Sulfuric Acid ([3-(3-Silicapropyl)sulfanyl]propyl)ester as a Recyclable Catalyst for the Synthesis of 1,4-Dihydropyrano[2,3-c]pyrazole Derivatives

A new method for the preparation of 1,4-dihydropyrano[2,3-c]pyrazole derivatives via the mixing of an aromatic aldehyde, malononitrile and 5-methyl-2-phenyl-2,4-dihydro-3H pyrazol-3-one in thepresence of sulfuric acid ([3-(3-ailicapropyl)sulfanyl]propyl)ester (SASPSPE) as a solid acid catalyst was reported. The corresponding products were obtained in high yields (82–89 %).

Keywords:

Aldehyde , 5-Methyl-2-phenyl-2 , 4-dihydro-3Hpyrazol-3-one , Malononitrile