Aminothiazole derivatives. I. A convenient synthesis of monocyclic and condensed 5-aminothiazole derivatives

Treatment of diamides derived from α-amino acids with phosphorus pentasulfide or Lawesson's reagent was shown to provide a convenient method to prepare 5-aminothiazoles. By this method, in addition to mono-cyclic 5-aminothiazoles 19 , novel bicyclic 5-aminothiazole derivatives such as 4,5,6,7-tetrahydrothiazolo[5,4-b]pyridines 11 , 5,6,7,8-tetrahydro-4H-thiazolo[5,4-b]azepines 7 , 4,5,6,7,8,9-hexahydrothiazolo[5,4-b]azocine 16 and related compounds were prepared in moderate to good yields from simple diamides, suggesting the wide versatility of the method.