HK1231498B - Silylated imine and carbamate polymeric benzoate compounds, uses, and compositions thereof - Google Patents

Description

Benzoate compounds of methylsilyl imine and carbamate polymerization, their uses and compositions

Technical Field

The present invention relates to silicone polymers containing benzoic acid esters in particulate form, which are intended for use in topical formulations for providing protection against sunlight or other radiation.

Background Art

The demand for sunscreens is growing among the population exposed to increasing amounts of damaging sunlight. The damage can be immediate or long-term, with effects ranging from sunburn, rashes, and cell and tissue damage to premature wrinkling and skin cancer. In this sense, many sunscreen chemicals have been developed in the past to protect against the harmful effects of UV-A and/or UV-B wavelengths and even shorter wavelengths. These chemicals are usually incorporated into widely known and used cosmetic or pharmaceutical preparations, either alone or in combination with each other.

Most UV filters used in sunscreen compositions are monomeric compounds that are inherently hazardous, meaning they can penetrate the skin barrier, a highly unfavorable effect. Consequently, a major drawback associated with the use of common sunscreens is adverse reactions, including skin problems such as allergic contact reactions, photoreactions, and dryness or tightening of the skin. Subjective irritation associated with a burning or stinging sensation without objective erythema is the most common sensitivity complaint associated with sunscreens. This irritation is most often observed in the ocular area. However, persistent objective irritant contact dermatitis is a more common side effect. Individuals with pre-existing eczema are significantly more susceptible to sensitization associated with their compromised skin barrier. Furthermore, certain antibiotics, birth control pills, diuretics, antihistamines, and antidepressants are among the commonly used medications that can increase sensitivity to the sun's rays. Furthermore, some of these skin problems are induced by degradation products formed from sunscreens upon exposure to sunlight.

Attempts have been made to address the risk of skin penetration by encapsulating at least one type of UV filter present in sunscreen formulations. For example, WO 93/04665, WO 94/06404, EP 538431, EP 392883, and EP 358584 describe UV filters based on polysiloxanes, which can be linear or cyclic. These polysiloxanes offer a lower risk of skin penetration, but incorporation into sunscreen compositions can sometimes be difficult due to incompatibility issues. Patent application WO 2005/053631 relates to microcapsules with UV filter activity, in which at least one type of crosslinkable chromophore with UV-A and/or UV-B and/or UV-C filter activity and, optionally, at least one type of crosslinkable monomer without UV-A and/or UV-B and/or UV-C filter activity undergo a crosslinking reaction in the absence of non-crosslinkable chromophores with UV-A and/or UV-B and/or UV-C filter activity. The present invention also relates to sunscreen compositions containing these microcapsules.

The prior art also describes some UV absorbers in particulate form. In this context, patent application WO 2005/120440 relates to particles comprising an inorganic network and an organic compound covalently bonded to the network via spacer groups, characterized in that the organic compound is present in the interior of the particles and optionally also on the surface of the particles. The present invention also relates to formulations and compositions comprising such particles.

Patent application WO 2009/101016 and Walenzyk, T. et al., International Journal of Cosmetic Science (2005), 27(3), 177-189 relate to particles obtainable by reacting inorganic nanoparticles with organic molecules containing functional groups and their use as UV absorbers in cosmetic or dermatological applications.

WO2006/100225 has discovered and disclosed some benzoate compounds, as well as their use as photochemical precursors of UV absorbers, methods related thereto, cosmetic or pharmaceutical compositions, personal care compositions and industrial compositions. US4328346 has also disclosed some silane-functionalized UV screener precursors. These compounds undergo photochemical conversion in the presence of sunlight, which enhances their UV shielding ability.

Document WO2011/045389 describes certain silyl-polymerized benzoate compounds in particulate form that have improved photostability and increased durability on the skin because they have essentially sealed physical properties, thereby avoiding the release of benzoate compounds and their photoconversion products, making them safer for sunscreen users and the environment. However, at typical light doses under actual solar irradiation conditions, the conversion rate is not fast enough to provide optimal protection to users. In addition, the synthesis of some of these compounds requires the use of hazardous starting compounds and expensive and lengthy purification steps, and the yields are not good enough to enable their production on an industrial scale. Moreover, the presence of standard UV filters in sunscreen formulations results in low conversion rates for these compounds, which further reduces their protective efficiency.

It would therefore be desirable to develop new sunscreen compounds which have a higher UV-screening capacity, a faster conversion rate, can be converted in the presence of additional UV filters and are accessible via cost-effective and easier synthetic routes.

Summary of the Invention

The authors of the present invention have developed novel monosilylated polymeric benzoate compounds in particulate form which are suitable as progressive photoprotective agents against UV radiation and which offer the particular advantage of a faster and more effective reaction even in the presence of standard UV filters in the finished sunscreen formulation. This enables them to exert their progressive action despite the inner filter effect provided by conventional filters and thus compensate for the losses in protective efficiency that usually affect standard UV filters.

In contrast to other monosilylated polymeric benzoate compounds of the prior art, the compounds of the present invention are characterized by having a silylated chain attached to the acyl ring of the benzoic acid group rather than the phenyl ring of the ester group, and the presence of an imine or carbamate group as a linker between the benzoate and the silylated chain.

In addition, these compounds can be synthesized from aldehyde compounds by means of short synthetic routes using non-toxic starting compounds that are also affordable and inexpensive. This synthesis provides compounds of higher purity and also higher yields at lower manufacturing costs.

The polymers of the present invention also exhibit a progressive UV protection effect that depends on the duration of sun exposure and the degree of solar radiation. Therefore, compositions containing such compounds constitute a safer method of sunbathing than using conventional sunscreen products, because the protection effect increases with the duration of sun exposure and the intensity of radiation.

The polymers of the present invention themselves exhibit UV-absorbing properties and can be easily photochemically converted in situ into another screening compound having a higher UV protection effect.

In a first aspect, the present invention relates to a method for preparing a silicone progressive photoprotective polymer, comprising reacting a monomer of formula (I):

in:

R is selected from (i), (ii) and (iii):

in:

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independently selected from H, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR ₁₀ , NH ₂ , NHR ₁₁ , NR ₁₂ R ₁₃ , COOH, COOR ₁₄ , CONH ₂ , CONHR ₁₅ , CONR ₁₆ R ₁₇ , SO ₂ NH ₂ , SO ₂ NHR ₁₈ and SO ₂ NR ₁₉ R ₂₀ , with the proviso that at least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is not H, and with the proviso that at least one of R ₁ and R ₅ is H;

R ₆ , R ₇ , R ₈ and R ₉ are independently selected from hydrogen, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR′ ₁ , NH ₂ , NHR ₂ ′ and NR ₃ ′R ₄ ′;

R ₁₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₁ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₂ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₃ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₂ and R ₁₃ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₄ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₅ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₆ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₇ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₆ and R ₁₇ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₈ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₉ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₂₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₉ and R ₂₀ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

L is a linker selected from the group consisting of:

-CH＝N-

–(CH ₂ )-OC(O)-NH-

_Ra is a linear or branched ( _C1 - _C6 ) alkyl group, a linear or branched ( _C2 - _C6 ) alkenyl group, a ( _C3 - _C6 ) cycloalkyl group or a phenyl group;

R _b is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R _c is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R' ₁ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

_R'2 is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R' ₃ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

_R'4 is a linear or branched ( _C1 - _C6 ) alkyl group or a ( _C3 - _C6 ) cycloalkyl group; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

p is an integer selected from 2, 3 and 4;

s is an integer selected from 0 and 1;

t is an integer selected from 0 and 1;

With a compound of formula (IV):

in:

R _d is a linear or branched (C ₁ -C ₆ ) alkyl group;

R _e , R _f and R _g are independently linear or branched (C ₁ -C ₆ )alkyl, linear or branched (C ₂ -C ₆ )alkenyl, (C ₃ -C ₆ )cycloalkyl or phenyl,

_w1 and _w2 are independently 0 or 1,

The reaction was carried out in an alkanol/water mixture.

