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Title:
METHOD FOR THE SYNTHESIS OF GLUTATHIONE DERIVATIVES
Document Type and Number:
WIPO Patent Application WO/2019/102397
Kind Code:
A1
Abstract:
A synthesis method for the production of N-acyl glutathione, comprising an acylation step, during which, in a water solution with a pH ranging from 8 to 10, glutathione is caused to react with an anhydride with formula (RCO)2O with a formation of S,N-diacyl glutathione, and a subsequent S-acyl group selective alcoholysis step, during which the S,N-diacyl glutathione produced in the previous step is dissolved in an alkoxide/alcohol solution (R'O-/R'OH) and, subsequently, the obtained product is treated with a cation-exchange resin. R is H or a straight or branched hydrocarbon group with a number of carbon atoms ranging from C1 to C24 while R' is a straight or branched radical hydrocarbon group with a number of carbon atoms ranging from C1 to C4.

Inventors:
BARTOCCINI, Francesca (Via Saffi 2, Urbino, 61029, IT)
FRATERNALE, Alessandra (Via Saffi 2, Urbino, 61029, IT)
PIERSANTI, Giovanni (Via Saffi 2, Urbino, 61029, IT)
Application Number:
IB2018/059234
Publication Date:
May 31, 2019
Filing Date:
November 22, 2018
Export Citation:
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Assignee:
UNIVERSITA' DEGLI STUDI DI URBINO "CARLO BO" (Via Saffi 2, Urbino, 61029, IT)
International Classes:
C07K5/02
Foreign References:
JPS632922A1988-01-07
Other References:
PALAMARA A T ET AL: "NEW SYNTHETIC GLUTATHIONE DERIVATIVES WITH INCREASED ANTIVIRAL ACTIVITIES", ANTIVIRAL CHEMISTRY & CHEMOTHER, INTERNATIONAL MEDICAL PRESS, GB, vol. 15, no. 2, 1 March 2004 (2004-03-01), pages 83 - 91, XP009045775, ISSN: 0956-3202
ALAN KATRITZKY ET AL: "Efficient and Selective Syntheses of S-Acyl and N-Acyl Glutathiones", SYNLETT, vol. 2010, no. 09, 16 April 2010 (2010-04-16), DE, pages 1337 - 1340, XP055281907, ISSN: 0936-5214, DOI: 10.1055/s-0029-1219837
Attorney, Agent or Firm:
BOSMAN, Cesare et al. (Studio Torta S.p.A, Via Viotti 9, Torino, 10121, IT)
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Claims:
CLAIMS

1. A synthesis method for the production of N-acyl glutathione, characterized in that it comprises an acylation step, during which, in a water solution with a pH ranging from 8 to 10, glutathione is caused to react with an anhydride with formula (RCO) 2O with a formation of S,N-diacyl glutathione, and a subsequent S-acyl group selective alcoholysis step, during which the S,N-diacyl glutathione produced in the previous step is dissolved in an alkoxide/alcohol solution (R'Cr/R'OH) and, subsequently, the obtained product is treated with a cation-exchange resin; R being H or a straight or branched hydrocarbon group with a number of carbon atoms ranging from Cl to C24; R' being a straight or branched radical hydrocarbon group with a number of carbon atoms ranging from Cl to C4.

2. The synthesis method according to claim 1, characterized in that, during said acylation step, the water solution comprises a carbonate of an alkaline or alkaline earth metal or a bicarbonate of an alkaline metal.

3. The synthesis method according to claim 1 or 2, characterized in that R is chosen in the group consisting of a straight or branched C1-C24 alkyl group, a straight or branched C2-C24 alkenyl group, a C6-C24 aryl group, a straight or branched group with a C6-C14 aryl portion and a Cl—C6 alkyl portion, a mixed C6-C14 aryl and C1-C6 alkyl or alkenyl group; said aryl group having 0 to more equal or different substituents, which are comprised in the group consisting of atom of halogen, hydroxy, straight or branched, saturated or unsaturated C1-C6 alkoxide, amino, possibly monosubstituted or polysubstituted, substituted with a straight or branched C1-C6 alkyl group .

