TW201623213A - Method of preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropy lamine - Google Patents

Abstract

A method of preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine includes introducing a chlorine acetyl group to a benzene ring of 1,2-difluorobenzene by Friedel-Crafts reaction; performing a reduction reaction using boron hydride compound, and then performing a ring closure reaction to form racemic 3,4-difluorophenyl oxirane; performing hydrolysis reaction on the racemic 3,4-difluorophenyl oxirane with water to form (s)-3,4-difluorophenyl oxirane; reacting (s)-3,4-difluorophenyl oxirane with triethyl phosphonoacetate, and then performing ammonolysis and Hofmann degradation reaction to form (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine.

Description

Method for preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine

The invention relates to a method for preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine, belonging to the technical field of medicinal chemistry.

Ticagrelor is a new type of small molecule anticoagulant with selective effects. The European Union and the US Food and Drug Administration (FDA) approved the sale in December 2010 and July 2011, respectively. Currently, more than 40 countries including the European Union, the United States, Brazil, Canada, Australia and Russia have approved ticagrelor for the treatment of acute coronary syndrome (ACS). Clinical trials have confirmed that, unlike thiophene pyridine, prasugrel and other thienopyridine anticoagulants, ticagrelor can reversibly act on adenosine diphosphate (ADP) receptor subtype P2Y12, significantly inhibiting ADP Platelet aggregation, and rapid oral administration, can help improve the symptoms of ACS patients, reduce the risk of thrombosis in ACS clinical treatment, especially for the need for coronary artery bypass Patients with pathology (coronaryarterybypassgraft, CABG) overcome the deficiencies of clopidogrel and prasugrel.

(1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine is a key intermediate for the synthesis of ticagrelor.

In the prior art, there are mainly two methods for synthesizing (1R, 2S)-2-(3,4-difluorophenyl)cyclopropylamine: one is by synthesizing racemic 2-(3,4-difluorobenzene) () Cyclopropylamine, then by resolution to give (1R, 2S)-2-(3,4-difluorophenyl)cyclopropylamine; this will lose half of the raw materials, causing a great waste, and the synthesis efficiency is also very low. The second is to synthesize (1R,2S)-2-(3,4-difluorophenyl) by synthesizing a chiral (S)-(3,4-difluorophenyl)oxirane. Cyclopropylamine; however, the currently published reagents for the synthesis of chiral epoxy compounds are relatively expensive and the final cost is still high.

Therefore, there is a need to develop more methods for preparing (1R, 2S)-2-(3,4-difluorophenyl)cyclopropylamine to reduce the cost of synthesis, thereby reducing the cost of preparation of ticagrelor.

It is an object of the present invention to provide a process for the preparation of (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine. The method comprises the following steps: (1) subjecting 1,2-difluorobenzene and ruthenium chloride to a Friedel-Craft reaction under the action of aluminum trichloride to form a compound A, wherein the chemical formula of ruthenium chloride is Wherein R is hydrogen, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and the chemical structural formula of compound A is (2) subjecting compound A to a boron hydride compound to form a product B, and product B is versus (3) subjecting product B to a ring closure reaction to form product C, product C is versus (4) subjecting product C with water under hydrolysis of a catalyst to form compound D and compound E, the chemical structural formula of compound D is , the chemical structural formula of compound E is (5) esterification reaction of compound D with triethyl phosphonium acetate under the action of a tert-butanol compound to form compound F, the chemical structural formula of compound F is (6) The compound F is reacted with methyl formate under an atmosphere and under the action of sodium alkoxide to form a compound G, and the chemical structural formula of the compound G is , the atmosphere is ammonia gas, guanamine gas or a combination thereof; and (7) compound G is subjected to Hofmann degradation reaction to form (1R, 2S)-2-(3,4-difluorophenyl)cyclopropylamine, Its chemical structure is

According to an embodiment of the invention, the catalyst comprises a metal chiral ligand, the chemical structural formula of which is Wherein M is iron, cobalt or nickel and A is hydrogen, halogen, alkyl or ester group ( ).

According to an embodiment of the present invention, in the step (1), the molar ratio of 1,2-difluorobenzene, aluminum trichloride and ruthenium chloride is 1: (1~10): (1~10), and the reaction temperature is 0~40°C, the reaction time is 3~30 hours; in step (2), the molar ratio of compound A to borohydride is 1: (0.2~2), the reaction temperature is 0~50°C, and the reaction time is 0.5. ~10 hours; in step (3), the reaction temperature is 0-40 ° C, the reaction time is 1 to 12 hours; in step (4), the molar ratio of product C, metal chiral ligand to water is 1: ( 0.01~0.1): (0.4~0.8), anti The temperature should be 10~60 ° C, the reaction time is 12~60 hours; in step (5), the molar ratio of compound D, t-butanol compound and triethyl phosphonium acetate is 1: (1~3): (1 ~2), the reaction temperature is 40~110 °C, the reaction time is 1~30 hours; in step (6), the molar ratio of compound F, sodium alkoxide and methyl formate is 1: (0.5~2): (0.5~2) The reaction temperature is 40 to 65 ° C, the pressure of the atmosphere is 0 to 10 Torr, and the reaction time is 10 to 80 hours. In the step (7), the compound G is subjected to a Hofmann degradation reaction under the action of a base, and the base contains hydrogen. The molar ratio of sodium oxide and sodium hypochlorite, compound G, sodium hydroxide and sodium hypochlorite is 1: (1~5): (2~8), the reaction temperature is 40~65 °C, and the reaction time is 1~80 hours.

