Dimethylmaleic anhydride → 3,5-Bis-(dimethylmaleimidyl)-phthalic anhydride

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Reaction Conditions

Reaction Steps

7.20 g (0.039 mol) of disodium 3,5-diaminophthalate, dissolved in 200 ml of water, are added to a solution of 8.82 g (0.078 mol) of dimethylmaleic anhydride in 80 ml of toluene. This mixture is boiled under reflux for 1 hour. It is then evaporated to dryness in a rotary evaporator, the residue is dissolved, at 90° C, in 100 ml of N,N-dimethylacetamide and 50 ml of water and the solution is rendered acid to Congo Blue with 10% strength hydrochloric acid. After cooling, the slurry-like mixture is filtered and the residue is rinsed with acetone and then dried in vacuo at 80° C. The dry residue is then suspended in 100 ml of acetic anhydride and this mixture is warmed to about 100° C for 1 hour. It is then evaporated to dryness and the residue is recrystallised from 1,2-dichlorobenzene. 8.9 g (69% of theory) of 3,5-bis-(dimethylmaleimidyl)-phthalic anhydride are obtained; colour; light brownish; melting point 298° C (decomposition). H1NMR: (DMSO-d6, TMS = O) 2H (aromatic) 7.94 and 7.98 ppm, 12H (methyl protons 1.98 ppm). Analysis for C20H14N2O7 (molecular weight 394.12): calculated: C 60.92%; H 3.58%; N 7.11%. found: C 60.67%; H 4.44%; N 7.32%.

Provenance & Evidence