Trifluoroacetic acid → HCID 20154010, compound

Participants

Reaction Steps

A mixture of 7.5 g 6-methoxythiochroman-3-one [J. Org. Chem. 34, 1566 (1969)], 5.8 g of methyl 3-(propylamino)-propionate and 0.8 ml of trifluoroacetic acid in 80 ml of toluene is heated under reflux for 22 hours in a Dean Stark apparatus. Additional 0.8 ml portions of trifluoroacetic acid are added after 2, 5, and 16 hours. The solvent is removed, the residue is taken up in ether and the product is extracted with 3N hydrochloric acid. After neutralization the aqueous layers are extracted with ethyl acetate, the organic layer is dried and the solvent is removed. The product crystallized from a small volume of methanol to afford 9-methoxy-4-propyl-1,2,3,5-tetrahydro-4H-[1]-benzothiopyrano[3,4-b]pyridine-1-one, melting point 108°-110°.

Provenance & Evidence