Preparation method of saxagliptin impurity

Abstract

The invention relates to the technical field of compound synthesis, and particularly provides a preparation method of a saxagliptin impurity, which comprises the following steps: by taking (1S, 3S, 5S)-3-(aminocarbonyl)-2-azabicyclo [3.1. 0] hexane-2-tert-butyl formate as a raw material, carrying out acid BOC removal reaction to obtain an intermediate 1, condensing the intermediate 1 and N-tert-butyloxycarbonyl-3-hydroxy-1-adamantyl-D-glycine to obtain an intermediate 2, and carrying out condensation reaction on the intermediate 2 and N-tert-butyloxycarbonyl-3-hydroxy-1-adamantyl-D-glycine to obtain the saxagliptin impurity. The saxagliptin impurity B and the saxagliptin impurity A are obtained from the intermediate 2 through a one-pot method under the action of acid, the saxagliptin impurity A and the saxagliptin impurity B are not recorded in the Chinese Pharmacopoeia at present, and the high-purity saxagliptin impurity A and the saxagliptin impurity B prepared through the method can be used as reference substances in saxagliptin research and finished product detection. The method provides powerful guarantee for controlling the quality of saxagliptin drugs, and is suitable for drug quality research.

Description

Technical Field

[0001] The present invention relates to the technical field of compound synthesis, and particularly relates to a preparation method of saxagliptin impurities. Background Art

[0002] Saxagliptin was jointly developed by Bristol-Myers Squibb Company and AstraZeneca. This drug can increase the levels of endogenous glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) by selectively inhibiting DPP-4, thereby regulating blood sugar. In May 2011, saxagliptin, a novel dipeptidyl peptidase-IV (DPP-IV, endogenous incretin) inhibitor, was officially approved by the SFDA in China. Currently, saxagliptin impurities are not included in the Chinese Pharmacopoeia. There are three saxagliptin impurities included in the European Pharmacopoeia, namely A, B, and C, and their structures are as follows:

[0003] Impurity A: (1As,4S,6aR,7aS)-6-amino-1,1a,4,6a,7,7a-hexahydro-4-(3-hydroxytricyclo[3.3.1.1 3,7 dec-1-yl)-3H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazin-3-one

[0004]

[0005] C 18 H 25 N 3 O 2 Molecular weight: 315.41.

[0006] Impurity B: (1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxyadamantan-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carboxamide

[0007]

[0008] C 18 H 27 N 3 O 3 Molecular weight: 333.43.

[0009] Impurity C: (1aS,4S,6aR,7aS)-hexahydro-4-(3-hydroxytricyclo[3.3.1.1 3,7 dec-1-yl)-1H-cyclopropa[4,5]pyrrolo[1,2-α]pyrazine-3,6-dione

[0010]

[0011] C18 H 24 N 2 O 3 Molecular weight: 316.39.

[0012] There have been no reports on the related syntheses of saxagliptin impurities A and B. Therefore, it is of great significance for the quality research of saxagliptin to provide a method with short reaction steps, high yield and safe operation for synthesizing saxagliptin impurities A and B. Summary of the Invention

[0013] In view of this, the present invention provides a method for preparing saxagliptin impurities with short reaction steps, high yield and safe operation.

[0014] The technical solution of the present invention is realized as follows: The present invention provides a method for preparing saxagliptin impurities, wherein the saxagliptin impurities are saxagliptin impurity A: ((1As,4S,6aR,7aS)-6-amino-1,1a,4,6a,7,7a-hexahydro-4-(3-hydroxytricyclo[3.3.1.13,7]dec-1-yl)-3H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazin-3-one) and saxagliptin impurity B: ((1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxyadamantan-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carboxamide), and the preparation method includes the following steps:

[0015] Step 1: Using (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylic acid tert-butyl ester as a raw material, an intermediate 1 is obtained through an acid de-BOC reaction.

[0016] Step 2: Intermediate 1 is condensed with N-tert-butoxycarbonyl-3-hydroxy-1-adamantyl-D-glycine under the action of a condensing agent and a base to obtain intermediate 2.

[0017] Step 3: Intermediate 2 is subjected to a one-pot method under the action of an acid to obtain both saxagliptin impurity B and saxagliptin impurity A.

[0018] The specific synthesis route is as Figure 1 shown.

