Synthesis of 5H-pyrazolo[4,3-c]quinolines

A convenient synthesis of 3-aryl-5H-pyrazolo[4,3-c]quinolines is described. The key reactions include alkylation of 3-aroyl-1H-quinolin-4-ones with alkyl halides in DMF in the presence of sodium hydride, followed by hydrazine-mediated cyclization of the alkylated products in acetic acid.