JPS6236484A - Ultraviolet absorber - Google Patents

Abstract

PURPOSE:To provide an ultraviolet absorber which has a large absorbing effect in a medium wavelength ultraviolet region and is excellent in thermal stability, light stability and compatibility with polymer materials as well as excellent in solubility in water, vegetable and animal oils and org. solvents and which comprises a particular alpha-dehydroamino acid derivative. CONSTITUTION:An ultraviolet absorber having a strong absorption at a wavelength of 240-360nm and comprising an alpha-dehydroamino acid derivative of the formula (wherein A is a substituent having pi-electrons such as phenyl, imidazolyl, indolyl, furyl, pyrrolyl, thiofuryl or pyridyl; R<1> is H, alkyl, aryl, hydroxy, alkoxy, aryloxy, amino, acyloxy, nitro, mercapto or cyano; COR<2> is carboxyl or its salt, ester or amide; and R<3> is acyl, alkyl, aryl, tosyl or benzyloxycarbonyl). The alpha-dehydroamino acid derivative can be produced by condensing an aldehyde with acylglycine.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to an ultraviolet absorber characterized by using at least one type of compound represented by the general formula (1). The present invention is effective in preventing sunburn, preventing yellowing of fibers and resins, and protecting containers and packaging materials and their contents from ultraviolet rays, and is useful in a wide range of fields such as paints, resins, medicines, foods, and cosmetics. can be adapted to

BACKGROUND OF THE INVENTION Conventionally, in the field of cosmetics, ultraviolet absorbers have long attracted attention and have been developed in large numbers in order to prevent the harmful effects of ultraviolet rays on the skin.

As the ultraviolet absorber, benzophenone absorbent, salicylic acid absorbent, cinnamic acid absorbent, para-aminobenzoic acid absorbent, etc. are used.

However, among the above-mentioned ultraviolet absorbers, there are very few that combine effectiveness, safety, solubility, stability, etc.

For example, benzophenone absorbent is 320 to 400n
It has an absorption effect on long-wavelength ultraviolet rays (290-320 m), but medium-wavelength ultraviolet rays (290-320 m), which are thought to cause blisters,
nm), the absorption capacity is relatively low.

Barraminobenzoic acid-based and cinnamic acid-based absorbents have high absorption effects, but are said to have stability problems. Also,
Salicylic acid-based absorbents have a weak absorption effect and are not as effective as expected unless they are added in large quantities.

In addition to the above-mentioned ultraviolet absorbers, inorganic powders such as titanium dioxide, zinc oxide, and iron oxide, which have an effective function of physically reflecting and scattering ultraviolet rays, can also be used.

However, inorganic powders are limited in the types of cosmetics that can be blended with them, and they also have the problem of coloring when blended in large amounts.

On the other hand, as resin additives, in addition to salicylic acid-based and benzophenone-based absorbers, triazole-based and cyanoacrylate-based ultraviolet absorbers are used.

However, salicylic acid-based and benzophenone-based absorbents contain 300 to 32 O, which is said to affect polyethylene, polypropylene, and vinyl chloride resin.
It is said that triazole-based absorbents pose safety and health problems because of their weak absorption in the nanometer range.

Further, cyanoacrylate absorbents have problems such as high cost.

Problems to be Solved by the Present Invention As mentioned above, various UV absorbers have been developed in the fields of cosmetics and resins, but they lack UV absorbing ability, safety, solubility in solvents and resins, and stability. The reality is that a UV absorber that satisfies all of these properties has not yet been found, and a UV absorber that has both of these properties is desired.

Means for Solving the Problems In view of the above circumstances, the present inventors conducted intensive research and found that the α-dehydroamino acid derivative represented by the general formula (1) has a large absorption effect in the medium wavelength ultraviolet region. The present invention was completed based on the discovery that the ultraviolet absorber has the following properties, is soluble in water, various animal and vegetable oils, fats and oils, and organic solvents, and is effective in preventing erythema on the skin and preventing deterioration of resins.

