To a stirred solution of Ethyl 10-amino-4-oxo-3-((phenylcarbonyl)oxy)-4,6,7,8,9,10-hexahydro-7,10-ethanopyrimido[1,2-a]azepine-2-carboxylate hydrochloride (200 mg, 0.461 mmol) in 1,2-dichloroethane (10 mL) was added triethylamine (0.064 mL, 0.461 mmol) and the resulting mixture stirred for 5 min. Benzaldehyde (0.186 mL, 1.844 mmol), AcOH (0.053 mL, 0.922 mmol) and NaCNBH3 (87 mg, 1.383 mmol) were then added and the mixture stirred for 6 h. Acetaldehyde (0.182 mL, 3.23 mmol) was then added to the reaction and the this was stirred at room temperature for 16 h. The mixture was then quenched with sat. NaHCO3 and extracted with dichloromethane, dried (Na2SO4), filtered and concentrated to afford title compound.
