Reaction Steps
Piperidine (0.13 mL, 1.4 mmol) was added to a suspension of 3,4-dimethoxybenzaldehyde (0.22 g, 1.4 mmol) and 5-bromo-2-[(carboxyacetyl)amino]benzoic acid (0.34 g, 1.1 mmol) in toluene (4.0 mL) and treated according to Procedure 2, acidifying with 1 M HCl. (E)-2-[[3-(3,4-Dimethoxyphenyl)-1-oxo-2-propenyl]amino]-5-bromobenzoic acid (0.30 g, 66%) was obtained as a yellow crystalline solid; mp 210-213° C.; δH (400 MHz, DMSO-d6) 3.79 (s, 3H, OCH3), 3.82 (s, 3H, OCH3), 6.78 (d, J=15.6 Hz, 1H, CH═CHCO), 6.98 (d, J5′,6′=8.4 Hz, 1H, H5′), 7.24 (d, J5′,6′=8.4 Hz, 1H, H6′), 7.36 (s, 1H, H2′), 7.56 (d, J=15.6 Hz, 1H, CH═CHCO), 7.78 (dd, J3,4=8.4, J4,6=2.0 Hz, 1H, H4), 8.06 (d, J4,6=2.0 Hz, 1H, H6), 8.62 (d, J3,4=8.4 Hz, 1H, H3), 11.30 (s, 1H, NH), 13.61 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 28.6, 55.5, 55.6, 110.4, 111.6, 114.0, 119.5, 122.5, 122.7, 127.1, 133.1, 136.4, 140.2, 142.0, 149.0, 150.7, 164.2, 168.1; HRMS (ESI) calculated for C13H16BrNO5 [M+Na]+ 428.0104. found 428.0105; vmax 1026, 1247, 1510, 1595, 1698, 2515, 2829, 3226, 3619 cm−1.
