MXPA01007489A - Bis-styrylbiphenyl compounds - Google Patents

Abstract

Asymmetrical bis-styrylbiphenyl compounds of formula (1) wherein R1 to R6 are as defined in claim 1, are excellently suitable as optical brighteners, for example for polyesters in the spinning melt.

Description

BIS-ESTIRILBIFENILO COMPOUNDS The present invention relates to novel asymmetric bis-styrylbiphenyl compounds, to a process for their preparation and to their use as optical brighteners, in particular for polyester centrifugation fusions. The bis-styrylbiphenyl compounds which are suitable as optical brighteners are already known, for example from GB-A-1, 247, 934 which also describes processes for their preparation. However, these processes provide almost exclusively symmetrical compounds, ie compounds that transport the same substituents in the same positions in the terminal phenyl radicals. The preparation of asymmetric bis-styrylbiphenyl compounds is described only in admixture with symmetrical compounds from which they must be separated by elaborate measures, for example by recrystallization. Naturally, the resulting yield of asymmetric compounds is unsatisfactory. A process for the preparation of asymmetric bis-styrylbiphenyl compounds has now been found which provides them with high yields and good purity. When used as optical brighteners in polyester spin fusions, the obtained bis-styrylbiphenyl compounds have surprisingly improved whiteness, as compared to the corresponding symmetrical compounds. Accordingly, this invention relates to asymmetric bis-styrylbiphenyl compounds of the formula wherein Ri and R2 each independently of the other is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, wherein R-. and R2 are not both hydrogen at the same time and these substituents are different if they are in the same position of the phenyl ring, and R3 / R4, R5 and R6 each independently represent hydrogen, halogen, alkyl, cycloalkyl or alkoxy. Preferred compounds of this invention correspond to the formula wherein Rx and R2 independently of the other are hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, at least one of which is not hydrogen, and R3j R4, R, 3 and R6 independently from each other are hydrogen, halogen, alkyl or alkoxy. Preferred meanings of R x and R 2 independently of one another are cyano, chloro, hydroxy, alkyl with 1 to 4 carbon atoms, alkoxy with 1 to 4 carbon atoms or phenyl. R3 to R6 preferably each independently of one another are hydrogen, chloro, alkyl with 1 to 4 carbon atoms or alkoxy with 1 to 4 carbon atoms. In particular, preferred compounds of the formula (1) or (2), all these substituents are hydrogen. Halogen is fluorine, bromine, iodine or preferably chlorine.

The alkyl groups in the alkyl, alkoxy, alkoxycarbonyl, alkylcarbonyloxy and aralkyl radicals contain, for example, 1 to 12 carbon atoms, preferably 1 to 6 carbon atoms and more preferably 1 to 4 carbon atoms. In the optical brighteners of formulas (1) and (2), alkyl is preferably alkyl having 1 to 4 carbon atoms, for example methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl. Cycloalkyl is preferably cycloalkyl with to 7 carbon atoms, more preferably cyclohexyl. Alkoxy preferably means alkoxy with 1 to 4 carbon atoms, for example methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, isobutoxy and tert-butoxy. Aryl, for example, is naphthyl or preferably phenyl and these radicals can be substituted, for example, by alkyl, alkoxy, sulfo, carboxy, halogen or alkoxycarbonyl. Aralkyl preferably means alkylenephenyl with 1 to 4 carbon atoms, more preferably benzyl. Very particularly preferred novel compounds correspond to the formula wherein R x is hydrogen, cyano, halogen, hydroxy, alkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl. Of these compounds, those in which Rx is alkyl with 1 to 2 carbon atoms, alkoxy with 1 to 2 carbon atoms, cyano or phenyl are particularly preferred. The compounds of the formula (1) are prepared, for example, by reacting 1 mol of a dialdehyde of the formula wherein R3 R4, R5 and R6 each independently of one another are hydrogen, halogen, alkyl or alkoxy, with 1 mol of a compound of the formula wherein Rx is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R7 and R8 are alkyl, cycloalkyl, aryl or aralkyl, to give an intermediate of the formula and then react this intermediate with 1 mole of a compound of the formula wherein R2 is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R7 and R8 are alkyl, cycloalkyl, aryl or aralkyl wherein Rx and R2 are not both hydrogen at same time and these substituents are different if they are in the same position of the phenyl ring to give a compound of the formula (1). R7 and R8 are preferably alkyl with 1 to 4 carbon atoms, phenyl or benzyl. In particularly preferred compounds of the formulas (5) and (7) these substituents are alkyl having 1 to 2 carbon atoms. The compounds (4), (5) and (7) are known or can be prepared in a manner known per se. The reaction of a compound of the formula (4) with a compound of the formula (5) and the reaction of an intermediate of the formula (6) with a compound of the formula (7) are carried out in the presence of a strongly basic compound. These strongly basic compounds, for example, are alkali metal hydroxides, alkali metal amides, alkali metal carbonates, alkali metal hydrogen carbonates or alkali metal alcoholates, in particular lithium, potassium or sodium compounds. The potassium or sodium alcoholates of alcohols with 1 to 4 aliphatic carbon atoms are particularly preferred. The solvent employed for the reaction of a compound of the formula (4) with a compound of the formula (6) is a solvent that is inert to the reactants, preferably an aliphatic alcohol, and more preferably an alcohol with 1 to 6 atoms of carbon. Suitable are, for example, methanol, ethanol, n-propanol, isopropanol, butan-1-ol, butan-2-ol, tert-butanol, pentan-1-ol and hexan-1-ol. Of these methanol is preferred. The reaction temperature is usually in the range from room temperature to the boiling temperature of the solvent. It is preferred to work at about 20 to 80 ° C, more preferably at 30 to 70 ° C. The reaction time depends among others on the type of reagents used and the reaction temperature. The temperature is usually in the range of 2 to 48 hours. After the reaction is complete, the reaction mixture is processed in the usual manner and the compounds of the formula (6) are isolated, if desired, for example by evaporation or by filtration if they are insoluble in the solvent employed. The intermediaries of the formula wherein Rx is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R3) R4, R5 and R6 independently each other represents hydrogen, halogen, alkyl or alkoxy, at least one of the substituents R3r R4, R5 and R6 are not hydrogen, they are novel and also an object of this invention. To react a compound of the formula (6) with a compound of the formula (7) an aprotic solvent is used which is inert towards the reactants and wherein the compound of the formula (6) is at least partially soluble. It is possible to use, for example, dimethylformamide, diethylformamide, dimethylacetamide, dimethyl sulfoxide and N-methylpyrrolidone. The reaction temperature is usually in the range from room temperature to the boiling point of the solvent. It is preferred to work at about 20 to 80 ° C, more preferably at 20 to 40 ° C.