α-dehydroamino acids are, for example, Organic R
actions Vol. 10, pp. 198-239 (1
Although it is a known compound, the synthesis method of which was studied by the author (1999), there has been no example of using α-dehydroamino acid as an ultraviolet absorber.

The present inventors synthesized various α-dehydro amino acids and measured their ultraviolet absorption ability. As a result, the compounds having a π electron system at the β position, that is, the compound represented by the general formula (1), as shown in Table 1. It has been found that it has strong absorption in the wavelength range of 240 to 360 nm, making it an effective ultraviolet absorber.

The compound represented by the general formula (1) can generally be obtained by (1) condensation of an aldehyde with an acylglycine or an azlactone thereof, (2) hydrolysis of an azlactone, alcoholysis, or amitrilysis. (Formula 1).

R’ACHO+　R’CNHCH2C02H.

○ RIA CH=C-C=0 N O fart / RI A CHO + H2C-C = 0N.

PE/RIACH=CH-C=0 N O N / OR2 11111→ RIACH=C (Formula 1)%Formula% Also, using α-keto acid or its ester as a raw material, phosphinimine (Formula 2), Amide or nitrile (formula 3
) can also yield (1).

OR2 RIACH=C (Formula 2) %Formula% RIACH=C (Formula 3) (1) NHR3 Furthermore, (1) can also be obtained by dehydration of N-hydroxylamino acid ester (Formula 4).

R+ACH2CHCOR2 HOH 3X -11-→RIACH2CHCOR2 Betsu3NOH OR2 Dehydration / 1---→ RIACH=C (Formula 4) %Formula% (However, in the above formula, A is a substituent with a π electron system, and specifically is phenyl, imidazolyl, indolyl, furyl, picolyl, thiofuryl, pyridyl.
is a hydrogen atom, alkyl, aryl, hydroxy, alkoxy, aryloxy, amino, acyloxy, nitro, mercapto, or cyano group. C0R2 is a carboxyl group, a salt thereof, an ester group, or an amide group. Further, R is an acyl group, an alkyl group, an aryl group, a tosyl group, or a benzyloxycarbonyl group. Furthermore, formula 1
R4 represents an alkyl group or an aryl group. ) Examples of compounds obtained in this way include N-
) Sil-α-dehydrophenylalanine, N-penzoyl-O-methyl-α-dehydrotyrosine, N-benzoyl-0-methyl-α-dehydrotyrosine ethyl ester, N-benzoyl-α-dehydrotyrosinamide, N-
Benzoyl-α-dehydrotributophane methyl ester, N-benzoyl-β-furanyl-α-dehydroalanine, N-benzoyl-β-furanyl-α-dehydroalanine sodium salt, N-phenyl-α-dehydrohistidine triethanolamine salt, N-benzoyl-
Examples include β-thiofuranyl-α-dehydroacilone, N-benzyloxycarbonyl-β-thiofuranyl-α-dehydroalanine calcium salt, and N-acetyl-β-pyridyl-α-dehydroalanine magnesium salt.

Effects of the Invention As shown in Table 1, the α-dehydroamino acid derivative represented by the general formula (1) used in the present invention has 270 to 33
Ultraviolet rays from 290 to 320 nm, which have a high molecular extinction coefficient of 104 or more at 0 nm and are thought to cause skin erythema, and from 300 to 320 nm, which are thought to cause deterioration of resins such as polyethylene, polypropylene, and polyvinyl chloride. However, it has a high absorption capacity. Of the general formula (1), those in which C0R2 is a carboxyl group or an amide group exhibit good solubility in alcohols such as ethanol,
Further, salts in which C0R2 is a carboxyl group (eg, sodium salt, triethanolamine salt) exhibit high solubility in water. Furthermore, when C0R2 is an ester group, it dissolves well in organic solvents such as olive oil and liquid paraffin. In this way, in general formula (1), C0R2 can be changed as appropriate.
Depending on the selection, it can be dissolved well in water, animal and vegetable oils, and organic solvents, making it suitable for use in lotions, hair creams,
When added to cosmetics such as sunscreen oil, it is possible to obtain stable formulations. Further, the α-dehydroamino acid derivative represented by the general formula (1) has a 190 to 24
Since it has a high melting point of 0°C, when blended into resin, it is stable at kneading and molding temperatures, and molded products with good thermal stability can be obtained. The general formula (1) used in the present invention
) Display α−de.

