Novel and convenient routes to substituted pyrroles and imidazoles

S-Melhyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithiation of the corresponding N-(benzotriazol-1-ylmelhyl) thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes 2 + 3] cycloaddition reactions with ,β-unsaturated -esters, -ketones and -nitriles, and vinylpyridines which are followed by elimination of benzotriazole and the thioalkoxy group, to give 2,3,4-trisubstituted pyrroles. Lithiaiion of 6 followed by reactions with imines gives cyclized 4,5-dihydroimidazoles 14 which upon further treatment with ZnBr₂ or direct refluxing in toluene yield the 1,25-trisubstituted imidazoles 15 in good yields.