Preparation method of nebivolol

Abstract

The invention discloses a preparation method of nebivolol, which combines an enzyme method and a chemical method, and integrates enzyme selectivity and operability of the chemical method. Meanwhile, nebivolol is constructed by adopting a brand new intermediate, chiral center construction is efficient and convenient, the chemical purity and optical purity of the product meet the quality requirements of raw material medicines, atoms are more economical, preparation is more efficient, and industrialization is facilitated.

Description

Technical Field

[0001] The present invention relates to a preparation method of nebivolol, and particularly to a preparation method of nebivolol that is conducive to industrialization. Background Art

[0002] Nebivolol ((S,R,R,R)-configuration and (R,S,S,S)-configuration 1:1 mixture) is a selective β-blocker with vasodilatory effects, mainly used for the treatment of essential hypertension. It combines the effects of β-blockers and vasodilators, does not cause vasoconstriction when exerting β-blocking effects, does not cause reflex tachycardia when exerting vasodilatory effects, and has good tolerance for heart failure patients.

[0003]

[0004] The synthesis methods of DL-nebivolol disclosed in EP0145067, US4654362, and EP0334429 first react (2R,2'R)-6-fluoro-2-(2'-oxiranyl)chroman and (2S,2'S)-6-fluoro-2-(2'-oxiranyl)chroman with benzylamine respectively, and then react with (2S,2'R)-6-fluoro-2-(2'-oxiranyl)chroman and (2R,2'S)-6-fluoro-2-(2'-oxiranyl)chroman, and finally hydrogenate them respectively to obtain nebivolol. This method uses four 6-fluoro-2-(2'-oxiranyl)chromans containing two different chiral centers, and all these four compounds need to be prepared by chiral resolution or asymmetric synthesis respectively, with a very high degree of process complexity and difficulty in industrialization.

[0005] Summary of the Invention

[0006] Object of the Invention: The present invention aims to provide a preparation method of nebivolol with a novel route, high preparation efficiency, and suitability for industrialization.

[0007] Technical Solution: The preparation method of nebivolol described in the present invention comprises the following steps:

[0008] (1) Prepare racemic 6-fluorochroman-2-carboxylic acid into racemic methyl 6-fluorochroman-2-carboxylate, and then selectively hydrolyze the S-configuration methyl 6-fluorochroman-2-carboxylate therein with ester hydrolase to obtain S-configuration 6-fluorochroman-2-carboxylic acid S-01; then hydrolyze the R-configuration methyl 6-fluorochroman-2-carboxylate therein with sodium hydroxide or potassium hydroxide to obtain R-configuration 6-fluorochroman-2-carboxylic acid R-01;

[0009]

[0010] (2) The S-configured 6-fluorochroman-2-carboxylic acid S-01 and the R-configured 6-fluorochroman-2-carboxylic acid R-01 are respectively prepared into chloroketones S-02 and R-02 through substitution, removal, esterification, chlorination, and acidolysis reactions.

[0011]

[0012] (3) The chloroketone S-02 is subjected to benzylamine substitution and then undergoes a substitution reaction with the chloroketone R-02 to obtain the intermediate 03.

[0013]

[0014] (4) The intermediate 03 is chirally reduced to the intermediate L-04 by the carbonyl reductase E1, and the intermediate 03 is chirally reduced to the intermediate D-04 by the carbonyl reductase E2.

[0015]

[0016] (5) The intermediates L-04 and D-04 are respectively deprotected, and the crystals are combined and crystallized to obtain nebivolol.

[0017]

[0018] The present invention designs a novel, highly efficient, and industrialization-suitable preparation method of nebivolol with the aid of a selective ester hydrolase and a chiral carbonyl reductase. First, two configurations of 6-fluorochroman-2-carboxylic acid are respectively prepared by enzymatic hydrolysis combined with chemical hydrolysis. That is, the S-configured 6-fluorochroman-2-carboxylic acid methyl ester is hydrolyzed by the selective ester hydrolase to obtain the S-configured 6-fluorochroman-2-carboxylic acid; then the R-configured 6-fluorochroman-2-carboxylic acid methyl ester is hydrolyzed by a chemical method to obtain the R-configured 6-fluorochroman-2-carboxylic acid. A synthetic route for preparing nebivolol via the intermediate 03 is proposed for the first time. The reductase is used to simultaneously reduce two carbonyl groups to obtain a hydroxyl product with chiral retention, more efficiently realizing the construction of the chiral center of nebivolol, and finally obtaining nebivolol with an SRRR / RSSS configuration ratio of (49.5 - 50.5):(50.5 - 49.5).

