How Cysteine Reacts with Citral:An Unexpected Reaction of beta,beta-Disubstituted Acroleins with Cysteine Leading to Hexahydro-1,4-thiazepines

摘要

The reaction of beta,beta-disubstituted acroleins [3-methyl-2-butenal(1),3-methyl-2-hexenal(2),and citral(3)] with cysteine gave 1:2 adducts of a novel structural type,namely hexahydro-1,4-thiazepines.To the best of our knowledge,the spontaneous formation of a seven-membered heterocycle from the addition of cysteine to alpha,beta-unsaturated aldehydes is unprecedented.The adduct 6 obtained from citral,under acidic conditions,reacted further to give the new bicyclic compound 8.