JPH0819072B2 - (2S, 3R) -3-Amino-2-acyloxy-4-phenylbutyronitrile derivative and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] (In the formula, R ¹ is a linear or branched alkanoyl group having 1 to 4 carbon atoms, an aroyl group optionally substituted with a chlorine atom or a methoxy group, a linear or branched alkoxycarbonyl group having 1 to 5 carbon atoms. Or a aralkoxycarbonyl group which may be substituted with a chlorine atom or a methoxy group, and R ² is substituted with a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a chlorine atom or a methoxy group. (2S, 3R) -3-amino-2-acyloxy-4-phenylbutyronitrile derivative represented by the formula (1), which represents an optionally substituted aryl group, and a method for producing the same.

The (2S, 3R) -3-amino-2-acyloxy-4-phenylbutyronitrile derivative represented by the general formula (I) of the present invention is an intermediate for producing bestatin useful as a carcinostatic agent due to its immunostimulating action. It can be used as a raw material for the synthesis of optically active (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid (J. Antibiot., 29 , 600 (1976)., J. Anti.
biot., 36 , 695 (1983)., J. Med. Chem., 20 , 510 (1977).,
Tetrahedron Lett., 25 , 5079 (1984)., And reference examples).

[Conventional technology]

Optically active (2S, 3R) -an intermediate for the production of bestatin
3-Amino-2-hydroxy-4-phenylbutyric acid has conventionally been synthesized from 1) D-phenylalanine (R) -2.
-A method for synthesizing a cyanohydrin derivative from an acidic sodium sulfite adduct of benzyloxycarbonylamino-3-phenylpropanal and hydrolyzing it (J. Antiti
biot., 29, 600 (1976 )., and J.Med.Chem., 20, 510 (19
77). 2) 2) Aldol addition reaction of N-benzoylphenacylamine and glycolic acid was synthesized as a key step.
Method for optical resolution of dl-form (2S ^* , 3R ^* )-3-benzoylamino-2-hydroxy-4-phenylbutyric acid (J. An
tibiot., 36 , 695 (1983). 3) A method applying the halocyclocarbamoylation reaction of (S) -N-benzyl-N-benzyloxycarbonyl-1-benzylallylamine synthesized from D-phenylalanine (Tetrahedron Let
t., 25 , 5079 (1984). ) Is synthesized by. 1)
The method has a very low stereoselectivity of the reaction at the 2-position,
This gave a mixture of compounds with the desired (S) -configuration and unwanted compounds with the (R) -configuration, the separation of which was very difficult. In the method 2), low-efficiency chemical resolution is performed, and the desired (2S, 3R) -3-amino-
The yield of 2-hydroxy-4-phenylbutyric acid was very low. In addition, the method of 3) has multiple stages, and
Industrially impossible steps such as removal of N-benzyl group using sodium metal in liquid ammonia are used.

[Problems to be solved by the invention]

The present inventors searched for a method for highly stereoselectively producing an optically active (2S, 3R) -3-amino-2-hydroxybutyric acid derivative, which is an intermediate for the production of bestatin, and as a result, the compound of the present invention and its The manufacturing method was found and the present invention was completed.

[Means for solving problems]

The novel (2S, 3R) -3- represented by the general formula (I)
The amino-2-acyloxy-4-phenylbutyronitrile derivative can be produced according to the following reaction formula.

(In the formula, R ¹ and R ² have the same meanings as described above, and R ⁴ has 1 carbon atom.
4 represents a straight chain or branched lower alkyl group. (Step 1) In this step, a protective group for an amino group is introduced into D-phenylalanine ester hydrochloride represented by the general formula (II), and then the ester group is reduced to obtain the compound represented by the general formula (III) (R ) -2-Aminopropanol derivative is produced (see Reference Example).

Examples of D-phenylalanine ester hydrochloride include D-
Examples thereof include phenylalanine methyl ester hydrochloride, D-phenylalanine ethyl ester hydrochloride, D-phenylalanine isopropyl ester hydrochloride and the like, which can be produced by a known method (Chem.Pharm.Bul.
l., 13 , 995 (1965)., and SR Sandler and W. Karo,
"Functional Group Preparations", Academic Press, Ne
w York, 1968, pp 245-265.).

