UNUSUAL SUGARS OF THE GPL-TYPE ANTIGEN OF MYCOBACTERIUM-AVIUM SEROVAR-19 - STEREOSELECTIVE SYNTHESIS OF METHYL 3-C-METHYL-2,4-DI-O-METHYL-ALPHA-L-MANNOPYRANOSIDE AND ITS C-4 EPIMER

Authors
GYERGYOI K TOTH A BAJZA I LIPTAK A
Citation
K. Gyergyoi et al., UNUSUAL SUGARS OF THE GPL-TYPE ANTIGEN OF MYCOBACTERIUM-AVIUM SEROVAR-19 - STEREOSELECTIVE SYNTHESIS OF METHYL 3-C-METHYL-2,4-DI-O-METHYL-ALPHA-L-MANNOPYRANOSIDE AND ITS C-4 EPIMER, Synlett, (2), 1998, pp. 127
Citations number
7
Categorie Soggetti
Chemistry Inorganic & Nuclear
Journal title
Synlett → ACNP
ISSN journal
09365214
Issue
2
Year of publication
1998
Database
ISI
SICI code
0936-5214(1998):2<127:USOTGA>2.0.ZU;2-F
Abstract
Completely reversed stereoselectivity of reduction of methyl -isopropy lidene-3-C-methyl-alpha-L-mannopyranoside (2) and its deisopropylidena ted derivative (7) was observed. Compound 2 gave exclusively the L-tal o-isomer (3) with NaBH4 in MeOH, but the reduction of 7 with NaBH4 in acetic acid resulted in the L-mannoderivative 8. It is assumed that in the first case the stereoselectivity is determined by the steric acce ssibility of the carbonyl group, while in the second case free OH-grou ps direct the selectivity of the reduction by complexation or ligand e xchange.