JP2011011976A - Method for producing pteridine compound and l-biopterin - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method enabling to industrially advantageously obtain a pteridine compound in a good yield.SOLUTION: The method for producing the pteridine compound represented by formula (3) (wherein Ris H or a hydroxyl group-protecting group) is characterized by condensing an optically active (2R, 3S)-epoxy-4S-alkoxypentanal with 2,5,6-triamino-4-cyclohexyloxypyrimidine in the presence of an acid having a pKa of ≤4.5 in a polar solvent and then oxidizing the product.

Description

  The present invention relates to a method for producing L-biopterin and a pteridine compound which is a precursor thereof.

  L-biopterin is a compound useful as a synthetic intermediate for pharmaceutical compounds, and is used as an important synthetic intermediate for sapropterin hydrochloride, which is a therapeutic drug for inborn errors of metabolism, for example.

  Conventionally, as a method for producing L-biopterin, for example, the following methods are known. That is, starting from ethyl lactate, 2,3-diacetoxy-4-hydroxypentanal (a1), which is a 5-deoxyarabinose derivative, is obtained according to the following scheme A, and then phenylhydrazine acts on the compound (a1). To obtain phenylhydrazone (b1), then condensing the compound (b1) and the pyrimidine compound, oxidizing them to obtain an acetylpteridine compound (3A), and deacetylating the compound (3A) to give L-biopterin A method for obtaining (4) is known (see Patent Document 1).

  Further, using tartaric acid as a starting material, 5-deoxyarabinose (a2) is obtained according to the following scheme B, and then phenylhydrazine is allowed to act on the compound (a2) to acetylate the hydroxyl group to protect the hydroxyl group ( b2), then condensing the compound (b2) with the pyrimidine compound, oxidizing to give an acetylpteridine compound (3B), and deacetylating the compound (3B) to give L-biopterin (4) There is also a method (see Non-Patent Document 1).

  Furthermore, 5-deoxyarabinose (a3) was obtained from L-rhamnose as a starting material according to the following scheme C, and then phenylhydrazine was allowed to act on the compound (a3) to acetylate the hydroxyl group to protect the hydroxyl group. A hydrazone (b2) is obtained, then the compound (b2) and a pyrimidine compound are condensed, oxidized to obtain an acetylpteridine compound (3B), and the compound (3B) is deacetylated to give L-biopterin (4) There is also known a method of obtaining (see Patent Document 2).

JP-A-01-221380 JP 59-186986 A A. Fernandez et. Al., J. Org. Chem. 8698 (1996)

  However, the conventional method for producing L-biopterin has the following problems. That is, in the production method described in Patent Document 1, inexpensive and easily available ethyl lactate is used as a starting material, but the production process is complicated and the condensation reaction is low in yield. As a result, the total yield from ethyl lactate is very low at 7.9%. Also, in the production method described in Non-Patent Document 1, although tartaric acid that is inexpensive and easily available is used as a starting material, the condensation reaction has a low yield as in Patent Document 1, and the total yield from tartaric acid. The rate is also low at 8.6%. Furthermore, in the method described in Patent Document 2, 5-deoxyarabinose (a3) can be most efficiently produced, but the condensation reaction has a low yield, and the starting material L-rhamnose is a natural resource. In addition, there is a problem that it is difficult to obtain them in large quantities and the raw material supply is not stable.

Thus, the conventional method for producing L-biopterin is unlikely to be an industrially advantageous method. Therefore, creation of a production method capable of obtaining L-biopterin in an industrially advantageous and high yield is desired. ing.
Therefore, an object of the present invention is to provide a production method capable of obtaining L-biopterin and a pteridine compound, which is a precursor thereof, in an industrially advantageous and high yield.

