ONE-STEP SYNTHESIS OF NOVEL 2,2-BETA-BI(4,5-DIHYDRO-1,3,4-THIADIAZOLE) AND 2,3-DISUBSTITUTED 1,4-BENZOTHIAZINE DERIVATIVES

N,N'-Diaryloxalodihydrazonoyl dihalides 2 read with potassium thiocyan ate or thiourea and yield the hitherto unknown bi-4-5-dihydrothiadiazo l-5-imine derivatives 5. Reaction of 5 with acetic anhydride, benzoyl chloride and nitrous acid yield N-acetyl, N-benzoyl and N-nitroso deri vatives 7, 8 and 9, respectively. Thermolysis of 9 afforded the bi-4-5 -dihydrothiadiazol-5-ones 10. The dihalides 2 react also with 2-aminot hiophenol to afford the 1,4-benzothiazine derivatives 11 which upon ox idation gave 12.