A facile synthesis of 6-amino-2H, 4H-pyrano[2,3-с]pyrazole-5-carbonitriles in deep eutectic solvent

A convenient synthesis of 6-amino-2H,4H-pyrano[2,3-с]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-с]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.

Graphical abstractA convenient synthesis of 6-amino-2H,4H-pyrano[2,3-с]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-с]pyrazoles in shorter reaction time with high yields, and it avoids the use of typical toxic catalysts and solvents.Figure optionsDownload full-size imageDownload as PowerPoint slide