In a second aspect, the present invention relates to an organosilicon progressive photoprotective polymer obtainable by a process as defined above, characterised in that it is in the form of microparticles or nanoparticles.

In a third aspect, the present invention relates to the use of a silicone progressive photoprotective polymer as defined above for the preparation of a cosmetic or dermatological composition for protecting the human or animal living body from UV radiation.

In a fourth aspect, the present invention relates to the use of a photoprotective polymer as defined above as a photochemical precursor of a UV absorber.

In a fifth aspect, the invention relates to the use of a photoprotective polymer as defined above for preparing a cosmetic or dermatological composition intended for application to the human or animal body, characterized by a progressive UV protection depending on the duration of solar exposure and the degree of solar radiation.

In a sixth aspect, the present invention relates to a photoprotective polymer as defined above for use in protecting a living human or animal body from UV radiation.

In a seventh aspect, the present invention relates to a cosmetic or dermatological composition comprising a silicone progressive photoprotective polymer as defined above.

In an eighth aspect, the present invention relates to monomers of formula (I):

in:

R is selected from (i), (ii) and (iii):

in:

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independently selected from H, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR ₁₀ , NH ₂ , NHR ₁₁ , NR ₁₂ R ₁₃ , COOH, COOR ₁₄ , CONH ₂ , CONHR ₁₅ , CONR ₁₆ R ₁₇ , SO ₂ NH ₂ , SO ₂ NHR ₁₈ and SO ₂ NR ₁₉ R ₂₀ , with the proviso that at least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is not H, and with the proviso that at least one of R ₁ and R ₅ is H;

R ₆ , R ₇ , R ₈ and R ₉ are independently selected from hydrogen, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR′ ₁ , NH ₂ , NHR ₂ ′ and NR ₃ ′R ₄ ′;

R ₁₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₁ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₂ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₃ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₂ and R ₁₃ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₄ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₅ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₆ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₇ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₆ and R ₁₇ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₈ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₉ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₂₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₉ and R ₂₀ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

L is a linker selected from the group consisting of:

-CH＝N-

–(CH ₂ )-OC(O)-NH-

_Ra is a linear or branched ( _C1 - _C6 ) alkyl group, a linear or branched ( _C2 - _C6 ) alkenyl group, a ( _C3 - _C6 ) cycloalkyl group or a phenyl group;

R _b is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R _c is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R' ₁ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

_R'2 is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R' ₃ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

_R'4 is a linear or branched ( _C1 - _C6 ) alkyl group or a ( _C3 - _C6 ) cycloalkyl group; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

p is an integer selected from 2, 3 and 4;

s is an integer selected from 0 and 1;

t is an integer selected from 0 and 1;

or an enantiomeric form or a cosmetically or dermatologically acceptable salt thereof.

In a ninth aspect, the present invention relates to a process for preparing a monomer of formula (I) as defined above when L is a group -CH=N-, comprising making a compound of formula (II):

in:

R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are independently selected from H, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR ₁₀ , NH ₂ , NHR ₁₁ , NR ₁₂ R ₁₃ , COOH, COOR ₁₄ , CONH ₂ , CONHR ₁₅ , CONR ₁₆ R ₁₇ , SO ₂ NH ₂ , SO ₂ NHR ₁₈ and SO ₂ NR ₁₉ R ₂₀ , with the proviso that at least one of R ₁ , R ₂ , R ₃ , R ₄ and R ₅ is not H, and with the proviso that at least one of R ₁ and R ₅ is H;

R ₁₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₁ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₂ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₃ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₂ and R ₁₃ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₄ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₅ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₆ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₇ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₆ and R ₁₇ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

R ₁₈ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₁₉ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group;

R ₂₀ is a linear or branched (C ₁ -C ₆ )alkyl group or a (C ₃ -C ₆ )cycloalkyl group; or R ₁₉ and R ₂₀ together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine or morpholine ring;

and

R' is selected from (i'), (ii') and (iii'):

in:

R ₆ , R ₇ , R ₈ and R ₉ are independently selected from hydrogen, linear or branched (C ₁ -C ₆ )alkyl, (C ₃ -C ₆ )cycloalkyl, OR′ ₁ , NH ₂ , NHR ₂ ′ and NR ₃ ′R ₄ ′;

Reaction with a compound of formula (III):

in:

_Ra is a linear or branched ( _C1 - _C6 ) alkyl group, a linear or branched ( _C2 - _C6 ) alkenyl group, a ( _C3 - _C6 ) cycloalkyl group or a phenyl group;

R _b is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R _c is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

p is an integer selected from 2, 3 and 4;

s is an integer selected from 0 and 1;

t is an integer selected from 0 and 1.

In a tenth aspect, the present invention relates to a process for preparing a monomer of formula (I) as defined above when L is -CH2 _- OC(O)-NH-, comprising:

a) subjecting a compound of formula (II) as defined above to a reduction reaction in the presence of a reducing agent to produce a compound of formula (V):

in:

R ₁ -R ₅ are as defined above; and

R" is selected from (i"), (ii") and (iii'):

as well as

b) reacting a compound of formula (V) as defined above with a compound of formula (VI):

in:

_Ra is a linear or branched ( _C1 - _C6 ) alkyl group, a linear or branched ( _C2 - _C6 ) alkenyl group, a ( _C3 - _C6 ) cycloalkyl group or a phenyl group;

R _b is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

R _c is a linear or branched (C ₁ -C ₆ )alkyl group, a linear or branched (C ₂ -C ₆ )alkenyl group, a (C ₃ -C ₆ )cycloalkyl group or a phenyl group;

p is an integer selected from 2, 3 and 4;

s is an integer selected from 0 and 1;

t is an integer selected from 0 and 1.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG1 shows the UV-Vis spectrum of 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate particles.

FIG2 shows the UV-Vis spectrum of 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate particles.

FIG3 shows the UV-Vis spectrum of 3-(dimethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate particles.

FIG4 shows the UV-Vis spectrum of 3-methoxyphenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate particles.

FIG5 shows the UV-Vis spectrum of 3-(dimethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate particles.

FIG6 shows the UV-Vis spectrum of 3-methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate particles.

FIG7 shows the photoconversion kinetics of the precursor 3-methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate (Compound 6).

FIG8 shows the photoconversion kinetics of the precursor 3-(3-(triethoxysilyl)propyloxy)phenyl benzoate (Comparative Compound A) .

Figure 9 shows the photoconversion kinetics of the precursor 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl )benzoate (Compound 1).

FIG10 shows the photoconversion kinetics of the precursor 3-(bis(3-(triethoxysilyl)propyl)amino)phenyl benzoate (Comparative Compound B).

Figure 11 shows the photoconversion kinetics of the precursor 3-methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate (Compound 6) in the presence of additional UV filters.

Figure 12 shows the photoconversion kinetics of the precursor 3-(3-(triethoxysilyl)propyloxy)phenyl benzoate (Comparative Compound A) in the presence of additional UV filters.