The reaction time depends, among others, on the type of reagents used and the reaction temperature and is generally in the range of 2 to 48 hours. After the reaction is completed, the reaction mixture is processed in the usual manner and the compound of the formula (1) is isolated, for example by evaporation or by filtration if it is insoluble in the solvent used. The compounds of the formula (1) have marked fluorescence in the dissolved or finely divided state. In this way they can be used for optical brightening of a range of materials, in particular organic materials. This invention thus also relates to the use of the compounds of the formula (1) for optically brightening organic materials, and to organic materials comprising at least one compound of the formula (1), as well as a process for optically brightening materials organic, this process comprises incorporating in, or applying to these materials at least one compound of the formula (1). The organic materials that can be brightened according to the invention by the compounds of the formula (1) include synthetic, semi-synthetic or natural, especially polymeric materials. Suitable materials are, for example, a) polymerization products based on organic compounds containing at least one polymerizable carbon-carbon double bond, for example polymers based on unsaturated carboxylic acids or their derivatives (such as acrylic esters, acrylic acids, acrylonitrile and their derivatives), in olefinic hydrocarbons (such as ethylene, propylene, styrene) or in vinyl compounds, or vinylidene compounds (such as vinyl chloride, vinyl alcohol, vinylidene chloride); b) polymerization products that are obtained by ring opening, for example polyamides of the caprolactam type, and also polymers which are obtained both by polyaddition and by polycondensation, such as polyethers or polyacetals; c) polycondensates, such as polyesters, polyamides, melamine resins or polycarbonates; d) polyaddition products, such as polyurethanes, or e) semi-synthetic materials, such as cellulose ester, cellulose ether, regenerated cellulose. Particular novel compounds are preferably used to optically polish polyesters, in particular polyethylene glycol terephthalate, in the spin melt, since they do not decompose at the required temperatures.

