US3525753A - Coumarin derivatives having optical whitening properties - Google Patents

Description

United States Patent Oflice Patented Aug. 25, 1970 US. Cl. 260-6431 4 Claims ABSTRACT OF THE DISCLOSURE New coumarin derivatives useful as optical whitening agents and their use in the treatment of textile materials. The coumarin derivatives are compounds of the formula Q o- ON wherein R is a hydrogen atom or alkyl group contain ing 1-4 carbon atoms and R is an alkyl group containing from 1 to 4 carbon atoms.

This invention is concerned with new chemical compounds of use as optical whitening agents es ecially in the whitening and/or brightening of polyamide, polyester and other synthetic fibres.

Optical whitening agents have in recent years found extensive use in the treatment of textile fibres, both in their preparation and during washing, and are designed in general to counteract the yellow or oil-white colour which white textiles may develop. Such optical whitening agents also tend to improve coloured textiles as they impart a general brightness to them.

The present invention is based upon the discovery of certain coumarin derivatives which have particularly advantageous properties as optical whitening agents.

According to the present invention, there are provided compounds of the general formula:

wherein R represents a hydrogen atom or an alkyl group which is if desired substituted by a non-ionogenic and non-colour producing substituent; and

R represents an alkyl group which is if desired substituted by a non-ionogenic and non-colour producing substituent.

As stated above, the compounds according to the invention have particularly advantageous properties as optieal whitening agents. In particular, they have excellent brightening properties for polyamide, polyester and other synthetic fibres when applied from aqueous and aqueous detergent baths, and have especially favourable fluorescent properties with a most desirable shade of blue-violet fluorescence.

In compounds of Formula I in which R and/or R represents a substituted or unsubstituted alkyl group, the said alkyl group preferably contains from 1 to 4 carbon atoms and is advantageously a methyl, ethyl, or isopropyl group. When R represents a substituted alkyl group, the substituent may for example be a halogen e.g. chlorine atom; R may thus represent a fi-chloroethoxy group. Alternatively, the substituent may be a radical of formula -NR R in which R, and R represent alkyl groups, preferably such groups containing from 1 to 14 carbon atoms; R may thus represent a group of formula --(CH ),,NR R wherein n represents an integer from 1 to 4. Quaternised derivatives of such compounds are also compounds in accordance with the present invention. An especially preferred compound of Formula I is the compound in which R represents a hydrogen atom and R represents a methyl group.

For the purpose of treating textile fibres in general, the compounds according to the invention may be advantageously be incorporated into compositions comprising at least one compound of Formula I together with a solid or liquid carrier. Such compositions may for example be adapted for use in the washing of finished polyamide and polyester fibres, and can take of the form of solutions suspensions and dispersions of compounds of Formula I in appropriate liquid carriers such as for example, sulpholane, dimethylformamide and dimethylsulphoxide. When dispersions are used, they conveniently include dispersing agents such as for example alkyl naphthalen sulphonates. Aqueous compositions may if desired also contain for example synthetic detergents, soaps or surface active agents. Alternatively the compositions may be solid form and comprise at least one compound according to the invention together with a solid synthetic detergent or soap as carrier. The compounds of Formula I may also be employed in the manufacture of synthetic fibres, e.g. by addition to compositions from which the fibres are prepared by spinning or extrusion,

The coumarin derivatives of Formula I may be prepared by any convenient method, but are advantageously prepared by one of the following processes:

(1) Reaction of a compound of formula Iii (wherein R is as defined above and X represents a cyano group or a group such as for example a nitro group convertible to a cyano group) with an approrpiate alkylating to a cyano group. The alkylating agent is conveniently a dialkyl sulfate (e.g. dimethyl or diethyl sulphate) or an alkyl iodide (e.g. methyl iodide or ethyl iodide). The compounds of Formula II used as starting material in the reaction can for example first be prepared as follows:

(a) Reaction of a compound of formula OH HO- 3 (c) Where R represents a hydrogen atom, heating of c (4' cyanophenyl) ,8 (2",4" dimethoxyphenyl) acrylonitrile in the presence of an anhydrous Friedel- Crafts catalyst such as for example aluminium chloride. The a (4' cyanophenyl) B (2",4" dimethoxyphenyl) acrylonitrile may if desired first be prepared by the reaction of p-cyanobenzyl cyanide with 2,4-dimethoxybenzaldehyde.

(2) Reaction of a compound of formula R20 /OH O I ll (wherein R and R are as defined above) with a compound of formula (wherein X represents a cyano group or a group such as for example a nitro group convertible to a cyano group) or a functional derivative thereof, and where necessary converting the group X to a cyano group.