4. The synthesis method according to one of the preceding claims, characterized in that R' is CH3.

5. The synthesis method according to one of the preceding claims, characterized in that said acylation step comprises a solution acidification operation, during which glutathione is caused to react with an anhydride with formula (RC0)20.

6. The synthesis method according to one of the preceding claims, characterized in that said acylation step and said selective alcoholysis step are carried out at room temperature .

Description:
"METHOD FOR THE SYNTHESIS OF GLUTATHIONE DERIVATIVES"

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian patent application no. 102017000133856 filed on 22/11/2017, the entire disclosure of which is incorporated herein by reference .

TECHNICAL FIELD

The present invention concerns a method for the synthesis of glutathione derivatives .

BACKGROUND ART

Glutathione is undoubtedly one of the most important antioxidant and detoxifying agents which the organism is able to produce and plays an important role in the immune response.

At a cellular level it is synthesized from glutamate, from glycine and from cysteine, which is the donor of the thiol group (-SH) responsible for the biological activity of glutathione .

Numerous physiopathological conditions (ageing, degenerative diseases, etc.) are characterized by oxidative stress and depletion of glutathione. In these states it is certainly advantageous to restore the physiological levels of glutathione in the tissues. However, the intake of glutathione from external sources is not particularly effective, since it lacks a specific carrier allowing it to cross the cell membrane .

It has been found that the glutathione derivative that best guarantees crossing of the cell membrane, at the same time maintaining the antioxidant and detoxifying characteristics of the glutathione, is N-acyl glutathione. So far, the synthesis methods used all have criticalities in production terms such as to jeopardize their use on a large scale. In this regard, one of the synthesis methods proposed entails N-acylation of the glutathione with activated ester followed by a reduction. However, in this method other susceptible groups are present in the molecule during the reduction .

Another synthesis method entails use of the trityl group to protect the thiol group of the glutathione, then proceeding with the N-acylation and subsequent deprotection of the trityl group. As will be immediately evident to a person skilled in the art, this method involves timescales, costs and yields that prevent its application on an industrial scale.

Another method entails the use of 4-nitrobenzoyl to protect the thiol group of the glutathione, then proceeding with acylation of the N¾ group with 1-acyl-lH-benzotriazole and subsequent deprotection, using pyrrolidine in dry methanol for four hours. Here again, timescales, costs and yields prevent the use of the method on a large scale.

The need was therefore felt for a method for synthesis of the N-acyl glutathione with technical characteristics such as to guarantee advantageous application thereof on an industrial scale .

DISCLOSURE OF INVENTION

The subject of the present invention is a synthesis method for the preparation of N-acyl glutathione characterized in that it comprises an acylation step in which, in a water solution with pH ranging from 8 to 10, the glutathione is caused to react with an anhydride with formula (RCO) 2O with the formation of S,N-diacyl glutathione, and a subsequent selective alcoholysis step of the S-acyl group, in which S,N-diacyl glutathione produced in the preceding step is dissolved in an alkoxide/alcohol (R'Cr/R'OH) solution and subsequently the product obtained is treated with a cation-exchange resin; R being H or a straight or branched hydrocarbon group with a number of carbon atoms ranging from Cl to C24; R' being a straight or branched radical hydrocarbon group with a number of carbon atoms ranging from Cl to C4.

Preferably, in said acylation step the water solution comprises a carbonate of an alkaline or alkaline earth metal or a bicarbonate of an alkaline metal .

