-benzylidene-1-deoxy-D-glycero-D-guloheptitol gave 1-acetamido-2,6-anhydro-5,7-O-benzylidene-1-deoxy-3,4-dimethanesulfonyl-D-glycero-D-guloheptitol, which reacted with methoxide to give the D-manno-2,3-epoxide, and mostly 2,6-anhydro-5,7-O-benzylidene-1-deoxy-D-glycero-D-gluco-heptitol [1,2,3, : 4',5',6']- 2'-methyl-2'-oxazine, presumably via a D-allo-2,3-epoxide. The condensation of 4,6-O-benzylidene-D-glucopyranose with nitroethane gave 2,6-anhydro-1,3-O-benzylidene-7,8-dideoxy-7-nitro-D-threo-L-gulooctitol and its diastereomer, which was obtained by an acetylation-deacetylation procedure. 2,6-Anhydro-1,3-O-benzylidene-7,8-dideoxy-7-nitro-L-erythro-L-gulooctitol was reduced by a mixture of elemental Fe°/Ni° in aqueous FHF under CO2 to 7-amino-2,6-anhydro-1,3-O-benzylidene-7,8-dideoxy-L-erythro-L-gulooctitol with retention of the 4,6-O-benzylidene blocking group. Acetylation of 2,6-anhydro-1,3-O-benzylidene-7,8-dideoxy-7-nitro-D-threo-L-gulooctitol produced an open chain compound. Cyclic product was not isolated. The oxime derivative, 4,5-di-O-acetyl-3,7-anhydro-6,8-O-benzylidene-1,2-dideoxy-2-oxime-D-glycero-D-guloheptitol, was separated as a byproduct from the acetylation. The condensation of nitropropane with 4,6-O-benzylidene-B-D-glucopyranose, followed by acetylation of the reaction solution, gave 4,5-di-O-acetyl-2,6-anhydro-1,3-O-benzylidene-7-nitro-7,8,9-trideoxy-D-threo-L-gulononitol and its diastereomer. Deacetylation of 4,5-di-O-acetyl-2,6-anhydro-1,3-O-benzylidene-7-nitro-7,8,9-trideoxy-D-threo-L-gulononitol gave 2,6-anhydro-1,3-O-benzylidene-7-nitro-7,8,9-trideoxy-D-threo-L-gulononitol, which could be reduced to the free amino compound by a mixture of elemental Fe°/Ni° in aqueous THF under CO2.

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