Reaction Steps
Piperidine (0.70 mL, 7.1 mmol) was added to a suspension of 4-methoxy-3-propargyloxybenzaldehyde (1.34 g, 7.06 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (1.50 g, 6.72 mmol) in toluene (5.0 mL) and treated according to Procedure 2, acidifying with 20% AcOH. The crude product was recrystallised from EtOH, filtered and washed with cooled EtOH to afford (E)-2-[[3-(3-methoxy-4-(prop-2-ynyloxy)phenyl)-1-oxo-2-propenyl]amino]benzoic acid (1.50 g, 64%) as a yellow crystalline solid; mp 183-185° C.; δH (400 MHz, DMSO-d6) 3.58 (t, J=2.0 Hz, 1H, HC≡C), 3.81 (s, 3H, OCH3), 4.87 (d, J=2.0 Hz, 2H, OCH2), 6.75 (d, J=15.6 Hz, 1H, CH═CHCO), 7.03 (d, J5′,6′=8.4 Hz, 1H, H5′), 7.16 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.29 (d, J5′,6′=8.4 Hz, 1H, H6′), 7.44 (s, 1H, H2′), 7.54 (d, J=15.6 Hz, 1H, CH═CHCO), 7.60 (t, J4,5=J5,6=8.0 Hz, 1H, H5), 8.00 (d, J3,4=8.0 Hz, 1H, H3), 8.61 (d, J5,6=8.0 Hz, 1H, H6), 11.34 (s, 1H, NH), 13.60 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 55.6, 56.1, 78.4, 79.2, 112.0, 112.6, 116.6, 120.0, 120.3, 122.7, 123.5, 127.0, 131.1, 134.0, 141.1, 141.5, 146.6, 151.0, 164.1, 169.5; HRMS (ESI) calculated for C20H17NO6 [M+Na]+ 374.0999. found 374.1002; vmax 750, 1029, 1135, 1217, 1506, 1582, 1667, 3270, 3520 cm−1.
