Novel and convenient routes to substituted pyrroles and imidazoles

Article abstract of DOI:10.1016/0040-4020(95)00851-X

S-Methyl N-(benzotriazol-1-ylmethyl)thioimidate 6 is obtained by lithiation of the corresponding N-(benzotriazol-1-ylmethyl)thioamide 5 and subsequent reaction with methyl iodide. Derivative 6 undergoes [2+3] cycloaddition reactions with α,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. Lithiation 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 1,2,5-trisubstituted imidazoles 15 in good yields.