Surprisingly, the novel asymmetric compounds of the formula (1) have a higher degree of whiteness in the materials mentioned than the corresponding symmetrical compounds. They are also distinguished by good firmness to sublimation in particular. The following Examples illustrate the invention in more detail. Parts and percentages are given by weight and temperatures are given in Ceisius degrees. Example 1: 4- \ 2 - (4"-Formil Ti, 1 '-bifenill -4 -yl) etenill benzonitrile 3.15 g (15 mmol) of 4,4' -bifenildialdehyde are suspended in 100 ml of methanol at room temperature. A solution of 1.62 g (30 mmol) of sodium methylate in 4.7 ml of methanol is added dropwise to this suspension for 10 minutes, and this mixture is then heated to 40 ° C. A solution of 3.38 g (15 mmol) of 4- (dimethoxyphosphonomethyl) benzonitrile in 16 ml of methanol is then added dropwise for 30 minutes.After completing the addition, the reaction mixture is allowed to cool to room temperature and is stirred for another 20 hours at room temperature. The precipitate is subjected to filtration, washed with 2 x 50 ml of methanol and once with 50 ml of hexane and then dried at 80 ° C. under vacuum, yielding 3.89 g (12.6 mmoles) of the compound of the formula 2. 5 g of this compound are recrystallized from 50 ml of 1,2-dichlorobenzene. The mixture is heated until the solid is completely dissolved and then cooled and loaded with 1.5 g of tonsil. This mixture is refluxed and subjected to hot filtration. The filtrate is again refluxed and then cooled in an oil bath. This produces 1.18 g of the analytically pure compound of the above formula. NMR spectrum H: (360 MHz, [D6] DMS0): d = 7.4 (d); 7.6 (m); 7.8 (m); 8.0 (AA'XX '); 10.1 (s) Example 2: 2- \ 2 - (4'-Formyl Ti, 1-biphenyl-4-yl) ethenyl benzonitrile 3.15 g (15 mmol) of 4,4 '-bifenyldialdehyde are suspended in 100 ml of methanol at room temperature. A solution of 1.62 g of sodium methylate in 4.7 ml of methanol is added dropwise to this suspension for 10 minutes, and this mixture is then heated to 40 ° C. A solution of 3.38 g (15 mmol) of 2- (dimethoxyphosphonomethyl) benzonitrile in 16 ml of methanol is added dropwise for 30 minutes at this temperature. After the addition is complete, the reaction mixture is allowed to cool to room temperature and is stirred for another 20 hours at room temperature. The precipitated solid is subjected to filtration, washed with 2 x 50 ml of methanol and once with 50 ml of hexane and then dried at 80 ° C under vacuum. This produces 3.2 g (10.3 mmoles) of the compound of the formula 2. 2 g of this compound are recrystallized from 40 ml of chlorobenzene. The mixture is heated until the solid is completely dissolved and then cooled and loaded with 0.5 g of tonsil. The mixture is refluxed and subjected to hot filtration. The filtrate is again refluxed and then cooled in an oil bath. This produces 1.25 g of the analytically pure compound of the above formula. NMR-1 spectrum !!: (360 MHz, [D6] DMSO): d = 7.4 - 8.1 (m); . 1 (s) Example 3: 2,4 '(Ri.l'-Bifenill-4,4'-diildi-2, l-etenediyl) bis-benzonitrile 46.41 g (0.15 mol) of 4- [2- (4' -formyl [1,1'-biphenyl] -4-yl) ethenyl] benzonitrile, obtained according to Example 1, and 37.16 g (0.165 mol) of 2- (di-methoxyphosphonomethyl) -benzonitrile are suspended in 400 ml of N, N-dimethylformamide. A solution of 10.80 g of sodium methylate in 32 ml of methanol is added dropwise to this suspension for 60 minutes. A beige to coffee suspension is obtained by stirring for another 3 hours at room temperature. After adding 150 ml of methanol, the mixture is stirred for 10 minutes and the precipitated solid is subjected to filtration. The filtrate is washed with 2 x 25 ml of water and then with 2 x 50 ml of methanol and dried at 80 ° C under vacuum. This produces 53.83 g of the compound of the formula 48. 83 g of this compound are recrystallized from 500 ml of 1,2-dichlorobenzene. The mixture is heated until the solid is completely dissolved and then cooled and loaded with 3.0 g of tonsil. This mixture is refluxed and subjected to hot filtration. The filtrate is again refluxed and then cooled in an oil bath. This produces 41.5 g of the analytically pure compound of the above formula.

