Reactions of arylazosulfones with the conjugate bases of (tert-butoxycarbonyl)methyl and tosylmethyl isocyanide. Synthesis of substituted 1-arylimidazoles

Article abstract of DOI:10.1016/S0040-4020(96)01108-8

The reactions of arylazosulfones 1 (ArN = NSO₂Ar') with the potassium salts of (tert-butoxycarbonyl)methyl 2 and tosylmethyl isocyanide 3 in DMSO afford 4,5-bis(tert-butoxycarbonyl)- 4 and 4-tosyl-1-arylimidazoles 5, respectively. Yields of imidazoles 4 and 5 vary from moderate to excellent depending on the nature both of Ar in 1 and of the nucleophile (2 or 3) employed. A comparison of the results obtained with those relevant to the reactions of the same nucleophiles with nitrosobenzene in analogous experimental conditions provides useful mechanistic indications on the transformation of 1 to 4 or 5.