Synthetic variations of the progesterone antagonist RU 38 486

Total assignment of 1H and 13C NMR spectra of 13α‐ and 13β‐estrone methyl ethers

“…Steroids with an unnatural configuration at C-13 (13˛-steroids) have potentially interesting applications regarding biological activity 1 or, as shown more recently in a paper relating on hydroxylation with the fungus Cephalosporium aphidicola, 2 can be utilized for unusual biotransformations. Moreover, as shown in a recent paper, 3 3-methoxy-13˛-estra-1,3,5(10)trien-17-one (1) is useful as a starting material for the synthesis of various 13˛-steroids with an atypical C-ring twist-boat and flexible D-ring conformations, useful for biochemical investigations.…”

Unnaturally configured 13‐epi steroids: full 1H and 13C assignments and ring C–D conformations from 1H, 1H vicinal couplings

“…Non-chair conformations of ring C have been noted before in 11-aryl, 17-alkyl, 13-epi steroids. 13,44 It is clear from Table 3 that the ring D vicinal couplings of 6 do not fit the pattern of any of the preceding 13-epi steroids (1)(2)(3)(4)(5). Inspection of Dreiding models leads to the conclusion that ring D of 6 is in a 16ˇenvelope conformation as shown in …”

“…Compound 6 is a modification to the structure of onapristone (ZK 98,299), 44,45 which is itself derived from RU 38,486. 46 Such compounds have antiprogestational and antiglucocorticoid activities and are of considerable interest as human fertility-modulating drugs.…”

Steroids: reactions and partial syntheses

“…Tracer experiments have shown that the oxygen atom in these products derives from the hydroxyl group of the starting material, rather than from mercuric oxide.89 Compound (1 13) and its 1 1 a-epimer are both converted into the 13a-isomers [as (1 14)] by irradiation with ultraviolet light; the ease of the reactions and the high yields are worthy of note. 90 The nitronate that can be derived from a 17P-nitrocompound and sodium ethoxide is converted (by irradiation with ultraviolet light) into a mixture of the hydroxamic acid (1 15) (as the major product), the 13a-and 13p-17-ketones (1 16), and the 17p, 18-cyclo-compound (1 17) ; 30-acetoxy-17P-nitro-13a-androstane yields the 17-ketone as the major product, as well as the 13a-isomer of the hydroxamic acid, but no cyclocompound can be detected. Irradiation of the oxaziridine (1 18) gives the lactam (119) as the predominant product.91…”