Reaction Steps
Piperidine (0.17 mL, 1.7 mmol) was added to a suspension of 3-methoxy-4-(hex-3-ynyloxy)benzaldehyde (0.40 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 providing (E)-2-[[3-(4-(hex-3-ynyloxy)-3-methoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.40 g, 65%) as a colourless crystalline solid; mp 165-166° C.; δH (400 MHz, DMSO-d6) 1.04 (t, J=7.6 Hz, 3H, CH3), 2.14 (q, J=7.6 Hz, 2H, CH3CH2), 2.61 (t, J=7.6 Hz, 1H, OCH2CH2C), 3.83 (s, 3H, OCH3), 4.05 (t, J=7.6 Hz, 2H, OCH2), 6.79 (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), 7.22 (d, J5′,6′=8.0 Hz, 1H, H6′), 7.38 (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), 13.57 (br s, 1H, CO2H); δC (100 MHz, DMSO-d6) 11.7, 14.0, 19.2, 55.7, 66.9, 76.1, 83.0, 110.9, 113.0, 116.6, 120.1, 120.3, 122.5, 122.6, 127.6, 131.1, 134.0, 141.0, 141.5, 149.1, 149.5, 164.1, 169.4; HRMS (ESI) calculated for C23H23NO5 [M+H]+ 394.1649. found 394.1647; vmax 755, 1235, 1510, 1601, 1669, 3234, 3563 cm−1.
