GB936477A - Improvements in or relating to substituted succinimides - Google Patents

Abstract

The invention comprises substituted succinimides (2 : 8- diazaspiro(4,5)decane- 1 : 3-diones) of the general formula <FORM:0936477/IV(a)/1> wherein R1 represents a hydrogen atom, a benzyl group or a C1-6 alkyl group and R2 represents a hydrogen atom or a C1-6 alkyl group, and their acid addition salts, and the preparation thereof by (a) reacting a substituted piperidone-4 of the general formula <FORM:0936477/IV(a)/2> (wherein R11 represents a C1-6 alkyl group or a benzyl group) with a compound of the general formula <FORM:0936477/IV(a)/3> (wherein X represents -CN) in the presence of a catalyst for splitting off water, to form a compound of the general formula <FORM:0936477/IV(a)/4> converting this into a compound of the general formula <FORM:0936477/IV(a)/5> by the incorporation of the elements of hydrocyanic acid, subjecting this compound to hydrolysis, decarboxylation and esterification with an alkanol to form a substituted succinic acid diester of the general formula <FORM:0936477/IV(a)/6> and reacting this with an amino compound R2NH2; or (b) (when R2 = H) preparing compound V as in (a) and subjecting it to partial hydrolysis, decarboxylation and ring closure (either simultaneously, e.g. by the action of a mixture of concentrated sulphuric acid and glacial acetic acid, or with intermediate formation of a 1-substituted-4-carbamoylpiperidyl-4-acetic acid, which is esterified with an alkanol and the resulting ester-amide heated in liquid form until bubbling ceases); and in either case, if desired, if R11 = benzyl, splitting off this group under reducing conditions, and, if desired, alkylating the resulting secondary amino group, and further, if desired, salifying the product with an inorganic or organic acid. The products are useful as cholinergic agents or as intermediates for the preparation of pharmaceuticals.