As the substituent R ¹ which is a protective group for the amino group introduced into D-phenylalanine ester hydrochloride, a formyl group,
Substituted with a chlorine atom such as an acetyl group, a propionyl group, a butyryl group, an isobutyryl group or a branched alkanoyl group having 1 to 4 carbon atoms, a benzoyl group, a p-chlorobenzoyl group, a p-methoxybenzoyl group or a methoxy group Aroyl group, methoxycarbonyl group, ethoxycarbonyl group, isopropoxycarbonyl group, t-butyloxycarbonyl group and the like having 1 to 1 carbon atoms
An unsubstituted or substituted aralkoxycarbonyl group such as a straight chain or branched alkoxycarbonyl group of 5, a benzyloxycarbonyl group, a p-chlorobenzyloxycarbonyl group and a p-methoxybenzyloxycarbonyl group is used. These protecting groups can be introduced by a known method (TW Greene, “Protective Groups in Organic Sy
nthesis ", John-Wiley & Sons, New York, 1980, pp218-287.
reference).

The reduction of the ester group of the amino-protected D-phenylalanine ester is carried out using sodium borohydride in the presence of a suitable reducing agent such as lithium chloride or lithium bromide (see Reference Example).

In this step, (R) represented by the general formula (III)
The 2-amino-3-phenylpropanol derivative is obtained without racemization.

(Second Step) In this step, the (R) -2-amino-3-phenylpropanol derivative represented by the general formula (III) is oxidized to give the (R) -2-amino represented by the general formula (IV). A method for producing a 3-phenylpropanal derivative. An example of a suitable oxidation method is a method using sulfur trioxide in dimethyl sulfoxide-pyridine complex-triethylamine (see Chem, Pharm. Bull., 30 , 1921 (1982)., And Reference Example). This step also proceeds without racemization.

(Third Step) In this step, the (R) -2-amino-3-phenylpropanal derivative represented by the general formula (IV) is converted to the general formula R ² COOCOR ^3- (V) (wherein R ² , R ^3's each independently represent a hydrogen atom or a carbon number of 1 to 4.
Represents a linear or branched alkyl group, or an aryl group which may be substituted with a chlorine atom or a methoxy group. ), A carboxylic acid anhydride and a hydrocyanic acid salt are reacted with a quaternary ammonium salt or a tertiary amine or a quaternary ammonium salt and a tertiary amine to give a compound of the present invention. (2S, 3R) -3-Amino-2-acyloxy-4-represented by formula (I)
A phenylbutyronitrile derivative is produced.

As the carboxylic acid anhydride represented by the general formula (V),
Formic acid butyric anhydride, acetic anhydride, propionic anhydride, isobutyric anhydride, benzoic anhydride, p-chlorobenzoic anhydride, p-methoxybenzoic anhydride and the like can be exemplified, but acetic anhydride or benzoic anhydride is preferably used. To be The carboxylic acid anhydride used is used in an amount of 1.0 to 20 equivalents relative to the (R) -2-amino-3-phenylpropanal derivative, and preferable results are obtained when used in 2.5 to 7.0 equivalents. Examples of the quaternary ammonium salt include tetrabutylammonium chloride, tetrabutylammonium bromide, benzyltrimethylammonium chloride, benzyltrimethylammonium bromide, benzyltriethylammonium chloride, benzyltributylammonium chloride, benzyltributylammonium bromide, and methyltrioctyl chloride. Ammonium, N-benzylquinidinium chloride, N-chloride
Examples thereof include benzylquininium, N-benzylcinchonidinium chloride, N-benzylcinchoninium chloride, and N-benzyl-N-methylephedrinium chloride. The quaternary ammonium salt is used in 0.005 to 0.20 equivalent with respect to the (R) -2-amino-3-phenylpropanal derivative, but when 0.01 to 0.07 equivalent is used, preferable results are obtained.

Examples of the tertiary amine include trimethylamine, triethylamine, ethyldiisopropylamine, tributylamine, N, N-tetramethylethylenediamine, N-methylpyrrolidine, N-ethylpyrrolidine, N-benzylpyrrolidine, N-methylmorpholine and N-ethylmorpholine. , N-benzylmorpholine, 1,4-diazabicyclo [2,2,2] octane, 1,5-diazabicyclo [4,3,0] non-5-ene, 1,8-diazabicyclo [5,4,0] Undec-7-ene, pyridine, 2-methylpyridine, 2,4,5-
Trimethylpyridine, 4-dimethylaminopyridine, quinoline and the like can be exemplified, but preferably, pyridine and 4-
Dimethylaminopyridine is used. The tertiary amine is used in 0.001 to 0.10 equivalent with respect to the (R) -2-amino-3-phenylpropanal derivative, and preferably 0.005.
~ 0.02 equivalents are used.