  In view of the above problems, the present inventors have sought an intermediate to replace 5-deoxyarabinose or a derivative thereof with the intention of constructing a new synthetic route for L-biopterin. As a result, the following formula (I) is obtained. Furthermore, it has been found that optically active epoxy aldehyde can be an equivalent of 5-deoxyarabinose. The present inventors have scrutinized the conditions for the condensation reaction using optically active epoxy aldehyde as an intermediate, and found that the condensation reaction is dramatically accelerated only under specific conditions, leading to the completion of the present invention. It was.

  That is, the present invention provides an optically active epoxy aldehyde compound represented by the following general formula (1) and a pyrimidine compound represented by the following general formula (2) in the presence of an acid having a pKa of 4.5 or less. Provided is a method for producing a pteridine compound represented by the following general formula (3), characterized by condensing in a polar solvent and then oxidizing. The present invention also provides a method for producing L-biopterin, which comprises deprotecting the pteridine compound.

(In the formula, R ¹ represents a hydroxyl-protecting group, and R ² represents a hydrogen atom or a hydroxyl-protecting group.)

  According to the present invention, an optically active epoxy aldehyde compound is used as an intermediate and a condensation reaction with a pyrimidine compound is performed under specific conditions, whereby the condensation reaction can be dramatically accelerated. As a result, L-biopterin and its precursor pteridine compound can be obtained in high yield by simple operation without optical resolution. Therefore, since the production method of the present invention can greatly reduce the labor (number of steps, time, etc.) and cost required for production, L-biopterin on an industrial scale and a pteridine compound as a precursor thereof It is effective for production.

Hereinafter, the present invention will be described in detail.
First, definitions of symbols in each formula used in this specification will be described.
Examples of the hydroxyl protecting group for R ¹ include an alkoxyalkyl group, an aralkyloxyalkyl group, an alkyl group, an aralkyl group, an acyl group, and a silyl group.
As the alkoxyalkyl group, an alkoxyalkyl group having 2 to 8 carbon atoms is preferable, and a methoxymethyl group, an ethoxyethyl group, and a methoxyethoxymethyl group are particularly preferable.
As the aralkyloxyalkyl group, an aralkyloxyalkyl group having 8 to 15 (preferably 8 to 12) carbon atoms is suitable. The aralkyl group may be substituted with an alkyl group having 1 to 6 carbon atoms or an alkoxy group, and examples thereof include a methylbenzyl group, an ethylbenzyl group, and a methoxybenzyl group. Specific examples include benzyloxymethyl group, 2-benzyloxyethyl group, 4-methoxybenzyloxymethyl group, phenethyloxymethyl, phenethyloxyethyl and the like, and benzyloxymethyl group is particularly preferable.
As the alkyl group, a linear, branched or cyclic alkyl group having 1 to 6 (preferably 4 to 6) carbon atoms is preferable. Specific examples include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a cyclohexyl and the like, and an n-butyl group and a cyclohexyl are particularly preferable. .
The aralkyl group is preferably an aralkyl group having 7 to 22 carbon atoms (preferably 7 to 19 carbon atoms), and the aralkyl group may be substituted with an alkyl group or alkoxy group having 1 to 6 carbon atoms. Specific examples include benzyl group, methylbenzyl group, ethylbenzyl group, 4-methoxybenzyl group, phenethyl group, trityl group, 4-methoxytrityl group, 4,4′-dimethoxytrityl group, etc. A trityl group is preferred.

As the acyl group, for example, a formyl group; a linear, branched or cyclic alkyl-carbonyl group having 1 to 12 carbon atoms (for example, an acetyl group, a propionyl group, a butyryl group, an isobutyryl group, A valeryl group, a pivaloyl group, a hexanoyl group); a C6-C14 aryl-carbonyl group (for example, a benzoyl group, a naphthoyl group), etc. are illustrated. Of these, an alkyl-carbonyl group and an aryl-carbonyl group are preferable, and an acetyl group and a benzoyl group are particularly preferable.
As the silyl group, a trimethylsilyl (TMS) group, a triethylsilyl group, a triisopropylsilyl group, a t-butyldimethylsilyl (TBS) group, a t-butyldiphenylsilyl group, a phenyldimethylsilyl group, and the like are preferable. A butyldimethylsilyl (TBS) group is preferred.
In addition, allyl group, benzyloxymethyl group, tetrahydropyranyl group, methoxycarbonyl group, 9-fluorenylmethoxycarbonyl group, 2,2,2-trichloroethoxycarbonyl group, benzyloxycarbonyl group, tert-butoxycarbonyl group Examples thereof include tetrahydropyranyl group.
Among these, as the hydroxyl-protecting group for R ¹ , an alkoxyalkyl group and a silyl group are particularly suitable.

