JP3497246B2 - Benzylidene hydantoin derivative, ultraviolet absorber and external preparation for skin containing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a benzylidene hydantoin derivative and a skin external preparation, and more particularly to a substance having a UV absorbing ability in the UV-A region and a skin external preparation.

[0002]

2. Description of the Related Art Ultraviolet rays contained in sunlight are dermatologically long wavelength ultraviolet rays (UV-) of 320 nm to 400 nm.
A) Medium wavelength ultraviolet rays (UV-
B) Classified as short wavelength ultraviolet rays (UV-C) of 290 nm or less. Of these, ultraviolet rays having a wavelength of 290 nm or less are absorbed by the ozone layer and do not reach the surface of the earth.

Ultraviolet rays reaching the surface of the earth have various effects on human skin. Of the ultraviolet rays that reach the ground, UV-
B forms erythema and blisters on the skin, and also promotes melanin formation. On the other hand, UV-A causes browning of the skin, lowers the elasticity of the skin and promotes the generation of wrinkles, resulting in rapid aging. It may also accelerate the onset of the erythema reaction, or enhance this reaction for some patients, and even cause phototoxicity or even a photoallergic reaction.

In order to protect the skin from such harmful effects of UV-A, various UV absorbers have been developed and blended in a skin external preparation. Examples of existing UV-A region ultraviolet absorbers include benzophenone derivatives, dibenzoylmethane derivatives, and benzotriazole derivatives.

[0005]

However, since the existing UV absorbers in the UV-A range have drawbacks such as coloring of clothes by reacting with metal ions and coloring, the amount of use thereof is extremely small. There is a drawback in that the function of the UV-A absorber is not fully exerted because it is limited to a small amount. The present invention has been made in view of the above problems of the prior art, and an object thereof is to provide a substance that is not colored by metal ions and that protects the skin from ultraviolet rays in the UV-A region, and a skin external preparation containing the substance. Especially.

[0006]

Means for Solving the Problems As a result of intensive studies by the present inventors in order to achieve the above-mentioned object, it was found that the novel benzylidene hydantoin derivative has excellent UV-A absorption and usability, and the present invention It came to completion. That is, the benzylidene hydantoin derivative according to the present application is represented by the following general formula 2.

[Chemical 2] (However, R ¹ represents a linear or branched alkyl group having 1 to 8 carbon atoms, and R ² represents a branched alkyl group having 5 to 18 carbon atoms.)

The ultraviolet absorbent according to the present invention contains one or more of the benzylidene hydantoin derivatives of the above Chemical Formula 2, and the external skin preparation according to the present invention contains one of the benzylidene hydantoin derivatives of the above Chemical Formula 2 or It is characterized by containing two or more kinds.

The structure of the present invention will be described in more detail below. In Chemical Formula 2, R ¹ is an alkyl group having 1 to 8 carbon atoms, which may be linear or branched. For example,
Alkyl such as methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, t-butyl group, pentyl group, isopentyl group, hexyl group, 2-ethylbutyl group, heptyl group, octyl group, 2-ethylhexyl group Groups.

Further, R ² is preferably a lower alkyl group (C ₄ or less) from the viewpoint of ultraviolet absorbing ability, but it has low solubility in an oily base and is difficult to be compounded in an effective amount, and C ₁₉ In the case of the above-mentioned alkyl group, the solubility is good, but the ultraviolet ray absorbing ability is lowered, so that there is a drawback that a large amount of compounding is required to exert its effectiveness, and therefore, there is a branching of C _{5 to} C ₁₈ . Alkyl groups are preferred. For example, isopentyl group, 2-ethylbutyl group, n-octyl group, 2-ethylhexyl group, 2-hexyldecyl group,
Examples include 2-heptylundecyl group and methyl-branched isostearyl group.

In the general formula ² , a benzylidene hydantoin derivative in which R ¹ is a methyl group and R ² is a straight-chain alkyl group having 8 to 20 carbon atoms is disclosed in JP-A-2-1117.
60. However, all of these compounds have low solubility in an oily base, and it is difficult to sufficiently exert the effect as an ultraviolet absorber. In the general formula 2, R ¹ is a methyl group and R ² is —CH.
_A benzylidene hydantoin derivative which is ₂ CH ₂ CO ₂ R is disclosed in JP-A-2-19314. However, these compounds also have the drawback of low solubility, especially in oily bases.