[0019] In some embodiments, in Step 1, the acid used in the acid de-BOC reaction is one of hydrochloric acid, methanesulfonic acid, and sulfuric acid, the molar ratio of the raw material (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylic acid tert-butyl ester to the acid is 1:(1.5 - 2.5), the reaction temperature of the acid de-BOC is 20 - 65°C, and the reaction time is 1 - 4 h.

[0020] In some embodiments, in Step 2, the condensing agent is ECDI.HCL or HOBT and EDC.HCl or CDI, and the molar ratio of Intermediate 1 to the condensing agent is 1:(1.5 - 2).

[0021] In some embodiments, in Step 2, the solvent used in the reaction system is at least one of acetonitrile and ethyl acetate.

[0022] In some embodiments, in Step 2, the base is an organic base, the organic base is triethylamine or N,N - diisopropylethylamine, and the molar ratio of Intermediate 1 to the base is 1:(1.5 - 2).

[0023] In some embodiments, in Step 2, the reaction temperature is 25 - 35°C, and the reaction time is 4 - 8 h.

[0024] In some embodiments, in Step 3, the acid is one of hydrochloric acid, sulfuric acid, and methanesulfonic acid.

[0025] In some embodiments, in Step 3, the molar ratio of the acid to Intermediate 2 is 1:(1.5 - 10).

[0026] In some embodiments, in Step 3, the reaction temperature is 30 - 70°C, and the reaction time is 4 - 30 h.

[0027] In some embodiments, in Step 3, the reaction solvent is a mixture of one of methanol, ethanol, and isopropanol and water, where the ratio of methanol, ethanol, isopropanol to water is 1:(0.5 - 2).

[0028] The present invention has the following beneficial effects compared with the prior art:

[0029] (1) Currently, there are no relevant patent reports on the synthesis route of saxagliptin impurities. The present invention first proposes a synthesis route for synthesizing saxagliptin impurity A and impurity B, and synthesizes saxagliptin impurity A: ((1As,4S,6aR,7aS)-6 - amino - 1,1a,4,6a,7,7a - hexahydro - 4-(3 - hydroxytricyclo[3.3.1.13,7]dec - 1 - yl)-3H - cyclopropa[4,5]pyrrolo[1,2 - a]pyrazin - 3 - one) and saxagliptin impurity B: ((1S,3S,5S)-2 - [(2S)-2 - amino - 2-(3 - hydroxyadamantan - 1 - yl)acetyl]-2 - azabicyclo[3.1.0]hexane - 3 - carboxamide) in one step;

[0030] (2) The preparation methods of saxagliptin impurity A and saxagliptin B provided by the present invention have the advantages of easily available raw materials, mild reaction conditions, short reaction steps, controllable product quality, high purity, and safe process;

[0031] (3) The high-purity saxagliptin impurity A and saxagliptin B prepared by the present invention can be used as reference substances in the research and finished product detection of saxagliptin, providing a strong guarantee for controlling the quality of saxagliptin drugs and being applicable to the research on drug quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1 It is the synthetic route diagram of the preparation method of the present invention;

[0034] Figure 2 It is the hydrogen spectrum of saxagliptin impurity A: ((1As,4S,6aR,7aS)-6-amino-1,1a,4,6a,7,7a-hexahydro-4-(3-hydroxytricyclo[3.3.1.13,7]dec-1-yl)-3H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazin-3-one) in Example 1 of the present invention;

[0035] Figure 3 It is the MS spectrum of saxagliptin impurity A: ((1As,4S,6aR,7aS)-6-amino-1,1a,4,6a,7,7a-hexahydro-4-(3-hydroxytricyclo[3.3.1.13,7]dec-1-yl)-3H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazin-3-one) in Example 1 of the present invention;

[0036] Figure 4 It is the carbon spectrum of saxagliptin impurity A: ((1As,4S,6aR,7aS)-6-amino-1,1a,4,6a,7,7a-hexahydro-4-(3-hydroxytricyclo[3.3.1.13,7]dec-1-yl)-3H-cyclopropa[4,5]pyrrolo[1,2-a]pyrazin-3-one) in Example 1 of the present invention;

[0037] Figure 5 It is the hydrogen spectrum of saxagliptin impurity B: ((1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxyadamantan-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carboxamide) in Example 1 of the present invention;

[0038] Figure 6This is the MS spectrum of saxagliptin impurity B: ((1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxyadamantan-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carboxamide) in Example 1 of the present invention. Detailed implementation manners

[0039] Next, in combination with the implementation manners of the present invention, the technical solutions in the implementation manners of the present invention will be clearly and completely described. Obviously, the described implementation manners are only a part of the implementation manners of the present invention, rather than all of the implementation manners. Based on the implementation manners in the present invention, all other implementation manners obtained by those of ordinary skill in the art without making creative efforts fall within the protection scope of the present invention.