[0019] Preferably, the ester hydrolase described in step (1) is selected from the ester hydrolase SZ-0138E.

[0020] Preferably, the dosage ratio of the ester hydrolase described in step (1) to the racemic 6-fluorochroman-2-carboxylic acid methyl ester is 0.55 - 0.65 w / w, and the activity of the hydrolase is not less than 10 U / g.

[0021] More preferably, the dosage ratio of the ester hydrolase described in step (1) to the racemic 6-fluorochroman-2-carboxylic acid methyl ester is 0.6 w / w.

[0022] Preferably, the reaction temperature of the ester hydrolase in step (1) is 30-35 °C, and the pH value of the reaction system is 6.5-7.0.

[0023] More preferably, the ester hydrolase reacts in a 1.0 M PBS buffer solution with a pH value of 7.0.

[0024] More preferably, the pH value of the reaction system is maintained at 6.5-7.0 with an aqueous solution of sodium carbonate or sodium hydroxide.

[0025] Even more preferably, the pH value of the reaction system is maintained at 6.5-7.0 with a 10% aqueous solution of sodium carbonate or a 2% aqueous solution of sodium hydroxide.

[0026] Preferably, the methyl (6-fluorochroman-2-yl)carboxylate obtained by racemization in step (1) is first hydrolyzed by an ester hydrolase to isolate S-(6-fluorochroman-2-yl)carboxylic acid S-01, and then the reaction residue is continuously hydrolyzed with sodium hydroxide or potassium hydroxide to obtain R-(6-fluorochroman-2-yl)carboxylic acid R-01.

[0027] More preferably, the reaction residue is an organic phase system of toluene and dichloromethane.

[0028] Preferably, the carbonyl reductase E1 in step (4) is selected from carbonyl reductase SZ-0135E1, and the carbonyl reductase E2 is selected from carbonyl reductase SZ-0135E2.

[0029] Preferably, the dosage ratio of the carbonyl reductase E1 and the carbonyl reductase E2 to the intermediate 03 in step (4) is 0.3-0.4 w / w, wherein the activities of the carbonyl reductase E1 and the carbonyl reductase E2 are not less than 10 U / g.

[0030] More preferably, the dosage ratio of the carbonyl reductase E1 to the intermediate 03 is 1:3 w / w, and the dosage ratio of the carbonyl reductase E2 to the intermediate 03 is 0.35 w / w.

[0031] Preferably, coenzyme E3 is further added in step (4), and the dosage ratio of coenzyme E3 to the carbonyl reductase E1 is 1:20 w / w, and the dosage ratio of coenzyme E3 to the carbonyl reductase E2 is 1:17.5 w / w.

[0032] Preferably, the reaction temperature of the carbonyl reductase E1 and the carbonyl reductase E2 in step (4) is 30-35 °C, and the pH value of the reaction system is 6.5-7.0.

[0033] Preferably, after the intermediate L-04 and D-04 in step (5) complete the deprotection reaction, the products are respectively filtered, the filtrates are combined, and crystallization is carried out by mixing and stirring at 10-30 °C to obtain nebivolol.

[0034] Further preferably, the mass ratio of the (S,R,R,R)-configuration product to the (R,S,S,S)-configuration product in nebivolol is (49.5-50.5):(50.5-49.5).

