JP7109056B2 - Method for producing S-ICA ribosylhomocysteine - Google Patents

Description

Application of Article 30, Paragraph 2 of the Patent Act (1) Summary of the 138th Annual Meeting of the Pharmaceutical Society of Japan Date of publication February 1, 2018 Address of publication http://nenkai. pharm. or. jp/138/pc/ipdfview. asp? i = 1438 (2) Name of publisher: The Pharmaceutical Society of Japan Publication name: The 138th Annual Meeting of the Pharmaceutical Society of Japan Abstract: DVD Date of issue: March 5, 2018 (3) Name of publisher: The Pharmaceutical Society of Japan Publication name The 138th Annual Meeting of the Pharmaceutical Society of Japan Abstract Booklet Date of publication March 5, 2018 (4) Abstracts of the 138th Annual Meeting of the Pharmaceutical Society of Japan Application Publication date March 16, 2018 Posting address Google Download from the play store and the App store (5) Name of the meeting: The 138th Annual Meeting of the Pharmaceutical Society of Japan Date: March 25-28, 2018 (announcement on the 28th)

The present invention relates to a method for producing S-ICA ribosylhomocysteine.

S -adenosylmethionine (SAM), which controls methylation of nucleic acids, is known and used as a therapeutic agent for osteoarthritis and depression. has been proposed (Patent Document 1).
In addition, the demethylated SAM (SAH) is also highly expected as a lead drug because it has various biological activities such as SAH hydrolase activity, antiviral activity, and tumor activity.

JP 2017-193501 A

An object of the present invention is to provide a novel technology related to a method for producing S-ICA ribosylhomocysteine.

The compound represented by the formula (1) (S-ICA ribosylhomocysteine) was found in the extract after administration of imidazolecarboxamide (ICA), a novel plant growth promoting substance (fairy compound) isolated from Komurasakishimeji to rice plants. Isolated.
The inventor believed that S-ICA ribosylhomocysteine could be expected to have various biological activities, and started synthetic research to complete the present invention.

で表される化合物又はその塩の製造方法であって、
式（２）：

（式中、Ｒ^１はカルボン酸の保護基であり、Ｒ^２はアミノ基の保護基である。）で表される化合物と、
式（３）：

（式中、Ｘは脱離基であり、Ｒ^３はヒドロキシル基の保護基である。）で表される化合物とを反応させて式（４）：

（式中、Ｒ^１、Ｒ^２およびＲ^３は前記定義に同じ）で表される化合物を生成させ、
得られた前記式（４）で表される化合物に対し保護基の除去処理を行うことを含む、前記式（１）で表される化合物の製造方法。
［２］ 前記式（２）で表される化合物を光学活性メチオニンから変換することにより得ることをさらに含む、［１］に記載の製造方法。
［３］ 前記光学活性メチオニンがＬ－メチオニンまたはＤ－メチオニンである［１］に記載の製造方法。 The gist of the present invention is as follows.
[1] Formula (1):

A method for producing a compound or a salt thereof represented by
Formula (2):

(wherein R ¹ is a carboxylic acid-protecting group and R ² is an amino-protecting group);
Formula (3):

(wherein X is a leaving group and R3 is a hydroxyl ^- protecting group) to give the formula (4):

(wherein R ¹ , R ² and R ³ are the same as defined above) to produce a compound represented by
A method for producing a compound represented by the above formula (1), which comprises subjecting the obtained compound represented by the above formula (4) to treatment for removing a protecting group.
[2] The production method according to [1], further comprising converting the compound represented by the formula (2) from optically active methionine.
[3] The production method according to [1], wherein the optically active methionine is L-methionine or D-methionine.

ADVANTAGE OF THE INVENTION According to this invention, the novel technique regarding the manufacturing method of S-ICA ribosylhomocysteine can be provided.

One embodiment of the present invention is described in detail below.
In the following description, the definition of the functional group in the general formula may be omitted by citing the definitions already described.