[0040] Unless otherwise defined, all technical terms and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which the embodiments of the present invention belong. If the definitions stated in this part are contrary to or inconsistent with other aspects of the definitions stated in the patents, patent applications, published patent applications, and other publications incorporated herein by reference, the definitions listed in this part shall prevail over the definitions incorporated herein by reference.

[0041] Unless otherwise specified, the methods used in the following examples are all conventional methods. The materials, reagents, and instruments used, unless otherwise specified, are all conventional materials, reagents, and instruments in the art, and those skilled in the art can obtain them through commercial channels.

[0042] When an equivalent, concentration, or other value or parameter is expressed as a range, a preferred range, or a range defined by a series of upper limit preferred values and lower limit preferred values, it should be understood that all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value are specifically disclosed, regardless of whether the ranges are separately disclosed. For example, when the range "1 to 5" is disclosed, the described range should be interpreted as including the ranges "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5", etc. When a numerical range is described in this application, unless otherwise stated, the range is intended to include its end values and all integers and fractions within the range. In the specification and claims of this application, range limitations can be combined and / or interchanged, and if not otherwise stated, these ranges include all sub-ranges contained therein.

[0043] The specific preparation process of this application is further described through specific examples.

[0044] Example 1

[0045] Using tert-butyl (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate as the raw material and isopropanol as the solvent, add 283 g of isopropanol and 56 g of the raw material into the reaction flask, heat up to 55 °C, add dropwise 31 g of methanesulfonic acid. After the addition is complete, keep the temperature at 60 °C and react for 3 hours. Cool down to ≤20 °C and continue stirring for 4 hours. Filter, and the wet intermediate 1 is dried under reduced pressure at 50 - 60 °C for 8 hours to obtain 54 g of intermediate 1.

[0046] Add 153 g of acetonitrile, 90 g of ethyl acetate, and 61 g of N,N-diisopropylethylamine into the reaction flask, stir and mix to obtain the lye for standby.

[0047] Take 167 g of acetonitrile, 70 g of N-Boc-3-hydroxy-1-adamantyl-D-glycine, 50 g of intermediate 1, 33 g of 1-hydroxybenzotriazole, and 45 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and add them into the reaction flask. Dropwise add the prepared lye, and stir and react at 25 - 30 °C for 4 hours after the addition is complete. Add 658 g of ethyl acetate, dilute hydrochloric acid (21 g of 36% hydrochloric acid / 88 g of water), 105 g of purified water, and saturated sodium chloride solution (184 g of purified water / 67 g of sodium chloride), stir for 10 min, let it stand for 10 min, separate the aqueous layer, and the organic layer is washed twice with 20% KHCO 3 solution (305 g of purified water / 76 g of KHCO 3 ). After the organic layer is concentrated to dryness under reduced pressure, add 56 g of isopropanol, 70 g of purified water, and 23 g of 36% hydrochloric acid, and stir at 60 - 65 °C for 10 hours. Then, add 136 g of purified water and 292 g of dichloromethane, stir for 10 min, and let it stand for 10 min. Separate the lower dichloromethane layer, add 292 g of dichloromethane to the remaining aqueous layer, adjust the pH value to 6 - 7 with sodium hydroxide aqueous solution (7 g of sodium hydroxide / 32 g of purified water), and then slowly add 25% potassium carbonate aqueous solution (21 g of potassium carbonate and 64 g of purified water) until the pH value is 8.5 - 9, separate the lower dichloromethane ①, add 292 g of dichloromethane again, slowly add 25% potassium carbonate aqueous solution (21 g of potassium carbonate and 64 g of purified water) until the pH value is greater than 9.5, separate dichloromethane ②. After concentrating the two portions of dichloromethane, add silica gel to dichloromethane ①, mix the sample, and pass through a 400-mesh silica gel column with a mobile phase of dichloromethane:methanol = 15:1 to obtain 1.8 g of saxagliptin impurity A. Add silica gel to dichloromethane ②, mix the sample, and pass through a 400-mesh silica gel column with a mobile phase of dichloromethane:methanol = 10:1 to obtain 20 g of saxagliptin impurity B.

