Synthesis and solvolysis of a new group of reactive halides, the imidazolin-2-ylidenehydrazonyl chlorides; a route to 6,7-dihydro-3-aryl-5H-imidazolo[2,1-c]-s-triazoles

Abstract

Reaction of 1-aryl-1,4,4-trichloro-2,3-diazabutadienes (5) with ethylenediamine forms the new N-(imidazolin-2-ylidene)benzohydrazonyl chlorides (6), which cyclise rapidly and in high (90%) yields to the new 6,7-dihydro-3-aryl-5H-imidazolo[2,1-c]-s-triazoles (8). The trichlorides (5) with NN′-dimethylethylenediamine yielded not only the corresponding N-(1,3-dimethylimidazolin-2-ylidene)-substituted benzohydrazonyl chlorides (14) but also the new NN′-(1,6-dichloro-2,5-dimethyl-2,5-diazahexane-1,6-diylidene)bis(benzohydrazonyl chlorides)(15). Hydrolysis of the hydrazonyl chlorides (14) yields the substituted N′-(1,3-dimethylimidazolidin-2-ylidene)benzohydrazides (16), accompanied by varying quantities of the corresponding 3,6-diaryl-1,2,4,5-tetrazines (17), whereas the tetrachlorides (15) gave the NN′-bis-(5-aryl-1,3,4-oxadiazol-2-yl)-NN′-dimethylethylenediamines (26) under more vigorous conditions. The hydrazonyl chlorides (14) formed the corresponding N-phenylbenz-amide N′-(1,3-dimethylimidazolidin-2-ylidene)hydrazones (24) with aniline; the tetrachlorides (15) yielded 3-anilino-5-aryl-4-phenyl-1,2,4-triazoles (25).