On the other hand, the benzylidene hydantoin derivative of the present invention has a significantly improved solubility in an oily base due to the introduction of a branched alkyl group, and as a result, exhibits a sufficient effect as an ultraviolet absorber. The benzylidene hydantoin derivative of the present invention has the following method (a) or (b)
It can be manufactured by the method.

[Chemical 3] (However, R ¹ X and R ² X each represent an alkyl halide.)

The condensation reaction between a benzaldehyde derivative and hydantoin is a general condensation reaction between an aldehyde and active methylene, for example, "Experimental Chemistry Course 18 Reaction of Organic Compound II.
(Middle), p81-303, edited by The Chemical Society of Japan ", JP-A-60
The reaction shown in No. 233063 or the like can be used. That is, pyridine, piperidine, morpholine,
Aminoethanol, sodium hydroxide, potassium hydroxide, amino acids, amino acid salts and the like may be used as a catalyst, and the reaction may be carried out at room temperature to 160 ° C. using a water-soluble solvent such as water, alcohol or glycerin or an aprotic solvent. .

The alkylation reaction using an alkyl halongenate is carried out at 50 ° C. in an aprotic solvent such as acetone, dimethylformamide, dimethylsulfoxide with sodium metal, sodium hydroxide, potassium carbonate and the like.
-150 degreeC, the method of making it react for 5 minutes-8 hours is mentioned. All of the benzylidene hydantoin derivatives according to the present invention show strong absorption at 320 to 370 nm, and UV
-A can be used as an absorbent.

The base of the external preparation for skin according to the present invention may be any as long as it can dissolve the above-mentioned benzylidene hydantoin derivative, but the solubility in an oily base is particularly good. The external preparation for skin of the present invention includes other components usually used in cosmetics, such as oil, lubricating oil, antioxidant, surfactant, preservative, sequestering agent, perfume, water, alcohol, thickener. Etc. can be appropriately blended as necessary. The external preparation for skin of the present invention may have any dosage form, such as powder, cream, paste, stick, liquid, spray, and foundation, and may be emulsified with an emulsifier.

The benzylidene hydantoin derivative of the present invention is sufficiently effective when used alone, but if necessary, other UV-B absorbers such as p-dimethylaminobenzoate such as 2-ethylhexyl p-dimethylaminobenzoate can be used. -Aminobenzoic acid derivatives, p-methoxycinnamic acid derivatives such as p-methoxycinnamic acid 2-ethylhexyl ester, salicylic acid derivatives, benzylidene camphor derivatives, urocanic acid or its derivatives, or inorganic pigments such as titanium dioxide and zinc oxide Besides, it is also possible to use it together with a UV-A absorber. Further, the amount of the benzylidene hydantoin derivative in the present invention to be compounded varies depending on the above-mentioned dosage form and the degree of UV protection required, but it is generally 0.1 to 20% by weight, preferably 0.5.
10 to 10% by weight.

[0016]

EXAMPLES The present invention will be described in more detail with reference to examples. The present invention is not limited to these examples. Further, the compounding amount is shown by weight% unless otherwise specified.

Example 1 5- (4-methoxybenzylide)
) -3- (2-Ethylhexyl) hydantoin production 6.8 g of p-methoxybenzaldehyde, 5.0 g of hydantoin, 0.1 g of sodium hydroxide, ion-exchanged water 2
5 ml was mixed and stirred at 90 ° C to 100 ° C for 7.5 hours. After cooling, the precipitated solid was collected by filtration, washed with water, and then methanol.
After washing well with water, 5.3 g of 4-methoxybenzylidenehydantoin as a pale yellow solid was obtained.

5.1 g of the obtained 4-methoxybenzylidene hydantoin, 5.0 of 2-ethylhexyl bromide
g and 3.2 g of anhydrous potassium carbonate were added to 30 ml of dimethylformamide, and the mixture was heated with stirring at 100 ° C to 110 ° C for 5 hours. After cooling, the insoluble matter was filtered off, the filtrate was distilled under reduced pressure to remove the solvent, and then ethanol was added to cool the solution, whereby crystals were precipitated. The crystals were recrystallized with ethanol to obtain 5.8 g of the desired product as colorless needle crystals. The maximum absorption wavelength (λ _max ) of the obtained target substance, mass spectrum data, and melting point were as follows. λ _max (Ethanol) 334 nm (ε = 32,0)
00) Mass spectrum M ⁺ m / e 330 Melting point 156-158 ° C

