JPH027306B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides novel 3-
This invention relates to (3,4-dihydroxyphenyl)serine derivatives and methods for producing the same. More specifically, firstly, the present invention is based on the following formula The present invention relates to a new substance threo-3-(3,4-dihydroxyphenyl)-N-methylserine represented by the following formula and its salt or hydrate, and also relates to a method for producing the same. 3-(3,4-dihydroxyphenyl)serine (DOPS) has been synthesized for a relatively long time, but in recent years, its physiological and pharmacological effects have begun to attract attention. Regarding its usefulness as a medicine, anti-parkinsonian agent (Japanese Patent Application Laid-Open No. 125630/1982) and antidepressant (Japanese Patent Application Laid-Open No. 1983-125630)
20747) and is known to be useful as an antihypertensive agent, and its derivatives can be expected to have similar or better medicinal effects than DOPS. It is already known that 3-(3,4-dihydroxyphenyl)serine undergoes metabolism in the living body and is converted into noradrenaline, which is an important substance in the living body, and is further converted into adrenaline. have recently found that threo-type 3-(3,4-dihydroxyphenyl)-N-methylserine, which was newly synthesized by monomethylating the amino group of DOPS, is directly metabolized to adrenaline in vivo.
Based on this, the present invention was completed based on the idea that this new substance would be a more useful drug than DOPS. 3-(3,4-dihydroxyphenyl)-N-methylserine was described by FG Mann and CEDalgliesh in J.Chem.Soc.1947, 658 and Nature 158 ,
375 (1946) only describes the synthesis. They condensed 3,4-diethoxycarbonyloxybenzaldehyde with sarcosine and deprotected it to yield 3-(3,4-dihydroxyphenyl)-N-methylserine.
It is reported that the compound was obtained at 3.5%, but the yield was poor, and the details of the three-dimensional structure of the obtained compound are unknown, as there is no description of whether it is of the threo or erythro type. be. As an anti-Parkinsonian, DOPS is known to have activity only against the threo type and not against the erythro type (Japanese Patent Application Laid-open No. 125630/1983).
(3,4-dihydroxyphenyl)-N-methylserine is presumed to have the same effect, so the threo-type 3-(3,4-dihydroxyphenyl)-
N-methylserine, the compound of the present invention, is very useful as a medicine. The inventors have determined that the following formula General formula () obtained by condensation of the O-protected form of 3,4-dihydroxybenzaldehyde shown in and glycine [In the formula, R ₁ and R ₂ represent a protecting group for a phenolic hydroxyl group (preferably a benzyl group). It was discovered that the 3-(3,4-dihydroxyphenyl)serine derivative represented by We successfully synthesized threo-3-(3,4-dihydroxyphenyl)-N-methylserine and erythro-3-(3,4-dihydroxyphenyl)-N-methylserine, respectively.
Threo-3-(3,4-dihydroxyphenyl)-N-methylserine obtained here is a new substance that has not been described in any literature. The melting point of threo-3-(3,4-dihydroxyphenyl)-N-methylserine obtained by the present inventors is 163-165°C (decomposition),
Erythro-3-(3,4-dihydroxyphenyl)
-N-Methylserine has a melting point of 221 to 223°C (decomposition), and is also clearly different from the melting point of 3-(3,4-dihydroxyphenyl)-N-methylserine, 233°C (decomposition), described in the literature by CEDalgliesh et al. In the course of research on the above-mentioned synthesis, the present inventors immediately discovered that N
- Even if methylation was attempted, monomethylation of the amino group could not be successfully achieved, and once the substituted or unsubstituted benzyl group (

It has been found that mono-N-methylation can be achieved while preserving the steric configuration by protecting the compound with [Formula]) and then carrying out the N-methylation reaction. Then, from the mono-N-methylated form, O-protecting groups (R ₁ , R ₂ ) and N
-Protecting group (

[Formula]) can be deprotected while maintaining the steric configuration, resulting in the desired threo-type 3-(3,4-dihydroxyphenyl).