[0035] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0036] The enzymatic method is combined with the chemical method, which combines the selectivity of the enzyme and the operability of the chemical method; at the same time, a new intermediate is used to construct nebivolol, the construction of chiral centers is efficient and convenient, the chemical purity and optical purity of the product meet the quality requirements of the raw drug, the atoms are more economical, the preparation is more efficient, and it is conducive to industrialization. Description of the drawings

[0037] Figure 1 It is the HPLC chromatogram of the chemical purity of Example 6;

[0038] Figure 2 It is the HPLC chromatogram of the chiral purity of Example 6;

[0039] Figure 3 It is the HPLC chromatogram of the chemical purity of Example 7;

[0040] Figure 4 It is the HPLC chromatogram of the chiral purity of Example 7. Detailed implementation manners

[0041] The ester hydrolase SZ-0138E, the carbonyl reductase SZ-0135E1, the carbonyl reductase SZ-0135E2, and the coenzyme SZ-0135E3 are from Shangke Biopharmaceuticals (Shanghai) Co., Ltd.

[0042] Example 1: Preparation of optically pure 6-fluorochroman-2-carboxylic acid (S-01 / R-01)

[0043]

[0044] Add 250 g of 6-fluorochroman-2-carboxylic acid and 750 g of anhydrous methanol to the reaction flask, cool down to 0-10 °C with stirring, and dropwise add 182 g of thionyl chloride. The dropping is completed in about 60 min. After the reaction is completed, concentrate under reduced pressure, then add 750 g of toluene and 200 g of 10% NaHCO 3 solution, stir and let it stand for layer separation, discard the aqueous layer, wash the organic layer with water again, and then concentrate to dryness under reduced pressure to obtain 273.1 g of 6-fluorochroman-2-carboxylic acid methyl ester, with a weight yield of 101.9% and an HPLC purity of 99.95%.

[0045] Add 200 g of methyl 6-fluorochroman-2-carboxylate, 1.0 M PBS buffer solution with pH 7.0, and purified water into the reaction flask. Heat up to 30 - 35 °C, then add 120 g of the aqueous solution of ester hydrolase SZ-0138E. Maintain the pH of the system (6.5 - 7.0) by dropwise adding 10% sodium carbonate solution. When the ratio of S-methyl ester / R-methyl ester in the in-process control ≤ 0.5 / 99.5, add 500 g of toluene and 100 g of diatomaceous earth into the reaction solution, stir for more than 30 min, filter, and layer the filtrate.

[0046] Adjust the pH value of the aqueous layer to 1.5 - 2.0 with hydrochloric acid, precipitate solids, filter to obtain 83.1 g of S-configured 6-fluorochroman-2-carboxylic acid (S-01), with a yield of 83.1% and a chiral purity of 99.56% / 0.44%.

[0047] Concentrate the toluene layer until no liquid drips out, add aqueous sodium hydroxide solution and stir for hydrolysis at room temperature. After the reaction ends, adjust the pH value to 1.5 - 2.0 with hydrochloric acid, precipitate solids, filter to obtain 84.3 g of R-configured 6-fluorochroman-2-carboxylic acid (R-01), with a yield of 84.3% and a chiral purity of 0.54% / 99.46%.

[0048] Example 2: Preparation of optically pure 6-fluorochroman-2-carboxylic acid (S-01 / R-01)

[0049] Add 250 g of 6-fluorochroman-2-carboxylic acid and 750 g of anhydrous methanol into the reaction flask. Cool down to 0 - 10 °C with stirring, and dropwise add 182 g of thionyl chloride. Finish the dropping in about 60 min, continue the reaction for 1 - 2 h, terminate the reaction, and concentrate under reduced pressure at 35 - 45 °C until no liquid drips out. Add 750 g of ethyl acetate, stir at room temperature for 30 min, then dropwise add NaHCO 3 solution to adjust the pH value to neutral, let it stand for layering, discard the aqueous layer, wash the organic layer with water again, and then concentrate to dryness under reduced pressure at 45 - 50 °C to obtain 264.4 g of methyl 6-fluorochroman-2-carboxylate, with a weight yield of 98.7% and an HPLC purity of 99.98%.

