Water → 4,5-Dimethoxy-2-[(4-ethoxy-1,4-dioxobutyl)amino]benzoic acid ethyl ester

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Reaction Steps

A solution of ethyl succinyl chloride (1.284 g, 5.7 mmol) in toluene (15 ml) was added dropwise to a cooled solution of 2-amino-4,5-dimethoxybenzoic acid ethyl ester (1.240 g, 7.4 mmol) and pyridine (0.67 ml) in toluene (1 ml) with stirring under nitrogen. The resulting suspension was stirred for 4 hours at 20° C. and water (13 ml) and dichloromethane then added. The organic phase was washed with hydrochloric acid (10%) and aqueous sodium carbonate solution (5%), dried (sodium sulfate) and evaporated. The residue was crystallised from ethanol to yield the title compound (1.42 g, yield 70%) as colourless crystals, mp 125° C.; 1H-NMR (DMSO-d6, 300 MHz): δ (ppm)=11.26 (br s; 1 H), 8.43 (s; 1H), 7.46 (s; 1H), 4.39 (q, 2H), 4.18 (q, 2H), 3.92 (s, 3H), 3.87 (s; 3H), 2.75 (m; 4H), 1.42 (t, 3H), 1.23 (t, 3H).

Provenance & Evidence