Hydroamino acid derivatives are mixed with commercially available ultraviolet absorbers (e.g.
When compared to benzophenone-based, triazole-based, and salicylic acid-based absorbents), it has an excellent suppressing effect on the effects of ultraviolet rays, especially in the presence of oxygen. ■High thermal stability and photostability, and long-lasting effects. 02 to 10 times the ultraviolet ray molecular extinction coefficient. ■Since it has good compatibility with various polymer materials, it can be used as a plasticizer for fibers, resins, etc., and can also be used as an anti-yellowing agent.

As mentioned above, the scope of application of the present invention is the cosmetics industry, the plastics industry, the organic medicine industry, the photography industry, the food industry,
The textile industry is extremely wide.

In particular, the ultraviolet absorption wavelength is 240 to 360 nm (maximum absorption wavelength 300 to 340 nm), and when used in cosmetics, it is a tanning agent with unparalleled selective absorption.
It can be used as an anti-erythema cosmetic product, and when mixed into polymers such as polyethylene, polypropylene, and polyvinyl chloride, it significantly reduces deterioration caused by ultraviolet rays.

Next, the present invention will be explained in more detail by giving synthesis examples, formulation examples, and examples, but the present invention is not limited thereto.

Synthesis example 1 2-phenyl-4-(4-methoxybenzylidene)-5
-Synthesis of Oxacylone 20 ml of anisaldehyde, 50 ml of acetic anhydride, 33.7 g of hippuric acid and 6.7 g of sodium acetate were mixed thoroughly and heated in a water bath for 30 minutes.

The precipitated crystals were washed with warm water and then filtered. By recrystallizing from benzene and drying, 2-phenyl-4-(4
40 g of -methoxybenzylidene)-5-oxacilone was obtained. Yield 83% Synthesis Example 2 Synthesis of N-benzoyl-〇-methyl-α-dehydrotyrosine 10 g of 2-phenyl-4-(4-methoxybenzylidene)-5-oxacilone obtained in Synthesis Example 1 was mixed with hot alcohol. Dissolve in 100ml of 2% sodium hydroxide aqueous solution
1 was added and heated in a water bath for 15 minutes. After cooling, the reaction solution was made acidic with dilute sulfuric acid, and the precipitated crystals were filtered and washed with water. By recrystallizing from water-methanol and drying, N
-Penzoyl-〇-methyl-α-dehydrotyrosine9.
5g was obtained. Yield 89% Synthesis Example 3 Synthesis of 2-phenyl-4-intra-5-oxacilone Indole aldehyde 18g, hippuric acid 25.5g,
Grind and mix 9.9 g of sodium acetate, and add 45 g of acetic anhydride.
ml and heated at 100°C for 15 minutes. After cooling, the precipitated crystals are collected by filtration, washed with water, and dried.
2-phenyl-4-intra-5-oxacylone 2
9g was obtained. Yield 80% Synthesis Example 4 Synthesis of N-benzoyl-α-dehydrotryptophan 14.4 g of 2-phenyl-4-intra-5-oxacilone obtained in Synthesis Example 3 was dissolved by heating in a 1% aqueous sodium hydroxide solution. Ta. The reaction solution was made acidic with dilute hydrochloric acid, and the precipitated crystals were collected by filtration, washed with water, recrystallized from methanol, and dried to obtain 11 g of N-benzoyl-α-dehydrotryptophan. Yield 70% Formulation Example 1 Sunscreen oil N-benzoyl-α-dehydrotyrosine methyl ester 1 part, liquid paraffin 60 parts, olive oil 39 parts.