Figure 13 shows the photoconversion kinetics of the precursor 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl )benzoate (Compound 1) in the presence of additional UV filters.

Figure 14 shows the photoconversion kinetics of the precursor 3-(bis(3-(triethoxysilyl)propyl)amino)phenyl benzoate (Comparative Compound B) in the presence of additional UV filters.

In all figures, the ordinate axis represents absorbance or extinction 1% and the abscissa axis represents wavelength in nm. The insets in the figures depict absorbance kinetic measurements at selected wavelengths as indicated.

DETAILED DESCRIPTION

In the context of the present invention, the following terms have the meanings detailed below.

"C ₁ -C ₆ alkyl" refers to a straight or branched hydrocarbon chain group consisting of 1 to 6 carbons, without unsaturation, and connected to the rest of the molecule by a single bond, for example, methyl, ethyl, 1-propyl, 2-propyl, 1-butyl, tert-butyl, 1-pentyl, etc. The alkyl group may be optionally substituted with one or more substituents such as aryl, halo, hydroxy, alkoxy, carboxyl, cyano, carbonyl, acyl, amino, nitro, mercapto, alkylthio, etc., provided that they do not interfere with the polymerization process.

"C ₂ -C ₆ alkenyl" refers to an alkyl group as defined above consisting of 2 to 6 carbon atoms and having one or more unsaturated bonds.

"C ₃ -C ₆ cycloalkyl" refers to a stable 3- to 6-membered monocyclic group that is saturated or partially saturated and consists only of carbon and hydrogen atoms, such as cyclohexyl or adamantyl. The cycloalkyl group may be optionally substituted with one or more substituents such as alkyl, halo, hydroxy, amino, cyano, nitro, alkoxy, carboxyl, etc., provided that they do not interfere with the polymerization process.

The term "alkanol" refers to a straight or branched hydrocarbon chain radical having 1 to 6 carbon atoms and containing a hydroxyl group.

The term "cosmetically or dermatologically acceptable salt" in the context of the present invention must be understood as any salt that is physiologically tolerated (generally meaning that it is non-toxic, in particular as a result of the counterion) when applied or used, in particular in humans and/or mammals. Examples of such salts include acid addition salts and base addition salts. Acid addition salts include mineral acid addition salts, for example hydrochlorides, hydrobromides, hydroiodides, sulfates, nitrates, phosphates; and organic acid addition salts, for example acetates, maleates, fumarates, citrates, oxalates, succinates, tartrates, malates, mandelates, methanesulfonates and p-toluenesulfonates. Examples of base addition salts include inorganic salts, for example sodium, potassium, calcium, ammonium, magnesium, aluminum and lithium salts; and organic base salts, for example ethylenediamine, ethanolamine, N,N-dialkyleneethanolamine, triethanolamine, glucosamine and basic amino acid salts.

In a first aspect, the present invention relates to a process for preparing silicone progressive photoprotective polymers (from now on referred to as process 1 ) comprising reacting a monomer of formula (I) as defined above with a compound of formula (IV) as defined above in an alkanol/water mixture.

In a preferred embodiment, in the monomer of formula (I) used in process 1 according to the invention, R ₁ , R ₃ , R ₄ and R ₅ are H.

In another preferred embodiment, R ₂ is selected from OR ₁₀ , NH ₂ , NHR ₁₁ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are linear (C ₁ -C ₆ ) alkyl groups. Even more preferably, R ₂ is selected from OR ₁₀ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₂ and R ₁₃ are also linear (C ₁ -C ₆ ) alkyl groups, more preferably methyl or ethyl groups.

Even more preferably, in the monomer of formula (I) used in process (1), R ₁ , R ₃ , R ₄ and R ₅ are H, and R ₂ is selected from OR ₁₀ , NH ₂ , NHR ₁₁ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are linear (C ₁ -C ₆ ) alkyl groups. Even more preferably, R ₂ is selected from OR ₁₀ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₂ and R ₁₃ are also linear (C ₁ -C ₆ ) alkyl groups, more preferably methyl or ethyl groups.

In another preferred embodiment, R ₆ -R ₉ are all H.

In another preferred embodiment, p is 3.

In another preferred embodiment, s and t are both 1.

In another preferred embodiment, _Ra , _Rb and _Rc are linear ( _C1 - _C6 ) alkyl groups, more preferably ethyl groups.

In even another preferred embodiment, R is (i).

In another preferred embodiment, in the monomer of formula (I) used in method 1 of the present invention, R ₁ , R ₃ -R ₅ are H; R ₆ -R ₉ are H; R ₂ is selected from OR ₁₀ , NH ₂ , NHR ₁₁ and NR ₁₂ R ₁₃ , more preferably selected from OR ₁₀ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are linear (C ₁ -C ₆ ) alkyl, more preferably methyl or ethyl; p is 3; s and t are 1; and _Ra , R _b and R _c are linear (C ₁ -C ₆ ) alkyl. In a specific embodiment of this preferred embodiment, R is (i). It has been observed that these compounds provide the best conversion efficiency and, therefore, provide an increased level of photoprotection.

In another preferred embodiment, the monomers of formula (I) used in process 1 according to the invention are selected from:

—3-(Diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-(Dimethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-Methoxyphenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-(Diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

—3-(Dimethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

—3-Methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

In a specific embodiment, in the silane of formula (IV) used in process 1 of the present invention, R _d , _Re , R _f and R _g are independently linear or branched (C ₁ -C ₆ )alkyl, more preferably they are all linear (C ₁ -C ₆ )alkyl, even more preferably they are ethyl.

In another preferred embodiment, in the silane of the formula (IV) used in process 1 according to the invention, _w1 and _w2 are both 1.

Even more preferably, the silane of formula (IV) is tetraethoxysilane (TEOS).

In a particular embodiment of the present invention, method 1 is carried out in the presence of a nitrogen-containing basic compound selected from ammonia, monoalkylamines, dialkylamines, trialkylamines, monoalkanolamines, dialkanolamines and trialkanolamines. The alkyl and alkanol groups are both linear or branched and have 1 to 6 carbon atoms. Preferably, the nitrogen-containing basic compound is ammonia.

In a second aspect, the present invention relates to a silicone progressive photoprotective polymer obtainable by process 1 according to the present invention.

The photoprotective polymers of the present invention, which can be obtained as shown in this specification, are in the form of microparticles or nanoparticles. Moreover, such particles have a uniform and spherical or quasi-spherical form and are substantially sealed.

In the context of the present invention, the term "micro- or nanoparticle form" is understood to mean particles having an average particle size of less than 100 micrometers. Typically, the particles have an average particle size ranging from 10 nm to 10 micrometers, preferably from 100 to 1500 nm.

The advantage of preparing the particles by process 1 according to the invention is that the product is obtained in the form of a suspension containing approximately 1 to 25% of solids consisting of encapsulated spherical or quasi-spherical particles, which can be used directly in the cosmetic or dermatological compositions according to the invention. As mentioned above, encapsulation is a relevant physical property of the polymers according to the invention, since the release of benzoic acid esters or their photoconversion products is minimized.

The photoprotective activity is due to the in situ conversion to a sunscreen 2-hydroxybenzophenone polymer via a photo-Fries rearrangement of the benzoate moiety to a 2-hydroxybenzophenone moiety, as shown in Scheme 1 for illustrative purposes:

wherein R ₁ -R ₅ , and n is the number of monomer units constituting the polymer.