Examples of the hydroxyl protecting group for R ² include the same groups as those for R ¹ described above. Among them, a straight chain, branched or cyclic alkyl group having 1 to 6 carbon atoms (preferably 3 to 6) and an allyl group are preferable, and in particular, a cyclohexyl group, an n-butyl group, a pentyl group, and an allyl group Is preferred.

  Next, the manufacturing method of this invention is demonstrated. The production method of the present invention can be represented by the following reaction scheme (see Scheme 1).

(Condensation process)
In the condensation step, an optically active epoxy aldehyde compound represented by the general formula (1) (hereinafter also referred to as “compound (1)”) in a polar solvent in the presence of an acid having a pKa of 4.5 or less, A compound represented by the above general formula (5) (hereinafter referred to as “compound (5)”) is condensed with a pyrimidine compound represented by the above general formula (2) (hereinafter also referred to as “compound (2)”). The order of addition of each reagent is not particularly limited, and can be added sequentially or simultaneously. Among these, it is preferable to sequentially add the acid and the compound (1) into the solution of the compound (2) and the polar solvent.
Compound (1) can be synthesized, for example, by the method described in Tetrahedron Letters, 7847 (2004). Moreover, it is also possible to use an unprotected pyrimidine compound in which the hydroxyl group is not protected as the compound (2). In addition, introduction | transduction of a protecting group can be performed by a well-known method, and the usage-amount of a protecting reagent is 1-20 equivalent normally with respect to a compound (2), Preferably it is 1-2 equivalent, Compound (1 The same applies to the above.

The upper limit of the pKa of the acid used in the present invention is 4.5, but is preferably 4. Thereby, a condensation reaction is accelerated | stimulated rapidly and the production | generation of a by-product can be prevented. Further, from the viewpoint of suppressing the production of by-products, the lower limit of pKa is desirably -7.
As an acid, if pKa is 4.5 or less, an organic acid, an inorganic acid, a solid acid, etc. can be used without limitation. Moreover, this acid can be used individually or in combination of 2 or more types. In the present specification, pKa refers to an acid dissociation constant at 25 ° C., and in the case of a polyvalent acid, is the first acid dissociation constant.
Examples of the organic acid include aliphatic or aromatic carboxylic acid, aliphatic or aromatic sulfonic acid, and the aliphatic or aromatic carboxylic acid may be a monovalent acid or a polyvalent acid. Hereafter, an example of the acid which can be used in this invention is shown.

Examples of the aliphatic carboxylic acid include trifluoroacetic acid, oxalic acid, formic acid, acetylacetic acid, lactic acid, succinic acid, and adipic acid.
Examples of the aromatic carboxylic acid include difluorobenzoic acid, m-fluorobenzoic acid, p-nitrobenzoic acid, benzoic acid and the like.
Examples of the aliphatic sulfonic acid include methanesulfonic acid and trifluoromethanesulfonic acid.
Examples of the aromatic sulfonic acid include benzenesulfonic acid and p-toluenesulfonic acid.
Examples of the solid acid include acidic ion exchange resins such as Dowex (manufactured by Dow Chemical), Nafion (manufactured by DuPont), and DIAION (manufactured by Mitsubishi Chemical), activated clay, silica-alumina, and the like.
Examples of inorganic acids include hydrochloric acid, sulfuric acid, nitric acid, nitrous acid, and the like.
Among these, as the acid, aliphatic carboxylic acid or inorganic acid is preferable, and formic acid and hydrochloric acid are particularly preferable.

