Phosphorus oxychloride → 4-Chloro-7,8-dimethoxybenzo[g]quinoline-3-carbonitrile

Participants

Reaction Steps

A mixture of 356.2 mg (1.3 mmol) of 7,8-dimethoxy-4-oxo-1,4-dihydrobenzo[g]quinoline-3-carbonitrile in 5 mL of phosphorus oxychloride and 4 drops of DMF is heated at 100–110° C. for 4.5 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 cooled brine and dried over sodium sulfate. The organic solvent is passed through a short column of silica gel, and the column is first eluted with additional methylene chloride, then a 99:1 methylene chloride/ethyl acetate solution. Removal of the solvent yields 187.0 mg (49.4%) of the product as a bright yellow solid, mp>265° C.

Provenance & Evidence