Synthesis of 4-alkylpyrazoles from 3,5-diaminopyrazoles

Abstract

The possibility of preparing 4-alkylpyrazoles from malononitrile (through C-alkyl malononitriles and 3,5-diamino-4-alkylpyrazoles) has been explored. Although some difficulties arise in the doubledeamination step, the method has allowed the synthesis of 4-benzyl- and 4-phenethyl-pyrazoles. New 3-halogenopyrazoles have also been prepared. The synthesis of 3,5-diamino-4-iodopyrazole is reported. This elusive compound has a ¹³C NMR spectrum in which an aromatic carbon (C-4) appears at δ 29.53.