Example 2 5- (4-methoxybenzylide)
Emissions) -3 isostearyl hydantoin prepared in Example 1 and the same way prepared 4-methoxy-benzylidene hydantoin 4.3 g, isostearyl bromide 5.9 g, anhydrous potassium carbonate 2.7 g, a mixture of dimethyl formamide 20 ml 100 Heated and stirred at ~ 110 ° C for 5 hours. After completion of the reaction, the mixture was cooled to room temperature and the insoluble matter was filtered off. The solvent was distilled off from the filtrate under reduced pressure, and the residue was treated with methanol.
When dissolved in 40 ml of water and cooled, a solid was precipitated. This solid was recrystallized from isopropyl alcohol to obtain 4.5 g of the target substance as an amorphous solid. The maximum absorption wavelength (λ _max ) of the obtained target substance, mass spectrum data, and melting point were as follows. λ _max (Ethanol) 334 nm (ε = 31.5)
00) Mass spectrum M ⁺ m / e 470 Melting point 100-103 ° C

Example 3 5- {4- (2-ethylhexyl)
Roxy) benzylidene} -3- (2-ethylhexyl)
Production of hydantoin 16.7 g of p-hydroxybenzaldehyde, 13.7 g of hydantoin, 6.4 g of sodium hydroxide and 70 ml of ion-exchanged water were mixed, and heated and stirred at 90 ° C to 100 ° C for 4 hours. After cooling to room temperature, 500 ml of deionized water was added and the pH was adjusted to 6 to 7 with hydrochloric acid. The precipitated solid was collected by filtration, washed with water, 200 ml of ethanol was added, and the mixture was refluxed for 30 minutes. After cooling, the solid was collected by filtration and dried to obtain 21 g of 4-hydroxybenzylidene hydantoin.

4-Hydroxybenzylidene hydantoin 10.2 g, 2-ethylhexyl bromide 21.3
A mixture of g, 13.8 g of anhydrous potassium carbonate and 100 ml of dimethylformamide was heated and stirred at 100 to 110 ° C. for 6 hours, cooled to room temperature, and the insoluble matter was filtered off. After the solvent of the filtrate was distilled off under reduced pressure, 200 ml of hexane was added to the residue and the mixture was stirred with heating, and the insoluble matter was filtered off. Hexane was distilled off from the filtrate under reduced pressure, and the residue was separated and purified by silica gel column chromatography (eluted with a 10% ethyl acetate-hexane mixed solution) to obtain 11.4 g of the desired product as colorless needle crystals.

The maximum absorption wavelength (λm
ax), mass spectrum data, and melting point were as follows. λ _max (ethanol) 336 nm (ε = 32,5)
00) Mass spectrum M ⁺ m / e 428 Melting point 90-92 ° C

Ultraviolet absorption effect Using the above-mentioned Examples 1 and 3 and the comparative compound (2-hydroxy-4-methoxybenzophenone; UV-A absorber), the ultraviolet absorption effect was measured by absorbance according to the following measuring method. <Measurement method> An ethanol (99.5%, reagent grade) solution having a concentration of 10 ppm of Examples 1 and 3 and the comparative compound was prepared and manufactured by JASCO Corporation using a quartz cell (1 cm x 1 cm). It was measured with a UVIDEC-610 type spectrophotometer.

The results are shown in Table 1.

[Table 1] ──────────────────────────────────── Wavelength (nm) Example 1 Example 3 Comparative compound ──────────────────────────────────── 300 0.36 0.24 0.39 3100 .53 0.39 0.35 320 0.74 0.55 0.40 330 0.95 0.73 0.42 340 0.94 0.76 0.34 350 0.80 0.68 0.20 360 0 .40 0.40 0.11 370 0.10 0.14 0.03 380 0.02 0.03 0.00 ──────────────────────── ──────────────────────────────────────────────────────────────────────── It has a strong UV absorption effect and a high sun protection effect.

Reaction with Metal Ions In Examples 1, 2, 3 and the comparative compounds, 2-hydroxy-4-methoxybenzophenone and 2-hydroxy-5-methylphenylbenzotriazole with trivalent iron ions. The reaction was tested. <Method> 0.1 g of each of the compounds of Examples 1, 2 and 3 and the comparative compound was dissolved in 10 ml of 99.5% ethyl alcohol (special grade reagent), and ferric chloride (FeCl ₃ ) 0.0
2% 99.5% ethyl alcohol (reagent grade) solution 2
After adding ml and stirring well, the change in color tone of the solution was observed.

The results are shown in Table 2 below.

