The conversion of 5,6-dihydro-4-methoxy-2-pyrones into 3-alkyl-5-hydroxypyrazoles

Abstract

The production and characterisation of 3-[(2-aryl-2-hydroxy)ethyl]-5-hydroxy-1H-pyrazoles (2a–d) and 3-[(2-aryl-2-hydroxy-2-methyl)ethyl]-5-hydroxy-1H-pyrazole (2e) by the reaction of hydrazine with 6-substituted-5,6-dihydro-4-methoxy-2-pyrones is described. The products exist as 5-hydroxypyrazoles rather than pyrazolin-5-ones.