Trifluoroacetic acid → 1,2-Dimethyl-4-(3,4,5-trimethoxyphenyl)-7-methoxy-1,4-dihydro-3(2H)-isoquinolinone

Participants

Reaction Steps

A solution of the amide from step 2 above (4.2 g) in dichloromethane (60 ml) and trifluoroacetic acid (20 ml) was refluxed for 4 hours. The reaction mixture was concentrated to dryness and the residue was submitted to chromatography on silica gel using dichloromethane-ethyl acetate (6:4) as eluent. The first fraction was concentrated to dryness and the residue was crystallized from methanol giving diastereomer I, m.p. 135-140° C. The third fraction contained diastereomer II, which was recovered as an amorphous solid.

Provenance & Evidence