Sulfuric Acid → HCID 14719578, compound

Participants

Reaction Steps

1.16 g of α-[[(-3-thenyl)amino]methyl]-6-fluoro-3,4-dimethoxybenzyl alcohol was dissolved in 11 ml of trifluoroacetic acid, and after adding thereto 0.31 ml of conc. sulfuric acid under ice cooling, the mixture was stirred for 4 hours. The reaction solution was concentrated, and chloroform and water were added to the residue. The mixture was basified by addition of 10 ml of conc. aqueous ammonia under ice cooling. The chloroform layer was collected after a separating procedure, washed with water, and dried over anhydrous magnesium sulfate. The solvent was distilled off, and the residue was recrystallized form ethanol, affording 0.76 g of 7-(6-fluoro-3,4-dimethoxyphenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine, m.p. 108°-111° C. (2) 0.62 g of 7-(6-fluoro-3,4-dimethoxyphenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine (obtained above) was dissolved in 13 ml of dichloromethane; and to the mixture was added dropwise 12 ml of 1M borontribromide-dichloromethane solution under an argon gas stream at -30°--60° C. (internal temperature) under cooling while stirring. The mixture was stirred for 2 hours at room temperature, and to the mixture was added dropwise 20 ml of methanol under ice cooling. The solment was distilled off, and the residue was recrystallized from ethanol, affording 0.30 g of 7-(6-fluoro-3,4-hydroxyphenyl)-4,5,6,7-tetrahydrothieno[3,2-c]pyridine hydrobromide.

Provenance & Evidence