Ring Transformation of 3,1-Benzothiazin-2,4-dithiones with Carboxylic Acid Hydrazides to Substituted 1,3,4-Thiadiazoles or in the Presence of Hydroxid Ions to 3-Acylamino-quinazolin-2,4-dithiones

Article abstract of DOI:10.1007/BF00799952

The substituted 1,3,4-thiadiazoles 4-14 were prepared in one step by reaction of 3,1 benzothiazin-2,4-dithiones 1 and 3 with RCONHNH2 (R=Me, Ph, substituted Ph, 4-Pyridyl, CONHNH2).Reaction of 1 with RCONHNH2 in the presence of HO(-) leads to substituted quinazolin-2,4-dithiones 18-20.Under the action of CS2 the yield of 19 and 20 increases.Possible reaction mechanisms are discussed. - keywords: 2H-3,1-Benzothiazin-2,4(1H)-dithione; Carbocyclic acid hydrazides; Quinazolin-2,4(1H,3H)-dithione; Ring transformation; 1,3,4-Thiadiazoles