According to an embodiment of the present invention, in the step (1), the molar ratio of 1,2-difluorobenzene, aluminum trichloride and ruthenium chloride is 1:1.2:1.2, the reaction temperature is reflux temperature, and the reaction time is 10 hours. In the step (2), the molar ratio of the compound A to the boron hydride compound is 1:0.25, the reaction temperature is 10 ° C, and the reaction time is 2 hours; in the step (3), the reaction temperature is 25 ° C, and the reaction time is 8 Hour; in step (4), the molar ratio of product C, metal chiral ligand to water is 1:0.025:0.5, the reaction temperature is 25 ° C, and the reaction time is 48 hours; in step (5), compound D, The molar ratio of the tert-butanol compound to triethyl phosphonium acetate is 1:1.5:1.5, the reaction temperature is 80 ° C, and the reaction time is 11 hours; in the step (6), the compound F, the sodium alkoxide and the methyl formate are used. The molar ratio is 1:0.75:1, the reaction temperature is 40 ° C, the pressure of the atmosphere is 2 Torr, and the reaction time is 48 hours; in the step (7), the molar ratio of the compound G, sodium hydroxide and sodium hypochlorite is 1 : 5:2, the reaction temperature was 40 ° C, and the reaction time was 8 hours.

According to an embodiment of the present invention, in the step (1), the 1,2-difluorobenzene and the ruthenium chloride are subjected to the action of aluminum trichloride in a solvent and under nitrogen. a reaction, the solvent is dichloromethane, dichloroethane or a combination thereof; in the step (2), the compound A and the boron hydride compound are subjected to a reduction reaction in a solvent, and the boron hydride compound is sodium boron hydride, potassium borohydride or In combination, the solvent is an alcohol; in the step (3), the product B is subjected to a ring closure reaction in a solvent and under the action of a base, the solvent is dichloromethane, dichloroethane or a combination thereof, and the alkali is an inorganic base or an organic The base or a combination thereof, the inorganic base is potassium hydroxide, sodium hydroxide or a combination thereof, and the organic base is ammonia water, triethylamine, tributylamine, 1,8-diazabicycloundec-7-ene, pyridine , imidazole or a combination thereof; in the step (5), the esterification reaction of the compound D with triethyl phosphonium acetate in a solvent and a tert-butanol compound, the solvent is benzene, toluene, xylene or In combination, the tert-butanol compound is sodium t-butoxide, potassium t-butoxide or a combination thereof; in the step (6), the compound F and the methyl formate are subjected to an aminolysis reaction under the action of an atmosphere and an alcohol and under the action of sodium alkoxide. The alcohol is methanol, ethanol or a combination thereof, and the sodium alkoxide is sodium methoxide, sodium ethoxide or a combination thereof.

According to an embodiment of the present invention, in the step (2), the alcohol is methanol; and in the step (3), the base is triethylamine.

According to an embodiment of the invention, the step (1) comprises: after the reaction is finished, cooling the reaction liquid; pouring the reaction liquid into ice water and stirring until stratification; extracting the layered water layer with dichloromethane, and merging the organic layer The organic layer is washed with water, saturated with sodium hydrogencarbonate and washed with water; the organic layer is dried with magnesium sulfate; and the organic layer is filtered and concentrated to obtain compound A; step (2) comprises: after the reaction is finished, the reaction liquid is cooled; sequence and dichloromethane was added dropwise NH ₄ Cl solution to the reaction mixture, stirred until delamination; the aqueous layer was extracted with dichloromethane stratification, then the organic layers combined; the organic layer was dried with saturated aqueous sodium chloride solution; and Filtration and concentration of the organic layer to obtain product B; step (3) comprises: after the reaction is completed, the reaction liquid is cooled and layered; the layered aqueous layer is extracted with dichloromethane, and the organic layer is combined; and washed, dried and The organic layer is concentrated to obtain product C; step (4) comprises: after the reaction is completed, n-hexane and water are added to the reaction liquid, and then stirred and filtered to separate the layers; the layered aqueous layer is extracted with n-hexane, and then combined. Organic layer; Washing, drying and concentrating the organic layer to obtain compound D; step (4) further comprises: extracting the layered aqueous layer with n-hexane, and then combining the aqueous layer; adding sodium chloride to the aqueous layer, and then using acetic acid The ester is extracted, and the organic layer is further combined; and the organic layer is washed with a saturated aqueous solution of sodium chloride, dried and concentrated to obtain compound E; step (5) comprises: after the reaction is finished, the reaction solution is cooled; and water is added to the reaction solution for standing. To the layering; the layered aqueous layer is extracted with toluene, and the organic layer is further combined; and the organic layer is concentrated by water washing and under reduced pressure to obtain a compound F; the step (6) comprises: after the reaction is finished, the reaction liquid is cooled; The reaction solution is further filtered to obtain a filter cake; the mixture is washed with a mixture of methanol and water, washed with water and diisopropyl ether; and the filter cake is dried under vacuum to obtain compound G; step (7) comprises: reaction After completion, the reaction solution is cooled; isopropyl acetate is added to the reaction solution to stand until the layer is separated; the layered aqueous layer is extracted with isopropyl acetate, and the organic layer is further combined; and the organic layer is washed with water and concentrated to obtain ( 1R,2S)-2-(3,4-difluorophenyl) Propylamine.

