3-Formyl-3,4-dihydro-1H-isoquinoline-2-carboxylic acid tert-butyl ester (1.83 g, 7 mmol) was combined with AcOH (25 mL) to which was immediately added 1-phenyl-propane-1,2-dione (3.11 g, 21 mmol) and NH4OAc (13.49 g, 175 mmol). The reaction mixture was then placed on a steam bath and heated under an argon atmosphere for 20 minutes. The reaction mixture was cooled in an ice bath and then added to an ice slurry (44 g). The resulting mixture was basified by addition of concentrated NH4OH (50 mL) and then extracted twice with diethyl ether (150 mL each). The combined organic phases were dried over MgSO4, filtered and concentrated to yield crude product. This material was purified by preparative HPLC to yield the title compound as a white solid.
