Reaction of γ-nitro ketones with thionyl chloride: formation and X-ray crystal structure of an α-sulfinyl ketone

Abstract

Reaction of thionyl chloride on 4-methyl-4-nitro-1-phenylpentan-1-one (2) yields 4-methyl-4-nitro- 1-phenyl-2-thioxopentan-1-one S-oxide (4), the structure of which has been clarified by X-ray crystallography. The corresponding methoxyphenyl compound (10) has been obtained similarly. The sulfinyl ketone (4) underwent base hydrolysis to the methylene ketone (2) and photoconversion into the diketone (12), which was independently prepared by nitrous acid treatment of the hydroxyimino ketone (11).

The unusual formation of the sulfinyl ketones (4) and (10) appears selective for the reaction with unhindered γ-nitro ketones and arises on account of a neighbouring group effect from the nitro substituent.