Dichloromethane → HCID 53681824, compound

Participants

Reaction Steps

3.02 kg of bromine is added during 35 minutes to a mixture of 4.83 kg of 4-(3-aminopropyl)-8-methoxy-2H-[1]-benzopyran hydrochloride and 58 l of dichloromethane at 16°-23°, and once addition is complete the reaction is stirred for 3.5 hours at room temperature. 5.8 kg of triethylamine is added to yield 4-(3-aminopropylidene)-3-bromo-8-methoxy-2H-[1]-benzopyran. The reaction is heated at 60° for 4 hours and then stirred overnight at room temperature. The mixture is washed five times with 12 l water each and 8 l of brine, dried with anhydrous sodium sulfate, filtered and the filtrate is evaporated at reduced pressure to give an oil. This is dissolved in 12 l of isopropanol, treated with 400 g of charcoal, and the mixture is filtered. The filtrate is cooled at 10°, treated with 1.8 l of 10N ethanolic hydrogen chloride and stirred for 1 hour at 5°-10°. The suspension is filtered; the product is washed three times with 4 l isopropanol each and dried 72 hours at 40°/400 Pa to give 7-methoxy-2,3,4a,5-tetrahydro-4H-[1]-benzopyrano[3,4-b]pyridine hydrochloride, m.p. 195°-198° (dec).

Provenance & Evidence