Preferably, R is chosen from the group composed of a straight or branched C1-C24 alkyl group, a straight or branched C2-C24 alkenyl group, a C6-C24 aryl group, a straight or branched group with a C6-C14 aryl portion and a C1-C6 alkyl portion, a mixed C6-C14 aryl and C1-C6 alkyl or alkenyl group; said aryl group having 0 to more equal or different substituents which are comprised in the group consisting of atom of halogen, hydroxy, straight or branched, saturated or unsaturated C1-C6 alkoxide, amino, possibly monosubstituted or polysubstituted, substituted with a straight or branched C1-C6 alkyl group.

Preferably, R' is CH3.

Preferably, said acylation step comprises a solution acidification operation in which the glutathione is caused to react with an anhydride with formula (RC0) 2 0.

Preferably, said acylation step and said selective alcoholysis step are carried out at room temperature.

BEST MODE FOR CARRYING OUT THE INVENTION

Some embodiment examples are given below purely by way of non limiting example.

- Acylation step -

A 1M water solution of Na2C0 3 in which 100 mg of glutathione are dissolved was placed in a three-necked flask. To this solution 0.668 mmoles of acetic anhydride ((CH 3 C0)20) were added dropwise and the solution thus produced was kept under stirring for two hours . Subsequently, the solution was acidified to pH 3.5 by the addition of approximately 0.2 mL of a 6N solution of HC1. The water phase was washed three times with 3 mL of ethyl ether and then acidified to pH 1.5 by the addition of approximately 0.1 mL of a 6N solution of HC1. Subsequently, the water solution was concentrated at reduced pressure up to half volume and then decanted.

The same procedure as above was repeated using an anhydride different from acetic anhydride.

In particular, the procedure was repeated using butanoic anhydride ( (CH 3 CH 2 CH 2 CO) 2 O) , 2,2-dimethyl propionic anhydride ( (CH 3 CH 3 CH 3 CC0) 2 0) and benzoic anhydride ( (PhCO) 2 O) respectively .

The compounds S,N-diacyl glutathione produced underwent spectroscopic analysis to verify their identity.

The mass spectroscopy and magnetic resonance values obtained for each of the four S,N-diacyl glutathiones prepared are reported below:

R = Me

Yield: 77%

MS (ESI) : 392 (M+l) + .

1H NMR (400 MHz, MeOH-d ) d 4.60 (dd, J1 = 8.5 and J2 = 5.0 Hz, 1H) , 4.30 (dd, J1 = 8.0 and J2 = 5.0 Hz, 1H) , 3.85 (d, J =

17.0 Hz, 1H) , 3.75 (d, J = 17.0 Hz, 1H) , 3.48 (dd, J1 = 14.0 and J2 = 5.0 Hz, 1H) , 3.15 (dd, J1 = 14.0 and J2 = 8.5 Hz, 1H) , 2.37-2.33 (m, 5H) , 2.20-2.11 (m, 1H) , 2.03-1.96 (m, 4H) .

13C NMR (100 MHz, MeOH-d4) d 195.7, 176.1, 174.1, 173.9,

171.5, 170.6, 53.6, 52.7, 42.5, 31.9, 30.2, 29.0, 28.0, 21.4.

R = n-Pr

Yield: 85%

MS (ESI) : 448 (M+l) + .

1H NMR (400 MHz, D20) d 4.62 (dd, J1 = 8.0 and J2 = 5.0 Hz, 1H) , 4.32 (dd, J1 = 9.0 and J2 = 5.0 Hz, 1H) , 3.96 (s, 2H) , 3.42 (dd, J1 = 14.5 and J2 = 5.0 Hz, 1H) , 3.13 (dd, J1 = 14.5 and J2 = 8.0 Hz, 1H) , 2.59 (t, J = 7.0 Hz, 2H) , 2.39 (t, J = 7.5 Hz, 2H) , 2.24 (t, J = 7.0 Hz, 2H) , 2.19-2.12 (m, 1H) ,

2.00-1.91 (m, 1H), 1.65-1.54 (m, 4H) , 0.88 (t, J = 7.0, 3H) ,

0.87 (t, J = 7.0, 3H) .