These photoprotective polymers exhibit a progressive UV protection effect that depends on the duration of sun exposure and the dose of solar radiation absorbed by the polymer. This progressive UV protection property is demonstrated in their UVB and UVA screening capabilities. The extent of the photo-Fries rearrangement indicates the amount of UVB radiation received.

Thus, compositions containing these photoprotective polymers provide a safer method of sunbathing than using conventional sunscreen products because protection increases with the duration of sun exposure and the dose of radiation.

Therefore, in another aspect, the present invention relates to the use of a photoprotective polymer as defined above for the preparation of a cosmetic or dermatological composition for protecting the human or animal living body against UV radiation.

In another aspect, the present invention relates to the use of a photoprotective polymer as defined above as a photochemical precursor of a UV absorber.

In another aspect, the invention relates to the use of a photoprotective polymer as defined above for preparing a cosmetic or dermatological composition intended for application to the human or animal body, characterized by a progressive UV protection depending on the duration of solar exposure and the degree of solar radiation.

In another aspect, the present invention relates to a photoprotective polymer as defined above for use in protecting a living human or animal body from UV radiation.

Another aspect of the invention relates to a cosmetic or dermatological composition comprising a silicone progressive photoprotective polymer as defined above or a mixture thereof.

The invention also relates to a cosmetic or dermatological composition as mentioned previously comprising an effective amount of a polymer as defined above or a mixture thereof, susceptible to being photochemically converted in situ into a sunscreen compound having enhanced UV protective capacity.

In a particular embodiment of the present invention, the photoprotective polymer is present in the cosmetic or dermatological composition in an amount ranging from 0.01% to 40% by weight, based on the total weight of the composition. Preferably, the amount is in the range of 0.05 to 25% by weight, more preferably in the range of 0.1 to 15% by weight.

The cosmetic or dermatological composition according to the invention may also contain at least one additional organic sunscreen compound for filtering UVB or UVA rays. In a preferred embodiment, the additional sunscreen compound is selected from avobenzone, 2-ethylhexyl p-methoxycinnamate, oxybenzone, octyldimethyl p-aminobenzoic acid, dioxybenzone, ethyl 4-[bis(hydroxypropyl)]aminobenzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl salicylate, glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexyl salicylate, benzoylmethanesulfonate ... Ester, methyl anthranyl, p-dimethylaminobenzoic acid, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2-p-dimethylaminophenyl-5-sulfoniumbenzoxazole acid, sulisobenzone, 2-(4-diethylamino-2-hydroxybenzoyl)benzoic acid hexyl ester, 2-(4-methylbenzylidene)-camphor, and 4-isopropyldibenzoylmethane.

Furthermore, the compositions according to the invention may additionally contain customary adjuvants and additives, such as preservatives, antioxidants, fatty substances, oils, water, organic solvents, silicones, thickeners, emollients, emulsifiers, defoamers, wetting agents, fragrances, surfactants, fillers, sequestering agents, anionic, cationic, nonionic or amphoteric polymers or mixtures thereof, propellants acidifying or alkalizing agents, dyes, colorants, pigments, nanopigments or any other ingredient customarily formulated into cosmetics, in particular for the production of sunscreen compositions.

The necessary amounts of cosmetic and dermatological adjuvants and additives can be easily selected by a person skilled in the art based on the desired product, and this will be illustrated in the examples, but not limited thereto. In a preferred embodiment of the present invention, the amount of adjuvants and/or additives in the cosmetic or dermatological composition ranges from 0.01% to 40% by weight, based on the total weight of the composition. Preferably, this amount is in the range of 0.05 to 25% by weight, more preferably in the range of 0.1 to 15% by weight.

In another particular embodiment, the cosmetic or dermatological composition according to the invention comprises a polymer according to the second aspect of the invention or a mixture thereof, characterized in that the polymer is present in an amount ranging from 0.01% to 40% by weight, preferably from 0.05% to 25% by weight and more preferably from 0.01% to 15% by weight, based on the total weight of the composition, and a sunscreen compound selected from phenoxybenzone, 2-ethylhexyl p-methoxycinnamate, oxybenzone, octyldimethyl p-aminobenzoic acid, dioxybenzone, ethyl 4-[bis(hydroxypropyl)]aminobenzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl salicylate, p-aminobenzoate The content of the sunscreen compound to be applied to a living human or animal body is in the range of 0.01 wt % to 40 wt %, preferably 0.05 wt % to 25 wt %, and more preferably 0.01 wt % to 15 wt %, based on the total weight of the composition, glyceryl formate, 3,3,5-trimethylcyclohexyl salicylate, methyl anthranilate, p-dimethylaminobenzoic acid, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2-p-dimethylaminophenyl-5-sulfoniumbenzoxazole acid, sulfisobenzophenone, 2-(4-diethylamino-2-hydroxybenzoyl) benzoic acid hexyl ester, 2-(4-methylbenzylidene)-camphor and 4-isopropyldibenzoylmethane. The content of the sunscreen compound to be applied to a living human or animal body is in the range of 0.01 wt % to 40 wt %, preferably 0.05 wt % to 25 wt %, and more preferably 0.01 wt % to 15 wt %, based on the total weight of the composition.

The cosmetic or dermatological composition according to the invention may in particular be provided in the form of creams, ointments, emulsions, suspensions, powders, oils, lotions, gels, sticks, foams, emulsions, dispersions, sprays, aerosols, lipsticks, foundations, make-up, loose or pressed powders, eye rouges, eye shadows, mascaras, nail polishes, nail lacquers and non-permanent coloring compositions for hair.

In another aspect, the invention relates to a monomer of formula (I) according to the eighth aspect of the invention.

In a preferred embodiment, R ₁ , R ₃ , R ₄ and R ₅ are H.

In another preferred embodiment, R ₂ is selected from OR ₁₀ , NH ₂ , NHR ₁₁ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are linear (C ₁ -C ₆ ) alkyl groups. Even more preferably, R ₂ is selected from OR ₁₀ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₂ and R ₁₃ are also linear (C ₁ -C ₆ ) alkyl groups, more preferably methyl or ethyl groups.

In another preferred embodiment, R ₆ -R ₉ are all H.

In another preferred embodiment, p is 3.

In another preferred embodiment, s and t are both 1.

In another preferred embodiment, _Ra , _Rb and _Rc are linear ( _C1 - _C6 ) alkyl groups, more preferably ethyl groups.

In even another preferred embodiment, R is (i).

In another preferred embodiment, R ₁ , R ₃ -R ₅ are H; R ₆ -R ₉ are H; R ₂ is selected from OR ₁₀ , NH ₂ , NHR ₁₁ and NR ₁₂ R ₁₃ , more preferably selected from OR ₁₀ and NR ₁₂ R ₁₃ , wherein R ₁₀ , R ₁₁ , R ₁₂ and R ₁₃ are linear (C ₁ -C ₆ ) alkyl, more preferably methyl or ethyl; p is 3; s and t are 1; and _Ra , R _b and R _c are linear (C ₁ -C ₆ ) alkyl. In a specific embodiment of this preferred embodiment, R is (i).

In another preferred embodiment, the monomer of formula (I) is selected from:

—3-(Diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-(Dimethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-Methoxyphenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

—3-(Diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

—3-(Dimethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

-3-Methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate.

In another aspect, the invention relates to a process for preparing a monomer of formula (I) as defined above when the linker L is a group -CH=N-, comprising reacting a compound of formula (II) with a compound of formula (III) according to the ninth aspect of the invention.