In the present specification, the amino-protecting group is not particularly limited as long as it is a protecting group commonly known as an amino-protecting group. ) and other aralkyl groups, methoxycarbonyl groups, ethoxycarbonyl groups, n-propyloxycarbonyl groups, isopropyloxycarbonyl groups, n-butyloxycarbonyl groups, isobutyloxycarbonyl groups, tert-butoxycarbonyl groups such as alkoxycarbonyl (Boc) groups aralkoxycarbonyl group such as benzyloxycarbonyl group, p-methoxybenzyloxycarbonyl group, p-nitrobenzyloxycarbonyl group, methoxymethyl group, methoxyethoxymethyl group, 1-(ethoxy)ethyl group, methoxyisopropyl group and acyl groups such as 1-(alkoxy)alkyl groups such as acetyl group, trifluoroacetyl group, propionyl group, butyryl group, pivaloyl group, benzoyl group and methylbenzoyl group.
Also, the carboxylic acid protecting group is not particularly limited as long as it is a protecting group commonly known as a carboxylic acid protecting group. and the like.
Also, the hydroxyl-protecting group is not particularly limited as long as it is a protecting group commonly known as a hydroxyl-protecting group. arylmethyl groups such as benzyl group and diphenylmethyl group; acyl groups such as acetyl group and propionyl group; lower alkoxymethyl groups such as methoxymethyl group and ethoxymethyl group; aralkyloxymethyl groups such as benzyloxymethyl group; A pyranyl group and the like are included.

The reaction pathway shown below, which is an example of the production method according to the present embodiment, will be described in detail.
In the following explanation, when the crude product is used as it is for the next treatment without purification, it is assumed that the substrate compound is converted to the product at a yield of 100%, and the amount of substrate used is is taken as the product usage.

In the reaction pathway, R ¹ represents a carboxylic acid protecting group, R ² represents an amino group protecting group, X represents a leaving group, and R ³ represents a hydroxyl protecting group.

[Step 1]
The compound represented by formula (ii) can be obtained by oxidizing methionine, which is the compound represented by formula (i), to form a disulfide bond to form a dimer.

The reaction can be carried out, for example, by treating the compound represented by formula (i) (methionine) with metallic lithium or the like in a reaction solvent such as liquid ammonia. The amount of metal lithium or the like used can be, for example, 2 to 10 equivalents relative to the compound represented by formula (i). Also, the reaction temperature can be, for example, -78 to -40°C.

[Step 2]
The compound represented by formula (iii) can be obtained by introducing a carboxylic acid protecting group and an amino group protecting group into the compound represented by formula (ii).

In the formula, R ¹ and R ² are the same as defined above.

The reaction can be appropriately determined by those skilled in the art, and can be carried out by a known method for introducing a carboxylic acid and an amino group-protecting group.
For example, assume that ^R1 is a methyl group and ^R2 is a Boc group.
In the reaction, first, the compound represented by formula (ii) is reacted with thionyl chloride, oxalyl chloride, or the like in a reaction solvent such as methanol. The amount of thionyl chloride or the like to be used can be, for example, 1 to 3 equivalents relative to the compound represented by formula (ii). Also, the reaction temperature can be, for example, 20 to 80°C.
Next, the resulting product is reacted with Boc ₂ O in a reaction solvent such as methanol in the presence of a base such as triethylamine. The amount of Boc ₂ O used can be, for example, 2 to 4 equivalents relative to the compound represented by formula (ii). Also, the reaction temperature can be, for example, 20 to 40°C.

[Step 3]
The compound represented by formula (2) can be obtained by reducing the compound represented by formula (iii) to cleave the disulfide bond and convert it into a monomer.

In the formula, R ¹ and R ² are the same as defined above.

The reaction can be carried out, for example, by reacting the compound represented by formula (iii) with zinc or the like in a mixed solution of acetic acid and diethyl ether. The amount of zinc or the like used can be, for example, 20 to 100 equivalents relative to the compound represented by formula (iii). Also, the reaction temperature can be, for example, 20 to 40°C.

[Step 4]
The compound represented by formula (4) can be obtained by reacting the compound represented by formula (2) with the compound represented by formula (3).

^In the formula, R3 has the same definition as above.

In the formula, R ¹ , R ² and R ³ are the same as defined above.

The reaction is performed, for example, by allowing the compound represented by formula (2) to act on the compound represented by formula (3) in a reaction solvent such as N,N-dimethylformamide (DMF) in the presence of a base. It can be carried out. As the base, organic bases such as pyridine, triethylamine, diisopropylethylamine, tetramethylethylenediamine, and N-methylimidazole can be used. The amount of the base used can be, for example, 2 to 10 equivalents relative to the compound represented by formula (3). Also, the reaction temperature can be, for example, 20 to 50°C.