According to an embodiment of the invention, the method for preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine further comprises: (i) subjecting compound E to trimethylchloromethane for substitution reaction, Forming compound H, the chemical structural formula of compound H is (ii) subjecting compound H to a sulfonium chloride compound to carry out a substitution reaction to form compound J, and the chemical structural formula of compound J is Wherein R ' is methanesulfonyl or p-toluenesulfonyl; and (iii) ring-closing reaction of compound J to form compound D, wherein step (i) is subjected to a substitution reaction under the action of a base, and the base comprises triethyl An amine, tributylamine, 1,8-diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; step (ii) is subjected to a substitution reaction under the action of a base, the base comprising triethylamine, three Butylamine, 1,8-diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; step (iii) is subjected to a ring closure reaction under the action of a base, the base is potassium hydroxide, sodium hydroxide, Potassium carbonate, sodium carbonate, potassium hydrogencarbonate, sodium hydrogencarbonate or a combination thereof.

According to an embodiment of the present invention, in the step (i), the compound E and the trimethylchloromethane are subjected to a substitution reaction in a solvent, the solvent is dichloromethane, dichloroethane or a combination thereof; in the step (iii), The compound J is subjected to a ring closure reaction in an alcohol and a base, and the base is potassium carbonate, sodium carbonate or a combination thereof.

According to an embodiment of the present invention, in the step (i), the molar ratio of the compound E, the base and the trimethylchlorodecane is 1: (1 to 1.5): (1 to 2), and the reaction temperature is The degree is 0~30 ° C, the reaction time is 1~12 hours; in step (ii), the molar ratio of the compound H, the base and the sulfonium chloride compound is 1: (1~1.2): (1~1.5), the reaction The temperature is 0~35°C, the reaction time is 1~8 hours; in step (iii), the molar ratio of compound J to alkali is 1: (1~10), the reaction temperature is 0~50°C, and the reaction time is 1 ~8 hours.

According to an embodiment of the present invention, in the step (i), the molar ratio of the compound E, the base and the trimethylchlorodecane is 1:1.2:1.0, the reaction temperature is 0 ° C, and the reaction time is 1 hour; step (ii) Wherein, the molar ratio of the compound H, the base and the sulfonium chloride compound is 1:1.0:1.0, the reaction temperature is 0 ° C, and the reaction time is 6 hours; in the step (iii), the molar ratio of the compound J to the base is 1 : 3, the reaction temperature was 0 ° C, and the reaction time was 2 hours.

According to an embodiment of the present invention, the step (ii) comprises: after the reaction is completed, adding water to the reaction liquid, stirring to separate the layers; extracting the layered aqueous layer with dichloromethane, and further combining the organic layers; and washing and drying The organic layer is evaporated to obtain the compound J; the step (iii) comprises: after the reaction is completed, the reaction solution is filtered to obtain a filtrate; the filtrate is concentrated, and water and ethyl acetate are added to the layer; the layered aqueous layer is treated with ethyl acetate The ester is extracted, and the organic layer is further combined; the organic layer is washed with brine, dried and concentrated; calcium hydrogen is added to the organic layer; and the organic layer is distilled under reduced pressure to give compound D.

According to an embodiment of the invention, the process for preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine further comprises: (iv) substituting compound E with tert-butyldimethylchloromethane Reaction to form compound K, the chemical structural formula of compound K is (v) subjecting compound K to a sulfonium chloride compound to form a compound L, and the chemical structural formula of compound L is Wherein R ' is a methanesulfonyl or p-toluenesulfonyl group; and (vi) a decoupling reaction of the compound L with tetrabutylammonium fluoride to form a compound M, the chemical structural formula of which is And (vii) subjecting compound M to a ring closure reaction to form compound D, wherein step (iv) is subjected to a substitution reaction under the action of a base comprising triethylamine, tributylamine, 1,8-diazabicyclo ring Eleven-7-ene, pyridine, imidazole or a combination thereof; step (v) is subjected to a substitution reaction under the action of a base comprising triethylamine, tributylamine, 1,8-diazabicyclohexadecyl -7-ene, pyridine, imidazole or a combination thereof; step (vii) is subjected to a ring closure reaction under the action of a base, the base being potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogencarbonate, sodium hydrogencarbonate or combination.

According to an embodiment of the present invention, in the step (iv), the compound E and the tert-butyldimethylchloromethane are subjected to a substitution reaction in a solvent, the solvent is dichloromethane, dichloroethane or a combination thereof; the step (vii) In the compound, the compound M is subjected to a ring closure reaction under the action of an alcohol and a base, and the base is potassium carbonate, sodium carbonate or a combination thereof.

According to an embodiment of the present invention, in the step (iv), the molar ratio of the compound E, the base and the tert-butyldimethylchloromethane is 1: (1 to 1.5): (1 to 2), and the reaction temperature is 0~. At 30 ° C, the reaction time is 1 to 12 hours; in step (v), the molar ratio of the compound K, the base and the sulfonium chloride compound is 1: (1 to 1.2): (1 to 1.5), and the reaction temperature is 0~ 35 ° C, the reaction time is 1 to 8 hours; in step (vi), the compound L is reacted with tetrabutylammonium fluoride in tetrahydrofuran at room temperature; in step (vii), the molar ratio of the compound M to the base It is 1: (1~10), the reaction temperature is 0~50 °C, and the reaction time is 1~8 hours.