Examples of the cyanide salt used in this reaction include alkali metal cyanide salts such as sodium cyanide and potassium cyanide. The cyanate salt is used in an amount of 1.0 to 10 equivalents relative to the (R) -2-amino-3-phenylpropanal derivative,
Preferred results are obtained when 1.5 to 6.0 equivalents are used.

This reaction is carried out in an organic solvent, more preferably a two-layer system of water and an organic solvent. The organic solvent used is dichloromethane, chloroform, carbon tetrachloride, 1,2
-Dichloroethane, halogenated hydrocarbon solvents such as 1,1,1-trichloroethane, ethyl acetate, acetic acid esters such as isoamyl acetate, toluene, hydrocarbon solvents such as xylene, which are immiscible with water, can be exemplified. Dichloromethane, chloroform and 1,2-dichloroethane are preferably used. When the reaction is carried out in a two-layer system of water and an organic solvent, the composition ratio is not particularly limited, but a composition ratio of 1: 1 gives the most preferable result.

This reaction is carried out at -10 to 50 ° C, but when the reaction is carried out in a two-layer system of water and an organic solvent, the most preferable result is obtained at 0 to 5 ° C.

According to this reaction, it is represented by the general formula (I) (2S, 3R)
3-Amino-2-acyloxy-4-phenylbutyronitrile derivatives having a -configuration are highly selective for 3-amino-2-acyloxy-4-phenylbutyronitrile derivatives having a (2R, 3R) -configuration Can be generated (up to 11: 1).

When this reaction is carried out in the absence of carboxylic acid anhydride, it is possible to obtain (2S, 3R)-and (2R, 3R) -3-amino- from (R) -2-amino-3-phenylpropanal derivative. An equal mixture of 2-hydroxy-4-phenylbutyronitrile derivative is obtained (see Comparative Examples 1 and 2).

(2S, 3R) -3-Amino-2-acyloxy-4-, represented by the general formula (I), obtained by the above-mentioned synthesis step
When phenylbutyronitrile derivative is hydrolyzed under acidic conditions to hydrolyze the nitrile group and simultaneously deprotect the 3-position amino group and 2-position hydroxyl group, the immunosuppressive effect of bestatin used as a carcinostatic agent Formula used as a manufacturing intermediate The optically active (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid hydrochloride represented by is obtained in good yield.

Hereinafter, the content of the present invention will be described in detail with reference to Examples, Reference Examples and Comparative Examples, but the present invention is not limited to these.

Reference example 1 (R) -Phenylalanine methyl ester hydrochloride 3.9g
(18 mmol) was suspended in 20 ml of anhydrous tetrahydrofuran, 5.5 ml (39 mmol) of triethylamine and 2.3 ml (20 mmol) of isopropyl chlorocarbonate were added under ice cooling, and the mixture was stirred at the same temperature for 1 hour. The reaction mixture was concentrated under reduced pressure, ethyl acetate was added to the residue, and the mixture was washed successively with 1M hydrochloric acid, saturated brine, saturated aqueous sodium hydrogen carbonate and saturated brine. After drying over anhydrous magnesium sulfate,
Concentrate under reduced pressure to give N- (isopropoxycarbonyl)-(R) -phenylalanine methyl ester as a white solid 4.
7 g (98%) were obtained.

Rf: 0.76 (chloroform / methanol = 30/1) IR (neat): 1735, 1680 cm ^-1 . NMR (CDCl ₃ ): δ1.21 (6H, d, J = 6Hz), 3.11 (2H, d, J =
6Hz), 3.72 (3H, s), 4.50-5.20 (2H, m), 4.92 (1H, qui)
ntet, J = 6Hz), 7.04 to 7.48 (5H, m). Reference example 2 4.7 g (18 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalanine methyl ester was dissolved in 23 ml of anhydrous tetrahydrofuran, and 2.3 g of lithium chloride (54 mmo)
l), sodium borohydride (53 mmol), and 45 ml of absolute ethanol were sequentially added, and the mixture was stirred at room temperature for 3 hours. The reaction solution was concentrated under reduced pressure, 1M hydrochloric acid was added (pH 2-3), and the precipitated crystals were collected by filtration. After washing with water, it was dried under reduced pressure over phosphorus pentoxide to obtain 3.6 g (86%) of N- (isopropoxycarbonyl)-(R) -phenylalaninol as a white solid.