The compound represented by Formula (3) can be obtained, for example, by performing the following steps A to D.

In the reaction pathway, X and R3 ^are the same as defined above.

[Step A]
A compound represented by formula (b) can be obtained by converting a compound represented by formula (a).

In the formula, Ar represents a 2,4-dinitrophenyl group ^, and R3 has the same definition as above.

^In the formula, R3 has the same definition as above.

In the reaction, for example, the compound represented by formula (a) is first reacted with ethylenediamine or the like in a reaction solvent such as DMF. The amount of ethylenediamine or the like used can be, for example, 10 to 30 equivalents relative to the compound represented by formula (a). Also, the reaction temperature can be, for example, 20 to 80°C.
Next, the product is reacted with sodium nitrite under acidic conditions in a reaction solvent to obtain a compound represented by formula (b). The amount of sodium nitrite used can be, for example, 3 to 10 equivalents relative to the product subjected to the reaction. The reaction solvent can be, for example, a mixture of tetrahydrofuran (THF) and water. Also, the reaction temperature can be, for example, 0 to 20°C.

The compound represented by formula (a) can be obtained based on Org. Biomol. Chem., 2014, 12, 3813-3815.

[Step B]
A compound represented by formula (c) can be obtained by converting a compound represented by formula (b).

^In the formula, R3 has the same definition as above.

The reaction can be carried out, for example, by reacting the compound represented by formula (b) with camphorsulfonic acid in a reaction solvent such as methanol. The amount of camphorsulfonic acid or the like used can be, for example, 0.2 to 2 equivalents. Also, the reaction temperature can be, for example, 0 to 40°C.

[Step C]
A compound represented by formula (d) can be obtained by converting a compound represented by formula (c).

^In the formula, R3 has the same definition as above.

The reaction can be carried out, for example, by reacting the compound represented by formula (c) with triethylamine and mesyl chloride in a reaction solvent such as methylene chloride. The amount of triethylamine and mesyl chloride used can be, for example, 1 to 5 equivalents relative to the compound represented by formula (c). Also, the reaction temperature can be, for example, 0 to 40°C.

[Step D]
The compound represented by formula (3) can be obtained by converting the compound represented by formula (d) to introduce a leaving group.

As used herein, a leaving group refers to a halogen atom, a C1-6 alkylsulfonyloxy group, an arylsulfonyloxy group, or the like. Among them, the leaving group is preferably a halogen atom, more preferably an iodine atom, because Step 4 proceeds more efficiently.
The treatment for introducing a leaving group is not particularly limited and can be set as appropriate, and may be carried out based on a known method.
For example, assume the leaving group is an iodine atom.
The reaction can be carried out by reacting the compound represented by formula (d) with sodium iodide or the like in a reaction solvent such as acetone. The amount of sodium iodide or the like used can be, for example, 1 to 5 equivalents relative to the compound represented by formula (d). Also, the reaction temperature can be, for example, 20 to 50°C.

[Step 5]
The compound represented by formula (1) can be obtained by removing the protective group from the compound represented by formula (4).

The reaction can be carried out, for example, by allowing a known deprotection reagent to act on the compound represented by formula (4) in a reaction solvent, for example, by combining known methods for removing each protecting group. can be done by
For example, assume that ^R1 is a methyl group, ^R2 is a Boc group ^, and R3 is a TBS group.
At this time, first, the Boc group is removed by reacting the compound represented by the formula (4) with ammonium fluoride or the like in a reaction solvent. The amount of ammonium fluoride or the like used can be, for example, 2 to 20 equivalents relative to the compound represented by formula (4). The reaction solvent can be, for example, a mixed solvent of THF and methanol. Also, the reaction temperature can be, for example, 20 to 60°C.
Next, the compound from which the Boc group has been removed is reacted with lithium hydroxide or the like in a reaction solvent to hydrolyze the methyl ester and remove the methyl group. The amount of lithium hydroxide or the like used can be, for example, 2 to 20 equivalents relative to the compound subjected to the reaction. The reaction solvent can be, for example, THF. Also, the reaction temperature can be, for example, 20 to 60°C.
Subsequently, the compound from which the methyl group has been removed is treated with trifluoroacetic acid or the like in a reaction solvent to remove the TBS group. The amount of trifluoroacetic acid or the like used can be, for example, 50 to 200 equivalents relative to the compound subjected to the reaction. The reaction solvent can be, for example, methanol. Also, the reaction temperature can be, for example, 20 to 70°C.

