Mit Oxazolverbindungen optisch aufgehellte Formkoerper und Verfahren zu deren Herstellung

1,127,227. o-Hydroxy-acylamino compounds. CIBA Ltd. 21 Oct., 1965 [27 Oct., 1964], No. 44646/65. Heading C2C. [Also in Division C3] o-Hydroxy-acylamino compounds containing at least one structural element of the formula in which A completes a benzene ring and B 1 represents a radical containing 5-11 double bonds conjugated with the CO group and one another and present in phenyl, phenylene, 2,5- thienylene, 2,5-furoylene, benzoxazole, naphthoxazole, benztriazole or naphthotriazole radicals or in an ethylene group conjugated with said radicals, are prepared by reacting a carboxylic acid halide of the formula with an o-amino compound of the formula where W is as B 1 above, preferably in the presence of an inert organic solvent at 100- 200‹ C. The amides may be substituted by non-chromophoric groups, e.g. alkyl, carbomethoxy and carboethoxy groups. The preparation of the following compounds is described The acid chloride reactants may be prepared by (I) for 1,4 - dibenzoxazolyl - (21,211) - benzene - 61,611 - dicarboxylic acid chloride, reacting terephthalic acid dichloride with 4-amino-3-hydroxybenzoic acid methyl ester, cyclizing the resultant diamide to the dibenzoxazolyl-dicarboxylic acid methyl ester, hydrolysing the ester to the di-acid and forming the chloride by reaction with thionyl chloride, (2) for benzoxazolyl - (21)- 4,61 - dicarboxylic acid chloride, using a similar reaction sequence, starting from terephthalic acid methyl ester chloride, (3) for 4 - benzoxazolyl - (21)- stilbene carboxylic acid chloride, using a similar reaction sequence starting from stilbene - 4,41 - dicarboxylic acid methyl ester chloride, (4) for 5 - [51 - t - butyl - benzoxazolyl - (21)]- thiophene - 2 - carboxylic acid chloride, using a similar reaction sequence starting from thiophene-2,5-dicarboxylic acid methyl ester chloride and 4-t-butyl-2-amino-1- hydroxybenzene, (5) for the acid chloride of the formula reacting stilbene-4,41-dicarboxylic acid methyl ester chloride with 4-t-butylbenzhydrazide, cyclizing the resulting diacyl hydrazine to the corresponding oxadiazole compound and converting the methyl ester group to the acid chloride as above.