13C NMR (100 MHz, D20) d 203.7, 177.3, 175.3, 174.9, 173.0,

172.1, 52.6, 52.1, 52.1, 45.3, 41.2, 37.3, 31.6, 29.9, 26.3,

18.9, 12.7, 12.6.

R = t-Bu

Yield: 83%

MS (ESI) : 476 (M+l) + .

1H NMR (400 MHz, MeOH-d4 ) d 4.57 (dd, J1 = 9.0 and J2 = 5.0 Hz, 1H) , 4.26 (dd, J1 = 7.0 and J2 = 5.5 Hz, 1H) , 3.84 (d, J =

17.0 Hz, 1H) , 3.73 (d, J = 17.0 Hz, 1H) , 3.46 (dd, J1 = 14.0 and J2 = 5.0 Hz, 1H) , 3.13 (dd, J1 = 14.0 and J2 = 9.0 Hz,

1H) , 2.32 (t, J = 7.5 Hz, 2H) , 2.17-2.02 (m, 2H) , 1.24 (s,

9H) , 1.23 (s, 9H) .

13C NMR (100 MHz, MeOH-d4) d 206.2, 179.1, 176.4, 174.2,

174.1, 170.6, 53.8, 52.8, 47.0, 46.1, 42.8, 31.8, 29.7, 28.2,

26.4, 26.3.

R = Ph

Yield: 72%

MS (ESI) : 516 (M+l) + .

1H NMR (400 MHz, MeOH-d4) d 7.94 (d, J = 7.5 Hz, 2H) , 7.86 (d, J = 7.5 Hz, 2H) , 7.64-7.44 (m, 6H) , 4.76 (dd, J1 = 8.5 and J2 = 5.0 Hz, 1H) , 4.59 (dd, J1 = 8.5 and J2 = 5.0 Hz, 1H) , 3.90

(d, J = 17.0 Hz, 1H) , 3.83 (d, J = 17.0 Hz, 1H) , 3.70 (dd, J1 = 14.0 and J2 = 5.0 Hz, 1H) , 3.36 (dd, J1 = 14.0 and J2 = 9.0

Hz, 1H) , 2.46 (t, J = 7.5 Hz, 2H) , 2.36-2.27 (m, 1H) , 2.19-

2.10 (m, 1H) .

13C NMR (100 MHz, MeOH-d4) d 189.8, 173.1, 172.5, 171.0,

169.3, 167.0, 135.1, 131.8, 129.4, 126.9, 126.6, 126.5, 125.5,

125.3, 51.2, 46.9, 39.9, 30.4, 28.5, 25.7

From the values reported above, the nature of the S,N-acylate compounds with the RCO groups deriving from the respective anhydrides used are ascertained.

- Selective alcoholysis step -

A solution in methanol of 0.31 mmol of S,N-diacyl glutathione prepared as described above was placed in a lOmL flask equipped with a magnetic anchor. 0.93 mL of a 1 M solution of sodium methoxide in methanol were added to the solution. The solution was kept under stirring for one hour at room temperature and then the solvent was evaporated at reduced pressure .

The solid residue obtained was solubilized in 1 mL of water and poured slowly into a beaker containing a cation-exchange resin (Dowex 50W-X8 (H) ) and 0.4 mL of water.

In particular, before use the resin was regenerated by means of a 0.25N solution of H2SO4 and subsequently washed with water until detecting an absence of sulphate and a pH equal to 7.

The suspension in the beaker was filtered and the resin was washed with 5 mL of water. The filtrate was concentrated at reduced pressure by means of coevaporation with 1 mL of xylene. The solid obtained was ground with 5 mL of ethyl ether and filtered. The respective N-acyl glutathione obtained underwent spectroscopic analysis to verify its identity.

