Dehydropregnenolone acetate

Dehydrocortisone, 87 8-Dehydroestradiol, 4 9(ll)-dehydroestradioI 3-methyl ether, 2 8(14)-DehydroestradioI 3-methyl ether, 3 Dehydrofluorination, 452 Dehydrofluorination of gem-difluorides, 446 Dehydrogenation, 306 Dehydrohalogenation of a-Halo ketones, 287 16-Dehydropregnenolone, 40 16-Dehydropregnenolone acetate, 48 16-Dehydropregnenolone tetrahydropyranyl ether, 40... 

Although a natural corticosteroid, cortexolone may be obtained in large amounts by chemical transformation from 16-dehydropregnenolone acetate, an intermediate in the Marker degradation of diosgenin (Figure 5.119). 

An efficient preparation of 1,5-diketones as precursors to D-ring annulated heterosteroids was elaborated by R.C. Boruah et al. [96] (Scheme 24). Readily available 16-dehydropregnenolone acetate (16-DPA) was used in a Michael reaction with enamines. 

The reaction of 16-dehydropregnenolone acetate (16-DPA) (149) with P4S10 afforded a novel adduct I6-DPA-P2S5 (150). The adduct undergoes... 

The addition of photochemically generated ethoxycarbonylnitrene to 16-dehydropregnenolone acetate to give three aziridines has been described.81 The corresponding addition of ethyl azidoformate to norbornene to give the aziridine (140) as the major product has been reported.82 The possible intervention of the triazoline (141) as an intermediate in the photoreaction has been excluded photoelimination of nitrogen from the triazoline (141) gave not only the aziridine (140) but also the imine (142) in a yield of 25%. 

A.V. Kamernitskii, T.N. Galakhova, l.S. Levina, B.S. El yanov, Cydoaddition of diazoacetic ester to 16-dehydropregnenolone acetate imder high pressure, BuU. Acad. Sd. USSR, Seriya Khim. 26 (1977) 2374—2375. 

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