According to an embodiment of the present invention, in the step (iv), the molar ratio of the compound E, the base and the tert-butyldimethylchloromethane is 1:1.2:1.0, the reaction temperature is 0 ° C, and the reaction time is 6 hours; In (v), the molar ratio of the compound K, the base and the sulfonium chloride compound is 1:1.0:1.0, the reaction temperature is 0 ° C, and the reaction time is 6 hours; in the step (vii), the molar of the compound M and the base The ratio was 1:3, the reaction temperature was 0 ° C, and the reaction time was 2 hours.

According to an embodiment of the present invention, the step (v) comprises: after the reaction is completed, adding water to the reaction liquid, stirring to stratification; extracting the layered aqueous layer with dichloromethane, and further combining the organic layer; and washing and drying Evaporating the organic layer to obtain compound L; Step (vi) comprises: after the reaction is completed, adding water to the reaction liquid, stirring to separate the layers; extracting the layered aqueous layer with dichloromethane, and combining the organic layer; and washing and drying the organic layer to obtain a compound M; Step (vii) comprises: after the reaction is completed, the reaction solution is filtered to obtain a filtrate; the filtrate is concentrated, and water and ethyl acetate are added to the layer; the layered aqueous layer is extracted with ethyl acetate, and the organic layer is combined. Washing, drying and concentrating the organic layer with brine; adding calcium hydrogen to the organic layer; and distilling the organic layer under reduced pressure to give Compound D.

The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

Example 1: Preparation of Compound A

450 ml of dichloromethane and 133.5 g (1 mol) of aluminum trichloride were added to the reaction flask, followed by stirring. Under a nitrogen atmosphere, 113 g (1 mol) of chloroacetic chloride was added dropwise to the reaction solution, and the dropwise addition time was not less than 10 minutes. At the end of the dropwise addition, the reaction solution was heated to reflux. After refluxing for 30 minutes, 97 g (0.85 mol) of 1,2-difluorobenzene was added dropwise under reflux, and the dropwise addition time was not less than 2 hours. After the completion of the dropwise addition, the reflux reaction was continued for 1 hour. After completion of the reaction, the reaction solution was cooled to 20 ° C, and the reaction solution was slowly poured into 500 g of ice water, and stirring was continued for 30 minutes. After layering, the aqueous layer was extracted with dichloromethane. The combined organic layers were washed with water, saturated sodium bicarbonate and washed with water. The organic layer was dried over an excess of magnesium sulfate, filtered and concentrated to dichloromethane. To give Compound A 158g, yield ^{98%; 1 H-NMR:} δ (ppm): 5.2 (2H, s); 7.6 (1H, dd), 7.8 (1H, m), 8.0 (1H, dd).

Example 2: Preparation of Product B

50 ml of methanol and 7.6 g (0.04 mol) of Compound A were added to the reaction flask. The reaction solution was cooled to 0 ° C under stirring. 0.378 g (0.01 mol) of sodium borohydride was slowly added to the reaction liquid, and the temperature during the addition was less than 5 °C. After the sodium borohydride was added, the temperature of the reaction solution was raised to room temperature to react. After completion of the reaction, the reaction solution was cooled to 0 ° C, dichloromethane was added, and 75 ml of a 10% aqueous NH ₄ Cl solution was added dropwise to the reaction mixture. After the completion of the dropwise addition, the mixture was stirred for 30 minutes. Layered. The aqueous layer was extracted with dichloromethane. The organic layers were combined and washed with brine. The organic layer was dried and filtered. The organic layer was concentrated to give the product B, 7.42 g,yield: 96%; ¹ H-NMR: δ (ppm): 3.9 (2H, dd); 5.3 (2H, dd); 7.3-7.5 (3H, m).

Example 3: Preparation of Product C

To the reaction flask were added 10.5 g (0.02625 mol) of 10% aqueous sodium hydroxide solution, 4.813 g (0.025 mol) of product B, and 50 ml of dichloromethane (DCM). The reaction was carried out at room temperature under stirring conditions. After the reaction was completed, it was cooled to room temperature and layered. The aqueous layer was extracted with dichloromethane; the organic layers were combined and washed with water. Drying, concentrating the organic layer to give the product C 3.8 g, yield 97.4%; ¹ H-NMR: δ 2.71-2.73 (1H, dd); 3.13 - 3.15 (1H, m); 3.82-3.83 (1H, m); 7.01-7.27 (3H, m).

Example 4: Preparation of catalyst

To the reaction flask, 22.96 g (0.2 mol) of (s,s)-cyclohexanediamine and 1000 ml of absolute ethanol were added, and the mixture was stirred and dissolved. Further, 94.35 g (0.4 mol) of the compound I was added to the reaction liquid. The reaction solution was heated to reflux for about 2 hours. After the reaction was completed, it was cooled to room temperature. 500 ml of water was added dropwise to the reaction mixture, followed by stirring. After filtration, the filter cake was washed with a small amount of 95% ethanol 25 ml, and dried by filtration. Obtained Compound II 106g, yield 97%; ¹ H-NMR: δ 1.24 (9H, s); 1.41 (9H, s); 1.45 (1H, m); 1.8-1.65 (1H, m); 2.0-1.8 ( 2H, m); 3.32 (1H, m); 6.98 (1H, d); 7.30 (1H, d); 8.3 (1H, s); 13.72 (1H, s).