The mass spectroscopy and magnetic resonance values obtained for each of the four N-acyl glutathiones prepared are reported below :

R = Me

Yield: 75%

MS (ESI) : 350 (M+l) +.

1H NMR (400 MHz, MeOH-d ) d 4.56 (dd, J1 = 7.0 and J2 = 4.5 Hz, 1H) , 4.38 (dd, J1 = 8.5 and J2 = 5.0 Hz, 1H) , 3.89 (s,

2H) , 2.94-2.87 (m, 2H) , 2.42 (t, J = 7.5 Hz, 2H) , 2.24-2.16

(m, 1H) , 2.10 - 1.94 (m, 4H) .

13C NMR (100 MHz, MeOH-d4) d 174.9, 173.8, 172.7, 171.8,

171.1, 55.6, 52.7, 41.5, 31.7, 27.5, 25.5, 21.2.

R = n-Pr

Yield: 91%

MS (ESI) : 378 (M+l) +

1H NMR (400 MHz, D20) d 4.52 (dd, J1 = 7.0 and J2 = 5.5 Hz, 1H) , 4.25 (dd, J1 = 9.0 and J2 = 5.0 Hz, 1H) , 3.89 (s, 2H) ,

2.92-2.83 (m, 2H) , 2.42 (t, J = 7.5 Hz, 2H) , 2.23 (t, J = 7.5

Hz, 2H) , 2.19 - 2.12 (m, 1H) , 1.99-1.91 (m, 1H) , 1.61-1.52 (m,

2H) , 0.87 (t, J = 7.5Hz, 3H) ;

13C NMR (100 MHz, D20) d 177.2, 176.0, 175.3, 173.8, 172.3,

55.5, 52.6, 41.7, 37.4, 31.6, 26.5, 25.5, 18.9, 12.8.

R = t-Bu

Yield: 80%

MS (ESI) : 392 (M+l) + .

1H NMR (400 MHz, MeOH-d4 ) d 4.58 (dd, J1 = 7.0 and J2 = 5.5 Hz, 1H) , 4.39 (dd, J1 = 9.0 and J2 = 5.0 Hz, 1H) , 3.94 (s,

2H) , 2.91-2.86 (m, 2H) , 2.44 (t, J = 7.0 Hz, 2H) , 2.29-2.21

(m, 1H) , 2.09-2.00 (m, 1H) , 1.23 (s, 9H) .

13C NMR (100 MHz, MeOH-d4) d 180.0, 174.1, 173.8, 171.6

171.3, 55.5, 52.3, 40.7, 38.2, 31.6, 26.6, 26.4, 25.6.

R = Ph

Yield: 73% MS (ESI) : 412 (M+l) + .

1H NMR (400 MHz, MeOH-d4 ) d 8.02 (d, J = 7.5 Hz, 2H) , 7.47-

7.42 (m, 3H) , 4.63-4.56 (m, 2H) , 3.87 (s, 2H) , 2.92-2.81 (m, 2H) , 2.55-2.48 (m, 2H) , 2.36-2.30 (m, 1H) , 2.19-2.10 (m, 1H) . 13C NMR (100 MHz, MeOH-d4) d 172.7, 172.3, 170.4, 169.6, 167.0, 130.9, 127.6, 126.5, 125.5, 53.9, 51.3, 39.4, 30.2,

25.3, 23.9.

From the above values the nature of the N-acylate products is ascertained with re-establishment of the SH group in the respective S,N-acyl glutathione substrate used.

From the above description it is immediately evident that the synthesis method subject of the present invention offers the great advantage of being extremely simple, inexpensive and guaranteeing a high yield. In fact, it should be highlighted that the acylation and selective alcoholysis reactions take place at room temperature, and that solvents are used such as water (for the acylation reaction) and methanol (for the selective alcoholysis reaction) .

The above advantages mean that the synthesis method subject of the present invention can be applied on an industrial scale without suffering the productivity problems typical of the methods of the known art .