Substantive hydrophobic cationic UV-absorbing compounds

Details Substantive hydrophobic cationic UV-absorbing compounds Substantive hydrophobic cationic UV-absorbing compounds

2001-07-31

2003-09-02

Davis, Brian (Department: 1621)

Drug, bio-affecting and body treating compositions

Preparations characterized by special physical form

Cosmetic, antiperspirant, dentifrice

C424S059000, C424S093200, C424S400000, C514S617000, C514S619000, C514S643000, C564S133000, C564S134000, C564S139000, C564S169000, C564S166000, C564S170000, C564S182000, C564S284000, C564S287000, C564S288000

Reexamination Certificate

active

06613340

ABSTRACT:

FIELD OF INVENTION
The invention relates to substantive hydrophobic cationic UV-absorbing compounds. More particularly, the invention relates to novel, cationic, non-hydrolysable, non-irritating UV-absorbing bis-quaternary salts of cinnamidoalkylamines which are substantive to fabric, skin and hair. The invention also relates to a process of manufacture of the said compounds and further to their use in hair, skin and fabric care formulations.
BACKGROUND AND PRIOR ART
The harmful effects of solar UV-radiation on skin are well known. The UV-B (290-320 nm) portion of solar spectrum is largely responsible for erythema (sunburn) and cancer. [M. M. Rieger, Cosmet. Toiletries, 102 (3), 91, (1987); L. Taylor, Skin Cancer Foundation J., 4, (90) (1986)].
Similarly, photodegradative effect of UV-radiation on human hair is well documented. Continuous exposure to sunrays lightens hair color and makes human hair rough, brittle and difficult to comb. UV rays are reported to damage the proteins of cuticles. Prolonged irradiation results in diminished tensile strength due to breaking of disulphide bonds in keratin. [R. Beyak et al, J. Soc. Cosmet. Chem. 22, 667-668 (1971), E. Hoting et al, J. Soc. Cosmet. Chem. 46, 85-99 (1995)].
In addition, UV light is also known to fade colored garments. [P. C. Screws, Text. Chem. Color, 11, 21 (1987); B. Milligan et al, Polym. Degrad. Stab. 10 (4), 335 (1985)].
A number of UV-absorbing compounds like derivatives of salicylic acid, benzophenones, benzotriazoles, cinnamic acid have been used in personal care products. However, all these molecules suffered from a major disadvantage of lack of substantivity. To make this UV-absorbing moieties more substantive, structural modification have been introduced. U.S. Pat. No. 5,427,773 (1995) discloses cationic substantive photofilters based on dimethylamino benzamide whereas U.S. Pat. No. 5,601,811 (1997) describes about cationic photofilters based on cinnamidoalkyl moiety for UV absorption that are water-soluble. High water-solubility is not always desirable for skin care applications due to possible toxic effects associated with long term usage of cosmetics on human skin. In terms of substantivity to the substrates like skin and hair, water-insoluble cationic photofilters were found to have superior substantivity when compared with water-soluble photofilters in rinse-off products.
The main object of the present invention is therefore to synthesise hydrophobic molecules containing most popular cinnamido moiety to provide UV-B absorption and with cationic centre to provide substantivity to skin, hair and fabric and a long alkyl chain to impart conditioning effect.
SUMMARY OF THE INVENTION
Thus the present invention provides a novel, substantive, organic-soluble cinnamidoalkylamine quaternary compounds of Formula I,
wherein
R
1
is selected from H, halo, —OH, —NH
2
, —NO
2
, —OCH
3
, —N(CH
3
)
2
, alkyl groups containing from 1 to 6 carbon atoms, alkoxy groups containing from 1 to 6 carbon atoms, alkylamino or N,N-dialkylamino groups containing from 1 to 6 carbon atoms;
R
2
is selected from hydrogen, alkyl group containing from 1 to 12 carbon atoms;
R
3
and R
4
are independently selected from benzyl, alkyl group containing from 1 to 12 carbon atoms,
n is an integer from 1 to 6;
R
5
is selected from an alkyl group containing from 8 to 22 carbon atoms; alkenyl groups containing from 8 to 22 carbon atoms;
R
7
is selected from bromo, chloro, nitro, methyl and ethyl groups.
A preferred compound of Formula I is, p-methoxy cinnamidopropyl dimethyllauryl ammonium tosylate, wherein, R
1
=—OCH
3
; R
2
=—H; R
3
,R
4
=CH
3
; n=3; R
5
=—Cl
12
H
25
; R
7
=—CH
3
is described.
