反应详情

69.7 g (0.26 mol) of 3-nitrophthalic acid diethyl ester in 690 ml of dioxane are hydrogenated in the presence of 7 g of a Raney nickel catalyst to give 3-aminophthalic acid diethyl ester. The reaction solution is filtered and 30.4 g (0.31 mol) of maleic anhydride are added, at room temperature, to the filtrate. The reaction mixture is kept at 25° C. for 12 hours and then concentrated in vacuo. 75 ml of acetic anhydride and 12.7 g of sodium acetate are added to the residue and the mixture is heated to 80° C. for 45 minutes and diluted with 500 ml of water. The crystalline precipitate is rinsed with water and dried in vacuo at 45° C. 68 g (82% of theory) of crystalline 3-maleimidyl-phthalic acid diethyl ester are obtained; melting point 86°-90° C. When the product is recrystallised from ethanol, the melting point rises to 92°-93° C.