Brönsted acidic ionic liquid as a recyclable catalyst for the one pot four-component synthesis of substituted pyrano[2,3-c]pyrazoles

Authors

• Leila Khazdooz ^{1, 2}
• Amin Zarei ³

1. Department of Science, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan 81595-158, Iran
2. Laser and Biophotonics in Biotechnologies Research Center, Isfahan (Khorasgan) Branch, Islamic Azad University, Isfahan 81595-158, Iran
3. Department of Science, Fasa Branch, Islamic Azad University, PO Box No. 364, Fasa 7461713591, Fars, Iran.

Abstract

An efficient, mild and environmentally friendly method was reported for the synthesis of An efficient, mild and environmentally friendly method was reported for the synthesis of pyranopyroles from aryl aldehydes, ethyl acetoacetate, malononitrile and hydrazine hydrate in the presence of catalytic amounts of Methyl imidazolium hydrogen sulfate ([Hmim][HSO4]) as an efficient catalyst. These syntheses were performed via a one-pot four-component condensation in water/ethanol (50%) at 50 ◦C. This method easily provides the coresponding products in good yield and relatively short reaction times. Also the reusability of the catalyst was investigated, the catalyst could be employed four times, although its activity gradually decreased.

Keywords

• Aldehydes
• Four-component reaction
• Methyl imidazolium hydrogen sulfate
• Pyranopyrazole
• Hydrazine hydrate