2-(4'-amidostyryl)-benzoxazoles and method for using the same for the optical brightening of textiles

The invention comprises compounds of the general formula wherein R1 and R2 each represent H or an alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, carboxyalkyl or sulphoalkyl group, an N,N-dialkylaminoalkyl group or a corresponding trialkylammoniumalkyl group or a substituted or unsubstituted aryl or aralkyl group, or R1 and R2 together complete a heterocylic ring which contains nitrogen, and R3 and R4 each represent H or halogen or an alkyl, alkoxy or aryl group, or R3 and R4 together complete a carbocyclic or heterocyclic ring. The compounds may be prepared (i) by reacting the acid chlorides of methyl esters of compounds of the formula with amines of the formula R1-NH-R2, (ii) by condensing compounds of the formula with compounds of the formula or (iii) (when R1 and R2 are both H) by saponification of compounds of the formula The compound of the formula is prepared by quaternization, using dimethyl sulphate, of the corresponding tertiary amine.ALSO:Textile materials are optically brightened by treatment with a compound of the general formula:- wherein R1 and R2 are each H or an alkyl, cycloalkyl, hydroxyalkyl, alkoxyalkyl, carboxyalkyl or sulphoalkyl group, an N, N-dialkylaminoalkyl group or a corresponding quaternary trialkylammoniumalkyl group or a substituted or unsubstituted aryl or aralkyl group, or R1 and R2 together complete a heterocyclic ring containing nitrogen, and R3 and R4 each represent H or halogen or an alkyl, alkoxy or aryl group, or R3 and R4 together complete a carbocyclic or heterocyclic ring. The compounds may be applied in the form of solutions in water and/or organic solvents or in the form of dispersions and may be used together with chemical bleaching agents and/or detergents.