GB835895A - Process for the manufacture of ª‡:ª‰-di-[aryloxazolyl-(2)]-ethylene compounds - Google Patents

Abstract

a ,b -Di-[aryloxazolyl-(2)]-ethylene compounds are manufactured by condensing two molecular proportions of an ortho-hydroxy aminoaryl compound at raised temperature with one molecular proportion of fumaric acid, malic acid or aspartic acid or an alkyl mono- or di-ester of one of these acids, and, without separating the condensation product, subjecting it to ring closure by heating to 100-200 DEG C. in the presence of a catalyst capable of eliminating the elements of water to form the di-oxazolyl compound, and, when malic acid or aspartic acid or one of their esters is used as starting material, splitting off water or ammonia, respectively, from the residues of these acids. The condensation is preferably carried out in the presence of an organic solvent, e.g. mono-, di- or tri-chlorbenzene, nitrobenzene, toluene, xylene or cumene. Suitable catalysts are, for example, sulphonic acids of the benzene series and boric acid, and these catalysts also eliminate water or ammonia from the dicarboxylic acid residue when necessary. The ortho-hydroxy amino aryl compounds used as starting materials may contain further substituents such as alkyl and alkoxy groups having 1-4 carbon atoms, halogen atoms and nitro groups. Examples are given of the preparation of <FORM:0835895/IV (b)/1> <FORM:0835895/IV (b)/2> <FORM:0835895/IV (b)/3> <FORM:0835895/IV (b)/4> <FORM:0835895/IV (b)/5> and <FORM:0835895/IV (b)/6> Specifications 835,892 and 835,898 are referred to.ALSO:a .b - di - [aryloxazolyl - (2)] - ethylene compounds are produced by condensing 2 molecular proportions of an o-hydroxy amino aryl compound at raised temperatures with one molecular proportion of fumaric acid, malic acid or aspartic acid or an alkyl mono- or di-ester of one of these acids, and, without separating the condensation product, subjecting it to ring closure by heating to 100-200 DEG C. in the presence of a catalyst capable of splitting off water and, when malic acid or aspartic acid or one of their esters is used as starting material, splitting off water or ammonia respectively from the residues of these acids. Suitable catalysts are, for example, sulphonic acids of the benzene series and boric acid. The o-hydroxy amino aryl compounds used as starting materials may contain further substituents such as alkyl and alkoxy groups having 1-4 carbon atoms, halogen atoms and nitro groups. Specifications 835,892 and 835,898 are referred to.