[Table 2] ──────────────────────────────────── Compound FeCl ₃ before addition FeCl ₃ after addition ─ ─────────────────────────────────── Example 1 colorless to faint yellow No change Example 2 colorless to faint No change in yellow Example 3 Colorless to slight yellow No change 2-Humanoxy-4-methoxybenzofenone Colored in pale yellow brown (Comparative compound) 2-Humanoxy-5-methylphenylbenzazotriazole Colored in light yellow blue (Comparative compound ) ──────────────────────────────────── As a result of the above, all the compounds according to the present invention are metallic. It is understood that it does not react with ions.

[0027]Solubility comparison The above-mentioned Examples 1, 2, 3 and 5- (4
-Methoxybenzylidene) -3-n-octylhydanto
In (Comparative Example 1, R¹= CH₃, R²= N-C₈H 1₇)as well as
5- (4-methoxybenzylidene) -3- {2- (2-
Ethylhexyloxycarbonyl) ethyl} hydantoin
(Comparative Example 2, R¹= CH₃, R²= CH₂CH₂CO₂C₈H
₁₇-I), the solubility in various solvents is compared.
It was

The results are shown in Table 3 below.

[Table 3] ──────────────────────────────────── Compound Ethyl alcohol (99.5%) Cetyl-2 -Ethyl hexanoate Olive oil ──────────────────────────────────── Example 1 1.2% 2 .1% 3.2% Example 2 4.0 14 17 Example 3 1.4 4 7 Comparative example 1 0.65 0.2 0.4 Comparative example 2 <1 <1 <1 <1 ────── ────────────────────────────── When comparing Example 1 and Comparative Example 1, R ¹ is the same and R ² is carbon. It is understood that although the numbers are the same and Example 1 is branched, Comparative Example 1 is different only in that it is linear, but the solubilities in respective solvents are greatly different. Further, in comparison with the conventional products of Comparative Examples 1 and 2, all the products of this example have excellent solubility.

Specific formulation examples of the external preparation for skin according to the present invention will be described below. Example 4 Sunscreen Cosmetic (Oil Type) (1) Decamethylcyclopentasiloxane 47.0% (2) Dimethylpolysiloxane (10cs / 25 ° C) 20.0 (3) Methylphenylpolysiloxane (20cs / 25 ° C) ) 18.0 (4) Silicone resin 10.0 (5) p-Dimethylaminobenzoic acid 2-ethylhexyl ester 3.0 (6) 5- {4- (2-ethylhexyloxy) benzylidene} -3- (2 -Ethylhexyl) Hindantin 2.0 <Production method> (1) to (6) are mixed, sufficiently dissolved and then filtered to obtain a product. In this case, it was easily dissolved at room temperature simply by stirring.

<Sunscreen effect> The sunscreen cosmetic according to Example 4 and 5- {4- (2-ethylhexyloxy) benzylidene} -3- (2-ethylhexyl) hydantoin (component (6)) were added. The sunscreen effect was tested using a comparative example in which the total amount was replaced with 2-ethylhexyl p-dimethylaminobenzoate. That is, in the actual use test on the beach, two samples were applied to each half of the body of 10 panelists and divided to examine the degree of sunburn and skin trouble.

The results are shown in Table 4.

[Table 4] ────────────────────────────────────                           Comparative Example of Example 4                           Sample coating section Sample coating section ────────────────────────────────────     Panel A ○ ○           B ○ ×           C △ ×           D ○ ○           E ○ △           F ○ △           G ○ △           H ○ ×           I ○ ×           J ○ × ────────────────────────────────────     Number of skin problems None 4                                             Itching 1                                             2 rashes ──────────────────────────────────── Evaluation criteria for the degree of sunburn Strong sunburn symptoms were observed ... × Sunburn symptoms were observed ... △ Almost no sunburn symptoms were observed ... ○

From these results, the skin external preparation containing the benzylidene hydantoin derivative according to the present invention is more effective than the skin external preparation containing the conventional UV absorber (p-dimethylaminobenzoic acid 2-ethylhexyl ester) in the UV protective effect. Was high, and there was no skin trouble and high safety. The following external preparations for skin of Examples 5 to 9 were also tested in the same manner as in the above-mentioned Example 4, and as a result, they were all excellent in the ultraviolet protection effect and had no skin trouble.

