Piperidine → HCID 10018452, compound

Participants

Reaction Steps

Piperidine (0.25 mL, 2.5 mmol) was added to a suspension of 3-hydroxy-4-methoxybenzaldehyde (0.39 g, 2.5 mmol) and 2-[(carboxyacetyl)amino]benzoic acid (0.50 g, 2.2 mmol) in toluene (5.0 mL). The reaction flask was fitted with a Dean-Stark apparatus and heated to reflux for 3 h, then cooled to rt and the resulting suspension was filtered and washed with toluene. The piperidinium salt was dissolved in MeOH (5.0 mL) and water (2.0 mL) at 40° C. and the solution was acidified with concentrated HCl. The precipitate was filtered, providing (E)-2-[[3-(3-hydroxy-4-methoxyphenyl)-1-oxo-2-propenyl]amino]benzoic acid (0.53 g, 76%) as a yellow crystalline solid; mp 215-216° C., lit.5 219-222° C.; δH (500 MHz, DMSO-d6) 3.81 (s, 3H, OCH3), 6.59 (d, J=15.5 Hz, 1H, CH═CHCO), 6.80 (d, J5′,6=8.5 Hz, 1H, H5′), 7.10-7.13 (m, 2H, H2′, H6′), 7.15 (t, J3,4=J4,5=8.0 Hz, 1H, H4), 7.47 (d, J=15.5 Hz, 1H, CH═CHCO), 7.60 (td, J4,5=J5,6=8.0, J3,5=1.5 Hz, 1H, H5), 7.99 (dd, J3,4=8.0, J3,5=1.5 Hz, 1H, H3), 8.58 (d, J5,6=8.0 Hz, 1H, H6), 11.25 (s, 1H, NH), 13.56 (br s, 1H, CO2H).

Provenance & Evidence