JPS5920663B2 - Manufacturing method of ammonium cinnamate compound - Google Patents

Description

[Detailed description of the invention] The present invention relates to a light shielding agent.

More particularly, the present invention relates to a method for producing certain ammonium cinnamates. The above-mentioned light shielding agent contains ammonium cinnamates as an active ingredient. This novel sunscreen can be used in methods to protect the skin from harmful ultraviolet radiation. The ammonium cinnamates provided by the method of the present invention have the general formula 5CH300CH=CH-C00
0Re(1) [wherein R is monoethanolamine, diethanolamine, triethanolamine, bis(21
ammonium ion of 0-hydroxypropyl)amine or tris(hydroxymethyl)aminomethane].

Salts of formula I are suitable for use under the sun's erythematous ultraviolet radiation (i.e. 280 m
and 320 mμ): 15 thus protecting living epidermal cells from these rays.

Salts of formula I can optionally be used as sunscreens. Preferred salts of formula I are tris(hydroxymethyl)-methylammonium p-methoxycinnamate and especially diethanolammonium p-methoxycinnamate.

The salts of formula I above have significant water solubility.

As a result, it is particularly suitable for incorporation into an aqueous solution of a cosmetic base or an aqueous/alcoholic solution thereof or a phase of a cosmetic base. Furthermore, since the salts of formula I are neutral substances, they do not irritate the skin at all. Furthermore, salts of formula I,
In particular, the melting points of diethanolammonium p-methoxycinnamate and tris(hydroxymethyl)methylammonium p-methoxycinnamate are low, so that they can be easily mixed into cosmetic formulations. This is very advantageous from a technical point of view. As described above,
The present invention discloses a sunscreen agent which contains salt 35 of formula I above as the essential sunscreen component.

This novel sunscreen can be used in a method of protecting the skin from harmful ultraviolet radiation, which method involves applying a sunscreen to the skin as defined above.

To provide the sunscreens of the present invention, conventional cosmetic bases with desirable physical and cosmetic properties are combined.
Salts of formula 1 above may be mixed.

This sunscreen can be used, for example, in creams, lotions, emulsions,
Form into ointments, gels, solutions, sprays, sticks, etc. Of course, the light blocking activity depends on the cosmetic base used. The efficacy of the light blocking activity also depends on the concentration of the salt of Formula 1 in the light blocking agent. A suitable concentration is, for example, 1% to 6%, preferably 3% to 5%. Salts of formula 1 may also be combined with other conventional sunscreen agents, and in that case a synergistic effect (ie, a synergistic effect) of the sunscreen activity may also occur.

The method provided by the present invention converts p-methoxy-cinnamic acid into a salt using monoethanolamine, diethanolamine, triethanolamine, bis(2-hydroxypropyl)amine or tris(hydroxymethyl)aminomethane. Salts of formula 1 are prepared by:

The starting materials are conveniently used in purified form and salt formation is conveniently carried out by mixing equal gram molecular weights of each component together.

In addition, the neutralization point can be determined by measuring, for example, using a glass electrode. Salt formation occurs in a solvent;
It is done conveniently.

For example, suitable solvents include alkanols containing 2 to 7 carbon atoms (e.g. ethanol, n-
propanol and preferably isopropanol). Salt formation is preferably carried out at elevated temperatures (eg the boiling point of the solvent).

Produce a solution of the components as concentrated as possible at this temperature,
Thereafter, the desired salt is precipitated in crystalline form by cooling the reaction mixture. If desired, the salts can be further purified by recrystallization, if desired with the aid of customary decolorizing agents.

A 1% aqueous solution of the salt obtained by precisely neutralizing the acid with an amine has a south value of 6.8 to 7.

The manufacturing method according to the present invention will be specifically explained in the following examples.

Example A) Pure dry p-methoxycinnamic acid 89.9 t (0.5 mol), distilled diethanolamine 52.6 - 0.5 mol)
and 188 d of isopropyl alcohol into a round bottom flask equipped with a stirrer, reflux condenser and thermometer.

The mixture is heated at reflux temperature for 1 hour. The mixture is filtered while hot and cooled to room temperature with stirring, thereby causing crystallization. After 12 hours, the mixture is further cooled to 0.degree. C. and then filtered.

The crystals are washed with a small amount of cold isopropyl alcohol and dried in a vacuum drying facility at 40°C. Thus diethanolammonium p-methoxycinnamate (white crystals) 125.6 with melting point 88 dry to 88.5°C.
Get 1. B) Instead of diethanolamine, equimolar amounts of monoethanolamine, triethanolamine, bis(
By carrying out the method described in the previous section using 2-hydroxypropyl)amine or tris(hydroxymethyl)-aminomethane, the melting points range from 154°C to 1% respectively.
Monoethanolammonium p-methoxycinnamate, 55°C, triethanolammonium p-methoxycinnamate, melting point 96°C to 96.5°C, melting point 7
bis(2-hydroxypropyl)ammonium p-methoxycinnamate at 3°C to 74°C and 153.
Tris(hydroxymethyl)methylammonium p-methoxycinnamate at a temperature of 5°C to 154°C is obtained.

In the following examples, exemplary sunscreens containing salts of formula 1 according to the present invention are illustrated.

A rod-shaped insect repellent with light-blocking activity may have the following composition:
The present invention includes the following aspects.

A process as claimed in the claims, in which p-methoxy-cinnamate is converted into a salt by means of diethanolamine.

Claims (1)

[Claims] 1. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) [In the formula, R
^■ stands for monoethanolamine, diethanolamine, triethanolamine, bis(2-hydroxypropyl)
amine or ammonium ion of tris(hydroxymethyl)aminomethane], monoethanolamine, diethanolamine,
A process as described above, characterized in that p-methoxycinnamic acid is converted into a salt with triethanolamine, bis(2-hydroxypropyl)amine or tris(hydroxymethyl)aminomethane.