GB824425A - 4-piperidyl esters - Google Patents

Abstract

The invention comprises compounds of the general formula <FORM:0824425/IV (b)/1> and acid addition salts thereof, wherein R1 represents an alkoxy (1-4 carbon atoms), an alkyl (1-4 carbon atoms), an NH-alkyl (1-4 carbon atoms), or an alkoxy-alkyl-NH group (2-8 carbon atoms), a chlorine or a bromine atom, and R2 represents an alkyl group (1-4 carbon atoms); and a process for the manufacture thereof by reacting a compound of the general formula <FORM:0824425/IV (b)/2> with a compound of the general formula <FORM:0824425/IV (b)/3> wherein R1 and R2 have the meaning above and X is a chlorine or bromine atom or an alkoxy group (1-3 carbon atoms). The reaction is preferably carried out at temperature of 150-200 DEG C., and in the presence of a condensing agent such as an alkali metal alcoholate or metallic sodium. In the process wherein X in formula III is chlorine or bromine, the reaction is effected in such a way that the two starting materials are dissolved in an inert organic solvent such as benzene, toluene or xylene, and the resultant hydrogen halide salt of the ester is treated with an alkali to obtain the free ester. In an example, p-n-butoxy-benzoyl chloride is reacted with 1-methyl-4-hydroxypiperidine in benzene, the free p-n-butoxybenzoic acid (1-methyl-4-piperidyl) ester being obtained by reaction with sodium carbonate. Similarly are prepared the anisic acid, p-ethoxybenzoic acid, p-toluylic acid, p-chloro-benzoic acid, p-butyl-amino-benzoic acid (1-methyl-4-piperidyl) esters from 1-methyl-4-hydroxypiperidine and the appropriate acid chloride. The p-n-butoxy-p-butyl-amino and p-methoxy-ethylamino - benzoic acid esters of 1 - methyl - 4 are also prepared by reacting the appropriate benzoic acid methyl or ethyl ester with the hydroxypiperidine in the presence of sodium ethylate. The monohydrochloride acid addition salts are prepared from the basic esters by reaction with hydrochloric acid.