To the reaction flask, 106 g (0.194 mol) of compound II and 1500 ml of ethanol were added, and the mixture was dissolved by heating. Further, 92.2 g (0.485 mol) of cobalt acetate tetrahydrate was added to the reaction liquid. The reaction solution was heated to reflux for about 2 hours. The reaction solution was cooled to 5 ° C, 750 ml of water was added, and stirred for 2 hours. Filtration gave a dark brown solid. It was rotary-steamed and dried at 80 ° to obtain 109 g of a cobalt ligand catalyst compound III in a yield of 85%.

By changing cobalt cobalt tetrahydrate to ferric chloride or nickel carbonate tetrahydrate, an iron ligand catalyst or a nickel ligand catalyst can be obtained in the same manner, for example. or , but not limited to this.

Example 5: Preparation of Compounds D and E

Product C 101 g (0.6474 mol), compound III 10.7 g (0.0169 mol) and water 5.83 (0.3237 mol) were added to the reaction flask. The reaction solution was allowed to react at room temperature. After reacting for 60 hours, 150 ml of n-hexane and 150 ml of water were added. Stir vigorously for 2 hours and filter. The filtrate was separated and the aqueous layer was extracted with n-hexane.

The organic layer was combined, washed with water, dried and evaporated, then, 2 g of calcium hydrogen was added, and the water was pumped under reduced pressure to obtain a compound D 30 g, an optical purity of 98.3%, [α] D15 = -4.2 ° (EtOH) yield 30%; ¹ H-NMR: δ 2.71-2.73 (1H, Dd); 3.13 - 3.15 (1H, m); 3.82-3.83 (1H, m); 7.01-7.27 (3H, m).

The aqueous layers were combined, and a salt was added to the aqueous layer and then ethyl acetate. Ethyl acetate was combined, washed with brine, dried and evaporated to ethylamine. 1H-NMR: δ 2.2-2.3 (1H, s); 2.71-2.73 (1H, s); 3.5-3.9 (2H, m); 4.7 (1H, d); 7.01-7.27 (3H, m).

Example 6: Preparation of Compounds D and E

Product C 101 g (0.6474 mol), iron complex catalyst 10 g and water 5.83 (0.3237 mol) were added to the reaction flask. The reaction solution was allowed to react at room temperature. After reacting for 65 hours, 250 ml of n-hexane and 150 ml of water were added. Stir vigorously for 2 hours and filter. The filtrate was separated and the aqueous layer was extracted with n-hexane.

The pentane was combined, washed with water, dried and concentrated to give 50 g of Compound D. 2 g of calcium hydrogen was added, and the water was pumped under reduced pressure to obtain 45 g of compound D, and the optical purity was 80%.

The aqueous layers were combined, and a salt was added to the aqueous layer and then ethyl acetate. The combined ethyl acetate was washed with brine, dried and evaporated

Example 7: Preparation of Compound H

Compound E 55.9 g (0.32126 mol), dichloromethane 560 ml, and triethylamine 66.52 g (0.6586 mol) were added to the reaction flask, followed by stirring. The reaction solution was cooled to -5 ° C, and slowly to the reaction liquid trimethylchloromethane 34.89 g (0. 32126 mol), keeping the temperature below -5 °C during the dropwise addition. After completion of the dropwise addition, the reaction solution was kept at 0 ° C for 1 hour to obtain a compound H. The reaction solution can be directly subjected to the next reaction (refer to Example 8).

Example 8: Preparation of Compound J

To the above reaction liquid droplets, 36.785 g (0.32126 mol) of methanesulfonate chloride was added dropwise, and the temperature was kept below 5 ° C during the dropwise addition. At the end of the dropwise addition, the reaction solution was kept at a temperature of less than 5 °C. After the completion of the reaction, water was added to the reaction mixture, and the mixture was stirred for 30 minutes and layered. The aqueous layer was extracted with dichloromethane. The combined organic layers were washed with water and dried to dryness to give compound J 102 g; ¹ H-NMR: δ 0.08-0.13 (9H, m); 2.80-3.00 (3H, d); 3.7-3.9 (2H, m); 5.48-5.52 ( 1H, m); 7.01-7.27 (3H, m).

Example 9: Preparation of Compound D

102 g of the compound J was dissolved in 1000 ml of methanol, and 132.4 g of potassium carbonate was added thereto, and the mixture was stirred for 2 hours. After the reaction was terminated, it was filtered, and the filtrate was concentrated. The aqueous layer was extracted with ethyl acetate. The combined ethyl acetate was washed with brine. The organic layer was dried and concentrated to give 42 g. 2 g of calcium hydrogen was added, and the water was pumped under reduced pressure to obtain 15 g of compound D, and the optical purity was 97.9%. ¹ H-NMR: δ 2.71-2.73 (1H, dd); 3.13 - 3.15 (1H, m); 3.82-3.83 (1H, m); 7.01-7.27 (3H, m).

