Phosphorus oxychloride → 4-Chloro-7-methoxybenzo[g]quinoline-3-carbonitrile

Participants

Reaction Steps

A reaction mixture of 767.7 mg (3.1 mmol) of 7-methoxy-4-oxo-1,4-dihydrobenzo[g]quinoline-3-carbonitrile in 12 mL of phosphorus oxychloride and 5 drops of N,N-dimethylformamide (DMF) is refluxed for 2 hours. After cooling, the mixture is concentrated to dryness in vacuo to give a dark residue. The residue is partitioned between methylene chloride and ice-cooled saturated aqueous sodium carbonate solution. The organic layer is washed with ice-cooled brine and dried over sodium sulfate. The crude product is passed through a short column of silica gel, and further eluted with additional methylene chloride, followed by 95:5 methylene chloride/ethyl acetate. Removal of the solvent in vacuo yields 532.0 mg (64.7%) of 4-chloro-7-methoxybenzo[g]quinoline-3-carbonitrile as a bright yellow solid, mp 242–243° C.

Provenance & Evidence