Simple and efficient protocol for the synthesis of novel dihydro-1H-pyrano2,3-cpyrazol-6-ones via a one-pot four-component reaction

Ba(OH) 2 catalyzed simple and efficient one-pot four-component reaction of Meldrums acid, ethyl acetoacetate, hydrazine hydrate, and aromatic aldehydes to give 3-methyl-4-aryl-4,5-dihydro-1H-pyrano2,3-cpyrazol-6-ones in refluxing water is reported. The yields are high and the reactions go to completion in 1-2 h. © 2012 Elsevier Ltd. All rights reserved