Replacement of the imino group by sulfur groups

When aziridines (ethyleneimines) are treated with hydrogen sulfide or thiols one C-N bond is broken and j8-aminoalkanethiols or / -(alkylthio)alkyl-amines, respectively, are formed 473 

The reaction can be extended to other mercapto derivatives such as a-mercapto ketones474 and a-mercapto carboxylic acids.475 For example, 3-ethyl-5,6-di-hydro-2-methyl-4i/-1,4-thiazine is obtained in 85-90% yield from aziridine and 2-mercapto-3-pentanone 474 

The preparation of cysteamine has been reported by Mills and Bogert.476 5-Methyl- and 5-ethylcysteamine477 are obtained when aziridine is added gradually to a methanolic solution of methane- or ethane-thiol, respectively, at —15° and the mixture is set aside at room temperature. 

An important method of preparing O-esters of thiocarboxylic acids is to treat imidic esters with hydrogen sulfide  

A large number of such O-esters have been obtained by this method.479-482 

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