5-ethyl-5-hydroxy-9-methoxy-4,5-dihydrooxepino[3,4-c]pyridin-3(1H)-one → 5-Ethyl-5-hydroxy-1,4,5,8-tetrahydrooxepino[3,4-c]pyridine-3,9-dione

Participants

Reaction Steps

5-Ethyl-5-hydroxy-9-methoxy-4,5-dihydrooxepino[3,4-c]pyridin-3(1H)-one (0.5 g, 2.1 mmol) is heated under reflux for 9 hours in 1N hydrochloric acid (20 ml). The reaction mixture is concentrated under reduced pressure and the residue is again dried by the addition and evaporation of toluene twice, then left overnight under reduced pressure in the presence of phosphorus pentoxide. The resultant oil is dissolved in anhydrous acetonitrile (5 ml) and agitated under argon for 24 hours. The precipitate is filtered out and dried, which produces 0.23 g (49%) of a white solid (M), m.p. 118-119° C.

Provenance & Evidence