[0050] Add 200 g of methyl 6-fluorochroman-2-carboxylate and 1.0 M PBS buffer solution with pH 7.0 into the reaction flask. Heat up to 30 - 35 °C, then add 120 g of the aqueous solution of ester hydrolase SZ-0138E. Maintain the pH of the system between 6.5 - 7.0 by dropwise adding 2% sodium hydroxide solution. When the in-process control: ratio of S-methyl ester / R-methyl ester ≤ 0.5 / 99.5, add 500 g of dichloromethane and 100 g of diatomaceous earth into the reaction solution, stir for more than 30 min, filter, and layer the filtrate.

[0051] The pH value of the aqueous layer was adjusted to 1.5-2.0 with hydrochloric acid to precipitate a solid, which was filtered to obtain 84.5 g of S-configuration 6-fluorochroman-2-carboxylic acid (S-01) with a yield of 84.5% and a chiral purity of 99.74% / 0.36%.

[0052] The dichloromethane layer was concentrated until no liquid dripped out, and sodium hydroxide aqueous solution was added to hydrolyze under stirring at room temperature. After the reaction was completed, the oil layer was separated by standing, and the pH value of the aqueous layer was adjusted to 1.5-2.0 with hydrochloric acid to precipitate solids. 82.9 g of R-configuration 6-fluorochroman-2-carboxylic acid (R-01) was obtained by filtration, with a yield of 82.9% and a chiral purity of 99.88% / 0.12%.

[0053] Example 3: Preparation of optically pure chloroketone (S-02)

[0054]

[0055] To a 1000mL four-necked flask, add 68.7g of S-configuration 6-fluorochroman-2-carboxylic acid and 487g of toluene, stir and react at room temperature for 2-3h, then add 65.2g of CDI solid in batches, react at room temperature for 1.5-2.5h, then add dropwise a solution of 60.5g of McBride's acid and acetonitrile, react at room temperature for 2-3h, then add 103.8g of tert-butanol and 103.8g of trifluoroacetic acid, add dropwise, raise the temperature to 60-65℃ and react for more than 16h, after the control is qualified, add water to quench the reaction, wash the organic phase with saturated sodium bicarbonate solution twice and drinking water once, then concentrate under reduced pressure at 40-50℃ until no liquid drips out, and obtain 111g of yellow S-configuration tert-butyl ester oil, HPLC purity 96.0%, chiral purity 98.99% / 1.01%.

[0056] To a 1000 ml reaction bottle, add 110 g of S-configuration tert-butyl ester oil, 400 g of ethyl acetate, and 57.4 g of sodium phosphate, and add 51.8 g of sulfonyl chloride dropwise at low temperature. After the addition is complete, react for 1 to 2 hours and control the temperature to <30°C. Add water dropwise to quench the reaction, wash the organic layer with water again, and then concentrate under reduced pressure at 35 to 40°C to constant weight.

[0057] To the concentrated residue was added 350 g of 94% formic acid, and the mixture was stirred for 4-5 h, and then concentrated under reduced pressure at 45-50 °C to constant weight, and then 105 g of isopropanol was added for recrystallization to obtain 64.8 g of off-white solid S-configuration chloroketone (S-02). The total yield of the two-step reaction was 81.0%, the HPLC purity was 99.88%, and the chiral purity was 99.19% / 0.81%.

[0058] Example 4: Preparation of optically pure chloroketone (R-02)

[0059]

[0060] In a 1000mL four-necked flask, 98.1 g of R-configuration 6-fluorochroman-2-carboxylic acid and 700 g of toluene were added, and the reaction was stirred at room temperature. Then, 93.0 g of CDI solid was added in batches. After the addition was completed, the feed liquid was still not suspended. After reacting at room temperature for 1.5 to 2.5 hours, a solution formed by 86.5 g of McBride's acid and acetonitrile was added dropwise. After reacting at room temperature for another 2 to 3 hours, 148 g of tert-butanol and 148 g of trifluoroacetic acid were added. After the addition was completed, the temperature was raised to 60 to 65 ° C and reacted for more than 16 hours. After the control was qualified, water was added to quench the reaction. The organic phase was washed twice with saturated sodium bicarbonate solution and once with drinking water, and then concentrated under reduced pressure at 40 to 50 ° C until no liquid dripped out, to obtain 168 g of yellow R-configuration tert-butyl ester oil, HPLC purity 95.8%, chiral purity 0.99% / 99.01%.

