The reaction studies of alpha-chloroformylarylhydrazines with thiols, thioureas and alpha-cyclodiketones

The reactions of alpha -chloroformylarylhydrazines 1 with various types of mercaptan, thiourea and alpha -cyclodiketone have been studied intensively. 1-Arylhydrazinecarbothioates 2 were obtained via thioesterization when alp ha -chloroformylarylhydrazines reacted with thiols. On the other hand, comp ounds 3 were obtained when alpha -chloroformylarylhydrazines reacted with t hio-containing heterocyclic compounds, which suggested a totally different mechanism in these types of reactions. Further studies on the reaction of a lpha -chloroformylarylhydrazines 1 with thiourea compounds confirmed a nove l cyclization and de-cyclization mechanism, which led to give 2-arylhydrazi necarboximidamides 5 and 1,3,4-thiadiazolin-5-ones 6. In addition, various 1,3,4-oxadiazines 9 were obtained by reacting alpha -chloroformylarylhydraz ines with alpha -cyclodiketones, showing ring cyclization was involved in t his type of reaction.