To a solution of ethyl (2Z)-3-(methylamino)-3-phenylacrylate (4.47 g, 21.77 mmol) in DCM (100 mL) was added 4-bromo-3-methoxyaniline (4 g, 19.80 mmol) and PPTS (5.47 g, 21.77 mmol). The mixture was then heated to reflux for 24 h. At this time crude 1H NMR revealed nearly complete consumption of the aniline. The reaction was then cooled to RT, filtered, and the solvent was removed in vacuo. The crude product was purified on silica (75% DCM/hexanes) to yield ethyl (2Z)-3-[(4-bromo-3-methoxyphenyl)amino]-3-phenylacrylate (6.5 g, 87%) which was used as is in subsequent reactions. 1H NMR (500 MHz, CDCl3) ppm: 10.32 (br s, 1H), 7.32 (m, 5H), 7.20 (d, J=8.5 Hz, 1H), 6.19 (dd, J=8.5 Hz, 2.5 Hz, 1H), 6.11 (d, J=2.5 z, 1H), 5.03 (s, 1H), 4.21 (q, J=7.0 Hz, 2H), 3.50 (s, 3H), 1.32 (t, J=7.0 Hz, 3H).