Formulation example 2: Anti-sunburn and dandruff A cream liquid paraffin 40 parts, cetyl alcohol 1 part, beeswax 3 parts,
1 part of isopropyl myristate, 2.13 parts of glyceryl stearate, 2.87 parts of cetyl ether polyoxyethylene, 5 parts of propylene glycol, N
-Benzoyl-α-dehydrotyrosinamide 1 part, purified water 44 parts.

Formulation Example 3 Foaming Air Spray Stearic acid 7 parts, propylene glycol 7 parts, triethanolamine 6 parts, olive oil 2 parts, N-benzoyl-α-dehydrotyrosine 0.3 parts, purified water 77.
7 parts of the mixed liquid and 90 parts of the mixed liquid and Freon gas (F2
1/F114=40/60) was charged into a pressure container.

Formulation example 4 Non-foaming lotion air spray Brobylene glycol 10 parts, 99% ethanol 30 parts, N-
Benzoyl-α-dehydrotyrosine 1 part, purified water 5
30 parts of the mixed liquid and Freon gas (F
12/F114=40/60) 70 parts were charged into a pressure container.

Example 1 The compound represented by general formula (1) was synthesized by Synthesis Examples 1 to 4 and a method based thereon. The maximum absorption wavelength and other physical property values are shown in Table 1.

Example 2 100 g of high density polyethylene was injected with 250 mg of N-
It was mixed with benzoyl-〇-methyl-α-dehydrotyrosine and processed in a roll mixer at a temperature of 120°C to form a colorless and transparent sheet. The sheet was pressed to a uniform thickness of 0.2 mm and then exposed to UV radiation for 2000 hours in a monotester.

Measurement of sheet deterioration is performed using Plastic Technology (P
Lastic Technology) May issue, 19
The method described in 1958, p. 427 was used. That is, the infrared spectrum (transmission spectrum) of the test sheet before and after exposure was measured, and the increase in the ketone carbonyl absorption band was used as a measure of deterioration.

A degraded carbonyl peak was measured at approximately 1720-1730 cm-'. In the case of the additive-free sheet, the carbonyl absorption intensity before exposure was 0.11, and after exposure it was 0.40. In the sheet stabilized with N-benzoyl-0-methyl-α-dehydrotyrosine, the film was 0.0% both before and after exposure.
12, deterioration was clearly suppressed.

Example 3 0.1 g of each of the sunscreen oil A and the oil-containing oil (a mixture of 60 parts of liquid paraffin and 39 parts of olive oil) prepared in 1 in Formulation Example 1 were added to 100 parts of an ethanol/hexane (1:1) mixed solution. Figure 2 shows the absorbance when dissolved in ml.

4. Brief explanation of the figures Figure 1 shows the relationship between the molecular extinction coefficient and wavelength of an ethanol solution of an α-dehydroamino acid derivative.

Figure 2 shows the relationship between the absorbance and wavelength of sunscreen oil containing α-dehydroamino acid derivatives.

Claims (1)

[Scope of Claims] An ultraviolet absorber comprising an α-dehydroamino acid derivative represented by the following general formula (1) as an active ingredient. ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (1) (However, A is a substituent with a π electron system, specifically phenyl, imidazolyl, indolyl, furyl, pyrrolyl, thiophryl, or pyridyl. Also, R^1 is a hydrogen atom, alkyl, aryl, hydroxy, alkoxy, aryloxy, amino, acyloxy, nitro,
It is a mercapto or cyano group. COR^2 is
A carboxyl group, a salt thereof, an ester group, an amide group, and R^3 is an acyl group, an alkyl group, an aryl group, a tosyl group, or a benzyloxycarbonyl group. )