Modular Approach to Triazole-Linked 1,6-α-d-Oligomannosides to the Discovery of Inhibitors of Mycobacterium tuberculosis Cell Wall Synthetase
摘要:
Aiming at developing inhibitors of mannosyltransferases, the enzymes that participate in the biosynthesis of the cell envelope of Mycobacterium tuberculosis, the synthesis of a range of designed triazole-linked 1,6-oligomannosides up to a hexadecamer has been accomplished by a modular approach centered on the Cu(I)-catalyzed azide-alkyne cycloaddition as key process. The efficiency and fidelity of the cycloaddition are substantiated by high yields (76-96%) and exclusive formation of the expected 1,4-disubstituted triazole ring in all oligomer assembling reactions. Key features of oligomers thus prepared are the anomeric carbon-carbon bond of all mannoside residues and the 6-deoxymannoside capping residue. Suitable bioassays with dimer, tetramer, hexamer, octamer, decamer, and hexadecamer showed variable inhibitor activity against mycobacterial alpha-(1,6)-mannosyltransferases, the highest activity (IC50 = 0.14-0.22 mM) being registered with the hexamannoside and octamannoside.
Studies on the opening of dioxanone and acetal templates and application to the synthesis of 1.alpha.,25-dihydroxyvitamin D2
作者:Juan R. Granja、Luis Castedo、Antonio Mourino
DOI:10.1021/jo00053a024
日期:1993.1
The Lewis-acid-mediated nucleophilic substitution of dioxanone and acetal templates for the construction of 25-hydroxylated side chains of vitamin D2 metabolites and analogs has been studied. As an application a highly stereoselective synthesis of 1alpha,25-dihydroxyvitamin D2 by the dienyne route is described.
Yamamoto, Yoshinori; Abe, Hidenori; Nishii, Shinji, Journal of the Chemical Society. Perkin transactions I, 1991, # 12, p. 3253 - 3257