Synthesis and cytotoxic activity of some 17-picolyl and 17-picolinylidene androstane derivatives

New 17-picolyl and 17-picolinylidene androstane derivatives, 3-10, 15, 18, 19, 22 and 23, were synthesized starting from 17 alpha-picolyl-androst-5-en-3 beta,17 beta-diol (1) and 17(Z)-picolinylidene-androst-5-en-beta 3-ol (2). Reaction of 1 with m-chloroperoxybenzoic acid gives 5 alpha,6 alpha-epoxy N-oxide derivative 3, or, with Jones reagent, 3,6-dione derivative 4; while 17 alpha-picolyl-androst-5-en-3 beta,4 alpha,17 beta-triol (5) or 3 beta,4 beta,17 beta-triol (6) derivatives are obtainable from 1 using SeO2 in dioxane. Base-catalyzed tosyl group elimination from 7 or 9 affords AB conjugated derivatives 8 and 10. Oppenauer oxidation of 1 and 2 yields 4-en-3-one derivatives 11 and 12, which, with H2O2 in 4 M NaOH, affords 4 alpha,5 alpha and 4 beta,5 beta-epoxides 14, 16 and 17. New 4-methoxy-3-keto derivatives 15 and 18 were obtained from 13 and 14, or, with methanol in 4 M NaOH, from 16 and 17. Reduction of 11 with NaBH4 gives 22, which was then acetylated to obtain 23. All new derivatives were screened for antitumor activity against human breast adenocarcinoma ER+, MCF-7; human breast adenocarcinoma ER-, MDA-MB-231; prostate cancer AR-, PC-3; human cervix carcinoma, HeLa; and colon cancer, HT-29 cells; as well as one human non-tumor cell line, MRC-5. Compounds 3, 5, 6, 8, 10, 18,19 and 22 exhibited significant antitumor activity against MDA-MB-231 breast cancer cells; while 5, 6 and 10 also showed strong cytotoxicity against HT-29. Only compound 19 exhibited significant activity against MCF-7 breast cancer cells. No compounds displayed cytotoxicity against non-tumor MRC-5 cells. (C) 2012 Elsevier Masson SAS. All rights reserved.