Utility of 1‐Chloro‐3,4‐dihydronaphthalene‐2‐carboxaldehyde in the Synthesis of Novel Heterocycles with Pharmaceutical Interest

Abstract

Ethyl α‐cyano‐β‐(1‐chloro‐3,4‐dihydronaphthalene‐2‐yl) acrylate (2) was prepared by the Knoevenagel condensation of 1 with ethyl cyanoacetate. Compound 2 was used as the key intermediate to prepare Schiff bases (3a, b), benzo[c]acridine (4), naphthyl thiopyrimidine (5), and pyrazolo[2,3‐a]‐benzo[h]quinazoline (6) derivatives through its reaction with hydrazines, p‐ansidine, thiourea, and 3,5‐diamino‐4‐phenylazopyrazole, respectively. Base‐catalyzed cyclocondensation of 1 with hippuric acid gives oxazolone derivative (7). Reaction of compound 7 with aniline gave imidazolone derivative (9). Treatment of compound 1 with different types of diaminopyrazoles gave 6,7‐dihydro‐pyrazolo[2,3‐a]‐benzo[h]quinazoline (10–13) derivatives. The multicomponent reaction of compound 1 with pyrazolone and malononitrile in the presence of ammonium acetate furnished pyrazolo[3,4‐b]‐benzo[h]quinoline (14) while in the presence of piperidine afforded benzo[h]chromeno[2,3‐c]pyrazole derivative 15.

Keywords:

• 1‐Chloro‐3,4‐dihydronaphthalene‐2‐carboxaldehyde
• chromeno[2,3‐c]pyrazole
• heterocycles
• pyrazolo[2,3‐a]quinazoline
• pyrazolo[3,4‐b]quinoline