JPH06145171A - Production of pyrroloquinolinequinone - Google Patents

Abstract

PURPOSE:To obtain the subject compound useful for medicines, etc., efficiently and in high yield by hydrolyzing a specific pyrroloquinolinequinone trimethyl ester in a given pH range. CONSTITUTION:Pyrroloquinolinequinone trimethyl ester of formula I is hydrolyzed under a condition of pH2-11 to give the objective pyrroloquinolinequinone dimethyl ester of formula II.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to dimethyl pyrroloquinoline quinone (4,5-dihydro-4,5-dioxo-1H-pyrrolo [2,3-f] quinoline-2,7,9-tricarboxylic acid). The present invention relates to a method for producing an ester body. Furthermore, specifically, 2,7-dimethoxycarbonyl-9-
Carboxy-4,5-dihydro-4,5-dioxo-1
The present invention relates to a method for producing H-pyrrolo [2,3-f] quinoline. This compound is a derivative of pyrroloquinoline quinone,
It is an important substance that can be developed as a drug.

[0002]

BACKGROUND OF THE INVENTION Pyrroloquinoline quinone (4,5-dihydro-4,5-dioxo-1H-pyrrolo [2,3-f] quinoline-2,7,9-tricarboxylic acid, sometimes referred to as PQQ hereinafter. ) Is not limited to bacteria, but eukaryotic molds,
It exists in yeast and plays an important role as a coenzyme. In addition, PQQ has been used until recently to promote cell growth (Japanese Patent Laid-Open Nos. 61-58584 and 63-2337).
83), anti-cataract effect (JP-A-63-41421).
No. 63-48215, No. 64-2931
3), a preventive / therapeutic action for liver diseases (JP-A-63-19).
2717), wound healing action (JP-A-63-152)
No. 309), anti-allergic action (JP-A-63-17).
493), reverse transcriptase inhibitory action (JP-A-63-1).
56724, JP-A-1-29313) and glyoxalase I inhibitory action-anticancer action (JP-A-63).
-215628, JP-A-1-29313)
Many physiological activities have been revealed.

However, it has recently been revealed that PQQ has nephrotoxicity (Watanabe et al., Hiroshima J. Me.
d. Sci., Vol. 38, No. 1, pp. 49-51 (1989)). In the process of developing a safe PQQ derivative with low toxicity and nephrotoxicity, many ester derivatives have been known (for example, JP-A-2-262581, JP-A-2-279798, JP-A-3). -123781
Gazette, Japanese Patent Application No. 3-259907). Of these, 2,7
A dimethyl ester in which the position is methyl esterified is known, but the synthesis method is disclosed in Japanese Patent Application No. 3-259909, in which PQQ trimethyl ester is hydrolyzed once to give 2
A PQQ monoester in which only the position was methyl esterified was obtained, which was also selectively produced by esterifying only the carboxylic acid in the 7 position.

PQQ can be produced by a methanol-assimilating bacterium or obtained by long-term synthesis. However, since any of these methods is expensive, a more efficient method for producing the above diester is required. Was wanted.

[0005]

DISCLOSURE OF THE INVENTION Problem to be Solved by the Invention
In light of the above circumstances, as a result of intensive studies on a method for producing an ester derivative of PQQ, a simpler production method than the conventional one was found, and the present invention was completed. That is,
In producing the dimethyl ester of pyrroloquinoline quinone represented by,

[0006]

[Chemical 3] A method for producing a trimethyl ester of pyrroloquinoline quinone represented by Chemical formula 4 by hydrolyzing under conditions of pH 2 to 11 was discovered.

[0007]

[Chemical 4] The present invention will be described in more detail below.

