New Synthesis Method of 4-Nitro-N-Methylphthalimide

Synthesis of 4-nitro-N-methylphthalimide (4-nitro-NMP) started from phthalic anhydride (PA) and aqueous methylamine (MA) toluene solution through an important intermediate N-NMP. When mole ratio n(PA)/n(MA) = 1:1.3, after reactive refluxing for 5 hr, conversion of PA reached 98%. Yield of NMP reached 94%. The NMP obtained was nitrated to end product (4-nitro-NMP) by mixed sulfuric and nitric acids, where n(NMP)/n(mixed acid) = 1:1.1 and n(H₂SO₄/n(HNO₃) = 3:1. Mixed acid was added at 20°-30°C, followed by reaction at 55°-60°C for 4 hr to obtain a yield of 81% of 4-nitro-N-methylphthalimide. The end product was identified by means of IR spectrometry.