Rf: 0.72 (chloroform / methanol = 5/1) IR (KBr): 1680 cm ^-1 . NMR (CDCl ₃ ): δ1.21 (6H, d, J = 6Hz), 1.96 to 2.30 (1
H, m), 2.88 (2H, d, J = 7Hz), 3.44 to 4.16 (3H, m), 4.65
~ 5.13 (1H, m), 4.92 (1H, quintet, J = 6Hz), 7.05 ~ 7.4
7 (5H, m). Reference example 3 N- (isopropoxycarbonyl)-(R) -phenylalaninol 150 mg (0.63 mmol), toluene 0.40 ml,
510 mg (3.2 mmol) of sulfur trioxide-pyridine complex salt was added to a mixture of dimethyl sulfoxide 0.80 ml (11 mmol) and triethylamine 0.46 ml (3.3 mmol), and the mixture was stirred at room temperature for 30 minutes. Ice water was added to the reaction solution, and the mixture was extracted with toluene, and the extract was washed with water, saturated aqueous sodium hydrogen carbonate and saturated brine in that order. The extract was dried over anhydrous sodium sulfate and then concentrated under reduced pressure to obtain 126 mg (85%) of N- (isopropoxycarbonyl)-(R) -phenylalaninal as white crystals. This product was used for the next production of the 3-amino-2-acyloxybutyronitrile derivative without purification.

Rf: 0.40 (hexane / ethyl acetate = 7/3) Example 1 25.0 mg (0.11 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 30.0 mg (0.13 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.3 ml of methylene chloride. Dissolves in
Acetic anhydride 0.06 ml (0.64 mmol), benzyltributylammonium chloride 2.1 mg (0.007 mmol), and 0.25N sodium cyanide aqueous solution 2.6 ml (0.64 mmol) were sequentially added under ice cooling, and the mixture was stirred at the same temperature for 3 hours. 50% Saturated saline was added to the reaction solution, extraction was performed with methylene chloride, and the extract was washed with water and saturated saline in this order. After drying over anhydrous sodium sulfate, the mixture was concentrated under reduced pressure and the residue was purified by thin layer chromatography (silica gel, hexane-ethyl acetate 7: 3) to give colorless oily (2S, 3R) -2-acetoxy-3. 11.5 mg (30%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) of a mixture of -isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form ) Got. The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was determined to be 10: 1 from the NMR spectrum (400 MHz).

Rf: 0.40 (hexane / ethyl acetate = 7/3) IR (neat): 1760,1700 cm ^-1 . NMR (CDCl ₃ ): (2R, 3R) -form; δ1.16,1.22 (6H, two d, J = each 6.0H
z), 2.16 (3H, s), 2.89 (1H, dd, J = 14.1,8.6Hz), 3.06
(1H, dd, J = 14.1,6.0Hz), 4.17 ~ 4.50 (1H, m), 4.62 ~
4.97 (2H, m), 5.40 (1H, d, J = 4.2Hz), 7.11 ~ 7.45 (5H,
m). (2R, 3R) -body; δ1.16,1.22 (6H, two d, J ＝ each 6.0H
z), 2.13 (3H, s), 2.97 (2H, d, J = 7.6Hz), 4.17 ~ 4.50
(1H, m), 4.62-4.97 (2H, m), 5.38 (1H, d, J = 4.1Hz),
7.11 to 7.45 (5H, m). MS (m / e): 304 (M ⁺ ), 245, 206. Example 2 26.8 mg (0.11 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 30.0 mg (0.13 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.3 ml of methylene chloride. Dissolves in
Acetic anhydride 0.06 ml (0.64 mmol), 4-dimethylaminopyridine 0.17 mg (0.0014 mmol), and 0.25 N sodium cyanide aqueous solution 2.6 ml (0.64 mmol) were sequentially added under ice cooling, and the mixture was stirred at the same temperature for 3 hours. Treated as in Example 1, colorless oily mixture of (2S, 3R) -2-acetoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form 5.7 mg. (19%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) was obtained.

The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was determined to be 10: 1 from the NMR spectrum (400 MHz) as in Example 1.

Example 3 N- (isopropoxycarbonyl)-(R) -phenylalaninol 95.7 mg (0.32 mmol) obtained from 90.2 mg (0.38 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal was added to 0.9 ml of methylene chloride. Dissolves in
Acetic anhydride 0.18 ml (1.9 mmol), 4-dimethylaminopyridine 0.47 mg (0.0038 mmol), benzyltributylammonium chloride 6.2 mg (0.02 mmol), water 0.52 ml, 5N sodium cyanide aqueous solution 0.38 ml (1.9 mmol) were ice-cooled. The mixture was added in order downward and stirred at the same temperature for 5 hours. The residue obtained by the same treatment as in Example 1 was purified by thin layer chromatography (silica gel, hexane-ethyl acetate 7: 3) to give a colorless oil (2
S, 3R) -2-acetoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R
This gave 54.2 mg (47%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) of a mixture with the R) -form. The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was 1 from the NMR spectrum (400 MHz) as in Example 1.
It was decided to be 1: 1.

