D,L-Proline-Catalyzed One-Pot Synthesis of Pyrans and Pyrano[2,3-c]pyrazole Derivatives by a Grinding Method under Solvent-Free Conditions

摘要

D,L-Proline was found to efficiently catalyze the one-pot condensation of aromatic aldehydes,malononitrile,and dimedone(1,3-cyclohexanedione or 3-mefhyl-1-phenyl-2-pyrazolin-5-one)2-Amino-3-cycano-4-aryl-7,7-dimethyl-5,6,7,8-tetrahy-drobenzo[b]pyrans and 6-amino-5-cyano-4-aryl-1,4-dihydropyrano[2,3-c]pyrazoles were synthesized by a grinding method under solvent-free conditions.The reaction proceeded cleanly at room temperature to afford the products in good yields.