It was also confirmed that -N-methylserine could be obtained. Therefore, in the second invention, the general formula [In the formula, R ₁ and R ₂ are protecting groups for a phenolic hydroxyl group, and R ₃ represents hydrogen, a lower alkoxy group, or a lower alkyl group] Threo-3-(3,4-dihydroxyphenyl) -N-protecting group (

[Formula]) and O-protecting groups (R ₁ , R ₂ ) are removed by a conventional method. do. Furthermore, in the third invention, the general formula [In the formula, R ₁ and R ₂ are protecting groups for a phenolic hydroxyl group, and R ₃ represents hydrogen, a lower alkoxy group, or a lower alkyl group] ) N-methylated serine derivative to form the general formula A threo-type N-methylated derivative represented by [wherein R ₁ , R ₂ and R ₃ have the same meanings as above] was obtained, and then an N-protecting group (

[Formula]) and O-protecting groups (R ₁ , R ₂ ) are removed by a conventional method. . The 3-(3,4-dihydroxyphenyl)serine derivative of the above general formula () is, for example, a 3,4-dihydroxyphenyl serine derivative whose hydroxyl group is protected with a phenolic hydroxyl protecting group represented by a benzyl group or an ethoxycarbonyl group. It is synthesized by a conventional synthesis method such as a method in which dihydroxybenzaldehyde is reacted with glycine. Further, from the resulting compound of formula (2), which is a mixture of the threo and erythro forms, each optical isomer can be separated by a conventional separation method, for example, by fractional crystallization from isopropanol. General formula () used as a raw material in the method of the third invention [In the formula, R ₁ and R ₂ are hydroxyl protecting groups as described above, preferably a benzyl group, and may also be an alkoxycarbonyl group such as an ethoxycarbonyl group, and R ₃ is hydrogen or a group such as methoxy or ethoxy. lower (C _1-6 ) alkoxy group, or methyl,
Represents a lower (C _1-6 ) alkyl group such as ethyl]
The threo-3-(3,4-dihydroxyphenyl)-serine derivative represented by the formula () is a compound of the general formula () (threo type) By reacting with a benzaldehyde derivative represented by the formula [wherein R ₃ is the same as above], a Schiff base-type addition compound is formed, which is then reacted with a compound such as sodium borohydride or sodium cyanoborohydride. It can be obtained by reduction with a reducing agent in a suitable reaction solvent such as an alcoholic aqueous solution. When R ₁ and R ₂ are benzyl groups and R ₃ is hydrogen, the obtained 3-(3,4-dibenzyloxyphenyl)-N-benzylserine has a melting point of 183 to 185 °C (decomposition ) is shown. The erythro form has a melting point of 173-174°C (decomposition). Also, clear differences between the threo type and erythro type can be seen in IR and NMR. In the method of the third invention, the general formula ()
An N-methylation reaction is performed on the starting material compound.
This gives us the general formula () A 3-(3,4-dihydroxyphenyl)-N-methylserine derivative represented by the formula [wherein R ₁ , R ₂ and R ₃ have the same meanings as above] is obtained. Although the N-methylation method of general formula () can be applied, after reacting the raw material compound of general formula () with formaldehyde in a solvent that does not affect the reaction such as hydrous alcohol, sodium cyanoborohydride, sodium borohydride, etc. It is preferable to use the N-methylation method, which consists of reduction with a reducing agent of R ₁ ,
When R ₂ is a benzyl group and R ₃ is hydrogen, the obtained 3
-(3,4-dibenzyloxyphenyl)-N-benzyl-N-methylserine has a melting point of
Shows 133-135℃. Erythro type has a melting point of 154-156
Indicates °C (decomposition). Also, in IR and NMR,
There are clear differences between the threotype and the erythrotype. In the third method of the present invention, as the next step (as the first step in the second method of the present invention), the N-methylated compound represented by the general formula () is subjected to a deprotection reaction. For this deprotection reaction, an appropriate method can be used depending on the type of protecting groups (R ₁ , R ₂ ) in the N-methylated compound ().
