NOVEL AND CONVENIENT ROUTES TO SUBSTITUTED PYRROLES AND IMIDAZOLES

S-Methyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithi ation of the corresponding N-(benzotriazol-1-ylmethyl)thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes [2 + 3] cycloaddition reactions with alpha,beta-unsaturated -esters, -ketones and -nitriles, and vinylpyridines which are followed by elimination o f benzotriazole and the thioalkoxy group, to give 2,3,4-trisubstituted pyrroles. Lithiation of 6 followed by reactions with imines gives cyc lized 4,5-dihydroimidazoles 14 which upon further treatment with ZnBr2 or direct refluxing in toluene yield the 1,2,5-trisubstituted imidazo les 15 in good yields.