Steroids. CCXXI.¹ Syntheses of Some Steroid Dienes

Abstract

Fraction 4 on treatment with 2,4-DNP reagent yielded an orange-red DNP (recrystallized from absolute ethanol), m.p.

Synthesis of 6β-(2,6-Dichlorobenzoyloxy)-2,4-cholestadiene and Related Compounds1a

“…Also, the strong absorption at 15.0-15.1 µ, which is present in all 2-cholestene derivatives in this series, is replaced in 1 by a strong absorption at 14.35 µ and a weaker one at 13.70 µ. We have also observed these latter absorptions in 2,4-cholestadien-6-one.4 Absorption in the ranges 14.2-14.6 and 13.7-13.9 µ has been observed in the 2,4-dienes reported by Berkoz, et al 8 The n.m.r. spectrum shows, in addition to the usual cholestane nucleus absorptions and a 3-proton resonance at 434 c.p.s.…”

“…Treatment of the epoxide 6 with 2,6-dichlorobenzoic acid in refluxing benzene smoothly opened the ring to give a good yield of the desired 6/3-(2,6-dichlorobenzoyl-oxy)-2-cholesten-5a-ol (8). While such ring-opening reactions commonly afford frans-diol esters with formic acid and acetic acid,12 they do not appear to have been exploited for the preparation of esters of other acids.13 Although attack of the sterically hindered 6/3-OH (or its sodium salt) of diol 3 on the sterically hindered carbonyl carbon of 2,6-dichlorobenzoyl chloride does not occur even under vigorous conditions, the epoxide ring-opening reaction does not involve any sp^sp3 transformation of the carbonyl carbon of the acyl moiety and is thus less subject to steric retardation.…”

The reaction of steroid 2,4-dienes with acetylenes

“…Its pmr spectrum confirmed the absence of a phthalonitrile moiety, and showed in the 6 4-7 region only a 2-proton multiplet at 6 6.05-6.65, assigned to the vinyl protons of 21 (cf. 22 (1 1): 6 6.06 and 6.44 (AB system, J = 7 Hz, 2H)); this spectrum also contraindicated structures 23 and 24, which would be expected to show signals corresponding to four vinyl protons in the 6 5-6 region. A I-proton multiplet at 6 3.85 is assigned to the bridgehead proton in 21, and the two 3-proton singlets at 6 0.88 and 1.00 are assigned to the C. 19 and C. 18 methyl groups, respectively, the former being shielded relative to the C. 19 methyl group in 12 (6 0.95) by a bridging ethylenic double bond.…”

Photooxygenation of 1,3-Cholestadiene and Related Compounds

“…Huffman been prepared by Corey in five steps from santonin and used in the synthesis of dihydrocostunolide. 4 In this synthesis of 4 the mixture of epimeric precursor alcohols (11) was dehydrated directly; however, in this work compound 4 was prepared from the mixture of epimeric allylic chlorides in the same manner used for the preparation of triene 1. Photooxygenation of 4, followed by treatment with basic alumina, gave no trace of tauremisin (5), but afforded instead mixtures of santonin (13) and hyposantonin (14).…”