KR100821688B1 - Separation method of enantiomer of Amlodipine racemate and process for preparing its hydrophilic drug - Google Patents

Abstract

The present invention relates to a process for obtaining enantiomers in a high yield and very high optical purity, a hydrophilic amlodipine prodrug and a process for preparing the amlodipine lasemide Formula 1 through a simple reaction process. Formula (2) and Formula (3) are separated from the mixture of)-and S-(-)-isomers to prepare new hydrophilized prodrugs (5) and (6), respectively.

Amlodipine Lassemide, Enantiomer, R-(+)-Amlodipine, S-(-)-Amlodipine, PEG, Hydrophilic, R-(+)-Amlodipine-mPEG, (S)-(-)-Amlodipine-mPEG

Description

Separation method of enantiomer of Amlodipine racemate and process for preparing its hydrophilic drug

Amlodipine is useful for the treatment of cardiovascular disorders such as angina, high blood pressure and hemorrhagic heart failure. Normally synthesized amlodipine exists in two symmetrical isomers, each with different pharmacological effects. That is, the S-(-)-isomer is very effective as a calcium channel blocker, and the R-(+)-isomer is effective in the treatment and prevention of atherosclerosis.

E. Wehinger et al. Synthesized 1,4-dihydropyridine derivative formula 4 (a) having pure chiral esters using chiral amino esters in DOS 2935451 (1981). JE Arrosmith et al. J. Med. Chem. (1986) 29 It was reported that two amlodipine bilaterally symmetric isomers were prepared by separating diastereomeric azide ester Formula 4 (b) at 1696.

Roman Davis et al. Synthesized pure 1,4-dihydropyridine derivative Formula 4 (c) using chiral sulfoxide in JACS (1988) 110 7873. S. Goldman et al. J. Med. Chem. (1992) 35 3341, the diastereomer amide isomer Formula 2 was isolated and prepared using chromatography. Also Angew. Chem. Int. It was described that the tartaric acid substituted in Edn. (Engl.) (1991) 30 1559 yielded pure left-right symmetry isomer (4) in various solvents.

However, the method described above does not yield satisfactory yield and purity of the symmetric isomer. In consideration of such a conventional method, there is a demand for a method of preparing a pure formula (2) in diastereomeric amlodipine isomer to reduce the reaction step and inhibit side reactions to maximize the process yield. In addition, since S-(-)-amlodipine has a very strong activity for the treatment of hypertension and angina, there is a problem to maximize the solubility in water. However, S-(-)-amlodipine has a low solubility in water, so it is important to absorb it in the body. Because solubility is very important in drug efficacy, S-(-)-amlodipine must be made into a hydrophilic prodrug.

Recent studies have reported that Poly (ethylene glycol) (hereinafter referred to as PEG) is harmless to humans, readily hydrolyzed in the body when bound to drugs, and increases solubility in water. Accordingly, the present invention solves the conventional non-economic problem, the pure amlodipine isomers of the general formula (2, 3) through the economic reaction step, the overall process is simple, and does not involve side reactions, and to increase their solubility in water It is an object of the present invention to provide a preparation method capable of obtaining a compound of formulas (5) and (6) to which PEG is bound by high yield.

In order to achieve the above object, the present invention obtains pure amlodipine isomer having excellent optical purity and yield by using a suitable chiral organic acid and organic solvent from the lamination formula 1, and combines it with PEG having various kinds of linkages in water. It is to make a new PEG-amplodipine prodrug that dissolves well.

The method for preparing (S)-(-)-amlodipine-methoxypolyethylene glycol of the general formula (5) of the present invention consists of the following steps.

Dissolve the amlodipine rasem compound of Formula 1 in anhydrous DMSO and use the enantiomer (S)-(-)-amlodipine-hemi-D-tartrate-mono-DMSO-solvate of Formula 7 using D-(-)-tartaric acid. Manufacturing step 1;

Enantiomer Step 2 of preparing a compound of enantiomer Formula 2 by dissolving a compound of Formula 7 in an organic solvent and reacting under a base; And

A process for preparing (S)-(-)-amlodipine-methoxypolyethylene glycol of formula (5) comprising step 3 of preparing enantiomer compound (5) by PEGylating the compound of formula (2).