Example 5 Sunscreen Cosmetic (W / O Cream) (1) Octamethylcyclotetrasiloxane 10.5% (2) Dimethylpolysiloxane (100cs) 5.0 (3) Dimethylpolysiloxane (2,500,000cs) 3.0 (4) Liquid paraffin 15.0 (5) Polyether-modified silicone 6.0 (6) P-Dimethylaminobenzoic acid 2-ethylhexyl ester 5.0 (7) 5- (4-Isopropoxybenzylidene)- 3- (2-Ethylhexyl) hydantoin 4.0 (8) Purified water 43.1 (9) L-sodium glutamate 3.0 (10) 1,3-butylene glycol 5.0 (11) Preservative 0.2 ( 12) Fragrance 0.2 <Production method> (1) to (7) and (12) are mixed and dissolved by heating and stirring to maintain the temperature at 70 ° C to form an oil phase portion. Separately, (8) to (11) are dissolved by heating and maintained at 70 ° C to form an aqueous phase. The aqueous phase part is added to this oil phase part, and it is sufficiently emulsified by an emulsifying machine. After emulsification, cool while stirring, and when the temperature becomes 35 ° C or lower, pour into a container and allow to cool to solidify.

Example 6 Sunscreen Cosmetic (O / W Cream) (1) Decamethylcyclopentasiloxane 3.0% (2) Liquid Paraffin 8.0 (3) Isopropylmyristate 2.0 (4) Vaseline 4 0.0 (5) cetanol 4.0 (6) stearic acid 3.0 (7) glyceryl monoisostearate 3.0 (8) p-methoxycinnamic acid 2-ethylhexyl ester 3.0 (9) 5- ( 4-Methoxybenzylidene) -3- (2-ethylhexyl) hydantoin 1.0 (10) Preservative 0.2 (11) Perfume 0.2 (12) Glycerin 10.0 (13) Propylene glycol 5.0 (14) Hyaluronic acid 0.01 (15) Potassium hydroxide 0.2 (16) Purified water 53.39 <Production method> (1) to (11) are dissolved by stirring with a disper at 70 ° C to form an oil phase portion. (12) to (16) are heated to 70 ° C. to completely dissolve them and then used as an aqueous phase part. The oil phase part is added to the water phase part and emulsified by an emulsifier. The emulsion is cooled to 30 ° C. in a heat exchanger and then filled to obtain a product.

Example 7 Sunblock Lotion (1) Dimethylpolysiloxane (5cs) 3.0% (2) Methylphenylpolysiloxane (20cs) 17.0 (3) Stearic acid 1.0 (4) p-Dimethylamino Benzoic acid 2-ethylhexyl ester 5.0 (5) 5- {4- (2-ethylhexyloxy) benzidine} -3- (2-ethylhexyl) hydantoin 2.0 (6) Preservative 0.2 (7) Perfume 0.2 (8) Glycerin 5.0 (9) Montmorillonite 0.5 (10) Potassium hydroxide 0.2 (11) Purified water 65.9 <Production Method> (1) to (7) are heated to 70 ° C. Dissolve by hand stirring to obtain the oil phase. (8) to (11) are heated to 70 ° C. and dissolved to form an aqueous phase. The oil phase part is added to the water phase part and emulsified by an emulsifying machine. The emulsion is cooled to 30 ° C. in a heat exchanger and then filled in a container to obtain a sunscreen lotion.

Example 8 Sunscreen Foundation (1) Silicone treated titanium oxide 9.5% (2) Silicone treated mica 40.0 (3) Silicone treated talc 20.45 (4) Silicone treated iron oxide 7.5 ( 5) Spherical nylon powder 10.0 (6) Trimethylolpropane triisostearate 5.0 (7) Squalane 3.0 (8) Beeswax 2.0 (9) 5- (4-Methoxybenzylidene) -3- Isostearyl allyl hydantoin 0.5 (10) Sorbitan trioleate 1.0 (11) Preservative 0.5 (12) Vitamin E 0.05 (13) Perfume 0.5 <Production method> (1) to (5) The mixture was mixed with a Henschel mixer, and the mixture of (6) to (13) heated and dissolved and mixed was added and mixed, and then the mixture was crushed and molded into a medium dish to obtain a sunscreen foundation.

