Action of nitrogen trichloride on certain proteins II. Synthesis of methionine sulphoximine and other sulphoximines

Abstract

Abstract Methionine sulphoximine (I, R ═ CH2CH2CH(NH2)COOH, R' ═ CH3) can be synthesized by the action of hydrazoic acid on methionine sulphoxide in the presence of concentrated sul-phuric acid as a catalyst and is shown to be identical with the toxic factor isolated from nitrogen trichloride-treated proteins. S-methylcysteine sulphoximine (I, R ═ -CH2CH(NH2)COOH, R' ═ CH3) and dimethyl. sulphoximine (I, R, R' ═ CH3) are prepared by a similar method from the corresponding sulphoxides; in rabbits, S-methylcysteine sulphoximine does not produce the toxic symp­toms obtained with methionine sulphoximine. Possible mechanisms are discussed for the reaction between hydrazoic acid and a sulphoxide.