In Formula 5, the bridged is trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole or succinimidyl succinate.

In addition, the preparation method of (R)-(+)-amlodipine-methoxy polyethylene glycol of the formula (6) of the present invention consists of the following steps.

Dissolve the amlodipine rasem compound of Formula 1 in anhydrous DMSO and use the enantiomer (S)-(+)-amlodipine-hemi-D-tartrate-mono-DMSO-solvate of Formula 8 using L-(+)-tartaric acid. Manufacturing step 1;

Enantiomer Step 2 of preparing a compound of enantiomer Formula 3 by dissolving a compound of Formula 8 in an organic solvent and reacting under a base; And

A process for preparing compound (R)-(+)-amlodipine-methoxypolyethylene glycol of formula 6 comprising step 3 of preparing enantiomer compound 6 by enzymatically reacting the enantiomer compound of formula 3.

[Formula 1]

In Formula 6, the bridged is trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole, or succinimidyl succinate.

In the process for the preparation of (S)-(-)-amlodipine-methoxypolyethylene glycol of the formula (5) of the present invention and in the process for the preparation of the compound (R)-(+)-amlodipine-methoxy polyethylene glycol of the formula (6),

In step 1, the reaction temperature is 0 to 40 ^° C., and the organic solvent used is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), H ₂ O, MeOH, EtOH, Pyridine, Acetone Single or mixed solvents of tetrahydrofuran (THF), Dioxane, hexamethylphosphoramide (HMPA) are used.

In step 2, the reaction temperature is 0 to 40 ^o C, and the organic solvent used is DMSO, DMF, DMAc, H ₂ O, MeOH, EtOH, Pyridine, Acetone, THF, Dioxane HMPA, CH ₂ Cl ₂ , Chloroform (CHCl ₃ ) Is a single or mixed solvent, and the base used is organic base NEt ₃ , diisopropyl amine, 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), 1,5-diazabicyclo- [4.3 .0] non-5-ene (DBN), one or more selected from NH ₄ OH aqueous solution, the inorganic base is selected from NaHCO ₃ , Na ₂ CO ₃ , NaOH, KOH, BaOH, or LiOH aqueous solution The above can be used in 0.1 to 5N concentration.

In step 3, the reaction temperature is 0 to 40 ^o C, and the organic solvent used is DMSO, DMF, DMAc, H ₂ O, MeOH, EtOH, Pyridine, Acetone, THF, Dioxane, HMPA, CH ₂ Cl ₂ Or a single or mixed solvent of CHCl ₃ , and the base used is NEt ₃ , diisopropyl amine, DBU, DBN or. At least one selected from an aqueous NH ₄ OH solution, and at least one selected from an aqueous NaHCO ₃ , Na ₂ CO ₃ , NaOH, KOH, BaOH, or LiOH solution may be used at a concentration of 0.1 to 5N.

In addition, it is possible to use 38 to 46 ethylene glycol repeating units of the polyethylene glycol used in step 3.

Looking at each of the reaction step according to the present invention in detail, first, by using the difference in the solubility of the salt formed by reacting the partial steric amlodipine isomer with D-(-)-tartaric acid in DMSO solvent as shown in Scheme 1 below to obtain the formula (7) as a solid.

Subsequently, as shown in Scheme 2, Chemical Formula 7 is desalted into an aqueous basic solution in an organic solvent to obtain Chemical Formula 2 which is in a free base state.

As in Scheme 1, Formula 8 is obtained as a solid using the difference in solubility of salts formed by reacting the diastereomeric amlodipine isomer with L-(+)-tartaric acid in a DMSO solvent.

As in Scheme 2, Chemical Formula 8 is desalted into an aqueous basic solution in an organic solvent to obtain Chemical Formula 3 which is in a free base state.

Formula 5 is prepared by combining Formula 2 with linked PEG carbonate Formula 9.

As in Scheme 5, Chemical Formula 6 is prepared by combining Chemical Formula 3 with linked PEG carbonate Chemical Formula 9.

The linking groups of PEG in Schemes 5 and 6 include tresylate, succinimidyl carbonate, benzotriazole carbonate, p -nitrophenyl carbonate, trichlorophenyl carbonate, carbonyl imidazole, succinimidyl succinate, and the like. These linkers are readily hydrolyzed after PEG is attached to the protein, and succinimidyl succinate is most preferred because it can easily act as a hapten that not only hydrolyzes but also immunizes the remaining protein.