Example 4 25.2 mg (0.11 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 30.0 mg (0.13 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.3 ml of methylene chloride. Dissolves in
Acetic anhydride 0.06 ml (0.64 mmol), pyridine 0.055 ml (0.68 m
mol), benzyltributylammonium chloride 2.1 mg (0.
007mmol), 0.25N sodium cyanide aqueous solution 2.6ml (0.6
(4 mmol) was sequentially added under ice cooling, and the mixture was stirred at the same temperature for 3 hours.
The same treatment as in Example 1 was carried out to give colorless oily (2S, 3R)-
A mixture of 2-acetoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form 11.1 mg (37%: N- (isopropoxycarbonyl)-(R) -phenylalaninol Total yield from)
I got

The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was determined to be 11: 1 from the NMR spectrum (400 MHz) as in Example 1.

Example 5 25.6 mg (0.11 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 30.0 mg (0.13 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.3 ml of methylene chloride. Dissolves in
Benzoic anhydride 0.12 ml (0.64 mmol), 4-dimethylaminopyridine 0.17 mg (0.0014 mmol), benzyltributylammonium chloride 2.1 mg (0.007 mmol), 0.25N aqueous sodium cyanide solution 2.6 ml (0.64 mmol) under ice cooling. In addition,
The mixture was stirred at the same temperature for 3 hours. The residue obtained by the same treatment as in Example 1 was purified by thin layer chromatography (silica gel, hexane-ethyl acetate 7: 3) to give a colorless oily (2S, 3
R) -2-Benzoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R)
This gave 20.7 mg (45%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) of the mixture with the -form. The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was determined to be 9: 1 from the NMR spectrum (400 MHz) as in Example 1.

Rf: 0.50 (hexane / ethyl acetate = 7/3) IR (neat): 1735, 1725, 1700 cm ^-1 . NMR (CDCl ₃ ): (2S, 3R) -form; δ1.18,1.24 (6H, two d, J = each 6.0H
z), 2.90 (1H, dd, J = 14.1,8.6Hz), 3.06 (1H, dd, J = 14.
1,6.1Hz), 4.26 to 5.00 (3H, m), 5.64 (1H, d, J = 4.6H
z), 7.10 to 7.75 (8H, m), 7.98 to 8.18 (2H, m). (2R, 3R) -body; δ1.18,1.24 (6H, two d, J ＝ each 6.0H
z), 2.98 (2H, d, J = 7.5Hz), 4.26 to 5.00 (3H, m), 5.63
(1H, d, J = 4.4Hz), 7.10 to 7.75 (8H, m), 7.98 to 8.18 (2
H, m). MS (m / e): 307,206. Example 6 According to the method described in the literature (see Chem, Pharm. Bull., 30 , 1921 (1982).), N- (benzyloxycarbonyl)-
98.6 mg (0.35 mmol) of N- (benzyloxycarbonyl)-(R) -phenylalaninal obtained from 122 mg (0.43 mmol) of (R) -phenylalaninol was added to methylene chloride 1.
Dissolve in 8 ml, acetic anhydride 0.12 ml (1.3 mmol), 4-dimethylaminopyridine 0.54 mg (0.0044 mmol), benzyltributylammonium chloride 6.8 mg (0.022 mmol), water 1.55 m
0.26 ml (1.3 mmol) of 5N sodium cyanide aqueous solution was sequentially added under ice cooling, and the mixture was stirred at the same temperature for 2 hours. The residue obtained by the same treatment as in Example 1 was purified by thin layer chromatography (silica gel, hexane-ethyl acetate 7: 3) to give (2S, 3R) -2-acetoxy-3-benzyloxy as a colorless oil. 84.4 mg (56%: total yield from N- (benzyloxycarbonyl)-(R) -phenylalaninol) of a mixture of carbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form was obtained. It was (2S, 3R) -body and (2R, 3R)
The production ratio with respect to the -form was the same as in Example 1 except that the NMR spectrum (400
Mhz) was determined to be 4: 1.

