Synthesis and biological evaluation of some new A,B-ring modified steroidal D-lactones.

Starting from the D-homo lactones of androst-4-en-3-one 3 and 4, prepared from 1 and 2, the new 17a homolactones 5-12, 14 and 15, were synthesized. The 4-hydroxy compounds 9 and 10 were obtained through the reaction of 4alpha,5alpha- (5 and 7) and 4beta,5beta- (6 and 8) epoxides with formic acid. The epoxides 5 and 6 were prepared from compound 3, and epoxides 7 and 8 from compound 4 by oxidation with H(2)O(2) under basic conditions. Compound 1 served as a starting substance for obtaining lactones 11-13. Oxidation of compound 1 with m-chloroperbenzoic acid yielded 11 and 12, but compound 13 gave 14. Compound 15 was obtained from 13 by oxidation with H(2)O(2) under basic conditions. The structures of epoxides 6 and 14 were confirmed by X-ray structural analysis. Cytotoxic activity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) was evaluated. Compounds 6 and 14 showed strong activity against PC3, the IC(50) being 10.6 and 2.2 microM, respectively, whereas compounds 3 and 8 showed strong activity against MDA-MB-231 (IC(50) is 9.3 and 3.6 microM, respectively). Aromatase inhibition assay showed that the tested compounds 9, 10, and 14 possess lower activity compared to formestane.

Synthesis and biological evaluation of a series of A,B-ring modified 16,17-secoandrostane derivatives.

The starting compound for the synthesis of 16,17-secoandrostane derivatives with the 4-en-3-on, 1,4-dien-3-on, 4,6-dien-3-on, and 1,4,6-trien-3-on systems was 3beta-hydroxy-17-methyl-16,17-secoandrost-5-en-16-nitrile-17-one (1), the Oppenauer oxidation of which yielded the corresponding 4-en-3-one derivative 2. Dehydrogenation of compound 2 with the aid of 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil) gave the three products: 17-methyl-16,17-secoandrosta-1,4-dien-3,17-dione-16-nitrile (3), 17-methyl-16,17-secoandrosta-4,6-dien-3,17-dione-16-nitrile (4), and 17-methyl-16,17-secoandrosta-1,4,6-trien-3,17-dione-16-nitrile (5). On the other hand, epoxidation of compound 2 resulted in a mixture of alpha and beta isomers of 4,5-epoxy-17-methyl-16,17-secoandrosta-3,17-dione-16-nitrile (6 and 7). Opening of the oxirane rings of the mixture of 6 and 7 by the action of formic acid yielded the 4-hydroxy-4-en derivative 8. Antiaromatase activity and in vitro cytotoxicity against three tumor cell lines (human breast adenocarcinoma ER+, MCF-7, human breast adenocarcinoma ER-, MDA-MB-231, and prostate cancer PC3) of selected compounds were evaluated. Compound 2 exhibited a relatively strong inhibition of aromatase and extremely potent cytotoxicity against PC3 cells. Compound 8 showed satisfactory cytotoxicity against MCF-7 cells.