When R ₁ and R ₂ are benzyl, for example, the compound () can be converted into methanol, ethanol, propanol,
It is appropriate to dissolve it in a lower alcohol such as butanol, acetic acid, a mixed solvent thereof, or a mixed solvent thereof and water, and carry out a catalytic reduction method using a heavy metal catalyst such as palladium carbon. In addition, it is possible to remove the protecting group using generally well-known deprotection methods. In this way, the desired threo-3-(3,4-dihydroxyphenyl)-N-methylserine can be obtained. Table 1 shows the threo type data of the obtained 3-(3,4-dihydroxyphenyl)-N-methylserine. Data for the Erythro type is also included.

[Table] Threo- and erythro-3-(3,4-dihydroxyphenyl)-N-methylserine have melting points,
It is clearly different from NMR as shown in Table 1.
Also, since their IRs are different, they are different substances. The threo type and erythro type of 3-(3,4-dihydroxyphenyl)-N-methylserine obtained by the above method are amphoteric substances and can form salts with acids and bases. Salts thus produced are also included in the present invention. Examples of such acids include pharmaceutically acceptable inorganic acids such as sulfuric acid, hydrochloric acid, bromic acid, and pharmaceutically acceptable organic acids such as trifluoroacetic acid, citric acid, ascorbic acid, maleic acid, and the like. Examples of such bases include, for example, sodium hydroxide, potassium hydroxide, dicyclohexylamine, ephedrine,
-(p-nitrophenyl)-2-amino-1,3-
There are pharmaceutically acceptable bases such as propanediol. The compound of the present invention can be prepared and used in the form of a pharmaceutical composition containing the compound of the present invention as an active ingredient, for example, by blending it with a pharmaceutically compatible carrier. The carrier can be an inert organic or inorganic carrier material suitable for oral or parenteral administration, such as water, gelanti, lactose, starch, magnesium stearate, talc,
These include vegetable oil, gum arabic, polyalkylene glycol, and yellow petrolatum. The pharmaceutical compositions can be in solid form (eg, tablets, dragees, suppositories or capsules) or liquid form (eg, solutions, suspensions or emulsions). The pharmaceutical composition can be sterile and can contain adjuvants such as preservatives, stabilizers, wetting agents or emulsifying agents, salts or buffers for altering the osmotic pressure. The preparation can also contain other substances of therapeutic value. Hereinafter, the method for preparing the raw material compound used for producing the compound of the present invention will be listed as a reference example, and the production example of the compound of the present invention will be listed as an example, but the present invention is not limited thereto. In addition, a production example of a corresponding erythro type compound is also shown as a reference example. Reference example 1 21.0g of threo-3-(3,4-dibenzyloxyphenyl)serine in 500ml of methanol and 250ml of water
Dissolve benzaldehyde in a mixture of ice-cooled and stirred
16.0 g and 150 ml of 1N aqueous sodium hydroxide solution were added, and the mixture was stirred at room temperature for 3 hours. Subsequently, 5.70 g of sodium borohydride was added over 15 minutes under ice-cooling and stirring, and stirring was continued for an additional hour at room temperature. The reaction solution was ice-cooled again, acetic acid was added to decompose excess sodium borohydride, and neutralization was performed to form a precipitate. After stirring for 2 hours under ice cooling, the precipitate was collected, washed successively with water and methanol, and dried under reduced pressure to give threo-3-(3,4-dibenzyloxyphenyl)-N-benzylserine.