-(3) Reaction of a coumarin derivative of formula (wherein R and R are as defined above) with a diazonium compound of formula (wherein X represents a cyano group or a group such as for example a nitro group convertible to a cyano group), and where necessary converting the group X to a cyano group.

Where R represents a hydrogen atom, the compounds of Formulae III and VII are substituted benzaldehydes. 2,4-dihydroxybenzaldehyde (Formula III, R =H) may thus for example be used.

Alternatively compounds of Formula VII such as for example 2 hydroxy 4 methoxybenzaldehyde may be used which upon reaction with 4-cyanophenylacetic acid or a functional derivative thereof yield directly a compound of Formula I. Where compounds of Formula I are obtained in which R represents a group containing a tertiary amino radical, the tertiary amino radical can if desired be quaternised, for example by reaction with dimethyl sulphate, diethyl sulphate, methyl iodide or ethyl iodide as quaternising agent.

In order that the invention may be well understood the following examples (in which all parts are by weight) are given by way of illustration only:

(VII) (VIII) EXAMPLE 1 p-Aminobenzonitrile (4.2 pts.) in aqueous hydrochloric acid (18%) (50 pts.) was diazotised with sodium nitrite (2.5 pts.) in water (10 pts.) at 05 C. The diazo slurry was added to a mixture of sodium acetate (11.4 pts.), 7-methoxy-coumarin (6.3 pts.), acetone (24 pts.) and cupric chloride (1.5 pts.) in water (5 pts.). The temperature of the mixture rose 20 C. and nitrogen was evolved. The mixture was heated to 30 C. and held at that temperature for 3 hours. The reaction mixture was then cooled, filtered and dried. The precipitate was recrystallised from aqueous acetone to yield a pale grey powder (4.4 pts.) of 3(4' cyanophenyl) 7 methoxy coumarin. E =1010 at 348 m M.P 230-235" C.

4 EXAMPLE 2 p-Cyanobenzyl cyanide (142 pts.) and 2,4-dimethoxybenzaldehyde (166 pts.) are dissolved in methanol (1600 pts.), cooled to 50 C. and caustic soda solution (sp. gr. (7.5 pts.) are added to the solution. a-(4'-cyanophenyl) 5 (2",4" dimethoxyphenyl)acrylonitrile immediately precipitates. The reaction mixture is cooled to room temperature and the precipitate is collected, washed with ethanol and dried. Yield 235 pts., M.P. 199-200 C.

a (4' cyanophenyl) B (2",4 dimethoxyphenyl) acrylonitrile (145 pts.) is refluxed in o-dichlorobenzene (1200 pts.) with anhydrous aluminium chloride (250 pts.) for 8 hours. The reaction mixture is then cooled, filtered and thoroughly washed with water. The crude product is then steam distilled to remove o-dichlorobenzene. The product is then filtered, washed with water and dried. The product is 3 (4' cyanophenyl) 7 hydroxy coumarin, yield pts., M.P. 315 C.

3 (4 cyanophenyl) 7 hydroxycou marin (135 pts.), anhydrous potassium carbonate (100 pts.), dimethyl sulphate (100 pts.), and methylethylketone (2500 pts.) are refluxed for 9 hours. At the end of the reaction the solvent is distilled off and the residual solid boiled with water (4000 pts.). The solid is then filtered and dried. The 3- (4' cyanophenyl) 7 methoxy coumarin thus obtained is recrystallised from 35% acetic acid. M.P. 230 C., E 1040 at 348 mg.

The following compounds have been prepared by a process analogous to that described in Example 2:

C E 1 m n x 3-(4-cyanophenyl) -7-ethoxycoumarin 196-8 966 350 3(4-cyanophenyl)-7-isopropoxy-coumarin 216-8 958 351 EXAMPLE 3 Aqueous baths are prepared containing 0.1 g./ litre of 3 (4' cyanophenyl) 7 methoxy coumarin, 3 (4'- cyanophenyl) 7 ethoxycoumarin and 3 (4 cyanophenyl)-7-isopropoxycoumarin respectively.

In use terylene fabric is treated in the baths for /5 hour at the boil, the liquor ratio being 1:40. The terylene thus treated is subsequently rinsed and dried and is in the case of each of the baths much whiter and brighter than prior to the treatment.

I claim: 1. A compound of the formula 0 R20 \C:O

1&1 I

References Cited UNITED STATES PATENTS 3,351,482 11/1967 Raue 260343.2 XR

HENRY R. JILES, Primary Examiner J. M. FORD, Assistant Examiner U.S. Cl. X.R.