Hereinafter, the manufacturing method according to the present invention will be described in detail through preferred embodiments. only,

These examples are merely illustrative of the present invention, but the scope of the present invention is not limited to these.

Example 1 Preparation of (S)-(-)-Amlodipine-Hemi-D-Tartrate-Mono-DMSO-Solvate

Dissolve 7.65 g of amlodipine lasemide in 37.3 mL of DMSO and add 1.404 g of D-(-)-tartaric acid in 37.3 mL of DMSO dropwise at 0 ^° C. When crystals precipitate, the reaction temperature is raised to room temperature and stirred for 14 hours. The resulting crystals are filtered off, washed with 33.4 mL of DMSO and then with 33.4 mL of acetone. The obtained crystals are dried under reduced pressure at 50 ^° C. for 14 hours to afford 3.73 g of product.

¹ H NMR (DMSO-d ₆ ) δ 1.10 (t, 3H), 2.31 (s, 3H), 3.05 (q, 2H), 3.50 (s, 3H), 3.65 (t, 2H), 3.91 (s, 2H ), 3.98 (m, 2H), 4.56 (dd, 1H), 4.70 (dd, 1H), 5.30 (s, 1H), 7.12 (td, 1H), 7.22 (td, 1H), 7.27 (dd, 1H) , 7.34 (dd, 1 H), 8.61 (br s, 1 H)

Example 2 Preparation of (S)-(-)-Amlodipine

3.73 g of (S)-(-)-amlodipine-hemi-D-tartrate-mono-DMSO-solvate is slurried in 42 mL of CH ₂ Cl _{2 and} 42 mL of 2N NaOH at 0 ^° C. is added. The organic layer was separated, washed with 10 mL of H ₂ O, dehydrated with Na ₂ SO ₄ , filtered and concentrated under reduced pressure. Hexane was added to the concentrated product to make a slurry, followed by stirring and filtration to obtain a solid. The obtained crystals were dried under reduced pressure at 50 ^° C. for 14 hours to afford 2.51 g of the desired compound.

¹ H NMR (CDCl ₃ ) δ 1.18 (t, 3H), 2.35 (s, 3H), 2.97 (t, 2H), 3.58 (t, 2H), 3.61 (s, 3H), 4.03 (m, 2H), 4.77 (q, 2H), 5.40 (s, 1H), 7.03 (m, 1H), 7.13 (td, 1H), 7.22 (dd, 1H), 7.37 (dd, 1H), 7.83 (br s, NH)

Example 3 Identification of (S)-(-)-Amlodipine

At room temperature, 23.5 mg of Mosher's acid is dissolved in 3 mL of CH ₂ Cl ₂ , and 23 mg of DC (N, N-dicyclohexylcarbodiimide) is added. After the reaction temperature was lowered to 0 ^° C., 41 mg of (S)-(-)-amlodipine was added and stirred at room temperature for 12 hours.

The reaction solution was filtered, concentrated under reduced pressure, and the concentrated mixture was columned using a developing solution of EtOAc: Hex = 2: 3. Confirm that it is 1 spot by TLC and analyze by NMR to identify 1 isomer.

¹ H NMR (CDCl ₃ ) δ 1.20 (t, 3H), 2.21 (s, 3H), 3.40 (s, 3H), 3.60 (s, 3H), 3.68 (m, 4H), 4.04 (m, 2H), 4.71 (q, 2H), 5.39 (s, 1H), 7.26 (m, 9H)