Rf: 0.44 (hexane / ethyl acetate = 7/3) IR (neat): 1750,1710 cm ^-1 . NMR (CDCl ₃ ): (2S, 3R) -form; δ2.13 (3H, s), 2.90 (1H, dd, J = 14.2,
8.7Hz), 3.06 (1H, dd, J = 14.2,6.2Hz), 4.34 to 4.52 (1
H, m), 4.88 to 5.03 (1H, m), 5.07 (1H, d, J = 12.1Hz), 5.
08 (1H, dJ = 12.1Hz), 5.40 (1H, d, J = 4.4Hz), 7.10 ~
7.44 (10H, m). (2R, 3R) -body; δ2.08 (3H, s), 2.98 (2H, d, J = 7.4H
z), 4.34 to 4.52 (1H, m), 4.88 to 5.03 (1H, m), 5.07 (1
H, d, J = 12.1Hz), 5.08 (1H, d, J = 12.1Hz), 5.38 (1H, d,
J = 4.1Hz), 7.10 to 7.44 (10H, m). MS (m / e): 353 ([M + 1] ⁺ ), 261,207. Comparative Example 1 42.3 mg (0.18 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 50.0 mg (0.21 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.5 ml of methylene chloride. Dissolves in
Benzyltributylammonium chloride 3.4 mg (0.011 mmo
l), water 0.35 ml, 5N sodium cyanide aqueous solution 0.21 ml
(1.1 mmol) was sequentially added under ice cooling, and the mixture was stirred at the same temperature for 3.5 hours. Treated as in Example 1 to give crude (2S, 3R) -2-
Hydroxy-3-isopropoxycarbonylamino-4
A mixture of -phenylbutyronitrile and its (2R, 3R) -form was obtained. To this mixture 0.25 ml acetic anhydride, pyridine 0.
5 ml and a catalytic amount of 4-dimethylaminopyridine were added, and the mixture was stirred at room temperature for 1.5 hours. 1M hydrochloric acid was added to the reaction solution, which was extracted with ether, and the extract solution was saturated saline solution, saturated copper sulfate aqueous solution,
The extract was washed successively with saturated saline, 1M aqueous sodium hydroxide solution, and saturated saline. After drying over anhydrous sodium sulfate,
After concentration under reduced pressure, the residue was purified by thin layer chromatography (silica gel, hexane-ethyl acetate 7: 3), and colorless oily (2S, 3R) -2-acetoxy-3-isopropoxycarbonylamino-4- 38.9 mg (61%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) of a mixture of phenylbutyronitrile and its (2R, 3R) -form was obtained. (2S, 3R) -body and (2R, 3R)
The production ratio with respect to the -form was the same as in Example 1 except that the NMR spectrum (400
MHz) was determined to be 1: 1.

Comparative Example 2 25.0 mg (0.11 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninal obtained from 30.0 mg (0.13 mmol) of N- (isopropoxycarbonyl)-(R) -phenylalaninol was added to 0.3 ml of methylene chloride. Dissolves in
2.6 ml of 0.25N sodium cyanide aqueous solution under ice cooling (0.64 mmo
l) was added, and the mixture was stirred at the same temperature for 3 hours. The mixture was treated in the same manner as in Example 1 to obtain a crude mixture of (2S, 3R) -2-hydroxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form. To this mixture 0.15 ml acetic anhydride, 0.3 ml pyridine, catalytic amount of 4-
Dimethylaminopyridine was added, and the mixture was stirred at room temperature for 2 hours. The same treatment as in Comparative Example 1 was conducted to obtain colorless oily (2S, 3
R) -2-acetoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R)
17.9 mg (60%: total yield from N- (isopropoxycarbonyl)-(R) -phenylalaninol) of a mixture with the -form was obtained. The production ratio of the (2S, 3R) -form and the (2R, 3R) -form was determined to be 1: 1 from the NMR spectrum (400 MHz) as in Example 1.

Reference example 4 54.2 mg (0.18 mmol) of an 11: 1 mixture of (2S, 3R) -2-acetoxy-3-isopropoxycarbonylamino-4-phenylbutylnitrile and its (2R, 3R) -form was dissolved in 3 ml of ethyl acetate. , 3 ml of water and 3 ml of concentrated hydrochloric acid were added and the reaction solution was heated to 100 ° C. to distill off ethyl acetate. Further, 1.5 ml of concentrated hydrochloric acid was added, and the mixture was heated with stirring at 80 ° C for 10.5 hours. The reaction solution was concentrated to dryness under reduced pressure, and (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid hydrochloride and its (2R, 3R)-
51.6 mg of an 11: 1 mixture with the body was obtained quantitatively.

