Regioselective Synthesis of Heterocyclic Ketene N,N-, N,O- and N,S-acetals in Aqueous Medium

The reactions of ketene dithioacetals with ethane-1,2-diamine, propane-1,3-diamine, 2-aminoethanol, 3-aminopropanol, and 2-aminoethanethiol in ordinary water in the absence of any acid/base catalyst afforded the heterocyclic ketene N,N-, N,O and N,S-acetals in good