Example 4 Preparation of MeO-PEG-Succinimidyl Carbonate

28.5 g (15 mmol) of polyethylene glycol monomethyl ether (average molecular weight: 1900), MeO-PEG) was dissolved in 100 mL of anhydrous toluene under nitrogen, phosgene (48.5 mmol) in 25 mL of anhydrous toluene at 0 ^o C, and sodium carbonate 3.18 g (30 mmol) is added and stirred for 2 hours. The reaction mixture is filtered and then concentrated under reduced pressure. Add 100 mL of anhydrous CH ₂ Cl ₂ , dilute and filter quickly. The filtrate was concentrated under reduced pressure at 40 ^° C. to obtain a semisolid, and 125 mL of anhydrous acetonitrile was added to dissolve it and the temperature was lowered to 0 ^° C. And a solution dissolved in 6.75 mL (48.5 mmol) of triethylamine are added dropwise to the PEG-chloro formate solution at 0 ^° C. The reaction solution is stirred for 15 minutes and the mixture is filtered to remove triethylamine hydrochloride. The filtrate was concentrated under reduced pressure, the concentrated mixture was added to 100 mL of CH ₂ Cl _{2 and} 100 mL of H ₂ O to separate an organic layer, and the aqueous layer was reextracted with 50 mL of CH ₂ Cl ₂ again. Extracted CH ₂ Cl ₂ The solution is washed with 2.5% HCl and then with 1M NaHCO ₃ solution and water. The organic solution is dehydrated with MgSO ₄ , filtered and concentrated under reduced pressure. 200 mL of cold ethyl acetate is added to the obtained oil mixture, and the mixture is stirred vigorously. The precipitated MeO-PEG-succinimidyl carbonate was filtered and dried under reduced pressure to obtain 28.7 g of an off-white target product.

¹ H NMR (CDCl ₃ ) δ 2.40 (s, 4H), 3.35 (s, 3H), 3.40-4.0 (m, 170H), 4.40 (dd, 2H)

Example 5 Preparation of MeO-PEG- (bridged)-(S)-(-)-amlodipine

Dissolve 410 mg (1.0 mmol) of (S)-(-)-amlodipine in 20 mL of THF (tetrahydrofuran) and adjust to pH 8.5 by adding 0.1 M Na ₂ CO ₃ . To the solution was added 2.041 g (1.0 mmol) of MeO-PEG-succinimidyl carbonate and maintained at pH 8.5. The reaction mixture is stirred for 30 minutes, depressurized to remove THF and the product is extracted with CH ₂ Cl ₂ . Isopropyl ether was added to the product in the form of oil concentrated under reduced pressure to precipitate crystals. The precipitated crystals were dried under a reduced pressure to obtain the target product (2.08 g) (average molecular weight: 2450).

¹ H NMR (CDCl ₃ ) δ 1.20 (t, 3H), 2.21 (s, 3H), 3.35 (s, 3H), 3.40 (s, 3H), 3.40-4.0 (m, 170H), 3.60 (s, 3H ), 3.68 (m, 4H), 4.04 (m, 2H), 4.40 (dd, 2H), 4.71 (q, 2H), 5.39 (s, 1H), 7.26 (m, 9H)

Example 6 Preparation of MeO-PEG- (bridged)-(R)-(+)-amlodipine

410 mg (1.0 mmol) of (R)-(+)-amlodipine were dissolved in 20 mL of THF and adjusted to pH 8.5 by addition of 0.1 M Na ₂ CO ₃ . To the solution was added 2.041 g (1.0 mmol) of MeO-PEG-succinimidyl carbonate and maintained at pH 8.5. The reaction mixture is stirred for 30 minutes, depressurized to remove THF and the product is extracted with CH ₂ Cl ₂ . Isopropyl ether was added to the product in the form of oil concentrated under reduced pressure to precipitate crystals. The precipitated crystals were dried under a reduced pressure to obtain the target product (2.08 g) (average molecular weight: 2450).

¹ H NMR (CDCl ₃ ) δ 1.20 (t, 3H), 2.21 (s, 3H), 3.35 (s, 3H), 3.40 (s, 3H), 3.40-4.0 (m, 170H), 3.60 (s, 3H ), 3.68 (m, 4H), 4.04 (m, 2H), 4.40 (dd, 2H), 4.71 (q, 2H), 5.39 (s, 1H), 7.26 (m, 9H)

The present invention relates to a process for the preparation of amlodipine lasulfide with a high yield and very high optical purity through a simple reaction process, and to a method for the preparation of hydrophilic amlodipine prodrugs thereof, wherein R-(+)-of amlodipine The isomers of amlodipine are isolated from the mixture of and S-(-)-isomers and PEGylated, respectively, to provide hydrophilized prodrugs with increased solubility in water.