The polar solvent is not particularly limited as long as it does not inhibit this reaction, and may be a protic polar solvent or an aprotic polar solvent. A polar solvent can be used individually or in combination of 2 or more types.
As aprotic polar solvents, nitriles such as acetonitrile, propionitrile, benzonitrile; amides such as formamide, N-methylformamide, N, N-dimethylformamide, N, N-dimethylacetamide, hexamethylphosphoric triamide Lactams such as 2-pyrrolidone, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, ε-caprolactam, N-methyl-ε-caprolactam; sulfoxides such as dimethyl sulfoxide; diethyl ether, diisopropyl ether; Ethers such as tetrahydrofuran and dioxane; Ketones such as acetone, methyl ethyl ketone and methyl phenyl ketone; Esters such as ethyl formate, ethyl acetate and ethyl propionate; Halogenated hydrocarbon such as methylene chloride and chloroform Examples include primes and the like.
Protic polar solvents include water; monohydric alcohols such as ethanol, propanol, butanol, pentanol, hexanol; polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin; methyl cellosolve, ethyl cellosolve, methoxypropylene glycol, Examples include cellsolves such as dimethoxypropanol.
As the polar solvent, an aprotic polar solvent is preferable from the viewpoint of suppression of by-products, and in particular, nitriles, particularly acetonitrile, not only suppresses by-products but also can particularly accelerate the condensation reaction. preferable.

The amount of compound (2) to be used is preferably 1 to 2 equivalents, more preferably 1 to 1.5 equivalents, relative to compound (1).
The amount of the acid used is usually 1 equivalent or more with respect to the compound (2) in the case of an acid having a pKa of 3 to 4.5, but it is preferably used in excess. Specifically, it is preferable to use 2 to 20 equivalents, further 5 to 15 equivalents, particularly 12 to 13 equivalents, relative to compound (2). On the other hand, in the case of an acid having a pKa smaller than 3, it is preferable to use an approximately equivalent amount from a catalytic amount to the compound (2), specifically, 0.05 to 1 relative to the compound (2). .2 equivalents, more preferably 0.3-1 equivalents, especially 0.7-1 equivalents.
The amount of the polar solvent to be used is preferably 5 to 50 times mass, more preferably 20 to 30 times mass, with respect to compound (1).
The reaction temperature is preferably 0 to 50 ° C, more preferably 20 to 30 ° C. Moreover, reaction time becomes like this. Preferably it is 0.5 to 24 hours, More preferably, it is 1-2 hours.

  After completion of the reaction, an organic solvent (for example, hydrocarbons such as toluene) and water are added to the reaction solution, and the resulting organic layer is separated by washing with water, and the organic layer is concentrated to obtain compound (5). In the present invention, the compound (5) can be subjected to the oxidation step described later without isolation and purification.

(Oxidation process)
An oxidation process is a process of oxidizing a compound (5) and obtaining a compound (3). The oxidation of the compound (5) can be carried out by a known method. For example, the compound (5) is dehydrogenated in the presence of iodine or hydrogen peroxide or in the coexistence of iodine and hydrogen peroxide. To form a double bond.
The oxidation step can be performed continuously without isolating the compound (5) after completion of the condensation step. In this case, iodine and hydrogen peroxide are simultaneously added to the reaction solution after the condensation reaction, or iodine is added, and then hydrogen peroxide is added to subject the compound (5) to a dehydrogenation reaction. Alternatively, iodine or hydrogen peroxide may be added alone to the reaction solution after the condensation reaction to subject the compound (5) to a dehydrogenation reaction. In addition, hydrogen peroxide is normally used with the form of aqueous solution, The density | concentration is 30-35 mass%.