This reaction between the aldehyde group of the compound of formula (II) and the amine group of the compound of formula (III) yields an imine group (-CH=N-) and a stoichiometric amount of water. To eliminate water and prevent reversal of the reaction, any water removal method known to those skilled in the art can be employed. In a particular embodiment, the reaction is carried out in the presence of a water removal agent, such as anhydrous magnesium sulfate.

The present invention also relates to a method for preparing a monomer of formula (I) as defined above when the linker L is a group -( _CH2 )-OC(O)-NH-, which comprises subjecting a compound of formula (II) to a reduction reaction in the presence of a reducing agent according to the tenth aspect of the invention to produce a compound of formula (V), and reacting the compound of formula (V) with a compound of formula (VI).

Any reducing agent known to the skilled person for this type of reaction may be used in the synthesis of the monomer of formula (I). In a particular embodiment, the reducing agent is sodium borohydride.

Compounds of formula (II) and (III) can be prepared from commercially available starting materials by conventional methods of organic chemistry as described in the examples provided herein. For example, compounds of formula (II) can be obtained by the following reaction scheme [substituents R ₁ -R ₉ not shown]:

Cosmetically or dermatologically acceptable salts of the monomers of formula (I) are synthesized from parent compounds containing a basic or acidic moiety by conventional chemical methods. Typically, such salts are prepared, for example, by reacting the free acid or base forms of these compounds with a stoichiometric amount of an appropriate base or acid in water or in an organic solvent or in a mixture of the two. Typically, non-aqueous media such as ether, ethyl acetate, ethanol, isopropanol or acetonitrile are preferred.

The following examples are provided to further illustrate certain embodiments of the present invention, but are not to be construed as limiting the scope of the invention in any way.

Example

Example 1. 3-(Diethyl)-4-((3-(Triethoxysilyl)propylcarbamoyloxy)methyl)benzoate Synthesis of 4-amino)phenyl ester (Compound 1)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-(diethylamino)phenyl 4-formylbenzoate

1.01 g (6.13 mmol) of 3-(diethylamino)phenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acid chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. The resulting brown solid was recrystallized from cyclohexane to produce a pale yellow solid (50% yield, 95% purity as assessed by HPLC).

¹ H-NMR (CDCl ₃ ): 10.15ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.24ppm (t, 1H), 6.57ppm (dd, 1H), 6.47ppm (m, 2H), 3.35ppm (q, 4H), 1.23ppm (t, 6H)

Step 3: Synthesis of 3-(diethylamino)phenyl 4-(hydroxymethyl)benzoate

2.00 g (6.72 mmol) of 3-(diethylamino)phenyl 4-formylbenzoate was suspended in 50 mL of absolute ethanol and 0.80 g (3 eq) of sodium borohydride was added in small portions in an ice bath. After the addition was complete, the solution was stirred at room temperature for 30 minutes. 30 mL of water was then added and stirring continued for half an hour. Chloroform (3 x 50 mL) was added and the organic phase was extracted, dried over magnesium sulfate, and the solvent evaporated under reduced pressure to give the desired product as a yellow solid (90% yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm(d,2H),7.49ppm(d,2H),7.24ppm(t,1H),6.57ppm(dd,1H),6.47ppm(m,2H),4.80ppm(s,2H),3.35ppm(q,4H),1.23ppm(t,6H)

Step 4: Synthesis of 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

1.15 g (3.84 mmol) of 3-(diethylamino)phenyl 4-(hydroxymethyl)benzoate was dissolved in 100 mL of chloroform, and 2.85 mL (3 eq) of 3-(triethoxysilyl)propyl isocyanate and 1.60 mL (3 eq) of triethylamine were added. The resulting solution was refluxed for 48 hours. Once cooled to room temperature again, the solvent was evaporated under reduced pressure and the excess reactant was distilled under vacuum to produce the desired product as an oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm(d,2H),7.49ppm(d,2H),7.24ppm(t,1H),6.57ppm(dd,1H),6.47ppm(m,2H),5.19ppm(s,1H),4.80ppm(s,2H) ),3.85ppm(q,6H),3.35ppm(q,4H),3.20ppm(t,2H),1.61ppm(m,2H),1.23ppm(t,9H),1.18ppm(t,6H),0.69ppm(m,2H).

Example 2. 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoic acid 3-(dimethyl Synthesis of 4-amino)phenyl ester (Compound 2)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-(dimethylamino)phenyl 4-formylbenzoate

0.84 g (6.13 mmol) of 3-(dimethylamino)phenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acid chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. The resulting brown solid was recrystallized from cyclohexane to produce a pale yellow solid (60% yield, 95% purity as assessed by HPLC).

¹ H-NMR (CDCl ₃ ): 10.14ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.26ppm (t, 1H), 6.64ppm (dd, 1H), 6.54ppm (dd+t, 2H), 2.97ppm (s, 6H)

Step 3: Synthesis of 3-(dimethylamino)phenyl 4-(hydroxymethyl)benzoate

2.00 g (7.43 mmol) of 3-(dimethylamino)phenyl 4-formylbenzoate was suspended in 50 mL of absolute ethanol and 0.80 g (3 eq) of sodium borohydride was added in small portions in an ice bath. After the addition was complete, the solution was stirred at room temperature for 30 minutes. 30 mL of water was then added and stirring continued for half an hour. Chloroform (3 x 50 mL) was added and the organic phase was extracted, dried over magnesium sulfate, and the solvent evaporated under reduced pressure to give the desired product as a yellow solid (90% yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm (d,2H), 7.49ppm (d,2H), 7.26ppm (t,1H), 6.64ppm (dd,1H), 6.54ppm (dd+t,2H), 4.80ppm (s,2H), 2.97ppm (s,6H)

Step 4: Synthesis of 3-(dimethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

1.03 g (3.84 mmol) of 3-(dimethylamino)phenyl 4-(hydroxymethyl)benzoate was dissolved in 100 mL of chloroform, and 2.85 mL (3 eq) of 3-(triethoxysilyl)propyl isocyanate and 1.60 mL (3 eq) of triethylamine were added. The resulting solution was refluxed for 48 hours. Once cooled to room temperature again, the solvent was evaporated under reduced pressure, and the excess reactants were distilled under vacuum to produce the desired product as an oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm(d,2H),7.49ppm(d,2H),7.26ppm(t,1H),6.64ppm(dd,1H),6.54ppm(dd+t,2H),4.8 0ppm(s,2H),3.20ppm(t,2H),2.97ppm(s,6H),1.61ppm(m,2H),1.23ppm(t,9H),0.69ppm(m,2H)

Example 3. 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoic acid 3-methoxy Synthesis of phenyl ester (compound 3)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-methoxyphenyl 4-formylbenzoate

0.76 g (6.13 mmol) of 3-methoxyphenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acyl chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. A white solid was obtained, which was estimated by HPLC to be 96% pure (90% yield).

