Reaction Steps
Piperidine (0.26 mL, 2.6 mmol) was added to a suspension of 3-(hex-5-ynyloxy)-4-methoxybenzaldehyde (0.60 g, 2.6 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (0.52 g, 2.4 mmol) in toluene (5.0 mL) and treated according to Procedure 2, acidifying with 1M HCl. The crude product was recrystallised from EtOH/water providing (E)-2-[[3-(3-(hex-5-ynyloxy)-4-methoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.64 g, 70%) as a pale yellow crystalline solid; mp 135-137° C.; δH (400 MHz, DMSO-d6) 1.62 (p, J=7.2 Hz, 2H, CH2), 1.82 (p, J=7.2 Hz, 2H, CH2), 2.25 (dt, J=7.2, 2.4 Hz, 2H, CH2CCH), 2.78 (t, J=2.4 Hz, 1H, CCH), 3.80 (s, 3H, OCH3), 4.05 (t, J=7.2 Hz, 2H, OCH2), 6.77 (d, J=15.6 Hz, 1H, CH═CHCO), 6.99 (d, J5′,6′=8.0 Hz, 1H, H5′), 7.16 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.23 (d, J5′,6′=8.0 Hz, 1H, H6′), 7.37 (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), 8.00 (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) 18.1, 25.3, 28.5, 56.3, 68.4, 72.1, 85.0, 112.3, 112.5, 117.3, 120.5, 121.0, 123.3, 127.9, 131.8, 134.7, 141.7, 142.3, 149.0, 151.5, 164.8, 170.1; HRMS (ESI) calculated for C23H23NO5 [M+H]+ 394.1649. found 394.1650; vmax 753, 1257, 1512, 1586, 1675, 2941, 3242, 3536 cm−1.
