Reaction Steps
Piperidine (220 μL, 2.2 mmol) was added to a suspension of 3-methoxy-4-(pent-3-yloxy)benzaldehyde (0.50 g, 2.2 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (0.46 g, 2.1 mmol) in toluene (5 mL) and treated according to Procedure 2, acidifying with 20% AcOH. The crude product was recrystallised from EtOH/water providing (E)-2-[[3-(3-methoxy-4-(pent-3-yloxy)phenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.52 g, 66%) as a yellow crystalline solid; mp 82-85° C.; δH (400 MHz, DMSO-d6) 0.88 (t, J=7.2 Hz, 6H, CH3), 1.60 (p, J=7.2 Hz, 4H, CH2), 3.82 (s, 3H, OCH3), 4.25 (t, J=7.2 Hz, 1H, OCH), 6.76 (d, J=15.6 Hz, 1H, CH═CHCO), 6.98 (d, J5′,6′=8.0 Hz, 1H, H5′), 7.15 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.20 (dd, J5′,6′=8.0, J2′,6′=1.6 Hz, 1H, H6′), 7.36 (d, J2′,6′=1.6 Hz, 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), 8.62 (d, J5,6=8.0 Hz, 1H, H6), 11.28 (s, 1H, NH), 13.58 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 9.3, 25.5, 55.7, 80.1, 111.2, 114.5, 116.6, 119.8, 120.3, 122.5, 122.6, 127.1, 131.1, 134.0, 141.1, 141.6, 149.6, 149.9, 164.2, 169.5; HRMS (ESI) calculated for C22H25NO5 [M−H]− 382.1555. found 382.1649; vmax 749, 1139, 1259, 1505, 1584, 1650, 2934 cm−1.