21.0 g was obtained as a white powder. Melting point: 173-174℃ (decomposition) Elemental analysis: as C ₃₀ H ₂₉ O ₅ N Calculated values: C74.53%, H6.00%, N2.90% Actual values: C74.25%, H6.09%, N2.74% Reference example 2 Add 10 ml of methanol to 220 mg of erythro-3-(3,4-dibenzyloxyphenyl)serine,
Furthermore, 1.37 ml of 1N aqueous sodium hydroxide solution was added while stirring under ice cooling. Furthermore, benzaldehyde
Add 0.14ml and after 15 minutes sodium borohydride 34
mg was added, the temperature was raised to room temperature, and the mixture was stirred for 20 minutes. The mixture was cooled on ice again, and a small amount of acetic acid was added to decompose excess sodium borohydride. When 30 ml of water was added, a precipitate formed, and after being allowed to stand for 2 hours under ice cooling, the precipitate was collected and dried under reduced pressure to obtain 190 mg of white powder.
Suspend 190 mg of this white powder in 10 ml of methanol,
Add 2N aqueous sodium hydroxide solution to dissolve, neutralize with acetic acid, add 20 ml of water, leave to stand under ice cooling for 2 hours, collect precipitate, dry under reduced pressure and prepare erythro-3-(3,4- dibenzyloxyphenyl)-
N-Benzylserine was obtained as a white powder. Melting point: 173-174℃ (decomposition) Elemental analysis: as C ₃₀ H ₂₉ O ₅ N Calculated values: C74.53%, H6.00%, N2.90% Actual values: C74.31%, H6.07%, N2.70% Production of threo/erythro-3-(3,4-dibenzyloxyphenyl)serine used as a starting material in Reference Examples 1 and 2 above, and threo-3-( 3,4-dibenzyloxyphenyl)serine and erythro-
3-(3,4-dibenzyloxyphenyl)serine could be produced as follows. 20.4 g of 3,4-dibenzyloxybenzaldehyde was suspended in 83 ml of ethanol, and 10 ml of an aqueous solution containing 2.4 g of glycylin and 3.21 g of sodium hydroxide was added at once while stirring well at room temperature.
The bath temperature was heated to 77° C. over about 15 minutes to give a clear solution, and then heating was immediately stopped. When the mixture was allowed to cool to 37° C. with stirring for about 1 hour, a semi-oily precipitate was formed. 75 ml of 2N hydrochloric acid was added dropwise over about 15 minutes, being careful not to allow the internal temperature to rise above 37°C. During this time, the semi-oily precipitate disappeared and became a suspension. After further stirring at room temperature for 3 hours, the precipitate was removed and the solid matter was washed with a mixture of 5 ml of 3N hydrochloric acid and 5 ml of ethanol.The washings were combined, and while stirring at room temperature, 11.5 g of sodium acetate trihydrate was gradually added. When added, amino acids began to precipitate during the operation. After leaving it under ice cooling for 2 days, the crude amino acid crystals were taken and washed with 20 ml of water.
These crystals were gradually added to a mixture of 40 ml of water, 2.5 ml of concentrated hydrochloric acid, and 60 ml of ethanol at room temperature with stirring. After the solution became clear, 1.5 g of activated carbon was added and the mixture was stirred for 20 minutes at room temperature. passed. Approximately 3 ml of diethylamine was gradually added to the solution to bring the pH to 4, and amino acids gradually began to precipitate. This mixture is 0
The crystals were separated by standing overnight at ℃, and then dried under reduced pressure over phosphorus pentoxide overnight to obtain 3.89 g of threo/erythro-3-(3,4-dibenzyloxyphenyl)serine with a melting point of 138℃. I got it. 1.4 g of threo/erythro-3-(3,4-dibenzyloxyphenyl)serine and 8.4 ml of ethanol
and 2.8 ml of 3N hydrochloric acid to dissolve it, the solvent was distilled off under reduced pressure, and the residue was thoroughly washed with diethyl ether and dried to obtain 1.5 g of hydrochloride. 1.5 g of threo/erythro-3-(3,4-dibenzyloxyphenyl)serine hydrochloride was recrystallized from isopropanol.