[0061] To a 1000 ml reaction bottle, add 166 g of R-configuration tert-butyl ester oil, 575 g of ethyl acetate, and 82 g of sodium phosphate. After cooling to 0-5°C under mechanical stirring, add 74 g of sulfonyl chloride dropwise. After the addition is complete, react at 5-15°C for 1-2 h, control the temperature to <30°C, add water dropwise to quench the reaction, wash the organic layer once with water, and then concentrate under reduced pressure at 35-40°C to constant weight.

[0062] To the concentrated residue, add 500 g of 94% formic acid, raise the temperature to 45-50°C and react for 4-5 h. The feed liquid is concentrated under reduced pressure at 45-50°C to constant weight, and then 150 g of toluene is added and concentrated under reduced pressure at 45-50°C. Then, 150 g of isopropanol is added and recrystallized to obtain 96.8 g of off-white solid R-configuration chloroketone (R-02). The total yield of the two-step reaction is 84.7%, the HPLC purity is 99.88%, and the chiral purity is 0.39% / 99.61%.

[0063] Example 5: Preparation of Intermediate 03

[0064]

[0065] Add 23 g of S-configuration chloroketone (S-02) and 250 g of benzylamine to the reaction bottle, stir and heat to 60-65 ° C for more than 16 hours. After the central control is qualified, benzylamine is evaporated under reduced pressure and the residue is recrystallized with isopropanol / n-heptane to obtain 25.6 g of off-white solid with a yield of 85.0%, HPLC purity of 99.5%, and chiral purity of 99.81% / 0.19%.

[0066] 25.0 g of the solid obtained in the previous step, 150 ml of tetrahydrofuran, 20 g of R-configuration chloroketone (R-02), and 10 g of sodium bicarbonate solid were stirred and heated to 55-60 ° C for overnight reaction. After the mid-control was qualified, the solid was filtered out, the filtrate was concentrated to constant weight, and the residue was recrystallized from acetonitrile / water to obtain 34.9 g of white solid with a yield of 85.0% and a HPLC purity of 99.3%.

[0067] Example 6: Preparation of Intermediate L-04

[0068]

[0069] Add 30 g of Intermediate 03 and 300 g of isopropanol to a 1000 ml reaction flask. Under mechanical stirring, heat up to 30 - 35°C, then add an aqueous solution of 0.5 g of coenzyme SZ-0135E3 and an aqueous solution of 10 g of carbonyl reductase SZ-0135E1. After maintaining the reaction for 4 - 6 h, take a sample for in-process control. When the raw material ≤ 0.5%, add 9 g of concentrated hydrochloric acid dropwise to the reaction liquid to precipitate a solid, and stir at room temperature for more than 2 h to obtain 27.9 g of off-white solid L-04 (hydrochloride), with a yield of 85.9%, HPLC purity of 99.78%, and chiral purity of 100.00%.

[0070] Example 7: Preparation of Intermediate D-04

[0071]

[0072] Add 20 g of Intermediate 03 and 200 g of isopropanol to a 1000 ml reaction flask. Under mechanical stirring, heat up to 30 - 35°C, then add an aqueous solution of 0.4 g of coenzyme SZ-0135E3 and an aqueous solution of 7 g of carbonyl reductase SZ-0135E2. After maintaining the reaction for 4 - 6 h, take a sample for in-process control. When the raw material ≤ 0.5%, add 6 g of concentrated hydrochloric acid dropwise to the reaction liquid, and stir at room temperature for more than 2 h to obtain 18.8 g of off-white solid D-04, with a yield of 86.8%, HPLC purity of 99.95%, and chiral purity of 100.00%.

[0073] Example 8: Preparation of Nebivolol

[0074]

[0075] Add 15 g of Intermediate L-04, 135 g of anhydrous methanol, and 1.5 g of activated carbon to a 500 mL four-necked flask, stir and decolorize at 25 - 30°C for more than 30 min, filter, add 0.15 g of 5% palladium-carbon to the filtrate, maintain the reaction for 2 - 3 h, and filter again to obtain filtrate I.