As described above, according to the present embodiment, it is possible to provide a novel technology related to a method for producing S-ICA ribosylhomocysteine. In this method, the starting material is methionine, both enantiomers of which are readily available. That is, since it is possible to synthesize both the L and D isomers of S-ICA ribosylhomocysteine using optically active methionine such as L-methionine and D-methionine as a starting material, unnatural homocysteine can be synthesized. Synthesis of derivatives is also possible.

EXAMPLES The present invention will be described in more detail below based on examples, but the present invention is not limited to these.

[Example 1]
4,4'-Disulfanediyl (2S,2'S)-bis(2-((tert-butoxycarbonyl)amino)butanoate)dimethyl

About 100 mL of liquid ammonia was stored in an eggplant flask cooled to -78°C, and (L)-methionine (4.0 g, 26.8 mmol) and thinly sliced metallic lithium (555 mg, 80.0 mmol) were sequentially added, followed by stirring for 1.5 hours. Ammonium chloride was added to the reaction solution to stop the reaction, and then the temperature was raised to room temperature to volatilize ammonia. The resulting residue was dissolved in 40 mL of water and 1M hydrochloric acid was added until pH 4-5. 20 mL of 30% hydrogen peroxide was added to this aqueous solution while stirring under ice cooling, and the precipitate was collected by filtration and dried under reduced pressure to give (2S,2'S)-homocystine (1.56 g, yield 43). %) was obtained as a white solid.
(2S,2'S)-Homocystine (500 mg, 1.86 mmol) was suspended in methanol (MeOH) 18 mL, thionyl chloride 2.0 mL, 27.6 mmol was added, and the mixture was stirred at 70°C for 24 hours. After that, the reaction solution was concentrated under reduced pressure to obtain 688 mg of crude product.
200 mg of the crude product was dissolved in 6.8 mL of MeOH, 376 μL of triethylamine (2.71 mmol) and 440 mg of Boc ₂ O (2.02 mmol) were added under ice cooling, and the mixture was stirred at room temperature for 24 hours. After the reaction mixture was concentrated under reduced pressure, the residue was dissolved in 0.1 M hydrochloric acid and ethyl acetate. The separated organic layer was washed with an aqueous sodium carbonate solution and saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (developing solvent: hexane:ethyl acetate = 4:1 → 3:2) to give 4,4'-disulfanediyl (2S,2'S)-bis(2-(( Dimethyl tert-butoxycarbonyl)amino)butanoate (237 mg, 88% yield, 2 steps) was obtained as a white solid.
¹ H NMR (500 MHz, CDCl ₃ , δ): 5.12 (br d, J = 7.0 Hz, 2H), 4.36 (br s, 2H), 3.72 (s, 6H), 2.68 (t, J = 7.0 Hz, 4H), 2.18-2.22 (m, 2H), 1.94-1.99 (m, 2H), 1.40 (s, 18H).

[Example 2]
1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)tetrahydrofuran-2-yl) -1H-imidazole-4-carboxamide