¹ H-NMR (CDCl ₃ ): 10.14ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.34ppm (t, 1H), 6.84ppm (td, 2H), 6.78ppm (t, 1H), 3.83ppm (s, 3H)

Step 3: Synthesis of 3-methoxyphenyl 4-(hydroxymethyl)benzoate

2.00 g (7.75 mmol) of 3-methoxyphenyl 4-formylbenzoate was suspended in 50 mL of absolute ethanol and 0.80 g (3 eq) of sodium borohydride was added in small portions in an ice bath. After the addition was complete, the solution was stirred at room temperature for 30 minutes. 30 mL of water was then added and stirring continued for half an hour. Chloroform (3 x 50 mL) was added and the organic phase was extracted, dried over magnesium sulfate, and the solvent evaporated under reduced pressure to give the desired product as a yellow solid (90% yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm (d,2H), 7.50ppm (d,2H), 7.34ppm (t,1H), 6.84ppm (td,2H), 6.78ppm (t,1H), 4.8ppm (s,2H), 3.83ppm (s,3H)

Step 4: Synthesis of 3-methoxyphenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate

0.99 g (3.84 mmol) of 3-methoxyphenyl 4-(hydroxymethyl)benzoate was dissolved in 100 mL of chloroform, and 2.85 mL (3 eq) of 3-(triethoxysilyl)propyl isocyanate and 1.60 mL (3 eq) of triethylamine were added. The resulting solution was refluxed for 48 hours. Once cooled to room temperature again, the solvent was evaporated under reduced pressure, and the excess reactant was distilled under vacuum to produce the desired product as an oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.20ppm(d,2H),7.50ppm(d,2H),7.34ppm(t,1H),6.84ppm(td,2H),6.78ppm(t,1H),4.8p pm(s,2H),3.83ppm(s,3H),3.20ppm(t,2H),1.61ppm(m,2H),1.23ppm(t,9H),0.69ppm(m,2H)

Example 4. 3-(Diethylamino)-4-((3-(Triethoxysilyl)propylimino)methyl)benzoic acid Synthesis of phenyl ester (compound 4)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-(diethylamino)phenyl 4-formylbenzoate

1.01 g (6.13 mmol) of 3-(diethylamino)phenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acid chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. The resulting brown solid was recrystallized from cyclohexane to produce a pale yellow solid (50% yield, 95% purity as assessed by HPLC).

¹ H-NMR (CDCl ₃ ): 10.15ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.24ppm (t, 1H), 6.57ppm (dd, 1H), 6.47ppm (m, 2H), 3.35ppm (q, 4H), 1.23ppm (t, 6H)

Step 3: Synthesis of 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

50 mg (0.17 mmol) of 3-(diethylamino)phenyl 4-formylbenzoate was suspended in 20 mL of chloroform and 37 mg (0.17 mmol) of 3-(aminopropyl)triethoxysilane was added, followed by 100 mg of anhydrous magnesium sulfate. The resulting suspension was stirred at room temperature under a nitrogen atmosphere for 24 h. The crude material was filtered and the solvent was eliminated under reduced pressure to produce an orange oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.36ppm(s,1H),8.24ppm(d,2H),7.85ppm(d,2H),7.21ppm(t,1H),6.57ppm(dd,1H),6.47ppm(m,2H),3.84p pm(q,6H),3.67ppm(t,2H),3.35ppm(q,4H),1.86ppm(m,2H),1.23ppm(t,9H),1.17ppm(t,6H),0.69ppm(m,2H).

Example 5. 3-(Dimethylamino)-4-((3-(Triethoxysilyl)propylimino)methyl)benzoic acid Synthesis of phenyl ester (compound 5)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-(dimethylamino)phenyl 4-formylbenzoate

0.84 g (6.13 mmol) of 3-(dimethylamino)phenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acid chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. The resulting brown solid was recrystallized from cyclohexane to produce a pale yellow solid (60% yield, 95% purity as assessed by HPLC).

¹ H-NMR (CDCl ₃ ): 10.14ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.26ppm (t, 1H), 6.64ppm (dd, 1H), 6.54ppm (dd+t, 2H), 2.97ppm (s, 6H)

Step 3: Synthesis of 3-(dimethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

50 mg (0.19 mmol) of 3-(dimethylamino)phenyl 4-formylbenzoate was suspended in 20 mL of chloroform and 41 mg (0.19 mmol) of 3-(aminopropyl)triethoxysilane was added, followed by 100 mg of anhydrous magnesium sulfate. The resulting suspension was stirred at room temperature under a nitrogen atmosphere for 24 h. The crude material was filtered and the solvent was eliminated under reduced pressure to produce an orange oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.36ppm(s,1H),8.24ppm(d,2H),7.85ppm(d,2H),7.27ppm(t,1H),6.63ppm(dd,1H),6.55ppm(m,2 H),3.85ppm(q,6H),3.67ppm(t,2H),2.97(s,6H),1.86ppm(m,2H),1.23ppm(t,9H),0.70ppm(m,2H).

Example 6. 3-Methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate Synthesis of (Compound 6)

Step 1: Synthesis of 4-formylbenzoyl chloride

0.92 g (6.13 mmol) of 4-formylbenzoic acid was suspended in 50 mL of anhydrous toluene. 16 mL of thionyl chloride (0.22 mol) was added and the resulting suspension was heated at 130° C. for 3 hours under a nitrogen atmosphere, then cooled to room temperature and the solvent evaporated under reduced pressure. An additional 50 mL of toluene was added and evaporated under reduced pressure to eliminate any remaining thionyl chloride. This process was repeated twice. The resulting solid was used directly without further purification.

Step 2: Synthesis of 3-methoxyphenyl 4-formylbenzoate

0.76 g (6.13 mmol) of 3-methoxyphenol was suspended in 50 mL of dichloromethane and dissolved by the addition of 0.85 mL (6.13 mmol) of triethylamine. The resulting solution was stirred for 30 minutes, after which a solution of 4-formylbenzoyl chloride in dichloromethane (6.13 mmol of acyl chloride in 20 mL of solvent) was added dropwise. The resulting solution was stirred at room temperature for 5 hours, then extracted with a saturated aqueous solution of sodium carbonate (3 x 40 mL), dried over magnesium sulfate, and the solvent evaporated under reduced pressure. A white solid was obtained, which was estimated by HPLC to be 96% pure (90% yield).

¹ H-NMR (CDCl ₃ ): 10.14ppm (s, 1H), 8.37ppm (d, 2H), 8.02ppm (d, 2H), 7.34ppm (t, 1H), 6.84ppm (td, 2H), 6.78ppm (t, 1H), 3.83ppm (s, 3H)

Step 3: Synthesis of 3-methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate

50 mg (0.20 mmol) of 3-methoxyphenyl 4-formylbenzoate was suspended in 20 mL of chloroform and 43 mg (0.20 mmol) of 3-(aminopropyl)triethoxysilane was added, followed by 100 mg of anhydrous magnesium sulfate. The resulting suspension was stirred at room temperature for 24 h under a nitrogen atmosphere. The crude material was filtered and the solvent was eliminated under reduced pressure to produce an orange oil (quantitative yield).

¹ H-NMR (CDCl ₃ ): 8.36ppm (s, 1H), 8.24ppm (d, 2H), 7.85ppm (d, 2H), 7.32ppm (t, 1H), 6.83ppm (m, 2H), 6.79ppm (t, 1H), 3.83ppm (q+s, 6H+3H OMe),3.67ppm(t,2H),1.86ppm(m,2H),1.23ppm(t,9H),0.70ppm(m,2H).

Example 7. Preparation of particles

7.1. Particle characterization

The particles obtained according to the method described below were characterized by particle size distribution, UV-Vis spectroscopy and HPLC chromatography.

7.1.1. Particle morphology

The particle size distribution showed that the particles were monodisperse with a particle size of 370 ± 70 nm.

7.1.2. UV-Vis spectroscopy

A 3% (30 mg/mL) suspension of particles in PEG-300 was added to a PMMA plate at a rate of 1.3 mg/cm ^2. When UV-Vis spectra were recorded with an integrating sphere in diffuse transmittance mode, the particles showed strong absorption in the UVB region, with a shift towards UVA.

