Triethyl Phosphate → 5-Chloro-2,6-dimethoxy-4-methyl-8-nitroquinoline

Participants

Reaction Conditions

Reaction Steps

A 20-liter reactor equipped with a mechanical stirrer, thermowatch, and condenser was charged with triethylphosphate (6.3 liters) and 2,6-dimethoxy-5-chloro-4-methylquinoline (5) (500 g, 2.11 moles). Phosphorous pentoxide (1.052 kg, 7.11 moles) was added in one portion and the resulting slurry stirred for 60 minutes. Reaction temperature was adjusted to 35° C. and solid potassium nitrate (0.423 kg, 4.21 moles) added in one portion. N-hexane is added and the reaction temperature was maintained at 35-40° C. for 2 hours. Methanol (4.2 liters) was added and the mixture heated to reflux and held for 1 hour. The yellow slurry was cooled to 0-5° C. and held for 2 hours. The product was collected by suction filtration, washed with water to neutral pH, then methanol, air dried and oven dried at 60-70° C. to yield the title compound 350 g (68%); mp 199-200° C.;

Provenance & Evidence