Solvolysis of 5a,6a-epoxy-6-methyl steroids

In the course of synthetic efforts aimed at obtaining 6j5-fluoro steroids, Kirk and Petrow treated a 3)5-acetoxy-6-raethyl-5a,6a-epoxide with boron trifluoride etherate and unexpectedly obtained a fluorine-free acetoxy ketone. Later transformations established that the product was the A-homo-B-norsteroid (104). [Pg.389]

the model compound 5a, 6a-epoxy-6j -methyltigogenin acetate (103) affords 3)5-hydroxy-6)5-methyl-10(5 6)crZ)eo-(25S)-spirostan-5-one acetate (104) in 90 % yield. As expected, the j9-acetoxy ketone (104) loses the elements of acetic acid on passing through a column of alumina to give 6)5-methyl-10(5 - 6)-flZ eo-(25S)-spirost-3-en-5-one (105). [Pg.389]

The P configuration at C-6 is based on mechanistic considerations and analysis of optical rotatory dispersion curves. [Pg.389]

High yields of A-homo-B-norsteroids are also obtained on rearrangement of the 5a,6a-epoxides from 3)3-hydroxy-6-methylandrost-5-en-17-one and Sp, 17)5-diacetoxy-6-methylandrost-5-ene. [Pg.389]

Similar observations led Bernstein and co-workers to assign structure (108a) to the rearrangement product of 5a,6a-oxido-3)5,17a-dihydroxy-6j5-methylpregnan-20-one 17-acetate (106) with anhydrous hydrogen fluoride or [Pg.389]

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