p-Toluenesulfonic acid-catalyzed one-pot synthesis of 2-amino-4-substituted-1,4-dihydrobenzo[4,5]imidazolo[1,2-a]pyrimidine-3-carbonitriles under neat conditions
Résumé A simple, efficient, and green procedure for the preparation of 2-amino-4-substituted-1,4-dihydrobenzolo[4,5]imidazolo[1,2-a]pyrimidine-3-carbonitriles has been developed by multi-component condensation of 2-aminobenzimidazole with aldehydes and malononitrile in the presence of a catalytic amount of p-toluenesulfonic acid, affording excellent yields under neat conditions. The protocol avoids the use of expensive catalysts, toxic solvents, and chromatographic separation. We believe that this new environmentally metal-free procedure, combined to a solvent-free reaction, would be of importance in the search of green laboratory-scale synthesis.
Facile and efficient synthesis of pyrimido[1,2-a]benzimidazole and tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-one derivatives using Brönsted acidic ionic liquid supported on rice husk ash (RHA-[pmim]HSO4)
In this work, a green and efficient procedure has been reported for the synthesis of pyrimido[1,2-a]benzimidazole and tetrahydrobenzimidazo[2,1-b]quinazolin-1(2H)-onederivatives using Brönsted acidic ionicliquid supported on rice husk ash (RHA-[pmim]HSO4) as the catalyst. These reactions were performed at 100 °C under solvent-free conditions with high yields in very short reaction times.
在这项工作中,已经报道了使用布朗斯台德酸性离子液体载体合成嘧啶基[1,2- a ]苯并咪唑和四氢苯并咪唑并[ 2,1- b ]喹唑啉-1(2 H)-one衍生物的绿色高效方法。以稻壳灰(RHA- [pmim] HSO 4)为催化剂。这些反应是在100°C无溶剂条件下以极短的反应时间高收率进行的。