Example 10: Preparation of Compound F

To the reaction flask, 243.0 g of toluene, 32.22 g (0.34 mol) of sodium t-butoxide and 78.06 g (0.35 mol) of triethyl phosphonium acetate were stirred and dissolved to form a reaction liquid; then the reaction liquid was heated to 70 ° C; D 41.83 g (0.268 mol) was dissolved in 100 g of toluene, and the solution was added dropwise to the reaction liquid, and the temperature of the reaction liquid was maintained at 60 to 80 ° C during the dropwise addition. After the completion of the dropwise addition, the temperature of the reaction liquid was raised to 80 ° C to react, and the reaction time was about 11 hours. After the reaction was completed, it was cooled to room temperature, water was added, and the layers were separated. The aqueous layer was extracted with toluene, the organic layers were combined, washed with water, the organic layer was concentrated under reduced pressure, to give compound F 48.5g, yield ^{80%; 1 H-NMR:} δ1.22-1.26 (1H, m); 1.26-1.30 (3H , t); 1.57-1.62 (1H, m); 1.82-1.8 (1H, m); 2.45-2.50 (1H, m); 4.14-4.20 (2H, q); 6.82-6.91 (2H, m); 7.02 -7.09 (1H, m).

Example 11: Preparation of Compound G

To the reaction flask, Compound F 22.6 g (0.1 mol), methanol 67 ml (3 V), methyl formate 6 g (0.1 mol) and sodium methoxide 40.5 (0.075 mol) were added to the reaction mixture to form a reaction mixture. After the reaction solution was sealed, it was heated to 60 °C. Further, two atmospheres of ammonia gas were passed through the reaction solution. The reaction solution was kept at 60 ° C and the pressure was 2 atmospheres for 4 hours. After completion of the reaction, the mixture was cooled, the reactor was depressurized, poured out, and 134 g (6 V) of water was added thereto, and the mixture was heated to 60 ° C and stirred for 1 hour. After cooling to room temperature, stirring, filtration, methanol/water = 1 V / 1 V 40 ml, water 30 ml wash, diisopropyl ether (bp: 68.5 ° C) 30 ml wash. The filter cake was dried in vacuo at 50 ° C, compound G 15.8 g, yield 80%. ¹ H-NMR: δ 1.21-1.27 (1H, m); 1.56-1.64 (3H, m); 2.47-2.49 (1H, m); 5.45 (1H, br); 5.63 (1H, br); 6.90 (2H, m); 7.03-7.10 (1H, m).

Example 12: Preparation of (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine

In the reaction flask, 54.77 g (0.41 mol) of a 30% aqueous NaOH solution and 9 g (0.0457 mol) of a compound G were added and stirred; 71 g (0.1005 mol) of a 12% aqueous solution of NaClO was added dropwise to the reaction solution, and the temperature was maintained during the dropwise addition. After 30 ° C, the reaction was carried out at 30 ° C for 14 hours and at 40 ° C for 2 hours; the reaction was completed and cooled to room temperature. Isopropyl acetate (bp: 89 ° C) was added to the reaction solution, and the layers were separated, and the aqueous layer was extracted with isopropyl acetate. The organic layer was combined, washed with water and concentrated to give (1R, 2S)-2-(3,4-difluoro Phenyl) cyclopropylamine 6.57 g, yield 85%. ¹ H-NMR: δ 0.88-0.93 (1H, m); 1.03-1.08 (1H, m); 1.7 (2H, s); 1.79-1.84 (1H, m); 2.47-2.51 (1H, m); 6.72-6.79 (2H, m); 7.00-7.02 (1H, m).

It is to be noted that in the Hofmann degradation reaction, sodium hydroxide and sodium hypochlorite are preferred as the source of the base, and an aqueous solution thereof is used as the reaction system. Further, when the compound J is prepared from the compound H or the compound L is prepared from the compound K, the sulfonium chloride compound can be directly added to the reaction system of the compound H or the compound K which has been reacted, and the reaction can be continued, thereby saving Base and solvent; Of course, in other embodiments, compound H or compound K may be purified and then a new reaction system may be disposed.

Importantly, in the present invention, the catalyst is a metal chiral ligand, and a chiral ligand is synthesized by condensation of (s,s)-cyclohexanediamine with 3,5-di-tert-butylsalicylaldehyde. The ligand complexes with metal ions such as cobalt ions, iron ions or nickel ions to form different active metal chiral ligands. The metal chiral ligand provided by the invention has excellent catalytic effect, and can be recycled and reused, which can significantly reduce the cost.

In summary, the present invention has the following advantages over the prior art:

(1) Simple operation while avoiding the use of expensive reagents for chiral redox.

(2) The (S)-3,4-difluorophenyloxirane is obtained by kinetic resolution, the raw material cost is low, and the catalyst can be used repeatedly.

(3) The R-configuration by-product diol (ie, the above compound E) produced by the resolution can be subjected to configuration conversion, and (s)-3,4-difluorophenyloxirane (i.e., the above compound D) is recovered. ), can significantly reduce the cost of intermediates.

Although the present invention has been disclosed in the above embodiments, it is not intended to limit the present invention, and the present invention can be modified and modified without departing from the spirit and scope of the present invention. The scope is subject to the definition of the scope of the patent application attached.

