Cyclic imides IV. The reaction of some N-substituted nitrophthalimides with sodium methoxide

Treatment of methyl 4-nitrophthalimidoacetate (I) with sodium methoxide in refluxing methanol results in a Gabriel-Colman rearrangement to give 7 - nitro-4-hydroxy-3-carbomethoxy-1(2H) - isoquinolone (II). Under the same conditions, N-substituted 3-nitrophthalimides (IV) yield N-substituted 3-methoxyphthalimides (V).