Production of maleic anhydride derivatives

The invention comprises the production of N-substituted halomaleimides of the general formula where X is Cl or Br, and R is an aliphatic, an aromatic or an alicyclic group, by condensing, in solution in glacial acetic acid, the requisite dichloro- or dibromo-maleic anhydride with an aliphatic or alicyclic primary amine, or with an aromatic primary amine, which may be substituted in the aromatic nucleus by up to three chlorine atoms and/or by one nitro group. The invention also comprises the following compounds: N-cyclohexyl dichloromaleimide, N-butyl dichloromaleimide, N - p - tolyl dibromomaleimide, and N - cyclohexyl dibromo maleimide. In Example 1, a solution of p-toluidine in glacial acetic acid is added to a stirred solution of dichloromaleic anhydride in glacial acetic acid at a temperature of 77 DEG C. When the addition is completed, the mixture is maintained at 80 DEG C. for 12 minutes. A precipitate of N-p-tolyl dichloromaleimide is obtained. In Example 6, a solution of cyclohexylamine in glacial acetic acid is added to a solution of dibromomaleic anhydride at 100 DEG C., and heating is then continued at 100 DEG C. for one hour. The mixture is allowed to cool, and the light brown crystals of N-cyclohexyl dibromomaleimide are filtered off. A list of other halomaleimides, which can be produced by the process, is included in the Specification. This list includes: N-2,4,6-trichlorophenyl dichloromaleimide, N - 2 - chloro - 4 - nitrophenyl dichloromaleimide, and N-2,4-dimethyl phenyl dichloromaleimide.