[0048] Example 2

[0049] Using tert-butyl (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate as the raw material and isopropanol as the solvent, add 283 g of isopropanol and 56 g of the raw material into the reaction flask, heat up to 58 °C, dropwise add 45 g of concentrated hydrochloric acid. After the addition is complete, keep the temperature at 65 °C and react for 3 hours. Then cool down to ≤20 °C and continue stirring for 5 hours. Filter, and the wet intermediate 1 is dried under reduced pressure at 50 - 60 °C for 8 hours to obtain 30 g of intermediate 1.

[0050] Add 87 g of acetonitrile, 50 g of ethyl acetate, and 29 g of N,N-diisopropylethylamine into the reaction flask, stir and mix to obtain the lye for standby.

[0051] Take 82 g of acetonitrile, 38 g of N-Boc-3-hydroxy-1-adamantyl-D-glycine, 25 g of intermediate 1, 16.5 g of 1-hydroxybenzotriazole, and 23 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and add them into the reaction flask. Drop the prepared lye into it. After dropping, stir and react at 25 - 30 °C for 4 hours. Add 325 g of ethyl acetate, dilute hydrochloric acid (10 g of 36% hydrochloric acid / 42 g of water), 55 g of purified water, and saturated sodium chloride solution (80 g of purified water / 32 g of sodium chloride), stir for 10 min, let it stand for 10 min, separate the aqueous layer, and the organic layer is washed twice with 20% KHCO 3 solution (155 g of purified water / 35 g of KHCO 3 ) and concentrated under reduced pressure to dryness. Then add 25 g of methanol, 32 g of purified water, and 12 g of 36% hydrochloric acid, stir overnight at 60 - 65 °C, add 82 g of purified water and 150 g of dichloromethane, stir for 10 min, let it stand for 10 min. Separate the lower dichloromethane layer, add 150 g of dichloromethane, adjust the pH value to 6 - 7 with sodium hydroxide aqueous solution (3.5 g of sodium hydroxide / 16 g of purified water), then slowly add 25% potassium carbonate aqueous solution (11 g of potassium carbonate and 35 g of purified water) until the pH value reaches 8.5 - 9, and separate the lower dichloromethane layer ① , add 150 g of dichloromethane again, slowly add 25% potassium carbonate aqueous solution (11 g of potassium carbonate and 35 g of purified water) until the pH value is greater than 9.5, separate dichloromethane ②. After concentrating the two portions of dichloromethane, add silica gel to dichloromethane ①, mix the sample, and pass through a 400-mesh silica gel column with a mobile phase of dichloromethane:methanol = 15:1 to obtain 1.1 g of saxagliptin impurity A. Add silica gel to dichloromethane ②, mix the sample, and pass through a 400-mesh silica gel column with a mobile phase of dichloromethane:methanol = 10:1 to obtain 16 g of saxagliptin impurity B.

[0052] Example 3

[0053] Using tert-butyl (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylate as the raw material and isopropanol as the solvent, add 283 g of isopropanol and 56 g of the raw material into the reaction flask, heat up to 60 °C, dropwise add 31 g of methanesulfonic acid. After the addition is complete, keep the temperature at 55 °C and react for 3 hours. Then cool down to ≤20 °C and continue stirring for 5 hours. Filter, and the wet intermediate 1 obtained is dried under reduced pressure at 50 - 60 °C for 8 hours to obtain 54 g of intermediate 1.

[0054] Add 153 g of acetonitrile, 90 g of ethyl acetate, and 61 g of N,N-diisopropylethylamine into the reaction flask, stir and mix to obtain the lye for standby.