Claims (17)

A method for preparing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine, comprising: (1) conducting 1,2-difluorobenzene and ruthenium chloride under the action of aluminum trichloride Fuke reaction to form compound A, wherein the chemical structure of the ruthenium chloride is Wherein R is hydrogen, a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group, and the chemical structural formula of the compound A is (2) subjecting the compound A to a reduction reaction with a boron hydride compound to form a product B, the product B being versus (3) subjecting the product B to a ring closure reaction to form product C, which is C versus (4) subjecting the product C to hydrolysis reaction with water under the action of a catalyst to form a compound D and a compound E, the chemical structural formula of which is , the chemical structural formula of the compound E is (5) The compound D is esterified with triethyl phosphonium acetate under the action of a tert-butanol compound to form a compound F, and the chemical structural formula of the compound F is (6) subjecting the compound F to methyl formate under an atmosphere and under the action of sodium alkoxide to form a compound G, the chemical structural formula of which is The atmosphere is ammonia gas, guanamine gas or a combination thereof; and (7) the compound G is subjected to a Hofmann degradation reaction to form a (1R, 2S)-2-(3,4-difluorophenyl) ring Propylamine, its chemical structural formula is The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 1, wherein the catalyst comprises a metal chiral ligand, and the chemical structural formula is Wherein M is iron, cobalt or nickel and A is hydrogen, halogen, alkyl or ester group ( ). The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine as claimed in claim 1, wherein in the step (1), the 1,2-difluorobenzene, the three The molar ratio of aluminum chloride to the ruthenium chloride is 1: (1~10): (1~10), the reaction temperature is 0-40 ° C, and the reaction time is 3~30 hours; in the step (2), the The molar ratio of the compound A to the boron hydride compound is 1: (0.2 to 2), the reaction temperature is 0 to 50 ° C, and the reaction time is 0.5 to 10 hours; in the step (3), the reaction temperature is 0 to 40 ° C. , the reaction time is 1 to 12 hours; in the step (4), the molar ratio of the product C, the metal chiral ligand to the water is 1: (0.01~0.1): (0.4~0.8), the reaction temperature 10~60 ° C, reaction time 12~60 hours; in the step (5), the molar ratio of the compound D, the t-butanol compound and the triethyl phosphonium acetate is 1: (1~3): (1~2), the reaction temperature is 40~110 °C, and the reaction time is 1~30 hours; in the step (6), the molar ratio of the compound F, the sodium alkoxide and the methyl formate is 1: (0.5~2) ): (0.5~2), the reaction temperature is 40~65°C, the pressure of the atmosphere is 0~10 Torr, and the reaction time is 10~80 hours; in the step (7), the action of the compound G in the alkali is For the Hofmann rearrangement, the base comprises sodium hydroxide and sodium hypochlorite, the compound G, the molar ratio of the sodium hydroxide to the sodium hypochlorite is 1: (1 ~ 5): (2 ~ 8), the reaction temperature is 40 ~ 65 ° C, the reaction time is 1 ~ 80 hours. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 3, wherein in the step (1), the 1,2-difluorobenzene, the three The molar ratio of aluminum chloride to the ruthenium chloride is 1:1.2:1.2, the reaction temperature is the reflux temperature, and the reaction time is 10 hours; in the step (2), the compound A and the borohydride compound The molar ratio is 1:0.25, the reaction temperature is 10 ° C, and the reaction time is 2 hours; in the step (3), the reaction temperature is 25 ° C, and the reaction time is 8 hours; in the step (4), The molar ratio of the product C, the metal chiral ligand to the water is 1:0.025:0.5, the reaction temperature is 25 ° C, and the reaction time is 48 hours; in the step (5), the compound D, The molar ratio of the tert-butanol compound to the triethyl phosphonium acetate is 1:1.5:1.5, the reaction temperature is 80 ° C, and the reaction time is 11 hours; in the step (6), the compound F The molar ratio of the sodium alkoxide to the methyl formate is 1:0.75:1, the reaction temperature is 40 ° C, the pressure of the atmosphere is 2 Torr, and the reaction time is 48 hours; in the step (7) , the compound G, the hydrogen and oxygen The sodium hypochlorite is the molar ratio of 1: 5: 2, the reaction temperature is 40 ℃, the reaction time is 8 hours. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine as claimed in claim 1, wherein in the step (1), the 1,2-difluorobenzene is reacted with the The ruthenium chloride is subjected to the Friedel-Crafts reaction under the action of the aluminum trichloride in a solvent, and the solvent is dichloromethane, dichloroethane or a combination thereof; In the step (2), the compound A and the boron hydride compound are subjected to the reduction reaction in a solvent, the boron hydride compound being sodium boron hydride, potassium boron hydride or a combination thereof, the solvent being an alcohol; the step (3) The product B is subjected to the ring closure reaction in a solvent which is dichloromethane, dichloroethane or a combination thereof, and the base is an inorganic base, an organic base or a combination thereof, the inorganic The base is potassium hydroxide, sodium hydroxide or a combination thereof, and the organic base is ammonia water, triethylamine, tributylamine, 1,8-diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof. In the step (5), the compound D and the triethyl phosphonium acetate are subjected to the esterification reaction in the presence of the tert-butanol compound, and the solvent is benzene, toluene, xylene or In combination, the tert-butanol compound is sodium t-butoxide, potassium t-butoxide or a combination thereof; in the step (6), the compound F and the methyl formate are in the atmosphere and in the alcohol and in the sodium alkoxide. The aminolysis reaction is carried out under the action of methanol, ethanol or a combination thereof, and the sodium alkoxide is sodium methoxide, sodium ethoxide or a combination thereof. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 5, wherein in the step (2), the alcohol is methanol; in the step (3) The base is triethylamine. