Steroid-5-enes nitrosyl chloride

It is interesting to note that nitrosyl chloride addition to steroid-5-enes resulted in 5-a-chloro-6-j8-nitrosteroids exclusively [73]. 

Halo Nitro Compounds Reaction of Steroid-5-enes with Nitrosyl Chloride... 

Slow tram addition of nitrosyl chloride to steroid-5-enes was observed123- 1 26 however, the initially formed chloro nitroso adducts were oxidized by nitrosyl chloride to the 5a-chloro-6/ -nitro derivatives 1 dimerization does not occur for steric reasons. The diaxial configuration of adducts was deduced by the ready elimination of the chloro and nitro groups by zinc dust123, and from the H-NMR spectrum125,126. The stereochemistry can be explained by the occurrence of both ionic and free-radical mechanisms124. 

Nitrosyl chloride reacts with the double bond of methyl 3a,7a-diacetoxy-5)5-chol-ll-enoate yielding the ds-lla-chloro-12a-nitro-derivative (583). This compound was unaffected by hot collidine but was transformed, in low yield, into the 9(ll)-en-12-one on treatment with methanolic potassium hydroxide, whilst zinc-acetic acid regenerated the 11-ene in high yield. 5-Enes reacted with nitrosyl chloride to produce the expected trans-5a-chloro-6)5-nitro-steroids. 

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See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ , ]

See also in sourсe #XX -- [ ]

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