[0055] Take 167 g of acetonitrile, 70 g of N-Boc-3-hydroxy-1-adamantyl-D-glycine, 50 g of intermediate 1, 33 g of 1-hydroxybenzotriazole, and 45 g of 1-ethyl-(3-dimethylaminopropyl)carbodiimide hydrochloride and add them into the reaction flask. Dropwise add the prepared lye, and stir and react at 25 - 30 °C for 4 hours after the addition is complete. Add 658 g of ethyl acetate, dilute hydrochloric acid (21 g of 36% hydrochloric acid / 88 g of water), 105 g of purified water, and saturated sodium chloride solution (184 g of purified water / 67 g of sodium chloride), stir for 10 min, let it stand for 10 min, separate the aqueous layer, and wash the organic layer with 20% KHCO 3 solution (305 g of purified water / 76 g of KHCO 3 ) twice. After the organic layer is concentrated to dryness under reduced pressure, add 56 g of methanol, 70 g of purified water, and 23 g of 36% hydrochloric acid, stir at 60 - 65 °C for 10 h, then add 136 g of purified water and 292 g of dichloromethane, stir for 10 min, and let it stand for 10 min. Separate the lower dichloromethane layer, add 292 g of dichloromethane, adjust the pH value to 6 - 7 with sodium hydroxide aqueous solution (7 g of sodium hydroxide / 32 g of purified water), then slowly add 25% potassium carbonate aqueous solution (21 g of potassium carbonate and 64 g of purified water) until the pH value reaches 9 - 9.5. Separate the lower dichloromethane layer, heat the dichloromethane to reflux overnight, concentrate, add silica gel to the dichloromethane, mix the sample, and pass through a 400-mesh silica gel column with the mobile phase of dichloromethane:methanol = 13:1 to obtain 3.6 g of saxagliptin impurity A and 16 g of impurity B respectively.

[0056] Perform nuclear magnetic resonance hydrogen spectrum and mass spectrum detection on saxagliptin impurity A and impurity B prepared in Example 1 respectively, and perform carbon spectrum detection on impurity A. The obtained spectral results are as Figure 2-6 shown.

[0057] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing saxagliptin impurities, characterized in that: The saxagliptin impurities are saxagliptin impurity A: ((1As,4S,6aR,7aS)-6-amino 1,1a,4,6a,7,7a hexahydro-4-(3-hydroxytricyclo[ 3.3.1.1 ((1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxyadamantan-1-yl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carboxamide), the preparation method comprises the following steps: Step 1: Using (1S,3S,5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylic acid tert-butyl ester as raw material, subjecting the raw material to acid removal of BOC to obtain intermediate 1; Step 2, intermediate 1 is condensed with N-tert-butyloxycarbonyl-3-hydroxy-1-adamantyl-D-glycine in the presence of a condensing agent and a base to obtain intermediate 2; Step 3: The intermediate 2 is boiled in one pot under the action of acid to obtain saxagliptin impurity B and saxagliptin impurity A.

2. The method for preparing the saxagliptin impurity according to claim 1, wherein In step 1, the acid used in the acid de-BOC reaction is one of hydrochloric acid, methanesulfonic acid, and sulfuric acid, the molar ratio of the raw material (1S, 3S, 5S)-3-(aminocarbonyl)-2-azabicyclo[3.1.0]hexane-2-carboxylic acid tert-butyl ester to the acid is 1:(1.5-2.5), the reaction temperature of the acid de-BOC is 20-65°C, and the reaction time is 1-4h.

3. The method for preparing the saxagliptin impurity according to claim 1, wherein In step 2, the condensing agent is ECDI.HCL or HOBT and EDC.HCl or CDI, and the molar ratio of the intermediate 1 to the condensing agent is 1:(1.5-2).

4. The method for preparing the saxagliptin impurity according to claim 1, wherein In step 2, the solvent used in the reaction system is at least one of acetonitrile and ethyl acetate.

5. The method for preparing the saxagliptin impurity according to claim 1, characterized in that, In step 2, the base is an organic base, and the organic base is triethylamine or N,N-diisopropylethylamine.

6. The method for preparing the saxagliptin impurity according to claim 1, characterized in that, In step 2, the reaction temperature is 25-35°C and the reaction time is 4-8h.

7. The method for preparing the saxagliptin impurity according to claim 1, characterized in that, In step 3, the acid is one of hydrochloric acid, sulfuric acid and methanesulfonic acid.

8. The method for preparing the saxagliptin impurity according to claim 1, characterized in that, In step 3, the molar ratio of the acid to the intermediate 2 is 1:(1.5-10).

9. The method for preparing the saxagliptin impurity according to claim 1, wherein: In step 3, the reaction temperature is 30-70°C and the reaction time is 4-30h.

10. The method for preparing the saxagliptin impurity according to claim 1, characterized in that: In step 3, the reaction solvent is a mixture of one of methanol, ethanol, isopropanol and water, wherein the ratio of methanol, ethanol, isopropanol to water is 1:(0.5-2).

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