Indium(III)-catalyzed synthesis of N-substituted pyrroles under solvent-free conditions

A variety of N-substituted pyrroles have been synthesized by reacting γ-diketones (R¹C(O)CH2CH2C(O)R²: R¹, R² = Me, Ph) with amines (RNH2: R=Alkyl, Aryl, TsNH) or diamines (1,6-diaminohexane and 1,2-diaminoethane) in the presence of indium tribromide, indium trichloride or indium trifluoromethanesulfonate at room temperature under solvent-free conditions. The experiment protocol features simple operations, and the products are isolated in high to excellent yields (81-98%). Vários pirróis N-substituídos foram sintetizados pela reação de γ-dicetonas (R¹C(O)CH2CH2C(O)R²: R¹, R² = Me, Ph) com aminas (RNH2: R = Alkyl, Aryl, TsNH) ou diaminas (1,6-diaminohexano and 1,2-diaminoetano) na presença de tribrometo de índio, tricloreto de índio ou trifluorometanossulfonato de índio a temperatura ambiente e sem solventes. O protocolo envolve operações simples e os produtos são isolados em excelentes rendimentos (81-98%).