The maleamic acid (method-A) can be obtained from maleic anhydride under treatment of respective amines to get the maleamic acids derivatives (3a-3g). The maleamic acid derivatives (3a-3g) on treatment with sodium acetate to get corresponding maleimide derivatives 4a-4g, the yields after purification are low particularly for 2-Bismaleimidoethane, N-Propargylmaleimide, Moreover polyethylene 3d and free hydroxyl group substrates 3f and 3g giving impurities. Acetone Reflux, 1h 94-99%.