CH306792A - Process for preparing a succinimide. - Google Patents

Description

  

      Process for preparing a succinimide. The present invention relates to a process <B> (the </B> preparation of a- (o-chlorophenyl) -a- methvl-sueeinimide having a chemotherapeutic activity, of formula
EMI0001.0007
    This process is characterized in that one reacts a- (o-chlorophen5rl) -a-m-tlivl-sucinic acid or its anhydride with at least one equivalent of ammonia, and in that one heats the intermediate product thus formed to a temperature between 100 and. 350 C.



  By performing the first part of the process, it is. advantageous although not essential to employ an inert solvent such as water, a lower aliphatic alcohol or a mixture of such alcohols, ether, benzene, toluene or the like, to facilitate the. reaction of succinic acid or anhydride with ammonia.

    It is not necessary to use the reagents in exact particular proportions; however, from the point of view of economy, it is good to use several equivalents of ammonia per equivalent. a- (o-ehlorophenyl) -a-methyl-stieeinic acid or anhydride. When a- (o-chlorophenyl) - a-methyl-succinic anhydride is employed with one equivalent of ammonia, the intermediate is the semi-amide;

      while if two or more equivalents of ammonia are employed, the intermediate is the ammonium salt of α- (o-chlorophenyl) -α-methyl-suceinic acid half-amide. In the case where a- (o-ehlorophenyl) -a-methyl-suceinic acid is used as the raw material, the intermediate product is the mono- or di-ammonium salt of a- (o -chlorophenyl)

  -α-methyl-succinic. These intermediates can be converted to the desired sueeinimide by heating them to a temperature between 100 and 350 C. The preferred temperature for this conversion is in the region of 190 to 210 C, at which temperature the reaction is complete in about 1 hour.



  The product. obtained by the process according to the invention is all new substance; it has valuable therapeutic properties and is. particularly useful for the treatment of the petit mal type of epilepsy. Its melting point is between 152 and 155 C.



  <I> Example 1: </I> 14 g of <I> a - </I> (o - chlorophenyl) <I> - a </I> - methyl - succinic acid are gradually added to 20 ems of concentrated ammonium hydroxide and removes water and excess ammonia by distillation. The temperature of the residue is then raised and maintained at 200 C until there is no. phis elimination of ammonia. The residue is dissolved in a minimum quantity of absolute ethanol, the solution decolorized with animal charcoal and filtered.

   The solid product is separated from the cooled filtrate and dried to give the desired α- (o-chlorophenyl) -α-methyl-suecinimide; PF 152-155 C; yield 79%.



       Example ?: 10 g of a - (o - chlorophenyl) - a - methyl -siicciniqne anhydride is gradually added to 10 cma of concentrated ammonium hydroxide, then the water and excess ammonia are removed by distillation . The residue is heated to 210 C until there is no. plus elimination of ammonia, then, after cooling, it is dissolved in absolute ethanol and decolorized with animal black.

   The product which separates from the filtrate is the desired α- (o-chlorophenyl) -α-methyl-succinimide; PF 153-155 C; yield 82%.

 

Claims (1)

CLAIM: Process for preparing la, a- (o-ehloro-phenyl) -a-methyl-succinimide, characterized in that a- (o-chloroph6ny'1) -a acid is reacted. -methyl-suceinic or its anhydride with at least one equivalent of ammonia, and in that the intermediate product thus formed is heated to a temperature of between 100 and 3501, C. The suceinimide obtained is. a crystalline substance melting at l.52-155 C and is used in therapy. <B> SUB-CLAIMS: </B> 1. Process according to claim, characterized in that an excess of ammonia is used. 2. Method according to claim, character ized in that the intermediate product is heated to a temperature between 190 and 210 C.