HPLC chromatography

The particle sealing performance was determined by extraction with solvent at high temperature, and the extract was analyzed by HPLC. The particles (200 mg) and 100 mL of a mixture of methanol and water (80:20) were refluxed in a Soxhlet apparatus for 5 hours. The solvent samples were analyzed by HPLC under the following conditions:

—Equipment: HP 1090 liquid chromatograph

— Column: Reversed phase Kromasil C18 5μm 15x0.46

—Mobile phase: acetonitrile/water 80:20

—Flow rate: 1.0mL/min

—Detection: Absorption 254nm

The particle chromatogram shows only solvent dead time, thus indicating that the particles are essentially hermetic.

7.2. Particle Photoconversion

Particles suspended in PEG-300 were irradiated at 35°C in a Luzchem ICH-2 photoreactor equipped with 16 UVB lamps (irradiance 70 W/ ^m2 ).

7.2.1. UV-Vis spectroscopy

A 3% particle suspension in PEG-300 was added to a PMMA plate at a rate of 1.3 mg/cm ^2. The progress of photoconversion was controlled by measuring the diffuse transmittance of the sample between 280 nm and 400 nm.

The particle spectrum showed that the irradiated particles absorbed in both the UVB and UVA regions.

HPLC chromatography

HPLC chromatography of the irradiated microcapsules was performed in the same way as in the case of the non-irradiated microcapsules (2.4).

The particle chromatogram shows only solvent dead time, thus indicating that the particles are essentially hermetic.

7.3. Preparation of granules:

3-(Diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate granules (P1);

3-(Diethylamino)benzene 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate ester particles (P2);

3-(Dimethylamino)benzene 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate ester particles (P3);

3-Methoxyphenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoate granules (P4);

3-(Dimethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate granules (P5);

3-Methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate particles (P6)

Particles P1 were prepared as follows: A mixture of ethanol (3.8 mL, 0.082 mmol) and deionized water (1.4 mL, 0.078 mmol) was heated to 40°C in a water bath with stirring. A mixture of tetraethoxysilane (TEOS, 396 mg, 1.903 mmol) and 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate (150 mg, 0.326 mmol) was heated in the same bath without stirring. When the ethanol/water mixture reached 40°C, 1.7 mL of 30% ammonia (0.011 mmol) was added and stirring was increased to ensure a homogeneous mixture. When the temperature reached 40°C again, a solution of TEOS and 3-(3-(triethoxysilyl)propyloxy)phenyl benzoate was added and stirred for 15 seconds. The resulting suspension was allowed to stand at 40°C for 1 hour, then centrifuged and washed with water (25 mL x 3). Finally, the particles were resuspended in an aqueous solution containing 0.5% w/w PVP k-90 and HPMC as stabilizers. The chromophore content in the particles was 50% w/w, expressed as 3-(diethylamino)phenyl 4-methylbenzoate.

Particles P2-P6 were prepared from appropriate reagents following the synthetic protocol described above. All compounds were evaluated for HPLC sealability. Preparation and analytical details are summarized in Table 1.

Table 1

(1) Expressed as 3-(diethylamino)phenyl 4-methylbenzoate

(2) Expressed as 3-(dimethylamino)phenyl 4-methylbenzoate

(3) is represented by 3-methoxyphenyl 4-methylbenzoate

(4) is represented by 3-(dimethylamino)phenyl 4-methylbenzoate

(5) is represented by 3-methoxyphenyl 4-methylbenzoate

Example 8. Preparation of sunscreen composition

Sunscreen compositions were prepared using particles P1 as active ingredient.

The components of the composition are shown in the table below:

Combine the ingredients of Phase B. Stir and heat the mixture to 70-75°C. Combine the ingredients of Phase A. Heat the mixture to 70-75°C while stirring. Add Phase B to Phase A while stirring. Add the preservative. Stir the mixture and allow it to cool to room temperature.

Example 9 Comparative. 3-Methoxybenzene 4-((3-(triethoxysilyl)propylimino)methyl)benzoate Studies on the photoconversion of ester (Compound 6) and 3-(3-(triethoxysilyl)propyloxy)phenyl benzoate.

The photoconversion rate of the precursor 3-methoxyphenyl 4-((3-(triethoxysilyl)propylimino)methyl)benzoate (Compound 6 of the present invention ) was compared with the photoconversion rate of the precursor 3-(3-(triethoxysilyl) propyloxy )phenyl benzoate (Comparative Compound A) described in the prior art .

These precursors were dissolved in ethanol at a concentration of 1% w/v (10 mg/L) and exposed to simulated solar radiation in a SUNTEST ATLAS XLS+ equipped with a daylight filter (290-800 nm, 765 W/m ² ). Figures 7 and 8 show the extent of photoconversion of compound 6 of the present invention and comparative compound A, respectively. The inset in each figure shows the photoconversion kinetics at 335 nm.

The table below shows the final extinction value of each precursor after exposure to simulated solar radiation as well as the half-life of conversion ( _t50 , the number of MEDs required to reach 50% of the final extinction value).

It can be observed that the conversion of compound 6 is 3.3 times faster than that of comparative compound A. Therefore, the introduction of a silylated chain on the acyl ring accelerates its photoconversion.

Example 10 Comparative. 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl)benzoic acid 3- (Diethylamino)phenyl ester (Compound 1) and 3-(bis(3-(triethoxysilyl)propyl)amino)phenyl benzoate (Compound 1) Comparative study on the photoconversion of compound B).

The photoconversion rate of the precursor 3-(diethylamino)phenyl 4-((3-(triethoxysilyl)propylcarbamoyloxy)methyl) benzoate (Compound 1 of the present invention) was compared with the photoconversion rate of the precursor 3-(bis(3-( triethoxysilyl )propyl)amino)phenyl benzoate (Comparative Compound B) described in the prior art .

These precursors were dissolved in ethanol at a concentration of 1% w/v (10 mg/L) and exposed to simulated solar radiation in a SUNTEST ATLAS XLS+ equipped with a daylight filter (290-800 nm, 765 W/m ² ). Figures 9 and 10 show the extent of photoconversion of compound 1 of the present invention and comparative compound B, respectively. The inset in each figure shows the photoconversion kinetics at 360 nm.

The table below shows the final extinction value reached by each precursor after exposure to simulated solar radiation and the parameter _t50 representing the MED (minimum erythemal dose) of the irradiation dose required for each precursor to reach 50% of the final extinction value.

From the results cited above, it can be inferred that the introduction of a silylated chain on the acyl ring provides a 22% higher increase in extinction after conversion and a 60% faster conversion rate.

Example 11 Comparative. 4-((3-(Triethoxysilyl)propyl)-1,2-dimethoxy-1-[4-(3-(triethoxysilyl)propyl)-1 ... benzoic acid 3-(3-(triethoxysilyl)propyloxy)-1,3-dimethylamino)methyl)benzoate (Compound 6) and benzoic acid 3-(3-(triethoxysilyl)propyloxy) Photoconversion of phenyl ester (Comparative Compound A).

An ethanol solution (a) containing commercial UV filters Tinosorb-S (3.7 mg/L) and 4-MBC (4.9 mg/L) and compound 6 of the present invention (10 mg/L) was prepared. For comparative purposes, an ethanol solution (b) containing commercial UV filters Tinosorb-S (3.7 mg/L) and 4-MBC (4.9 mg/L) and comparative compound A (10 mg/L) was also prepared.

