GB835894A - Manufacture of di-(aryloxazolyl)-ethylene derivatives - Google Patents

Abstract

The invention comprises new di-(aryloxazolyl)-derivatives of formula <FORM:0835894/IV (b)/1> in which R1 and R2 indicate aryl residues condensed with the hetero ring as shown. These and other compounds, all of the general formula <FORM:0835894/IV (b)/2> in which R1 and R2 are as above and R3 is -CH=CH-group or a -CH=COH-group, may be manufactured by heating acylamino compounds of the general formula <FORM:0835894/IV (b)/3> in which R1 and R2 are aryl groups having the -OH and -NH- groups attached to adjacent carbon atoms and <FORM:0835894/IV (b)/4> or a <FORM:0835894/IV (b)/5> group, with agents that split off water. Suitable agents for splitting off water are, for example, boric acid, propionic acid, glacial acetic acid, sulphur trioxide and, particularly, zinc chloride. When sulphur trioxide, advantageously in the form of oleum, is used, sulphonation of the aromatic nuclei may also take place. The enolic group -CH= COH- which occurs in some of the compounds referred to above may exist in the tautomeric form -CH2-CO- and both enol and keto forms are included in the definition of R3. The acylamino compounds used as starting materials may be prepared according to the process described and claimed in Specification 835,893, in which malic acid or tartaric acid is condensed on both carboxylic acid groups with primary aryl amines that contain an hydroxyl group in adjacent position to the amino group. The R1 and R2 groups are preferably benzene nuclei which may contain as substituents low alkyl or alkoxy groups containing up to 4 carbon atoms, halogen atoms or nitro groups. In the examples the following compounds are prepared: <FORM:0835894/IV (b)/6> <FORM:0835894/IV (b)/7> <FORM:0835894/IV (b)/8> <FORM:0835894/IV (b)/9> <FORM:0835894/IV (b)/100> or its tautomer <FORM:0835894/IV (b)/111> <FORM:0835894/IV (b)/122> and (g) the sodium salts of <FORM:0835894/IV (b)/133> and <FORM:0835894/IV (b)/144>ALSO:The invention comprises new di-(aryloxazolyl) derivatives of formula <FORM:0835894/IV(c)/1> in which R1 and R2 indicate aryl residues condensed with the hetero ring as shown. These and other compounds, all of the general formula <FORM:0835894/IV(c)/2> in which R1 and R2 are as above and R3 is -CH = CH- or -CH = COH- may be obtained by heating acylamino compounds of formula <FORM:0835894/IV(c)/3> in which R1 and R2 are aryl groups having the -OH and -NH- groups attached to adjacent carbon atoms and R4 is a <FORM:0835894/IV(c)/4> group, with agents that split off water, e.g. boric acid, propionic acid, glacial acetic acid, sulphur trioxide and, particularly, zinc chloride. When sulphur trioxide is used, sulphonation of the aromatic nuclei may also take place. The aromatic nuclei R1 and R2 may contain as substituents alkyl or alkoxy groups containing up to 4 carbon atoms, halogen atoms or nitro groups.