When using iodine independently, the usage-amount of iodine becomes like this. Preferably it is 1.5-3 equivalent with respect to a compound (1), More preferably, it is 1.5-2 equivalent.
When hydrogen peroxide is used alone, the amount of hydrogen peroxide used is preferably 2 to 10 equivalents, more preferably 3 to 5 equivalents, relative to compound (1).
When iodine and hydrogen peroxide are used in combination, the amount of iodine used is preferably 0.1 to 2 equivalents, more preferably 0.1 to 1 equivalents relative to compound (1). The amount is preferably 2 to 10 equivalents, more preferably 3 to 5 equivalents, relative to compound (1). In addition, the usage-amount of hydrogen peroxide is a ratio of an active ingredient.
The reaction temperature is preferably 0 to 50 ° C, more preferably 20 to 30 ° C. Moreover, reaction time becomes like this. Preferably it is 0.5 to 24 hours, More preferably, it is 12 to 24 hours.

  After completion of the reaction, a reducing agent such as an aqueous sodium hydrogen sulfite solution is poured into the reaction solution and extracted with a solvent such as chloroform. The obtained organic layer is dried over anhydrous magnesium sulfate and then filtered. The filtrate is concentrated under reduced pressure, and the residue is purified by column chromatography, whereby compound (3) can be obtained in good yield.

(Deprotection process)
Deprotection step, compound (3) -OR ¹ and protecting group in -OR ² R ¹ and R ² are removed in, L- biopterin (hereinafter, "Compound (4)" and also referred to) is a step of obtaining a .
The removal method can be selected depending on the kind of the protecting group. For example, the compound (3) is hydrolyzed in a solvent in the presence of an acid or a base.
As the acid, a strong acid is preferably used, and specific examples include inorganic acids such as hydrochloric acid and sulfuric acid; and organic acids such as trichloroacetic acid, trifluoroacetic acid and p-toluenesulfonic acid.
Examples of the base include alkali hydroxides such as sodium hydroxide and potassium hydroxide.
As the usage-amount of an acid or a base, it is 0.1-20 equivalent normally with respect to a compound (3), Preferably it is 1-20 equivalent.

Any solvent may be used as long as it does not inhibit this reaction. Examples thereof include esters such as ethyl acetate, isopropyl acetate and butyl acetate; alcohols such as methanol, ethanol and isopropyl alcohol; ketones such as acetone and methyl isobutyl ketone. Examples: water and the like. These can be used alone or in combination of two or more.
The amount of the solvent to be used is preferably 3 to 50 times mass, more preferably 5 to 20 times mass, with respect to compound (3).
The reaction temperature is preferably 0 ° C. to heating reflux temperature, more preferably room temperature to heating reflux temperature. Moreover, reaction time becomes like this. Preferably it is 2 to 24 hours, More preferably, it is 12 to 24 hours.

  After completion of the reaction, the reaction solution is neutralized with an acid or basic aqueous solution (for example, aqueous ammonia, aqueous sodium hydroxide, aqueous sodium hydrogen carbonate), and then the precipitated crystals are collected by filtration to obtain compound (4). Can do.

  Thus, in the production method of the present invention, it is possible to isolate the pteridine compound and L-biopterin with high yield by simple means without using optical resolution. Therefore, according to the production method of the present invention, labor (number of steps, time, etc.) and cost required for production can be greatly reduced.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

Example 1
168 mg (0.75 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine was dissolved in 5 mL of acetonitrile, and 431 mg (pKa3.54, 9.37 mmol, 12.5 equivalents) of formic acid, (2R, 3S) -epoxy-4S-methoxy 100 mg (0.62 mmol) of methoxypentanal was added, and a condensation reaction was performed at room temperature for 1 hour. Next, 16 mg (0.06 mmol) of iodine and 354 mg (3.12 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide, and acetonitrile was removed by distillation under reduced pressure. Next, water was added to the concentrate, and the mixture was extracted with chloroform. The organic layer was further dehydrated and concentrated under reduced pressure, and the orange crude product was purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). Separated and purified. As a yellow amorphous, 142 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 62%.

