A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）...A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）, and hydrazine hydrate（4） in freshly prepared deep eutectic solvent, DES（choline chloride：urea）. This protocol has afforded corresponding pyrano[2,3-F]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.展开更多
文摘A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-F]pyrazole-5-carbonitriles has been accomplished by one pot four-component cyclocondensation of aromatic aldehydes（1a-o） malanonitrile（2）, ethyl acetoacetate（3）, and hydrazine hydrate（4） in freshly prepared deep eutectic solvent, DES（choline chloride：urea）. This protocol has afforded corresponding pyrano[2,3-F]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.
