Synthesis and cytotoxicity of leinamycin antibiotic analogues.

A simple synthesis of 1,2-dithiolan-3-ones from alpha,beta-unsaturated thiophenyl esters is reported. Introduction of the biologically active 1,2-dithiolan-3-one-1-oxide moiety of leinamycin into aldehydo-d-arabinose 11, the uridine derivative 16, and the deoxythymidine 21 was established. An extended bioactive part of leinamycin carrying a carbon-carbon triple bond was also synthesized.

A new class of semisynthetic anthracycline glycoside antibiotics incorporating a squaric acid moiety.

Treatment of the squaric acid amide esters (7, 9) of anthracycline glycoside antibiotics with aliphatic and aromatic primary and secondary amines, amino acids, peptides and aminodeoxy sugars furnished the new asymmetric diamides 16-19, 25-30, 32, 34 and 38-40 in stereoselective reactions which do not require protecting group-manipulations. The IC50 = 0.12 microM value measured for daunorubicin (1) on human leukemia (HL-60) cells is comparable to those obtained for the daunomycin-L-leucyl squaric acid diamide (30, IC50 = 0.

Synthesis of a novel N[bond]O-interglycosidic disaccharide.

The carbohydrate subunits carrying an N-O-interglycosidic bond play a very important role in the biological activity of the enediyne antibiotics. Condensation of O-(alpha- and beta-D-glucopyranosyl)hydroxylamine (5a and 5b) with the hex-3-ulopyranoside (6) furnished methyl 4,6-O-benzylidene-2,3-dideoxy-3-(2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyloxy)imino-alpha- and beta-D-erythro-hexopyranoside (7a and 7b). Stereoselective reduction of the Cz.