5-amino-1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)tetrahydrofuran- Dissolve 30.4 g, 39.6 mmol of 2-yl)-N-(2,4-dinitrophenyl)-1H-imidazole-4-carboxamide in 396 mL of DMF, add 66.2 mL, 991 mmol of ethylenediamine under ice-cooling, and heat at 60°C. Stirred for 8.5 hours. After cooling to room temperature, saturated aqueous ammonium chloride solution was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with 1M hydrochloric acid and saturated brine, and dried by adding anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure to obtain 26.1 g of crude product.
5.0 g of the obtained crude product was dissolved in 90 mL of THF, cooled with ice, added with 50 mL of water in which 4.0 g of sodium nitrite had been dissolved, and 90 mL of acetic acid, and stirred under ice cooling for 8 hours. After that, an aqueous sodium carbonate solution was added to the reaction solution, and the mixture was extracted with ethyl acetate, and the organic layer was washed with an aqueous sodium carbonate solution and saturated brine. Anhydrous magnesium sulfate was added to the organic layer to dry it, and after filtration, the filtrate was concentrated under reduced pressure. 1-((2R,3R,4R,5R)-3,4-bis((tert -Butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (2.17 g, 45% yield) was obtained as an orange Obtained as amorphous.
¹ H NMR (500 MHz, CDCl ₃ , δ): 7.79 (d, J = 1.1 Hz, 1H), 7.64 (d, J = 1.1 Hz, 1H), 6.92 (br s, 1H), 5.56 (d, J = 6.8 Hz, 1H), 5.30 (br s, 1H), 4.15-4.19 (m, 2H), 4.08 (br s, 1H), 3.82 (dd, J = 11, 3.4 Hz, 1H), 3.76 (dd, J = 11, 2.3 Hz, 1H), 0.95 (s, 9H), 0.93 (s, 9H), 0.82 (s, 9H), 0.17 (s, 3H), 0.14 (s, 3H), 0.10 (s, 6H ), -0.06 (s, 3H), -0.30 (s, 3H).

[Example 3]
1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide

1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(((tert-butyldimethylsilyl)oxy)methyl)tetrahydrofuran-2-yl) 100 mg, 171 μmol of -1H-imidazole-4-carboxamide was dissolved in 1.0 mL of MeOH, 49.5 mg, 213 μmol of camphorsulfonic acid was added, and the mixture was stirred at room temperature for 6.5 hours. After that, triethylamine was added to the reaction mixture to neutralize the acid, and the mixture was concentrated under reduced pressure. After ethyl acetate and water were added to the residue to dissolve it, the organic layer was separated, washed with saturated aqueous ammonium chloride solution and saturated brine, and dried by adding anhydrous magnesium sulfate. After filtration, the filtrate was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (developing solvent chloroform:methanol = 30:1) to give 1-((2R,3R,4R,5R)-3,4 -Bis((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (64.4 mg, 80% yield) was obtained as a white solid.
¹ H NMR (500 MHz, CD ₃ OD, δ): 7.84 (s, 1H), 7.83 (s, 1H), 5.53 (d, J = 7.2 Hz, 1H), 4.27 (dd, J = 12, 5.2 Hz , 1H), 4.12-4.13 (m, 1H), 3.92-3.93 (m, 1H), 3.63 (dd, J = 12, 3.6 Hz, 1H), 3.58 (dd, J = 12, 2.8 Hz, 1H), 0.82 (s, 9H), 0.68 (s, 9H), 0.01 (s, 6H), -0.16 (s, 3H), -0.42 (s, 3H).

[Example 4]
1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(methanesulfonyloxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4- Carboxamide

1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(hydroxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide ( 100 mg, 210 μmol) was dissolved in 350 μL of methylene chloride, 64 μL, 460 μmol of triethylamine and 18 μL, 230 μmol of mesyl chloride were sequentially added under ice-cooling, and the mixture was stirred for 22 hours under ice-cooling. After that, water was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. The residue was purified by silica gel column chromatography (developing solvent chloroform:methanol = 10:1) to give 1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl) Oxy)-5-(methanesulfonyloxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (97 mg, 83% yield) was obtained as a white solid.
¹ H NMR (500 MHz, CDCl ₃ , δ): 7.81 (d, J = 1.5 Hz, 1H), 7.59 (d, J = 1.5 Hz, 1H), 6.98 (br s, 1H), 5.85 (br s, 1H), 5.57 (d, J = 5.0 Hz, 1H), 4.43 (dd, J = 12, 3.5 Hz, 1H), 4.38 (dd, J = 12, 3.5 Hz, 1H), 4.23 (q, J = 3.5 Hz, 1H), 4.19 (t, J = 3.5 Hz, 1H), 4.15 (t, J = 5.0 Hz, 1H), 3.07 (s, 3H), 0.90 (s, 9H), 0.80 (s, 9H), 0.09 (s, 3H), 0.08 (s, 3H), -0.03 (s, 3H), -0.21 (s, 3H).