NMR-1 spectrum !!: (360 MHz, [D6] DMSO): d = 7.44 (m); 7.53 (d); 7.64 (d); 7.75 - 8.05 (m); 8.15 (d) Example 4: 3, 4 '- (Ti, 1'-Bifenill-4,4'-diildi-2, l-etendylyl) bis-benzonitrile to Under a weak stream of nitrogen, 4.64 g (0.015 mol) of 4- [2- (4 '-formyl [1,1'-biphenyl] -4-yl) -ethenyl] benzonitrile, obtained according to Example 1, and 4.39 g (0.0165 mol) of 3- (di-methoxyphosphonomethyl) benzonitrile are suspended in 40 ml of N, N-dimethylformamide. A solution of 3.6 g (0.02 mol) of 30% sodium methylate is then added dropwise to this suspension for 25 minutes. This mixture is stirred for four hours at room temperature and then for another hour at 50 ° C. After allowing the mixture to cool, 25 ml of methanol are added. After filtration, the product is washed with methanol and water and then dried at 70 ° C under vacuum. This produces 4.9 g of the product in the form of pale yellow crystals. Example 5: 2, 3 '- ([1, 1' -Biphenyl] -4,4'-diildi-2, 1-etenediyl) bisbenzonitrile C22H15NO to Under a weak nitrogen stream, 4.64 g (0.015 mol) of 2- [2- (4 '-formyl [1, 1-biphenyl] -4-yl) -ethenyl] benzonitrile, which is obtained according to Example 2, and 4.39 g (0.0165 mol) of 3- (dimethoxyphosphonomethyl) benzonitrile are suspended in 40 ml of N, N-dimethylformamide. A solution of 3.6 g (0.02 mol) of 30% sodium methylate is added dropwise to this suspension for 25 minutes. This mixture is stirred for five hours at room temperature and then for another hour at 50 ° C. After allowing the mixture to cool, 35 ml of methanol is added and the product is subjected to filtration, washed with methanol and water and then dried at 70 ° C under vacuum. This produces 4.45 g of the product in the form of pale yellow crystals.

Claims (1)

CLAIMS 1. A bis-styrylbiphenyl compound of the formula wherein R x and R 2 each independently of the other is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, wherein R: and R 2 are not both hydrogen at the same time and these substituents are different if they are in the same position of the phenyl ring, and R3r R4, R5 and R6 each independently of the other are hydrogen, halogen, alkyl, cycloalkyl or alkoxy. 2. A compound according to claim 1 of the formula (2), wherein R x and R 2 independently of each other are hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, at least one of the substituents is not hydrogen, and R 3; R4, R5 and R6 independently of one another are hydrogen, halogen, alkyl or alkoxy. 3. A compound according to any of claim 1 or claim 2, characterized in that R? and R2 each independently of the other are cyano, chloro, hydroxy, alkyl with 1 to 4 carbon atoms, alkoxy with 1 to 4 carbon atoms or phenyl. 4. A compound according to any of claims 1 to 3, characterized in that R3 to R6 each independently of the other are hydrogen, chloro, alkyl with 1 to 4 carbon atoms or alkoxy with 1 to 4 carbon atoms. 5. A compound according to any of claims 1 to 4, characterized in that R3 to R6 each is hydrogen. 6. A compound according to claim 1 of the formula wherein R 1 is hydrogen, cyano, halogen, hydroxy, alkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl. 7. A compound according to claim 6, characterized in that Rx is alkyl with 1 to 2 carbon atoms, alkoxy with 1 to 2 carbon atoms, cyano or phenyl. 8. A process for the preparation of the compound of the formula (1) according to claim 1, which comprises reacting 1 mol of a dialdehyde of the formula wherein R3f R4, R5 and R6 each independently of the other are hydrogen, halogen, alkyl or alkoxy, with 1 mol of a compound of the formula wherein Rx is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R7 and R8 are each alkyl, cycloalkyl, aryl or aralkyl, to give an intermediate of the formula and then react this intermediate with 1 mole of a compound of the formula wherein R2 is hydrogen, cyano, halogen, hydroxy, alkyl, cycloalkyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R7 and R8 are each alkyl, cycloalkyl, aryl or aralkyl, wherein Rx and R2 are not both hydrogen at the same time and these substituents are different if they are in the same position of the phenyl ring, to give a compound of the formula (1). 9. A process according to claim 8, characterized in that it comprises using compounds of the formulas (5) and (7), wherein R7 and R8 are each alkyl with 1 to 4 carbon atoms, phenyl or benzyl. 10. A process according to claim 8, characterized in that it comprises using compounds of the formulas (5) and (7), wherein R7 and R8 are identical and each is alkyl with 1 to 2 carbon atoms. 11. A process according to any of claims 8 to 10, characterized in that it comprises using a compound of the formula (4), wherein R3 / R4, R5 and R6 are each hydrogen. 12. An intermediary of the formula RxR6 wherein R: is hydrogen, cyano, halogen, hydroxy, alkyl, cycloal? [Uyl, alkoxy, carboxy, alkoxycarbonyl, alkylcarbonyloxy, aryl or aralkyl, and R3, R4, R5 and R6 each independently of the other are hydrogen, halogen , alkyl or alkoxy, at least one of the substituents R3 / R4, R5 and R6 is not hydrogen. 13. Use of the compound of the formula (1) according to claim 1, for optical brightening of organic materials. 14. An organic material comprising at least one compound of the formula (1) according to claim 1. 15. A method for optical brightening of organic materials, comprising incorporating into or applying to these materials at least one compound of the formula (1) according to claim

1.