Abstract: Coumarin compounds of the formula: ##STR1## in which R represents an alkyl group containing 1 to 5 carbon atoms, either unsubstituted or substituted by a non-ionic and non-chromophoric group, one of the substituents R.sub.1 or R.sub.2 represents a triazole radical, and the other represents hydrogen or a halogen, or an alkyl group containing from 1 to 3 carbon atoms, the triazole radical being unsubstituted or substituted by one or two substituents consisting of an alkyl group containing from 1 to 3 carbon atoms or an aryl group; processes for their preparation and their use as fluorescent brightening agents for polyester fibres.

Abstract: Coumarin of the formula: ##SPC1##In which R.sub.1 represents an alkyl group having 1 to 5 carbon atoms, and either unsubstituted or substituted by a non-ionic and non-chromophoric group, R.sub.2 represents a benzene, styryl or heterocyclic residue such residue being unsubstituted or substituted by one or two non-ionic and non-chromophoric groups; process for the preparation of a coumarin of the above formula which comprises reacting an orthohydroxy-benzaldehyde of formula (II) upon an acid of formula (III) or one of its functional derivatives: ##SPC2##Wherein R.sub.1 and R.sub.

Abstract: A process for the preparation of an optical brightening agent falling within the formula: ##SPC1##In which R represents an alkyl group containing 1 to 4 carbon atoms, R.sub.1 and R.sub.2 each represent a hydrogen atom, an alkyl group containing 1 to 4 carbon atoms or a phenyl group either unsubstituted or substituted by at least one alkyl group containing 1 to 4 carbon atoms, R.sub.3 and R.sub.4 each represent an alkyl group containing 1 to 4 carbon atoms and A.sup.- represents a monovalent anion which comprises reacting a compound of the formula: ##SPC2##In which R.sub.1, R.sub.2, R.sub.3, R.sub.4, and A.sup.- have the meanings given above, with an alcoholate of the formula RO-Me in which R represents an alkyl group containing 1 to 4 carbon atoms and Me is an alkali metal; compounds falling within the formula: ##SPC3##Wherein R.sub.1, R.sub.2, R.sub.3, R.sub.4 and A.sup.- have the meanings given above.