NMR (D ₂ O): (2S, 3R) -form; δ3.01 (1H, dd, J = 14.1,8.1Hz), 3.16
(1H, dd, J = 14.1,7.3Hz), 3.94 (1H, dt, J = 7.7,3.3H
z), 4.32 (1H, d, J = 3.3Hz), 7.33 to 7.47 (5H, m). (2R, 3R) -body; δ2.95 (1H, dd, J = 14.3,9.2Hz), 3.03
(1H, dd, J = 14.1,5.9Hz), 4.05 to 4.75 (1H, m), 4.60 (1
H, d, J = 3.0Hz), 7.33 to 7.47 (5H, m). Reference example 5 20.7 mg (0.056 mmol) of a 9: 1 mixture of (2S, 3R) -2-benzoxy-3-isopropoxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form was added to 1.5 ml of ethyl acetate. After dissolution, 1.5 ml of water and 1.5 ml of concentrated hydrochloric acid were added and the reaction solution was heated to 100 ° C. to distill off ethyl acetate.
Furthermore, 0.75 ml of concentrated hydrochloric acid was added, and the mixture was heated with stirring at 80 ° C. for 10.5 hours. The reaction mixture was concentrated to dryness under reduced pressure, and 15.5 mg of a 9: 1 mixture of (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid hydrochloride and its (2R, 3R) -form was quantitatively determined. Got to.

Reference example 6 74.5 mg (0.21 mmol) of a 4: 1 mixture of (2S, 3R) -2-acetoxy-3-benzyloxycarbonylamino-4-phenylbutyronitrile and its (2R, 3R) -form was added to 4.5 ml of ethyl acetate. Dissolve, add 2.0 ml of water, 2.9 ml of concentrated hydrochloric acid,
The reaction solution was heated to 100 ° C. and ethyl acetate was distilled off. Further, 1.2 ml of concentrated hydrochloric acid was added, and the mixture was heated with stirring at 80 ° C. for 11 hours. The reaction solution was concentrated to dryness under reduced pressure, and (2S, 3R) -3-amino-2-
Hydroxy-4-phenylbutyric acid hydrochloride and its (2R, 3R)
-Quantitatively 59.0 mg of a 4: 1 mixture with the body was obtained.

Reference example 7 170m 4: 1 mixture of (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid hydrochloride and its (2R, 3R) -form
g (0.73 mmol) was dissolved in 10 ml of methanol, and 0.31 ml (4.3 mmol) of thionyl chloride was added dropwise under ice cooling. After stirring at the same temperature for 1 hour, the temperature was gradually raised and the mixture was heated under reflux for 2 hours. The reaction solution was concentrated under reduced pressure to obtain a mixture of (2S, 3R) -3-amino-2-hydroxy-4-phenylbutyric acid methyl hydrochloride and its (2R, 3R) -form.

To the methyl ester hydrochloride, which is a mixture of the (2S, 3R) -form and the (2R, 3R) -form, 3.0 ml of pyridine, 1.5 ml of acetic anhydride and a catalytic amount of 4-dimethylaminopyridine were added, and the mixture was mixed at 16.5 at room temperature.
Stir for hours. 1M Hydrochloric acid was added to the reaction solution, which was extracted with ether. The extract was washed with saturated saline, saturated copper sulfate aqueous solution, saturated saline, 1M sodium hydroxide aqueous solution, and saturated saline in this order. After drying over anhydrous sodium sulfate, the mixture was concentrated under reduced pressure to obtain a mixture of methyl (2S, 3R) -2-acetoxy-3-acetylamino-4-phenylbutyrate and its (2R, 3R) -form. This mixture was separated and purified by thin layer chromatography (silica gel, ethyl acetate), (2S, 3R).
-Body 67.9 mg (32%) and (2R, 3R) -body 16.7 mg (8
%) As a colorless oil.

