Reaction Steps
Piperidine (0.17 mL, 1.7 mmol) was added to a suspension of 4-methoxy-3-(but-1-ynyloxy)benzaldehyde (0.35 g, 1.7 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (0.35 g, 1.6 mmol) in toluene (5 mL) and treated according to Procedure 2, acidifying with 1 M HCl. The crude product was recrystallised from EtOH/water providing (E)-2-[[3-(3-(but-3-ynyloxy)-4-methoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.40 g, 70%) as a colourless crystalline solid; mp 197-198° C.; δH (400 MHz, DMSO-d6) 2.65 (dt, J=6.8, 2.4 Hz, 2H, CH2CCH), 2.90 (t, J=2.4 Hz, 1H, CCH), 3.80 (s, 3H, OCH3), 4.13 (t, J=6.8 Hz, 2H, OCH2), 6.80 (d, J=15.6 Hz, 1H, CH═CHCO), 7.00 (d, J5′,6′=8.0 Hz, 1H, H5′), 7.16 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.26 (d, J5′,6′=8.0 Hz, 1H, H6′), 7.40 (s, 1H, H2′), 7.55 (d, J=15.6 Hz, 1H, CH═CHCO), 7.61 (t, J4,5=J5,6=8.0 Hz, 1H, H5), 7.99 (d, J3,4=8.0 Hz, 1H, H3), 8.61 (d, J5,6=8.0 Hz, 1H, H6), 11.27 (s, 1H, NH), 13.58 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 19.0, 55.6, 66.6, 72.5, 81.4, 111.9, 111.9, 116.6, 120.0, 120.3, 122.7, 123.0, 127.3, 131.1, 134.0, 141.0, 141.5, 147.8, 150.7, 164.2, 169.4; HRMS (ESI) calculated for C21H19NO6 [M+H]+ 366.1335. found 366.1337; vmax 753, 1263, 1512, 1581, 1671, 2833, 3250 cm−1.