[Example 5]
1-((2R,3R,4R,5S)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(iodomethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide

1-((2R,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(methanesulfonyloxymethyl)tetrahydrofuran-2-yl)-1H-imidazole-4- Carboxamide (135 mg, 250 µmol) was dissolved in acetone 1.4 mL, sodium iodide 147 mg, 980 µmol was added, and the mixture was stirred at 50°C for 21 hours. After that, the reaction mixture was concentrated under reduced pressure, and the residue was dissolved by adding aqueous sodium hydrogencarbonate solution and ethyl acetate, and then the organic layer and the aqueous layer were separated. The aqueous layer was extracted again with ethyl acetate, and the combined organic layer was washed with an aqueous sodium hydrogencarbonate solution and saturated brine, dried over anhydrous magnesium sulfate, filtered, and concentrated under reduced pressure. 1-((2R,3R,4R,5S)-3,4-bis((tert-butyldimethylsilyl) Oxy)-5-(iodomethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (124 mg, 87% yield) was obtained as a yellow oil.
¹ H NMR (500 MHz, CDCl ₃ , δ): 7.77 (d, J = 1.5 Hz, 1H), 7.63 (d, J = 1.5 Hz, 1H), 6.95 (br s, 1H), 5.64 (br s, 1H), 5.57 (d, J = 6.0 Hz, 1H), 4.15-4.18 (m, 1H), 4.04-4.07 (m, 2H), 3.36 (dd, J = 11, 6.0 Hz, 1H), 3.32 (dd , 11, 4.5 Hz, 1H), 0.91 (s, 9H), 0.81 (s, 9H), 0.14 (s, 3H), 0.11 (s, 3H), -0.05 (s, 3H), -0.22 (s, 3H).

[Example 6]
Methyl (tert-butoxycarbonyl)-L-homocysteate

4,4'-Disulfanediyl (2S,2'S)-bis(2-((tert-butoxycarbonyl)amino)butanoate)dimethyl (237 mg, 477 μmol) was dissolved in 14.6 mL of acetic acid and 0.8 mL of diethyl ether. The mixture was ice-cooled, 1.87 g (28.6 mmol) of zinc powder was added, and the mixture was stirred at room temperature for 24 hours. The reaction mixture was filtered through Celite to remove solids, and then concentrated under reduced pressure. After adding 0.1 M hydrochloric acid and ethyl acetate to dissolve the residue, the organic layer and the aqueous layer were separated. The aqueous layer was extracted again with ethyl acetate, and the combined organic layer was washed with 0.1 M hydrochloric acid, aqueous sodium hydrogencarbonate solution and saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. 236 mg of the obtained residue containing methyl (tert-butoxycarbonyl)-L-homocysteate was directly used for the next reaction.

[Example 7]
S-(((2S,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl )methyl)-N-(tert-butoxycarbonyl)-L-methyl homocysteate

1-((2R,3R,4R,5S)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(iodomethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (130 mg, 224 μmol) was dissolved in 800 μL of DMF, 200 μL of triethylamine, 1.44 mmol, and 110 mg, ca 441 μmol of methyl (tert-butoxycarbonyl)-L-homocysteate were added under ice cooling, and the mixture was stirred at room temperature for 24 hours. . After that, a saturated ammonium chloride aqueous solution was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. S-(((2S,3R,4R,5R)-3,4-bis(( tert-Butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl)methyl)-N-(tert-butoxycarbonyl)-L-homocysteate (116 mg, 74%) was obtained as a white amorphous.
¹ H NMR (500 MHz, CDCl ₃ , δ): 7.71 (s, 1H), 7.57 (s, 1H), 6.99 (br s, 1H), 6.05 (br s, 1H), 5.51 (d, J = 6.0 Hz, 1H), 5.47 (br s, 1H), 4.35 (br s, 1H), 4.14 (m, 1H), 4.09 (m, 1H), 4.01 (m, 1H), 3.68 (s, 3H), 2.70 -2.79 (m, 2H), 2.57-2.63 (m, 2H), 1.85-1.91 (m, 1H), 1.34 (s, 9H), 0.87 (s, 9H), 0.77 (s, 9H), 0.06 (s , 3H), 0.05 (s, 3H), -0.09 (s, 3H), -0.27 (s, 3H).

