50741-37-2

635-46-1

545-06-2

50741-37-2

Under cooling conditions in an ice bath, 1.33 g of 1,2,3,4-tetrahydroquinoline was dissolved in 10 mL of toluene, followed by the slow addition of 5.5 mL of a 2.02 M toluene solution of boron trichloride. The reaction mixture was placed in an oil bath and refluxed for 1 hour. Upon completion of the reaction, the toluene solvent was removed by atmospheric pressure distillation. The resulting residue was mixed with 2 mL of trichloroacetonitrile and heated in an oil bath at 60°C to 62°C for 20 hours. The reaction mixture was cooled, dissolved in 20 ml of dichloromethane and slowly poured into 40 ml of methanol solution containing 9.1 g of potassium carbonate under cooling in an ice bath. This mixture was refluxed in an oil bath for 1 hour and subsequently filtered to remove insoluble impurities. The filtrate was concentrated and subjected to liquid-liquid partition extraction with water and dichloromethane. The dichloromethane layer was washed with dilute hydrochloric acid, dried over anhydrous magnesium sulfate and subsequently concentrated to remove the solvent. The resulting crude product (1.53 g) was purified by Lobar column chromatography employing dichloromethane as eluent and the target fractions were collected. The product was further recrystallized using a mixed ether-hexane solvent, resulting in 1.07 g of 8-cyano-1,2,3,4-tetrahydroquinoline crystals with a melting point of 75°C to 76°C in 68% yield.