ChemInform Abstract: DERIVATE VON A‐NOR‐5ALPHA‐METHYL‐STEROIDEN

Abstract

Bei Behandlung des Cyclosteroids (I) mit HCl‐Eisessig entstehen A‐Nor‐pregnenon (II) und sein am C‐17 Epirneres.

A study of the Stork reductive cyclization of steroidal acetylenic ketones in aprotic media with the naphthalene anion radicals

“…This is borne out by deuteration studies. The deuterated 5e in which the hydrogen attached to the sp carbon has been replaced by deuterium gives the undeuterated alcohol 11. By the same token product 12 derived from this compound should have been 100% monodeuterated.…”

“…6a,6|S-DimethyI-4,5-secocholest-3-yn-5e-ol (11). To a solution of 410 mg (1 mmol) of acetylenic ketone 5a in 8 ml of methanol was added 185 mg (5 mmol) of NaBH4 in one portion.…”

“…Further elution gave 350 mg of the crystalline 6«,6/3-dimethyl-4.5-secocholest-3-yn-5e-ol (11). This had mp 76-77 °C when crystallized from methanol: [a]D +4°(c 0.13); ir (CCI4) 3580 (OH), 3310 (==CH), 2120 cm-1 (C=C); NMR (CC14) 0.70 (3 H, s, C-18 methyl), 0.93 (9 H, s, C-19 and C-6 methyls), 3.08 (1 H, s, C-5 H).…”

“…Reduction with L1AIH4 in ether gave the same compound. Acetylation of 11 with acetic anhydride in refluxing pyridine gave the corresponding acetate in quantitative yield. It had mp 68 °C; [a]D -20°(c 0.12); ir (CCI4) 3400 NCR), 2150 (C=C), 1770 cm"1 (0=0); NMR (CCI4) S 0.73 (3 H, s, C-18 methyl), 0.96 (9 H, s, C-19 and C-6 methyls), 2.10 (3 H, s, -OCOCH3), 4.5 (1 H, s, C-5 H).…”

“…Caled for C31H52O2: C, 82.50; H, 11.40. Found: C, 82.27; H, 11.21. Oxidation of 412 mg of 11 with CrOs and pyridine in CH2CI2 overnight at room temperature gave 350 mg of 5a.…”