dibenzyloxyphenyl) serine hydrochloride 0.846
g (melting point: 145-149°C) was obtained. The mother liquor was concentrated under reduced pressure, the resulting precipitate was collected, and erythro-3-(3,
4-Dibenzyloxyphenyl)serine hydrochloride
0.327g (melting point: 130-137°C) was obtained. Example 1 Threo-3-(3,4-dibenzyloxyphenyl)-N-benzylserine obtained in Reference Example 1 10.0
g was suspended in 300 ml of 75% aqueous ethanol, 60 ml of 1N aqueous sodium hydroxide solution and 4.8 ml of 37% formalin aqueous solution were added with stirring, and stirring was continued at room temperature for 3 hours, and the reaction solution became transparent. Subsequently, 3.80 g of sodium cyanoborohydride was added, and after stirring for 1 hour, the reaction solution was cooled with ice, and acetic acid was added to make it acidic, so that the product precipitated. After stirring for 2 hours under ice cooling, the precipitate was collected, washed successively with water and methanol, and dried under reduced pressure to give threo-3-(3,4-dibenzyloxyphenyl)-N-benzyl-N-
9.05 g of methylserine was obtained as white crystals. Melting point: 133-135℃ Elemental analysis: C ₃₁ H ₃₁ N ₅ Calculated values: C74.85%, H6.24%, N2.82% Actual values: C74.79%, H6.22%, N2.70% Reference Example 3 Erythro-3-(3,4-dibenzyloxyphenyl)-N-benzylserine obtained in Reference Example 2
93.5 ml was suspended in a mixture of 10 ml of methanol and 1 ml of water, 0.18 ml of a 1N aqueous sodium hydroxide solution was added to dissolve the suspension, and 0.2 ml of a 37% formalin aqueous solution was added with stirring at room temperature. After stirring at room temperature for 30 minutes, 55 mg of sodium cyanoborohydride was added, and after 20 minutes, acetic acid was added to adjust the pH to 6, and a small amount of acetone was added to decompose the excess sodium cyanoborohydride. After adding 20 ml of water and allowing the mixture to stand for 2 hours under ice cooling, the precipitate was collected. It was dried under reduced pressure to obtain 104 mg of white powder. After heating and dissolving 104 mg of this crude product in 10 mg of methanol, it was filtered, 15 ml of water was added to the liquid, and the mixture was left to stand for 2 hours under ice cooling.
The precipitate was collected. Dry under reduced pressure to make erythro-3-
75 mg of (3,4-dibenzyloxyphenyl)-N-benzyl-N-methylserine was obtained as a white powder. Melting point: 154-156℃ (decomposition) Elemental analysis: as C ₃₁ H ₃₁ O ₅ N Calculated values: C74.85%, H6.24%, N2.82% Actual values: C74.70%, H6.21%, N2.79% Example 2 5.00 g of threo-3-(3,4-dibenzyloxyphenyl)-N-benzyl-N-methylserine obtained in Example 1 was dissolved in a mixture of 150 ml of acetic acid and 150 ml of ethanol. 1.50 g of 10% palladium-carbon was added, and the mixture was stirred at room temperature under a hydrogen stream for 3 hours. After removing the catalyst from the reaction solution, the solution was concentrated under reduced pressure, and the residue was dissolved in 50 ml of methanol and left to stand to precipitate a product. The precipitated crystals were collected and dried under reduced pressure to obtain the crude product.
