N-(2,4-DIFLUOROPHENYL)MALEAMIC ACID synthesis

Yield:-

Reaction Conditions:

in chloroform at 20; for 1 h;

Steps:

4.1.1. Synthesis of maleimides

General procedure: The synthesis of maleimides 1-47 was performed by mixing an equimolar amount of the appropriate maleic anhydrides 68-72 in 5 mL of CHCl₃ and anilines 73, 78-90, amines 91-94 or phenylalkylamines 74-77 (5 mmol) dissolved in 1 mL of CHCl₃ and stirred during 1 h. The solid (maleamic acid) which precipitated out of the reaction mixture was filtered off. The whole amount of maleamic acid was dissolved in 5 mL of acetic anhydride and 100 mg of sodium acetate was added. The mixture was heated for 2 h under reflux. The reaction was cooled and quenched with water; then, the aqueous solution was extracted with Et₂O, dried with Na₂SO₄, filtered, and the solvent was evaporated. The product was purified by silica gel column chromatography using a mixture of hexane and ethyl acetate (9:1) as eluent. Compounds 1-10, 16-26, 31-34, 36, 38-42 and 43-47 were previously reported.^{[3], [8], [21], [22], [23], [24], [25], [26], [27] and [28]}

References:

Sortino;Garibotto;Cechinel Filho;Gupta;Enriz;Zacchino [Bioorganic and Medicinal Chemistry,2011,vol. 19,# 9,p. 2823 - 2834] Location in patent:experimental part