Example 9 Sunscreen Stick Cosmetic (1) Titanium oxide 10.0% (2) Zinc oxide 7.0 (3) Mica 16.0 (4) Red iron oxide 1.5 (5) Yellow iron oxide 1.5 (6) Black iron oxide 1.0 (7) Dimethylpolysiloxane (20cs) 29.4 (8) Trimethylolpropane-tri-2-ethylhexanoate 8.0 (9) Liquid paraffin 7.0 (10) Microcrystalline wax 2.0 (11) Ceresin 1.0 (12) Solid paraffin 6.0 (13) p-Dimethylaminobenzoic acid 2-ethylhexyl ester 5.0 (14) 5- (4-isopropoxy) Benzylidene-3- (2-hexyldecyl) hydantoin 3.0 (15) Perfume 0.5 (16) Antioxidant 0.1 (17) Sorbitan sesquioleate 1.0 <Production method> (1) to (6) Mix with mixer (7)
~ (9), (13), (14), (16), and (17) are added to and mixed by heating and stirring. Next, a solution obtained by dissolving (10) to (12) and (15) is added to the above mixture, sufficiently mixed, and then molded into a stick shape.

Example 10 Sunscreen Makeup Base (1) Squalane 19.0% (2) Glyceryltriisostearate 10.0 (3) Isopar G 5.0 (4) Sorbitan Sesquioleate 1.0 (5) Poly Siloxane Ethylene-modified organopolysiloxane 3.0 (6) Purified water 45.0 (7) 1,3-butylene glycol 5.0 (8) Fine particle titanium oxide 10.0 (9) 2-Ethylhexyl p-methoxycinnamate Ester 1.0 (10) 5- (4-Isobutoxybenzilidine) -3- (2-Ethylhexyl) Hindantine 1.0 (11) Preservative Amount (12) Antioxidant Amount (13) Perfume Amount < Manufacturing method> (1) to (5), (9), (10), (12), and (13) were dissolved by stirring with a disper at 70 ° C., and heated and dissolved at 70 ° C. in advance (6) to ( 8) and (11) were added, emulsified and dispersed, and then cooled to obtain a desired sunscreen makeup base.

Example 11 Sunblock Foundation (1) Silicone treated titanium oxide 9.5% (2) Silicone treated mica 40.0 (3) Silicone treated talc 20.45 (4) Silicone treated iron oxide 7.5 ( 5) Spherical nylon powder 10.0 (6) Trimethylolpropane triisostearate 5.0 (7) Squalane 3.0 (8) Beeswax 2.0 (9) 5- {4- (2-ethylhexyloxy) ) Benjendene} -3- (2-ethylhexyl) hydantoin 0.5 (10) Sorbitan trioleate 1.0 (11) Preservative 0.5 (12) Vitamin E 0.05 (13) Perfume 0.5 <Production method> Mix (1) ~ (5) with a Henschel mixer, add (6) ~ (13) heated and melt mixed to this, mix and grind, mold this into a medium dish to obtain a sunscreen foundation It was

Example 12 Sunblock Lotion (1) Dimethylpolysiloxane (5cs) 3.0% (2) Methylphenylpolysiloxane (20cs) 17.0 (3) Stearic acid 1.0 (4) p-Dimethylamino Benzoic acid 2-ethylhexyl ester 5.0 (5) 5- (4-methoxybenzylidene) -3- (2-ethylhexyl) hydantoin 1.0 (6) Preservative 0.2 (7) Perfume 0.2 (8) Glycerin 5.0 (9) Montmorillonite 0.5 (10) Potassium hydroxide 0.2 (11) Purified water 66.9 <Production Method> (1) to (7) are heated to 70 ° C and dissolved by stirring with a disper. The oil phase is used. (8) to (11) are heated to 70 ° C. and dissolved to form an aqueous phase. The oil phase part is added to the water phase part and emulsified by an emulsifying machine. The emulsion is cooled to 30 ° C. in a heat exchanger and then filled in a container to obtain a sunscreen lotion.

[0041]

As described above, according to the benzylidene hydantoin derivative of the present invention, excellent UV-A can be obtained.
It has absorption ability, does not react with metal ions to be colored, and has high solubility. In addition, a skin external preparation containing the same can exhibit excellent ultraviolet protection effect and usability.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Mikiko Kato 1050 Shinba-cho, Kohoku-ku, Yokohama-shi, Kanagawa Shiseido Co., Ltd. Research Center (56) Reference JP-A-5-345713 (JP, A) ( 58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 233/96

Claims (3)

(57) [Claims] 1. A benzylidene hydantoin derivative represented by the following general formula 1. [Chemical 1] (However, R ¹ represents a linear or branched alkyl group having 1 to 8 carbon atoms, and R ² represents a branched alkyl group having 5 to 18 carbon atoms.) 2. An ultraviolet absorber comprising the benzylidene hydantoin derivative according to claim 1. 3. A skin external preparation containing the ultraviolet absorber comprising the benzylidene hydantoin derivative according to claim 1.