¹ H-NMR (400MHz) δ (CDCl ₃ ) 1.25 (d, 3H, J = 6.0Hz), 1.30-1.50 (m, 3H), 1.61-1.74 (m, 3H), 1.83-1.90 (m, 2H) , 2.05-2.14 (m, 2H), 3.28 (s, 3H), 3.99 (dq, 1H, J = 5.2, 6.0Hz), 4.61 (d, 1H, J = 7.0Hz), 4.70 (d, 1H, J = 7.0Hz), 4.90 (d, 1H, J = 5.2Hz), 5.30 (tt, 1H, J = 4.0, 5.6Hz), 5.88 (br-s, 2H), 8.96 (s, 1H)

(Example 2)
2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxy) was prepared in the same manner as in Example 1 except that the amount of formic acid used relative to the pyrimidine compound was changed to 7.5 equivalents (259 mg, 5.62 mmol). Methoxy) propylpteridine was obtained in 52% yield. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 3)
2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxy) was prepared in the same manner as in Example 1 except that the amount of formic acid used relative to the pyrimidine compound was changed to 14.5 equivalents (500 mg, 10.9 mmol). Methoxy) propylpteridine was obtained with a yield of 51%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

Example 4
168 mg (0.75 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine was dissolved in 5 mL of acetonitrile, and 56 mg (pKa1.04, 0.62 mmol, 0.83 equivalent) of oxalic acid, (2R, 3S) -epoxy-4S- 100 mg (0.62 mmol) of methoxymethoxypentanal was added, and a condensation reaction was performed at room temperature for 1 hour. Next, 16 mg (0.06 mmol) of iodine and 354 mg (3.12 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide, and acetonitrile was removed by distillation under reduced pressure. Next, water was added to the concentrate, and the mixture was extracted with chloroform. The organic layer was further dehydrated and concentrated under reduced pressure, and the orange crude product was purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). Separated and purified. As a yellow amorphous, 102 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 45%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 5)
168 mg (0.75 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine was dissolved in 5 mL of acetonitrile, and 85 mg (pKa0.3, 0.75 mmol, 1 equivalent) of trifluoroacetic acid, (2R, 3S) -epoxy-4S -100 mg (0.62 mmol) of methoxymethoxypentanal was added, and a condensation reaction was carried out at room temperature for 1 hour. Next, 16 mg (0.06 mmol) of iodine and 354 mg (3.12 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide, and acetonitrile was removed by distillation under reduced pressure. Next, water was added to the concentrate, and the mixture was extracted with chloroform. The organic layer was further dehydrated and concentrated under reduced pressure, and the orange crude product was purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). Separated and purified. As a yellow amorphous substance, 109 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 48%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 6)
2-Amino-4-cyclohexyloxy-6- (1R-hydroxy-2S) was prepared in the same manner as in Example 3 except that the amount of trifluoroacetic acid used relative to the pyrimidine compound was changed to 0.41 equivalent (36 mg, 0.31 mmol). -Methoxymethoxy) propylpteridine was obtained with a yield of 49%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 7)
84 mg (0.38 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine was dissolved in 3 mL of acetonitrile, and 104 μL of 3N hydrochloric acid (pKa-7, 0.31 mmol, 0.82 equivalent), (2R, 3S) -epoxy-4S- 50 mg (0.31 mmol) of methoxymethoxypentanal was added, and a condensation reaction was performed at room temperature for 1 hour. Next, 8 mg (0.03 mmol) of iodine and 177 mg (1.56 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide, and acetonitrile was removed by distillation under reduced pressure. Next, water was added to the concentrate, and the mixture was extracted with chloroform. The organic layer was further dehydrated and concentrated under reduced pressure, and the orange crude product was purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). Separated and purified. As a yellow amorphous, 71 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 63%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 8)
2-Amino-4-cyclohexyloxy-6- (1R-hydroxy-2S) was prepared in the same manner as in Example 5 except that the amount of hydrochloric acid used relative to the pyrimidine compound was changed to 0.42 equivalents (52 μL of 3N hydrochloric acid, 0.16 mmol). -Methoxymethoxy) propylpteridine was obtained with a yield of 52%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