Of the seven possible types of simple methyl ester form of PQQ, trimethyl ester in which all carboxyl groups are methylated (hereinafter sometimes referred to as PQQ-TME, Duine et al., Eur. J. Biochem ., 1980, 108,
187) Monoester in which only the carboxyl group at the 2-position is methylated (hereinafter sometimes referred to as PQQ-2-ME, Ohshiro et al., Chem. Exp., 1, 315, 1986, Hamashishi et al., Nippon Pharmaceutical Co., Ltd. Meeting 109th Annual Meeting II, p39, 1989),
Dimethyl ester methylated at the 7- and 9-positions
-262581), diesters in which the 2-position and the 7-position to the 9-position are methylated (respectively PQQ-2,
7-ME and PQQ-2,9-ME, which are sometimes referred to as Japanese Patent Application No. 3-259907, Ohshiro et al., Proceedings of the 61st Annual Meeting of the Chemical Society of Japan, II, p2042, 1991) are known. ing.

Of these, PQQ-2-ME is PQQ-T
By partial hydrolysis of ME, PQQ-2,9-ME can also be obtained by partial hydrolysis of PQQ trimethyl ester under strong acidity, while PQQ-2,7-ME is obtained by PQQ-2,7-ME.
-ME is obtained by further methyl esterification under acidic conditions.

PQQ can be produced by a methanol-assimilating bacterium or obtained by long-term synthesis. However, since PQQ is expensive in any method, the above PQQ is used.
A more efficient method has been desired in the production of esters and the like.

Ohshiro et al. (Chem. Exp., 1, 315, 1986) P
PQ when hydrolyzing QQ-TME with carbonate
It has been reported that Q-2-ME was obtained (Chem. Ex.
p., 1, 315, 1986), and does not mention whether PQQ diester via PQQ-2,7-ME or PQQ-2,9-ME. Therefore, PQQ-TM
Although the partial hydrolysis of E was examined in detail, unfortunately, the intermediate product using carbonate was PQQ-2,9-M.
It was E. The present inventors further investigated the hydrolysis of PQQ-TME under a wide range of pH conditions, and as a result, the specific p
In the H range, PQQ-2,7-ME shown in Chemical formula 3
Was found to be an intermediate main product, and it was found to be practical as a production method.

PQQ-2,7-M shown in Chemical formula 3 below
The production method of E will be described in more detail. The concentration range of PQQ-TME in this reaction is not particularly limited, and a concentration range of 0.001 to 1000 mM is usually preferable.
The most important factor in this reaction is the pH of the reaction solution, which can be adjusted by externally adding a preparation solution or by using a buffer solution. In addition, PQQ-
The advantageous pH range for the production of 2,7-Me is from 2 to 11, more preferably from 2 to 7 without PQQ-2-ME by-product. Therefore, if the concentration of the substrate is not high, the reaction can be performed using distilled water.

The reaction temperature and the reaction time are appropriately determined depending on the pH of the reaction. In particular, in the present reaction, if the temperature and the time are not properly controlled, the hydrolysis further proceeds and PQQ-2-
Converted to ME. Usually the reaction temperature is 10-100 ° C
In this range, the reaction time is 0.2 to 100 hours, and it is necessary to appropriately select the reaction time suitable for the reaction temperature and pH.

Since PQQ-TME has low solubility in an aqueous solution, it is preferable to use a mixed solvent of an organic solvent and an aqueous solution whose pH is adjusted. In this case, examples of the organic solvent include dioxane, monoglyme, acetonitrile, dimethyl sulfoxide, dimethylformamide, dimethylacetamide and the like, which are miscible with water. PQQ-2,7-
Separation and purification methods of ME from the reaction mixture include concentration, extraction,
It can be carried out by appropriately adopting operations such as column chromatography, recrystallization, centrifugation and drying.

[0015]

EXAMPLES The present invention will be described in more detail by way of examples, but the present invention is not limited to these examples. Example 1 2,7-Dimethoxycarbonyl-9-carboxy-4,
5-dihydro-4,5-dioxo-1H-pyrrolo [2,2
Effect of pH on formation of 3-f] quinoline PQQ trimethyl ester 15 mg (0.40 mmo
1) was dissolved in 30 ml of dimethylformamide, to which 30 ml of boric acid or phosphate buffer of each pH was added. The reaction mixture was heated at 42 ° C. and sampled over time to quantify the reaction substrate and product by HPLC analysis. The HPLC analysis conditions are as follows. The reaction results are shown in Tables 1 to 3 below.

