A Versatile Synthesis of DihydropyrimidinoneC‐Nucleosides
摘要:
A versatile synthesis of N-substituted dihydropyrimidinone C-nucleosides (20-29) is described. Glycosyl amino esters (3-9), obtained by reductive alkylation of glycosyl amino esters 1 and 2, on condensation with different isocyanates afforded respective ureido derivatives (10-19) in good to quantitative yields. The latter on cyclative amidation with a combination of DBU/TBAB (tetrabutylammonium bromide)/4Angstrom molecular sieve gave the corresponding nucleosides (20-29) in good yields.
Asymmetric organocatalysis with glycosyl-β-amino acids: direct asymmetric aldol reaction of acetone with aldehydes
作者:Namrata Dwivedi、Surendra S. Bisht、Rama P. Tripathi
DOI:10.1016/j.carres.2006.08.007
日期:2006.11
Directasymmetricaldolreaction of acetone with aromatic aldehydes was achieved in good yields and high enantioselectivity using 5-amino-5-deoxy-beta-L-ido-(alpha-D-gluco)-heptofuranuronic acids as a new class of organocatalysts.
A series of glycosylated P-amino acids was prepared and evaluated against Mycohacterium tuberculosis, M. avium, M. fortuitum and M. smegmatis. The compounds were designed to mimic the enzyme D-alanine racemase and glycosyl transferase involved in the biosynthesis of essential cell wall peptidoglycan and arabinogalactan. Though most of the compounds exhibited little activity, however, one showed significant activity against all the strains in cell culture and activity was confirmed by BACTEC method. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.