[0076] Take another 500 mL four-necked flask, add 15 g of Intermediate D-04, 135 g of anhydrous methanol, and 1.5 g of activated carbon, stir and decolorize at 25 - 30°C for more than 30 min, filter, add 0.15 g of 5% palladium-carbon to the filtrate, maintain the reaction for 2 - 3 h, and filter again to obtain filtrate II.

[0077] Combine filtrate I and filtrate II, stir at room temperature for more than 1 h to precipitate a solid, and obtain 23.9 g of nebivolol.

Claims

1. A method for preparing nebivolol, characterized in that: The following steps are included: (1) preparing racemic 6-fluorochroman-2-carboxylic acid into racemic 6-fluorochroman-2-carboxylic acid methyl ester, and then selectively hydrolyzing the S-configuration 6-fluorochroman-2-carboxylic acid methyl ester therein into S-configuration 6-fluorochroman-2-carboxylic acid S-01 with an ester hydrolase; and then hydrolyzing the R-configuration 6-fluorochroman-2-carboxylic acid methyl ester therein into R-configuration 6-fluorochroman-2-carboxylic acid R-01 with sodium hydroxide or potassium hydroxide; (2) subjecting S-configuration 6-fluorochroman-2-carboxylic acid S-01 and R-configuration 6-fluorochroman-2-carboxylic acid R-01 to substitution, removal, esterification, chlorination, and acidolysis to obtain chloroketone S-02 and R-02, respectively; (3) Substituting chloroketone S-02 with benzylamine, and then reacting with chloroketone R-02 to obtain intermediate 03; (4) chiral reduction of intermediate 03 to intermediate L-04 using carbonyl reductase E1, and chiral reduction of intermediate 03 to intermediate D-04 using carbonyl reductase E2; (5) Deprotecting the intermediates L-04 and D-04 respectively, combining the filtrates and crystallizing to obtain nebivolol; 2. The preparation method according to claim 1, characterized in that: The esterase described in step (1) is selected from esterase SZ-0138E.

3. The preparation method according to claim 1, characterized in that: In step (1), the ratio of the esterase to the racemic 6-fluorochroman-2-carboxylic acid methyl ester is 0.55-0.65 w / w, wherein the activity of the esterase is not less than 10 U / g.

4. The preparation method according to claim 1, characterized in that: The reaction temperature of the esterase in step (1) is 30-35° C., and the pH value of the reaction system is 6.5-7.

0.

5. The preparation method according to claim 4, characterized in that: The esterase described in step (1) is reacted in a 1.0 M PBS buffer solution with a pH value of 7.

0.

6. The preparation method according to claim 1, characterized in that: In step (1), the racemic 6-fluorochroman-2-carboxylic acid methyl ester is first hydrolyzed by an ester hydrolase to separate the S-configuration 6-fluorochroman-2-carboxylic acid S-01, and then the reaction residue is further hydrolyzed by sodium hydroxide or potassium hydroxide to obtain the R-configuration 6-fluorochroman-2-carboxylic acid R-01.

7. The preparation method according to claim 1, characterized in that: The carbonyl reductase E1 in step (4) is selected from carbonyl reductase SZ-0135E1, and the carbonyl reductase E2 is selected from carbonyl reductase SZ-0135E2.

8. The preparation method according to claim 1, characterized in that: In step (4), the usage ratio of carbonyl reductase E1, carbonyl reductase E2 and intermediate 03 is 0.3-0.4w / w, wherein the activity of carbonyl reductase E1 and carbonyl reductase E2 is not less than 10U / g.

9. The preparation method according to claim 1, characterized in that: In step (4), coenzyme E3 is also added, and the ratio of coenzyme E3 to carbonyl reductase E1 is 1:20 w / w, and the ratio of coenzyme E3 to carbonyl reductase E2 is 1:17.5 w / w.

10. The preparation method according to claim 1, characterized in that: The reaction temperature of the carbonyl reductase E1 and carbonyl reductase E2 in step (4) is 30-35° C., and the pH value of the reaction system is 6.5-7.0.

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