(2S, 3R) -2-acetoxy-3-acetylamino-
Methyl 4-phenylbutyrate; Rf: 0.44 (ethyl acetate). ▲ [α] ²⁰ _D ▼ + 55.2 ° (c = 0.145, chloroform). IR (neat): 1745,1660,1550cm ^-1 . NMR (CDCl ₃ ): δ1.96 (3H, s), 2.23 (3H, s), 2.79 (1
H, dd, J = 13.6,9.0Hz), 2.94 (1H, dd, J = 13.6,6.6Hz),
3.69 (3H, s), 4.79 (1H, ddt, J = 9.0,6.6,2.2Hz), 4.90
(1H, d, J = 2.2Hz), 5.73 (1H, brd, J = 9.0Hz), 7.14 to 7.
34 (5H, m). MS (m / e): 294 ([M + 1] ⁺ ), 293 (M ⁺ ), 234,202,19
2. (2S, 3R) -2-acetoxy-3-acetylamino-4
-Methyl phenylbutyrate; Rf: 0.56 (ethyl acetate). ▲ [α] ²⁰ _D ▼ + 0.00 ° (c = 0.123, chloroform). IR (neat): 1750,1645,1550cm ^-1 . NMR (CDCl ₃ ): δ1.91 (3H, s), 2.18 (3H, s), 2.87 (2
H, d, J = 7.2Hz), 3.70 (3H, s), 4.79 (1H, ddt, J = 8.8,7.
2,4.3Hz), 5.11 (1H, d, J = 4.3Hz), 5.56 (1H, brd, J = 8.
8Hz), 7.17 to 7.34 (5H, m). MS (m / e): 294 ([M + 1] ⁺ ), 293 (M ⁺ ), 234,202,19
2. (2S, 3R) -2-acetoxy-3-acetylamino-4
-Methyl phenylbutyrate 82.9 mg (0.28 mmol) in ethyl acetate
It was dissolved in 2 ml, water (2 ml) and concentrated hydrochloric acid (2 ml) were added, and the reaction mixture was heated to 100 ° C. to distill off ethyl acetate. After further heating and stirring at 80 ° C. for 10 hours, the reaction solution was concentrated under reduced pressure to about 0.5 ml and left overnight, and then the precipitated crystals were collected by filtration. After washing with toluene, it was dried under reduced pressure to obtain white crystals of (2S, 3R) -3-amino-2.
-Hydroxy-4-phenylbutyric acid hydrochloride 28.8 mg (44%)
I got

▲ [α] ²² _D ▼ + 25.7 ° (c = 0.700,1N HCl). [Reference value: J. Antibiot., 29 , 100 (1976); ▲ [α] ²² _D ▼
+ 27.9 ° (c = 0.717, 1N HCl)]. IR (KBr): 1740 cm ^-1 . NMR (D ₂ O): δ3.01 (1H, dd, J = 14.1,8.1Hz), 3.16 (1
H, dd, J = 14.1,7.3Hz), 3.94 (1H, dt, J = 7.7,3.3Hz), 4.
32 (1H, d, J = 3.3Hz), 7.33 to 7.47 (5H, m). This NMR spectrum can be found in the literature (J. Antibiot., 29 , 100 (197
6). ) Matched with the one described.

MS (m / e): 196 ((MH-HCl) ⁺ ), 150,120,104.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Daiei Tsunemoto 2-24-5 Midorigaoka, Zama City, Kanagawa Examiner Reiko Imamura

Claims (2)

[Claims] 1. A general formula (In the formula, R ¹ is a linear or branched alkanoyl group having 1 to 4 carbon atoms, an aroyl group optionally substituted with a chlorine atom or a methoxy group, a linear or branched alkoxycarbonyl group having 1 to 5 carbon atoms. Or a aralkoxycarbonyl group which may be substituted with a chlorine atom or a methoxy group, and R ² is substituted with a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, or a chlorine atom or a methoxy group. (2S, 3R) -3-amino-2-acyloxy-4-phenylbutyronitrile derivative represented by (representing an optionally substituted aryl group). 2. General formula (In the formula, R ¹ is a linear or branched alkanoyl group having 1 to 4 carbon atoms, an aroyl group optionally substituted with a chlorine atom or a methoxy group, a linear or branched alkoxycarbonyl group having 1 to 5 carbon atoms. , Or an aralkoxycarbonyl group which may be substituted with a chlorine atom or a methoxy group.) And an (R) -2-amino-3-phenylpropanal derivative represented by the general formula R ² COOCOR ³ (formula In the formula, R ² and R ³ are each independently a hydrogen atom or a carbon number of 1 to 4.
Represents a linear or branched alkyl group, or an aryl group which may be substituted with a chlorine atom or a methoxy group. ) And carboxylic anhydrides and cyanates represented by
General formula characterized by reacting in the presence of a primary ammonium salt and / or a tertiary amine (In the formula, R ¹ and R ² have the same meanings as described above.) (2S, 3R) -3-amino-2-acyloxy-4-
Method for producing phenylbutyronitrile derivative.