Example 9
84 mg (0.38 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine is dissolved in 3 mL of ethyl acetate, and 215 mg (4.67 mmol, 12.3 equivalents) of formic acid, (2R, 3S) -epoxy-4S-methoxymethoxypentanal 50 mg (0.31 mmol) was added, and a condensation reaction was performed at room temperature for 1 hour. Next, 8 mg (0.03 mmol) of iodine and 177 mg (1.56 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Then, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide. The organic layer was dehydrated and concentrated under reduced pressure. The orange crude product was separated and purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). As a yellow amorphous, 52 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 46%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Example 10)
2,5,6-Triamino-4-pyrimidinol sulfate 351 mg (1.47 mmol) and hydrosulfite sodium 35 mg were dissolved in 6 mL of 1M aqueous sodium hydroxide solution, and neutralized to pH = 7 by adding hydrochloric acid. The precipitated crystals were collected by filtration to obtain 2,5,6-triamino-4-pyrimidinol. The obtained 2,5,6-triamino-4-pyrimidinol was suspended in a mixture of 2 mL of water and 2 mL of acetonitrile, and 366 mg (7.95 mmol) of formic acid, 196 mg (1.22) of (2R, 3S) -epoxy-4S-methoxymethoxypentanal. mmol) was added, and a reaction condensation reaction was performed at room temperature for 1 hour. Next, 700 mg (6.17 mmol) of 30% aqueous hydrogen peroxide was added to the reaction solution, and an oxidation reaction was performed at room temperature for 12 hours. Next, the precipitated crystals were collected by filtration, washed with water, and dried under reduced pressure at 50 ° C. overnight. As brown crystals, 114 mg of 2-amino-4-hydroxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 39%.

¹ H-NMR (400MHz) δ (DMSO-d ₆ ) 1.08 (d, 3H, J = 6.0Hz), 3.06 (s, 3H), 3.98 (dq, 1H, J = 5.6, 6.0Hz), 4.52 (d , 1H, J = 6.6Hz), 4.56 (d, 1H, J = 6.6Hz), 4.61 (dd, 1H, J = 4.8, 5.2Hz), 5.73 (d, 1H, J = 4.8Hz), 6.87 (br -s, 2H), 8.72 (s, 1H), 11.38 (br-s, 1H)

(Example 11)
2-Amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine (447 mg, 1.23 mmol) was dissolved in 1 mL of methanol, 5 mL of 3M hydrochloric acid was added, and the mixture was reacted at 50 ° C. for 24 hours. Ammonia water was added to the reaction solution to neutralize to pH = 7, and the precipitated crystals were collected by filtration, washed with water, and dried under reduced pressure overnight at 50 ° C. to give 240 mg of L-biopterin as ocher crystals in a yield of 82%. Obtained.

¹ H-NMR (400MHz) δ (CF ₃ COOD) 1.53 (d, 3H, J = 6.4Hz), 4.69 (m, 1H), 5.43 (d, 1H, J = 3.6Hz), 9.23 (s, 1H)

(Example 12)
104 mg (0.37 mmol) of 2-amino-4-hydroxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was dissolved in 1 mL of 3M hydrochloric acid and reacted at 50 ° C. for 4 hours. Aqueous ammonia was added to the reaction solution to neutralize to pH = 7, and the precipitated crystals were collected by filtration, washed with water, and dried under reduced pressure at 50 ° C. overnight to obtain 74 mg of L-biopterin as ocher crystals in a yield of 84%. Obtained. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 11.