2.12g was obtained. The above crude product was recrystallized from 50% aqueous methanol to obtain the desired threo-3-(3,4
-dihydroxyphenyl)-N-methylserine was obtained. Melting point: 163-165℃ (decomposition) NMR (δ value, heavy water-bihydrochloric acid, TMS as external standard): 3.05 (s, 3H), 4.57 (d, 1H, J = 7Hz),
5.52 (d, 1H), 7.23-7.42 (m, 3H) Elemental analysis: as C ₁₀ H ₁₃ O ₅ N・H ₂ O Calculated values: C48.99%, H6.12%, N5.71% Actual values: C48.91%, H6.24%, N5.54% Reference example 4 Erythro-3-(3,4-dibenzyloxyphenyl)-N-benzyl-N-methylserine 55 mg
Dissolve in a solution of 2 ml of ethanol and 2 ml of acetic acid to make 10
% palladium-carbon was added thereto, and the mixture was stirred at normal pressure under a hydrogen stream. After 2 hours, the reaction solution was filtered and the solution was concentrated to dryness. Adding 10 ml of ethanol and concentrating to dryness was repeated three times to completely remove acetic acid and obtain 16.8 mg of solid material. 16.8 mg of the crude product was dissolved in 1 ml of water with heating, and the insoluble matter was filtered out. and remove it,
After concentrating, 1 ml of ethanol was added and the mixture was left to stand under ice cooling for 1 day. The obtained crystals were collected and dried under reduced pressure to give erythro-3-(3,4-dihydroxyphenyl).
12.8 mg of -N-methylserine was obtained as white crystals. Melting point: 221-223℃ (decomposed) NMR (δ value, heavy water-bihydrochloric acid, TMS as external standard) 3.27 (s, 3H), 4.73 (d, 1H, J = 4Hz),
5.77 (d, 1H), 7.32-7.50 (m, 3H) Elemental analysis: as C ₁₀ H ₁₃ O ₅ N Calculated values: C52.86%, H5.77%, N6.17% Actual values: C52.72% , H5.80%, N6.15% Next, the usefulness of the novel substance of the present invention as a medicine will be explained using test examples. Test Example 1 An experiment was conducted on the suppressive effect on harmaline-induced tremor, which is often used as a screening method for anti-parkinsonian drugs. ddY mice (weight 20 to 30 g, male) (5 mice per group) were treated with 400 mg/Kg of threo-DOPS and threo-3-(3,4-dihydroxyphenyl)-N-methylserine (hereinafter referred to as the novel substance of the present invention). 400mg/Kg or 600mg/Kg of threo-adrenergic acid
mg/Kg of each drug was administered intraperitoneally, and 30 minutes later, 10 mg/Kg of harmaline was further intraperitoneally administered to observe the shortening of the duration of the tremor. Then, the reduction rate of the shaking duration was calculated using the following formula. Shortening rate = tremor duration of control - tremor duration of drug administration/tremor duration of control x 100 The results are shown in Table 2.

[Table] Test Example 2 It is well known that drugs that have an inhibitory effect on the decrease in body temperature caused by administration of reserpine have antidepressant effects. 4 mg/Kg of reserpine was intraperitoneally administered to a group of 5 ddY mice (body weight 20-30 g, male), and after 24 hours, a decrease in body temperature was observed, and then 1500 mg/Kg or 2000 mg/Kg of threoadrenergic acid of the present invention was administered. was administered intraperitoneally. Body temperature was measured 1 hour and 2 hours after drug administration. The results are shown in the table below.

【table】

Claims (1)

[Scope of Claims] 1. Threo-3-(3,4-dihydroxyphenyl)-N-methylserine, its pharmaceutically acceptable salts, and hydrates thereof. 2 General formula [In the formula, R ₁ and R ₂ are protecting groups for a phenolic hydroxyl group, and R ₃ represents hydrogen, a lower alkoxy group, or a lower alkyl group] Threo-3-(3,4-dihydroxyphenyl) Threo _{- 3-} (3 , 4-dihydroxyphenyl)-N-methylserine. 3 General formula [In the formula, R ₁ and R ₂ are protecting groups for a phenolic hydroxyl group, and R ₃ represents hydrogen, a lower alkoxy group, or a lower alkyl group] Threo-3-(3,4-dihydroxyphenyl) General formula obtained by N-methylating a serine derivative A threo-type N-methylated derivative represented by the formula [wherein R ₁ , R ₂ and R ₃ have the same meanings as above] was obtained, and then an N-protecting group ([formula]) and an O-protecting group ( A method for producing threo-3-(3,4-dihydroxyphenyl)-N-methylserine, which comprises removing R ₁ , R ₂ ) by a conventional method.