Reaction Steps
Piperidine (0.22 mL, 2.2 mmol) was added to a suspension of 3-methoxy-4-(pent-2-ynyl)oxybenzaldehyde (0.50 g, 2.3 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (0.49 g, 2.2 mmol) in toluene (5.0 mL) and treated according to Procedure 2, acidifying with 20% AcOH. (E)-2-[[3-(3-Methoxy-4-(pent-2-ynyloxy)phenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.50 g, 60%) was obtained as a colourless crystalline solid; mp 185.5-186.5° C.; δH (400 MHz, DMSO-d6) 1.05 (t, J=7.4 Hz, 2H, CH2CH3), 2.20 (q, J=7.4 Hz, 3H, CH2CH3), 3.84 (s, 3H, OCH3), 4.78 (s, 2H, OCH2), 6.80 (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), 7.24 (d, J5′,6′=8.4 Hz, 1H, H6′), 7.39 (s, 1H, H2′), 7.56 (d, J=15.6 Hz, 1H, CH═CHCO), 7.61 (t, J4,5=J5,6=8.0 Hz, 1H, H5), 8.00 (d, J3,4=8.0 Hz, 1H, H3), 8.62 (d, J5,6=8.0 Hz, 1H, H6), 11.31 (s, 1H, NH), 13.53 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 11.7, 13.5, 56.6, 56.4, 74.7, 89.3, 110.7, 113.3, 116.6, 120.2, 120.3, 122.2, 122.7, 127.9, 131.1, 134.0, 141.0, 141.5, 148.5, 149.2, 164.1, 169.5; HRMS (ESI) calculated for C22H21NO6 [M+Na]+ 402.1312. found 402.1317; vmax 747, 1001, 1253, 1508, 1583, 1661, 2980, 3246, 3523 cm−1.
