Reaction Steps
Piperidine (0.63 mL, 5.8 mmol) was added to a suspension of 3-cyclopentyloxy-4-methoxybenzaldehyde (1.4 g, 6.4 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (1.3 g, 5.8 mmol) in toluene (5.0 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-cyclopentyloxy-4-methoxyphenyl)-1-oxo-2-propenyl]amino}benzoic acid (1.4 g, 67%) as a yellow crystalline solid; mp 211-217° C.; δH (400 MHz, DMSO-d6) 1.57 (m, 2H, CH2), 1.70-1.72 (m, 4H, CH2), 1.91 (m, 2H, CH2), 3.78 (s, 3H, OCH3), 4.90 (t, J=5.6 Hz, 1H, OCH), 6.75 (d, J=15.6 Hz, 1H, CH═CHCO), 6.98 (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, Fe), 7.31 (s, 1H, H2′), 7.55 (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), 8.60 (d, J5,6=8.0 Hz, 1H, H6), 11.25 (s, 1H, NH), 13.57 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 23.6, 32.2, 55.6, 79.5, 112.0, 113.6, 116.7, 119.9, 120.4, 122.2, 122.7, 127.2, 131.1, 134.0, 141.0, 141.6, 147.1, 151.5, 164.2, 169.4; HRMS (ESI) calculated for C22H23NO5 [M+Na]+ 404.1468. found 404.1468; vmax 751, 1254, 1504, 1583, 1661, 2948, 3516 cm−1.
