One‐Pot Synthesis of Hydroxy Pyrazolo[1,2‐a][1,2,4]triazoles and Their Dehydration Using Recyclable Ionic Liquids as Reaction Media

An eco-friendly, simple, and efficient one-pot new procedure has been developed for the synthesis of hydroxy phenylhexahydropyrazolo[1,2-a][1,2,4]triazoles by condensation of 4-phenylurazole, aldehydes, and ethyl/methyl acetoacetate using ionic liquid [bmim]BF4 in presence of l-proline at 80 degrees C. The hydroxy pyrazolo[1,2-a][1,2,4]triazoles could be dehydrated in presence of [bmim]HSO4 to give corresponding phenyltetrahydropyrazolo[1,2-a][1,2,4]triazoles in high yields. High yields, less reaction time, operational simplicity, and recyclability of reaction media are the advantages of this protocol.