Both solutions were exposed to simulated solar radiation in a SUNTEST ATLAS XLS+ equipped with a daylight filter (290-800 nm, 765 W/m ² ).

Figures 11 and 12 show the absorption spectra of the two solutions (a) and (b), respectively. It can be observed that the final extinction value at 335 nm for the formulation containing compound 6 is higher than that for the formulation containing comparative compound A. Therefore, it can be inferred that the introduction of a silylated chain on the acyl ring provides a precursor with a better ability to enhance its sunscreen effect in the presence of additional UV filters.

Example 12 Comparative. 4-((3-(Triethoxysilyl)propylamino)-1,2-dimethyl-1-thiazolyl)propane in the presence of other commercial sunscreens. benzoic acid 3-(diethylamino)phenyl ester (compound 1) and benzoic acid 3-(bis(3-(triethoxymethyl) Photoconversion of 1,2-dimethylsilyl)propyl)amino)phenyl ester (Comparative Compound B).

An ethanol solution (c) containing commercial UV filters Tinosorb-S (3.7 mg/L) and 4-MBC (4.9 mg/L) and compound 1 of the present invention (10 mg/L) was prepared. For comparative purposes, an ethanol solution (d) containing commercial UV filters Tinosorb-S (3.7 mg/L) and 4-MBC (4.9 mg/L) and comparative compound B (10 mg/L) was also prepared.

Both solutions were exposed to simulated solar radiation in a SUNTEST ATLAS XLS+ equipped with a daylight filter (290-800 nm, 765 W/m ² ). Figures 13 and 14 show the absorption spectra of the two solutions (c) and (d), respectively.

It can be observed that the final extinction value at 365 nm is higher for the formulation containing compound 1, while the extinction at 365 nm remains almost unchanged after irradiation of 20 MEDs in the formulation containing comparative compound B. Therefore, it can be concluded again that the introduction of a silylated chain on the acyl ring provides a precursor with a better ability to increase its protective effect in the UV-A region in the presence of additional UV filters.

Claims (13)

1. A method for preparing an organosilicon progressive photoprotective polymer, comprising using a monomer of formula (I): in: R is selected from (i), (ii) and (iii): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ;} R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; L is selected from the following linker: -CH＝N- –CH ₂ -OC(O)-NH- _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _R'1 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; t is an integer selected from 0 and 1; With compounds of formula (IV): in: R _{_d} is a straight-chain or branched C_₁-C_₆ alkyl group; _Re , _Rf , and _Rg are independently straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl. _w1 and _w2 are independently 0 or 1. The reaction takes place in an alkanolate/water mixture. 2. The method for preparing organosilicon progressive photoprotective polymers according to claim 1, characterized in that it contains a nitrogen-containing basic compound selected from ammonia, monoalkylamine, dialkylamine, trialkylamine, monoalkanolamine, dialkanolamine and trialkanolamine, wherein the alkyl and alkanol groups are both straight-chain or branched and have 1 to 6 carbon atoms. 3. The method for preparing organosilicon progressive photoprotective polymer according to claim 1, wherein the alkanol/water mixture is an ethanol/water mixture. 4. An organosilicon progressive photoprotective polymer, which can be obtained by the method defined in any one of claims 1 to 3, characterized in that it is in the form of microparticles or nanoparticles. 5. Use of the organosilicon progressive photoprotective polymer as defined in claim 4 in the preparation of cosmetic or dermatological compositions for protecting living human or animal bodies from UV radiation. 6. Use of the organosilicon progressive photoprotective polymer as defined in claim 4 as a photochemical precursor for a UV absorber. 7. The use of the organosilicon progressive photoprotective polymer as defined in claim 4 in the preparation of cosmetic or dermatological compositions intended for use on living humans or animals, characterized by progressive UV protection depending on the duration and intensity of solar exposure. 8. A cosmetic or dermatological composition comprising a silicone progressive photoprotective polymer or a mixture thereof as defined in claim 4. 9. The cosmetic or dermatological composition according to claim 8, characterized in that the polymer content ranges from 0.01% by weight to 40% by weight based on the total weight of the composition. 10. The cosmetic or dermatological composition according to claim 8 or 9, further comprising a sunscreen compound selected from azirone, 2-ethylhexyl p-methoxycinnamate, oxybenzone, octyl dimethyl p-aminobenzoic acid, dioxybenzone, ethyl 4-[bis(hydroxypropyl)]aminobenzoate, 2-ethylhexyl 2-cyano-3,3-diphenylacrylate, 2-ethylhexyl salicylate, glyceryl p-aminobenzoate, 3,3,5-trimethylcyclohexyl salicylate, methyl anthracene, p-dimethylaminobenzoic acid, 2-ethylhexyl p-dimethylaminobenzoate, 2-phenylbenzimidazole-5-sulfonic acid, 2-p-dimethylaminophenyl-5-sulfonium benzoxazolium acid, sulfoisobenzone, hexyl 2-(4-diethylamino-2-hydroxybenzoyl)benzoate, 2-(4-methylbenzylene)-camphor, and 4-isopropyldibenzoylmethane. 11. A monomer of formula (I): in: R is selected from (i), (ii) and (iii): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ;} R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; L is selected from the following linker: -CH＝N- –CH ₂ -OC(O)-NH- _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl. _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _R'1 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; and t is an integer selected from 0 and 1; Or a salt that is acceptable in cosmetic or dermatological terms. 12. A method for preparing a monomer of formula (I), in: R is selected from (i), (ii) and (iii): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ;} R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; L is the linker -CH=N-; _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl. _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _R'1 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; t is an integer selected from 0 and 1; The method includes using a compound of formula (II): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; and R' is selected from (i'), (ii'), and (iii'): in: _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ; R'1} is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; Reaction with compounds of formula (III): in: _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl. _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; t is an integer selected from 0 and 1. 13. A method for preparing a monomer of formula (I), in: R is selected from (i), (ii) and (iii): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ;} R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; L is –CH ₂ -OC(O)-NH-; _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _R'1 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; t is an integer selected from 0 and 1; The method includes: a) Reduction of the compound of formula (II) as defined above in the presence of a reducing agent to produce the compound of formula (V): in: _R1 , _R3 , _R4 , and _R5 are H. _R2 is selected from OR ₁₀ and NR ₁₂ R ₁₃ ; R ₁₀ is a straight-chain _C1 - _C6 alkyl group; R ₁₂ is a straight-chain _C1 - _C6 alkyl group; R ₁₃ is a straight-chain _C1 - _C6 alkyl group; R” is selected from (i”), (ii”) and (iii”): in: _R6 , _R7 , _R8 and _R9 are independently selected from hydrogen, straight-chain or branched _C1 - _C6 alkyl, _C3 - _C6 cycloalkyl, _OR'1 , _NH2 , _NHR'2 and _{NR'3R'4 ; R'1} is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'2 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'3 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; _R'4 is a straight-chain or branched _C1 - _C6 alkyl or _C3 - _C6 cycloalkyl; or _R'3 and _R'4 together with the nitrogen atom to which they are attached form a pyrrolidine, piperidine, or morpholine ring; and b) React the compound of formula (V) as defined above with the compound of formula (VI): in: _Ra is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; _Rb is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl. _Rc is a straight-chain or branched _C1 - _C6 alkyl, straight-chain or branched _C2 - _C6 alkenyl, _C3 - _C6 cycloalkyl, or phenyl; p is an integer selected from 2, 3, and 4; s is an integer selected from 0 and 1; t is an integer selected from 0 and 1.