A NOVEL AND EFFICIENT SYNTHESIS OF 3-ARYL AND 3-HETEROARYL SUBSTITUTED-1H-INDAZOLES AND THEIR MANNICH DERIVATIVES

ABSTRACT

A general and highly convenient procedure for the synthesis of 3-heteroaryl and 3-aryl substituted-1H-indazoles has been developed. These compounds (3a–f) were synthesized in good yield by refluxing the NaHSO₃ adduct of heteroaromatic and aromatic aldehyde and phenyl hydrazine in DMF. This procedure is more general and shorter than earlier methods. Five new 3-hetero-aryl substituted-1H-indazoles were synthesized and characterized. New Mannich derivatives of 3-(1H-pyrrol-2-yl)-1H-indazole (3a) and 3-(1H-indol-3-yl)-1H-indazole (3b) were prepared from morpholine and formaldehyde.