A NOVEL SYNTHESIS OF HETEROCYCLES FROM THIOCARBOHYDRAZIDES

The reaction of thiocarbohydrazides 1a and thiocarbazones 1b with tetr acyanoethylene (TCNE) afforded the thiazol, thiadiazole, thiazine, and thiadiazepine derivatives 4-7. 2-Dicyanomethyleneindane- 1,3-dione (C NIND) reacted with 1a,b to give aminoindenopyrazolopyridazinone (12) a nd phenyl-1,2,3,4-tetraazacyclopentafluorene (13). The indazole and ox athiadiazole derivatives 17 and 19 were formed during the reaction of 1b with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDO). 6,7-Dichloro- 5-phenylpyrazolophthalazinol was obtained from the reaction of 1b with 2,3,5,6-tetrachloro-1,4-benzoquinone (CHL-p). The oxidative cyclizati on of thiodicarbazones 2a-d with the above accepters afforded the thia diazole and thiadiazine derivatives 8 and 10.