GB914719A - New derivatives of coumarin - Google Patents

Abstract

In Example 7 a mixture of polyvinyl chloride, dioctyl phthalate, titanium dioxide and 3-(5-methyl-benzoxazolyl-(2))-coumarin is made into a foil by rolling at 150 DEG -155 DEG C. on a two-roll calender. Other suitable coumarin derivatives are those of the formula <FORM:0914719/IV(a)/1> wherein R1, R3 and R4 each represent a hydrogen or chlorine atom or an alkyl group containing 1-4 carbon atoms, and R2 represents a hydrogen atom or an alkyl group containing 1-4 carbon atoms (see Group IV(b)). The compounds are optical brightening agents.ALSO:The invention comprises coumarin derivatives of the formula <PICT:0914719/IV (b)/1> wherein R1, R3 and R4 may be identical or different and represent a hydrogen or a chlorine atom or an alkyl group containing 1-4 carbon atoms, and R2 represents an alkyl group containing 1-4 carbon atoms. The compounds are prepared by the action of a watereliminating agent on (1) a coumarin-3-carboxylic acid and an ortho-amino-phenol of formulae <PICT:0914719/IV (b)/2> or (2) an intermediate amide or ester obtainable from reaction between the acid above or its functional derivatives and the aminophenol. Preferred compounds are those in which R1, R3 and R4 each represent a hydrogen or chlorine atom or a methyl group, these substituents being in the 6-position of the coumarin residue and in the 5- and 6-positions of the benzoxazole residue, and R2 represents a hydrogen atom or a methyl group. Suitable water-eliminating agents are zinc chloride, phosphoric acids of the formula Hn+2PnO3n+1 where n is an integer preferably greater than 1, mixtures of these phosphoric acids, or concentrated aqueous or anhydrous sulphuric acid. An elevated temperature is preferable for the water-eliminating step. Examples (1)-(4) describe the preparation of numerous compounds of the preferred class. In Example (5) an intermediate acylamino compound is prepared and is then cyclized. The intermediate coumarin-3-carboxylic acids are prepared by condensing the corresponding ortho-hydroxy-benzaldehyde or -phenyl ketone with (1) malonic acid, or (2) with malononitrile to give the corresponding nitrile which is then hydrolysed to the acid. The products may be used as light-filters for ultra-violet rays, as intermediates in the manufacture of dyestuffs, for photographic purposes, and as optical brightening agents for fibres and fabrics (see Groups IV(a) and IV(c)).ALSO:Compounds of the general formula <FORM:0914719/IV (b)/1> wherein R1, R3 and R4 each represent a hyd rogen or chlorine atom or an alkyl group containing 1-4 carbon atoms, and R2 represents a hydrogen atom or an alkyl group containing 1-4 carbon atoms (see Group IV(b)), may be used as optical brightening agents for fibres and fabrics, especially polyester fibres and polyester, polyamide and acetate rayon fabrics. The compounds may be applied to polyester fibres by known methods, e.g. in a fine dispersion from an aqueous bath. In Example (6) a polyester fabric is treated in a bath containing aqueous formic acid and one of the above compounds. In Example (8) a polyamide acetic acid and one of the above compounds; fabric is treated in a bath containing aqueous acetate rayon fabric may be treated similarly.