GB1041015A - Improvements in or relating to spiropiperidyl-succinimide derivatives - Google Patents

Abstract

The invention comprises a process for the production of succinimides of general formula <FORM:1041015/C2/1> wherein R1 signifies a hydrogen atom, an alkyl (C1 to C6) or benzyl radical, and R2 signifies a hydrogen atom, an alkyl (C1-C6), cycloalkyl, aryl or aralkyl radical and their acid addition salts, characterized in that a compound of formula R2NH2 is reacted with a dicarboxylic acid of general formula <FORM:1041015/C2/2> which may be prepared by either reacting an acid addition salt of a 4-piperidylene derivative of formula <FORM:1041015/C2/3> wherein R1 signifies the alkyl or benzyl radical, and A\sX denotes an anion, with an alkali metal cyanide, the resulting hydrogen cyanide addition product being hydrolysed and decarboxylated, or in the case where R1 signifies hydrogen by reacting a (1 - benzoyl - 4 - piperidylidene)-cyanoacetic ester with an alkali metal cyanide, then hydrolysing and decarboxylating with an inorganic acid; the resulting diammonium salt is heated to at least 150 DEG C. and the resulting succinimide, when R1 is to be hydrogen, is, if necessary, subjected to reductive splitting off of the benzyl radical. Salification with an organic or inorganic acid is effected when it is desired to produce an acid addition salt. (1 - Benzoyl - 4 - piperidylidene) - cyanoacetic acid ester is prepared by condensing 1-benzoyl-4-piperidone with a cyanoacetic acid ester.