Claims (8)

(S)-(-)-amlodipine-methoxy polyethylene glycol of the molecular weight 2250-2650 represented by following General formula (5). [Formula 5]

In Formula 5, the bridged is trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole or succinimidyl succinate. The average molecular weight is 2450. (R)-(+)-amlodipine-methoxy polyethylene glycol of the molecular weight 2250-2650 represented by following General formula (6). [Formula 6]

In Formula 6, the bridged is trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole or succinimidyl succinate. The average molecular weight is 2450. The amlodipine rasem compound of Formula 1 is dissolved in anhydrous dimethylsulfoxide (DMSO) and enantiomerized using the D-(-)-tartaric acid (S)-(-)-amlodipine-hemi-D-tartrate-mono- Step 1 to prepare a DMSO-solvate; Enantiomer Step 2 of preparing a compound of enantiomer Formula 2 by dissolving a compound of Formula 7 in an organic solvent and reacting under a base; And A process for preparing (S)-(-)-amlodipine-methoxypolyethylene glycol of formula (5) comprising step 3 of preparing enantiomer compound (5) by PEGylating the compound of formula (2). [Formula 1]

[Formula 2]

[Formula 5]

In Formula 5, the bridged is trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole or succinimidyl succinate. [Formula 7]

The amlodipine rasem compound of Formula 1 is dissolved in anhydrous dimethylsulfoxide (DMSO) and enantiomerized using the L-(+)-tartaric acid (S)-(+)-amlodipine-hemi-D-tartrate-mono- Step 1 to prepare a DMSO-solvate; Enantiomer Step 2 of preparing a compound of enantiomer Formula 3 by dissolving a compound of Formula 8 in an organic solvent and reacting under a base; And A process for preparing Compound (R)-(+)-Amlodipine-methoxy Polyethylene Glycol of Formula 6 comprising the step 3 of preparing enantiomer Compound 6 by PEGylation of the compound of Formula 3  [Formula 1]

[Formula 3]

[Formula 6]

In Formula 6, the bridged may be trisylate, succinimidyl carbonate, benzotriazole carbonate, p-nitrophenyl carbonate, trichloro carbonate, carbonyl imidazole or succinimidyl succinate. [Formula 8]

The method according to claim 3 or 4, wherein the reaction temperature in step 1 is from 0 to 40 ^o C, and the organic solvent used is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), A single or mixed solvent of H ₂ O, MeOH, EtOH, Pyridine, Acetone, tetrahydrofuran (THF), Dioxane, hexamethylphosphorami (HMPA). The process according to claim 3 or 4, wherein the reaction temperature in step 2 is 0 to 40 ^° C., and the organic solvent used is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), H Single or mixed solvent of ₂ O, MeOH, EtOH, Pyridine, Acetone, tetrahydrofuran (THF), Dioxane, hexamethylphosphoramide (HMPA), CH ₂ Cl ₂ or CHCl ₃ , and the base used is an organic base Is NEt ₃ , diisopropyl amine, 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), 1,5-diaza-bicyclo- [4.3.0] non-5-ene (DBN), NH ₄ At least one selected from an aqueous OH solution, as an inorganic base, characterized in that at least one selected from NaHCO ₃ , Na ₂ CO ₃ , NaOH, KOH, BaOH, or LiOH aqueous solution at 0.1 to 5N concentration . The method according to claim 3 or 4, wherein the reaction temperature in step 3 is 0 to 40 ^o C, and the organic solvent used is dimethyl sulfoxide (DMSO), dimethylformamide (DMF), dimethylacetamide (DMAc), H Single or mixed solvent of ₂ O, MeOH, EtOH, Pyridine, Acetone, tetrahydrofuran (THF), Dioxane, hexamethylphosphoramide (HMPA), CH ₂ Cl ₂ or CHCl ₃ , and the base used is an organic base. Is NEt ₃ , diisopropyl amine, 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU), 1,5-diaza-bicyclo- [4.3.0] non-5-ene (DBN) or NH ₄ At least one selected from an aqueous OH solution, as an inorganic base, characterized in that at least one selected from NaHCO ₃ , Na ₂ CO ₃ , NaOH, KOH, BaOH, or LiOH aqueous solution at 0.1 to 5N concentration . The method according to claim 3 or 4, wherein the ethylene glycol repeating unit of the polyethylene glycol used in step 3 is 38 to 46.