EVALUATION OF C-(BETA-D-GALACTOSYL) AND C-(2-DEOXY-D-LYXO-HEX-1-ENOPYRANOSYL) (D-GALACTAL TYPE) DERIVATIVES AS INHIBITORS OF BETA-D-GALACTOSIDASE FROM ESCHERICHIA COLI

摘要

C-(2-Deoxy-D-lyxo-hex-1-enopyranosyl)formamide was prepared from acetylated C-(beta-D-galactopyranosyl)formamide by a radical-mediated bromination-zinc/N-methylimidazole-induced reductive elimination-Zemplen deacetylation reaction sequence. The preparation of acetylated 5-(2-deoxy-D-lyxo-hex-1-enopyranosyl)tetrazole was improved. Methyl C-(2-deoxy-D-lyxo-hex-1-enopyranosyl)formimidate was transformed by benzylamine into N-benzyl-C-(2-deoxy-D-lyxo-hex-1-enopyranosyl)formamidine and, after hydrolysis to methyl C-(2-deoxy-D-lyxo-hex-1-enopyranosyl)formate, into N-benzyl-C-(2-deoxy-D-lyxo-hex-1-enopyranosyl)formamide. A series of C-(beta-D-galactopyranosyl) and C-(2-deoxy-D-lyxo-hex-1-enopyranosyl) derivatives was comparatively investigated for E. coli beta-D-galactosidase inhibitory activity. N-Benzyl-C-(2-deoxy-D-lyxo-hex-1-enopyranosyl)formamidine was the best inhibitor and had K-i = 6 mu M (on the basis of its free base concentration, K-i = 8.3 nM was obtained). Basicity and hydrophobicity of the aglycon proved to be more important factors for the inhibition than the conformation of the sugar ring. (C) 1996 Elsevier Science Ltd. [References: 34]