Eluent: Gradient time (minutes) from Solution A to Solution B as follows: Solution A% Solution B% ──────────────────── 0 100 0 2 0 100 100 0 100 ─────────────────── Solution A: water / phosphoric acid / 30% NaOH = 991/2/7 solution B; water / methanol / phosphoric acid / 30% NaOH = 363/635/2/7 Flow rate: 1.5 ml / min Column: Waters NOVOPAK C 18, 3.9 mm
Φ × 150mm Column temperature: 24 ℃ Detection: UV (259nm) Sample injection volume: 20μl

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

Experiment No. 1 in Table 1 is the pH condition for hydrolysis of Oshiro et al., And shows that the intermediate is PQQ-2,9-ME instead of PQQ-2,7-ME. . On the other hand, when the pH of the reaction system is lowered, PQQ-2,
7-ME by-product was observed, and PQQ-at pH 2 to 10.
2,7-ME is the main product.

Example 2 2,7-dimethoxycarbonyl-9-carboxy-4,
5-dihydro-4,5-dioxo-1H-pyrrolo [2,2
3-f] Production of quinoline (when phosphate buffer is used) PQQ trimethyl ester 150 mg (0.403 mm
ol) was dissolved in 5 ml of dimethylformamide, and this solution was added to a phosphate buffer (0.02 mol) 9 having a pH of 6.0.
The mixture was added to a mixed solution of 0 ml and 70 ml of dimethylformamide, and the mixture was heated with stirring at 56 ° C. for 6 hours. After diluting the reaction mixture with 100 ml of distilled water, pH was adjusted with 6N hydrochloric acid.
Adjusted to 1.5. After cooling in an ice bath, the precipitated crystals were separated by filtration and dried, and 132 mg (yield 91.8%, HPLC
The title compound with a purity of 98.7%) was obtained as red crystals.

The physical properties of this compound are as follows. Melting point 244-245 ° C. (decomposition) Hydrogen nuclear magnetic resonance spectrum (deuterium dimethyl sulfoxide,
Tetramethylsilane internal standard); δ = 3.88 (s, 3
H), 3.94 (s, 3H), 7.28 (s, 1H), 8.63 (s, 1H), 14.22 (s,
1H) ppm.

Example 3 2,7-Dimethoxycarbonyl-9-carboxy-4,
5-dihydro-4,5-dioxo-1H-pyrrolo [2,2
3-f] Production of quinoline (when using distilled water) PQQ trimethyl ester 150 mg (0.403 mm
ol) in 75 ml of dimethylformamide,
To this solution was added 75 ml of distilled water (pH of this solution was 6.6). This mixed solution was heated and stirred at 80 ° C. for 24 hours. The reaction mixture was diluted with 100 ml of distilled water and then adjusted to pH 1.5 with 6N hydrochloric acid. After cooling in an ice bath, the precipitated crystals were separated by filtration and dried to obtain 124 mg (yield 86.2%, HPLC purity 97.7%) of the title compound as red crystals. Melting point 243-245 ° C (decomposition)

[0024]

According to the present invention, the diester compound of pyrroloquinoliquinone can be produced more easily than the conventional method.

Front page continuation (72) Inventor Hisaya Araki 182 Shinwari, Tayuhama, Niigata City, Niigata Prefecture Mitsubishi Gas Chemical Co., Ltd. Niigata Research Center

Claims (1)

[Claims] 1. When producing a dimethyl ester of pyrroloquinoline quinone represented by Chemical formula 1, A process for producing a trimethyl ester of pyrroloquinoline quinone represented by Chemical formula 2 under the conditions of pH 2 to 11. [Chemical 2]