GB935776A - Improvements in or relating to imidazole compounds and the manufacture thereof - Google Patents

Abstract

2,21-Alkylenebisareneimidazoles are prepared by reacting an o-arylenediamine in which one of the ortho-amino groups is free from substitution and the other ortho-amino group is either free from substitution or is substituted by a single indifferent group (as defined in the Specification), with a protonated carbalkoxyacetimino alkyl ether which in the form of the free base has the formula <FORM:0935776/IV(a)/1> wherein R1 is hydrogen or an indifferent group and R2 and R3 are alkyl radicals, to obtain the corresponding alkyl 2-(2-areneimidazolyl) alkanoate, and heating the alkyl 2-(2-areneimidazolyl) alkanoate so obtained with an o-arylenene of the type specified above, to obtain the desired 2,21-alkylenebisareneimidazole. The invention also comprises unsymmetrically substituted compounds of the formula <FORM:0935776/IV(a)/2> and the pharmacologically acceptable acid addition salts thereof, wherein R4 and R8 are hydrogen or alkyl radicals, R5, R6 and R7 are alkyl radicals, the substitution in one benzene ring differing from that in the other benzene ring. The protonated carbalkoxyacetimino alkyl ethers are prepared by neutralising the free base with a strong mineral acid, or by treatment of the corresponding alkyl a -cyanoalkanoate with the appropriate acid in the presence of the appropriate alkanol. The alkyl a -cyano-alkanoates of formula <FORM:0935776/IV(a)/3> in which R1 is alkyl, aralkyl, aryloxyalkyl, alkoxyalkyl or haloalkyl, R2 being alkyl, may be prepared from the corresponding alkyl cyanoacetate by condensing the latter with an aldehyde of formula X-CHO wherein X is such that R1=X,CH2- to form a compound of formula <FORM:0935776/IV(a)/4> and hydrogenating the latter compound in the presence of a palladium-on-charcoal catalyst to give the alkyl a -cyanoalkanoate. The alkyl a -cyanoalkanoates of the above general formula in which R1 is aryl or substituted aryl may be prepared by reaction of the appropriately substituted benzyl cyanide with the appropriate dialkyl carbonate in the presence of sodamide. Numerous preferred substituents are listed. Examples are given.