[Example 8]
S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-L-homocysteine

S-(((2S,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl )methyl)-N-(tert-butoxycarbonyl)-L-methyl homocysteate (27 mg, 38.4 μmol) was dissolved in 0.3 mL of a 1:2 mixed solvent of THF and MeOH, and 14 mg, 384 μmol of ammonium fluoride was added. In addition, the mixture was stirred at 60°C for 48 hours. Thereafter, the reaction mixture was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (developing solvent chloroform:methanol = 19:1 → 4:1) to give N-(tert-butoxycarbonyl)-S-( Methyl ((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-L-homocysteate (8 mg) , 43%).
N-(tert-butoxycarbonyl)-S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl) Methyl)-L-methyl homocysteinate (8 mg, 16.9 μmol) was dissolved in 450 μL of THF, 5.3 mg, 34.0 μmol of sodium hydroxide dissolved in 50 μL of water was added, and the mixture was stirred at room temperature for 1 hour. After acidifying the solution by adding acetic acid to the reaction solution, it was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (developing solvent chloroform:methanol = 2:1) to give N-(tert-butoxycarbonyl) -S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-L-homocysteine ( 4 mg, 52%).
N-(tert-butoxycarbonyl)-S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl) Methyl)-L-homocysteine (4 mg) was dissolved in 100 μL of water, 100 μL of trifluoroacetic acid was added, and the mixture was stirred at room temperature for 54 hours. After that, the reaction mixture was concentrated under reduced pressure to give S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2- yl)methyl)-L-homocysteine (6 mg) was obtained as a white solid.
< ¹ >H NMR ₍ 500 MHz, D2O, [delta]): 8.33 (br s, 1H), 7.99 (br s, 1H), 5.79 (d, J = 4.5 Hz, 1H), 4.42 (t, J = 5.0 Hz , 1H), 4.20-4.26 (m, 2H), 3.87 (t, J = 6.0 Hz, 1H), 2.94 (dd, J = 15, 5.0 Hz, 1H), 2.85 (dd, J = 15, 7.0 Hz, 1H), 2.66 (t, J = 7.5 Hz, 2H), 2.03-2.15 (m, 2H).

[Example 9]
Methyl (tert-butoxycarbonyl)-D-homocysteate

4,4'-Disulfanediyl(2R,2'R)-bis(2-((tert-butoxycarbonyl)amino)butanoate)dimethyl (228 mg, 459 µmol) was dissolved in 15 mL of acetic acid and 0.3 mL of diethyl ether. and ice-cooled, 1.80 g (27.5 mmol) of zinc powder was added, and the mixture was stirred at room temperature for 10 hours. The reaction mixture was filtered through Celite to remove solids, and then concentrated under reduced pressure. After adding 0.1 M hydrochloric acid and ethyl acetate to dissolve the residue, the organic layer and the aqueous layer were separated. The aqueous layer was extracted again with ethyl acetate, and the combined organic layer was washed with 0.1 M hydrochloric acid, aqueous sodium hydrogencarbonate solution and saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. 213 mg of the obtained residue containing methyl (tert-butoxycarbonyl)-D-homocysteate was directly used for the next reaction.

[Example 10]
S-(((2S,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl )methyl)-N-(tert-butoxycarbonyl)-D-methyl homocysteate

1-((2R,3R,4R,5S)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(iodomethyl)tetrahydrofuran-2-yl)-1H-imidazole-4-carboxamide (200 mg, 344 μmol) was dissolved in DMF 680 μL, triethylamine 142 μL, 1.02 mmol and (tert-butoxycarbonyl)-D-methyl-D-homocysteate 158 mg, ca 634 μmol were added under ice cooling, and the mixture was stirred at room temperature for 24 hours. . After that, a saturated ammonium chloride aqueous solution was added to the reaction solution, and the mixture was extracted with ethyl acetate. The organic layer was washed with saturated brine, dried by adding anhydrous magnesium sulfate, filtered, and the filtrate was concentrated under reduced pressure. S-(((2S,3R,4R,5R)-3,4-bis(( tert-Butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl)methyl)-N-(tert-butoxycarbonyl)-D-methyl homocysteate (190 mg, 79%) was obtained as a white amorphous.
¹ H NMR (500 MHz, CDCl ₃ , δ): 7.71 (s, 1H), 7.58 (s, 1H), 6.97 (br s, 1H), 5.75 (br s, 1H), 5.53 (d, J = 5.5 Hz, 1H), 5.21 (br s, 1H), 4.36 (br s, 1H), 4.15 (dt, J = 6.0, 2.5 Hz, 1H), 4.00-4.08 (m, 2H), 3.70 (s, 3H) , 2.75 (d, J = 6.0 Hz, 2H), 2.58-2.61 (m, 3H), 1.86-1.92 (m, 1H), 1.39 (s, 9H), 0.89 (s, 9H), 0.79 (s, 9H ), 0.09 (s, 3H), 0.07 (s, 3H), -0.07 (s, 3H), -0.25 (s, 3H).