In another aspect the invention relates to a process of making a quaternary ammonium salt of cinnamidoalkylamine Formula I,
wherein
R
1
is a substituent, selected from H, halo, —OH, —NH
2
, —NO
2
, —OCH
3
, —N(CH
3
)
2
, alkyl groups containing from 1 to 6 carbon atoms, alkoxy groups containing from 1 to 6 carbon atoms, alkylamino or N,N-dialkylamino groups containing from 1 to 6 carbon atoms;
R
2
is selected from hydrogen, alkyl group containing from 1 to 12 carbon atoms;
R
3
and R
4
are independently selected from benzyl, alkyl group containing from 1 to 12 carbon atoms,
n is an integer from 1 to 6;
R
5
is selected from an alkyl group containing from 8 to 22 carbon atoms; alkenyl groups containing from 8 to 22 carbon atoms;
R
7
is selected from bromo, chloro, nitro, methyl and ethyl groups,
wherein the process a compound of Formula II is reacted with a compound of Formula III to give an intermediate of Formula IV, the intermediate of formula IV is quaternised with a compound of Formula V, wherein, R
1
, R
2
, R
3
, R
4
, R
5
, R
7
, n are same as in Formula I and R
6
of Formula II is selected form —OH, Cl
−
or —O(CH
2
)
p
CH
3
with p=0 to 3 to provide the compound of formula I.
According to a further aspect of the present invention there is provided skin care, hair care and fabric care formulations containing novel organic-soluble cinnamidoalkylamine quaternary ammonium compounds of Formula I and conventional active ingredients of skin and hair care products.
The unique combination of substantivity to hair and skin, conditioning, strong UV absorption and water-insolubility of these quaternary compounds of cinnamidoalkylamines is very desirable for personal care products, especially for skin care applications.
DETAILED DESCRIPTION OF THE INVENTION
The substantive UV absorbing compounds of the present invention are quaternary salts of cinnamidoalkylamines that are prepared by reacting lower alkyl ester of cinnamic acid or acid halides of cinnamic acid with an amino compound that is subsequently quaternised with substituted benzene sulphonate esters of fatty alcohols. The preferred compounds of the present invention are water-insoluble quaternaries of cinnamidoalkylamines.
In the process, the amidification reaction between a compound of the Formula II when R
6
=—OH or —O(CH
2
)
p
CH
3
with p=0 to 3, with that of Formula III is carried out at from about 120° C. to about 200° C., under pressure from about 10 psi to about 100 psi, in the presence of a basic catalyst such as sodium methoxide, sodium hydroxide from 0.25% to 5.0% by weight of the reaction mass, to afford the intermediate compound of Formula IV.
Preferred amount of such catalyst is 1.0% w/w of total reaction mass. The reaction is conveniently monitored by TLC or HPLC using UV detection. After the complete disappearance of cinnamic acid ester, the excess diamine is distilled off under vacuum.
Alternately, this reaction is carried out in the presence of a basic catalyst such as sodium methoxide, sodium hydroxide from 0.25% to 5.0% by weight of the reaction mass under atmospheric pressure, under blanket of nitrogen, with an arrangement for continuous selective removal of lower alcohol formed in the reaction.
Thus, the condensation reaction of one mole of cinnamic acid ester is carried with 1.0 to 3.0 moles of diamine at 120 to 200° C., preferably at 180° C., for 12 to 36 hours. The amines themselves can catalyse the reaction, however, the rates are found to be slower as compared with the bases like sodium methoxide and the like.
The same reaction can be performed using cinnamic acid in place of cinnamic acid ester at temperatures up to 200° C. and pressures of 100 psi, keeping the same stoichiometry (1:1.0 to 3). The excess diamine serves as solvent for the reaction.
Cinnamic acid esters and amino compounds are selected that are liquid within the disclosed temperature and pressure range. This reaction generates lower alcohol that need not be distilled out.
The amidification reaction between a compound of Formula II when R
6
=—Cl in the presence of a solvent, is carried out with that of Formula III at room temperature in the presence of solvent. The compounds of Formula IV are synthesised by reacting acid chlorides of Formula II (1.0 mole) when R
6
is —Cl with the diamines of For

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