To a solution of 2,5-difluorobenzaldehyde (1.09 g, 7.67 mmol) in ethanol (20 mL) were added methyl 4-nitrobutyrate (1.13 g, 7.04 mmol), benzylamine (0.98 mL, 7.67 mmol), sodium acetate (1.26 g, 15.3 mmol) and acetic acid (0.88 mL, 15.4 mmol). The mixture was stirred at rt for 12 h and then heated at reflux temperature overnight. After evaporation, the residue was purified by column chromatography (silica gel Biotage 40M™) eluting with ethyl acetate/hexane (gradient from 3% to 50%) to give the title compound as the racemic trans isomer. LC-MS: 347.1 (M+1).