(Comparative Example 1)
168 mg (0.75 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine was dissolved in 5 mL of acetonitrile, and 562 mg (pKa4.74, 9.37 mmol, 12.5 equiv) of acetic acid, (2R, 3S) -epoxy-4S-methoxy 100 mg (0.62 mmol) of methoxypentanal was added, and a condensation reaction was performed at room temperature for 14 hours. Next, 16 mg (0.06 mmol) of iodine and 354 mg (3.12 mmol) of 30% aqueous hydrogen peroxide were added to the reaction solution, and an oxidation reaction was performed at room temperature for 24 hours. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess peroxide, and acetonitrile was removed by distillation under reduced pressure. Next, water was added to the concentrate, and the mixture was extracted with chloroform. The organic layer was further dehydrated and concentrated under reduced pressure, and the orange crude product was purified by silica gel chromatography (SiO ₂ : 1.5 g, ethyl acetate: methanol = 50: 1). Separated and purified. As a yellow amorphous substance, 69 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 30%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

(Comparative Example 2)
Dissolve 463 mg (2.08 mmol) of 2,5,6-triamino-4-cyclohexyloxypyrimidine in 24 mL of methanol, add 277 mg (1.73 mmol) of (2R, 3S) -epoxy-4S-methoxymethoxypentanal, and neutral conditions At room temperature for 17 hours. Subsequently, 1.19 g (25.9 mmol) of formic acid and 540 mg (2.13 mmol) of formic acid were added to the reaction solution, and an oxidation reaction was performed at room temperature for 1 hour. Next, an aqueous sodium hydrogen sulfite solution was added to remove excess iodine, and methanol was removed by distillation under reduced pressure. Next, water is added to the concentrate, followed by extraction with chloroform. The organic layer is further dehydrated and concentrated under reduced pressure, and the orange crude product is separated and purified by silica gel chromatography (SiO ₂ : 10 g, chloroform: methanol = 30: 1). did. As a yellow amorphous, 203 mg of 2-amino-4-cyclohexyloxy-6- (1R-hydroxy-2S-methoxymethoxy) propylpteridine was obtained with a yield of 39%. In addition, it was confirmed that the obtained compound was in agreement with the spectrum data described in Example 1.

Claims (7)

The following general formula (1);

(In the formula, R ¹ represents a hydroxyl-protecting group.)
An optically active epoxy aldehyde compound represented by the following general formula (2);

(In the formula, R ² represents a hydrogen atom or a hydroxyl-protecting group.)
The following general formula (3), wherein the pyrimidine compound is condensed with a pyrimidine compound in a polar solvent in the presence of an acid having a pKa of 4.5 or less, and then oxidized.

(In the formula, R ¹ and R ² are as defined above.)
The manufacturing method of the pteridine compound represented by these. The following general formula (1);

(In the formula, R ¹ represents a hydroxyl-protecting group.)
An optically active epoxy aldehyde compound represented by the following general formula (2);

(In the formula, R ² represents a hydrogen atom or a hydroxyl-protecting group.)
Is condensed in a polar solvent in the presence of an acid having a pKa of 4.5 or less, and then oxidized to give the following general formula (3);

(In the formula, R ¹ and R ² are as defined above.)
And then deprotecting the pteridine compound. A method for producing L-biopterin, comprising:   The production method according to claim 1 or 2, wherein the acid is an aliphatic carboxylic acid or an inorganic acid.   The production method according to claim 3, wherein the aliphatic carboxylic acid is at least one selected from trifluoroacetic acid, oxalic acid, formic acid, acetylacetic acid, lactic acid, succinic acid, and adipic acid.   The production method according to claim 3, wherein the inorganic acid is hydrochloric acid.   The manufacturing method as described in any one of Claims 1-5 whose polar solvent is an aprotic polar solvent.   The production method according to claim 6, wherein the aprotic solvent is at least one selected from nitriles, amides, lactams, sulfoxides, ethers, esters, ketones and halogenated hydrocarbons.