[Example 11]
S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-D-homocysteine

S-(((2S,3R,4R,5R)-3,4-bis((tert-butyldimethylsilyl)oxy)-5-(4-carbamoyl-1H-imidazol-1-yl)tetrahydrofuran-2-yl )methyl)-N-(tert-butoxycarbonyl)-D-methyl homocysteate (190 mg, 270 μmol) was dissolved in 2.6 mL of a 1:1 mixture of THF and MeOH, and 100 mg, 2.70 mmol of ammonium fluoride was added. In addition, the mixture was stirred at 60°C for 48 hours. Thereafter, the reaction solution was concentrated under reduced pressure, and the residue was purified by silica gel column chromatography (developing solvent chloroform:methanol=19:1→4:1) to give N-(tert-butoxycarbonyl)-S-( Methyl ((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-D-homocysteate (128 mg) , quant) was obtained as a white amorphous.
N-(tert-butoxycarbonyl)-S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl) Methyl)-D-methyl homocysteinate (105 mg, 221 μmol) was dissolved in THF 2 mL, lithium hydroxide 26 mg, 1.09 mmol dissolved in water 200 μL was added, and the mixture was stirred at room temperature for 20 minutes. After diluting the reaction solution by adding water, THF was removed by concentration under reduced pressure, and the resulting aqueous solution was washed with diethyl ether. After that, 1M hydrochloric acid was added to acidify the solution and extracted with ethyl acetate and THF. Anhydrous magnesium sulfate was added to the organic layer to dry it, and after filtration, the filtrate was concentrated under reduced pressure to give N-(tert-butoxycarbonyl)-S-(((2S,3S,4R,5R)-5-(4- Carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl)methyl)-D-homocysteine (88 mg, 86%) was obtained as a white solid.
N-(tert-butoxycarbonyl)-S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2-yl) Methyl)-D-homocysteine (29 mg, 630 µmol) was dissolved in 100 µL of MeOH, 300 µL of trifluoroacetic acid was added, and the mixture was stirred at room temperature for 20 hours. After that, the reaction mixture was concentrated under reduced pressure to give S-(((2S,3S,4R,5R)-5-(4-carbamoyl-1H-imidazol-1-yl)-3,4-dihydroxytetrahydrofuran-2- yl)methyl)-D-homocysteine (30 mg) was obtained as a white solid.
< ¹ >H NMR ₍ 500 MHz, D2O, [delta]): 8.97 (br s, 1H), 8.14 (br s, 1H), 5.85 (d, J = 4.5 Hz, 1H), 4.40 (t, J = 5.0 Hz , 1H), 4.28 (dt, J = 6.5, 5.0 Hz, 1H), 4.17 (t, J = 5.0 Hz, 1H), 4.08 (t, J = 6.5 Hz, 1H), 2.94 (dd, J = 14, 5.0 Hz, 1H), 2.84 (dd, J = 14, 7.0 Hz, 1H), 2.69 (t, J = 7.5 Hz, 2H), 2.06-2.21 (m, 2H).

Claims (3)

Formula (1):

A method for producing a compound or a salt thereof represented by
Formula (2):

(wherein R ¹ is a carboxylic acid-protecting group and R ² is an amino-protecting group);
Formula (3):

(wherein X is a leaving group and R3 is a hydroxyl ^- protecting group) to give the formula (4):

(wherein R ¹ , R ² and R ³ are the same as defined above) to produce a compound represented by
A method for producing a compound represented by the above formula (1), which comprises subjecting the obtained compound represented by the above formula (4) to treatment for removing a protecting group. 2. The production method according to claim 1, further comprising converting the compound represented by formula (2) from optically active methionine. 3. The production method according to claim 2, wherein the optically active methionine is L-methionine or D-methionine.