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 1, wherein the step (1) comprises: after the reaction is finished, cooling the reaction solution; The liquid was poured into ice water and stirred until the layer was separated; the layered aqueous layer was extracted with dichloromethane, and the organic layer was combined; the organic layer was washed with water, saturated sodium hydrogen carbonate and washed with water; layer; and the organic layer was filtered and concentrated to afford the compound A; the step (2) comprises: after completion of the reaction, the reaction solution was cooled; dichloromethane were added sequentially and NH ₄ Cl aqueous solution was added dropwise to the reaction mixture, Stirring to the layering; extracting the layered aqueous layer with methylene chloride, and concentrating the organic layer; drying the organic layer with a saturated aqueous solution of sodium chloride; and filtering and concentrating the organic layer to obtain the product B; (3) comprising: after the reaction is completed, the reaction liquid is cooled and layered; the layered aqueous layer is extracted with dichloromethane, and the organic layer is further combined; and the organic layer is washed with water, dried and concentrated to obtain the product C; The step (4) comprises: after the reaction is completed, adding n-hexane and water to the reaction solution And stirring and filtering to the layer; the layered aqueous layer is extracted with n-hexane, and the organic layer is further combined; and the organic layer is washed with water, dried and concentrated to obtain the compound D; the step (4) further comprises: After the layered aqueous layer is extracted with the n-hexane, the aqueous layer is further combined; sodium chloride is added to the aqueous layer, extracted with ethyl acetate, and the organic layer is further combined; and a saturated aqueous solution of sodium chloride is used. Washing, drying and concentrating the organic layer to obtain the compound E; the step (5) comprises: after the reaction is finished, cooling the reaction liquid; adding water to the reaction liquid to stand until the layering; the layered water layer Extracting with toluene, and further combining the organic layer; and washing the organic layer with water and concentrating under reduced pressure to obtain the compound F; the step (6) comprises: after the reaction is finished, cooling the reaction solution; adding water to the reaction solution and filtering, To obtain a filter cake; sequentially washing with a mixture of methanol and water, washing with water and diisopropyl ether; and drying the filter cake in vacuo to obtain the compound G; the step (7) comprises: after the reaction is completed , cooling the reaction solution; adding isopropyl acetate to The reaction solution was allowed to stand until the layer was separated; the layered aqueous layer was extracted with isopropyl acetate, and the organic layer was combined; and the organic layer was washed with water and concentrated to obtain the (1R, 2S)-2-(3, 4-difluorophenyl)cyclopropylamine. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 1, further comprising: (i) subjecting the compound E to trimethylchlorodecane for substitution reaction To form compound H, the chemical structural formula of the compound H is (ii) subjecting the compound H to a sulfonium chloride compound to form a compound J, the chemical structural formula of the compound J is Wherein R ' is a methanesulfonyl or p-toluenesulfonyl group; and (iii) subjecting the compound J to a ring closure reaction to form the compound D, wherein the step (i) is carried out under the action of a base, The base comprises triethylamine, tributylamine, 1,8-diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; the step (ii) is carried out under the action of a base, The base comprises triethylamine, tributylamine, 1,8-diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; the step (iii) is carried out under the action of a base, The base is potassium hydroxide, sodium hydroxide, potassium carbonate, sodium carbonate, potassium hydrogencarbonate, sodium hydrogencarbonate or a combination thereof. A process for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine as claimed in claim 8, wherein in the step (i), the compound E and the trimethylchlorodecane are caused. The substitution reaction is carried out in a solvent, the solvent is dichloromethane, dichloroethane or a combination thereof; in the step (iii), the compound J is subjected to the ring closure reaction under the action of the base and the base. The base is the potassium carbonate, the sodium carbonate or a combination thereof. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 8, wherein in the step (i), the compound E, the base and the trimethyl group The molar ratio of chlorodecane is 1: (1~1.5): (1~2), the reaction temperature is 0-30 ° C, and the reaction time is 1~12 hours; in the step (ii), the compound H and the base are used. The molar ratio to the sulfonium chloride compound is 1: (1 to 1.2): (1 to 1.5), the reaction temperature is 0 to 35 ° C, and the reaction time is 1 to 8 hours; in the step (iii), the compound The molar ratio of J to the base is 1: (1~10), the reaction temperature is 0-50 ° C, and the reaction time is 1-8 hours. The process for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine as claimed in claim 10, wherein in the step (i), the compound E, the base and the trimethyl group The molar ratio of chlorodecane is 1:1.2:1.0, the reaction temperature is 0 ° C, and the reaction time is 1 hour; in the step (ii), the compound H, the base and the sulfonium chloride compound The ear ratio is 1:1.0:1.0, the reaction temperature The reaction time is 6 hours; in the step (iii), the molar ratio of the compound J to the base is 1:3, the reaction temperature is 0 ° C, and the reaction time is 2 hours. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 8, wherein the step (ii) comprises: after the reaction is completed, adding water to the reaction solution, stirring To the layering; the layered aqueous layer is extracted with dichloromethane, and the organic layer is further combined; and the organic layer is steamed and dried to obtain the compound J; the step (iii) comprises: after the reaction is finished, filtering The reaction liquid was taken to obtain a filtrate; the filtrate was concentrated, and water and ethyl acetate were added to the layer; the layered aqueous layer was extracted with ethyl acetate, and the organic layer was combined; the organic layer was washed with brine, dried and concentrated. Adding calcium hydrogen to the organic layer; and distilling the organic layer under reduced pressure to obtain the compound D. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 1, further comprising: (iv) the compound E and tert-butyldimethylchlorodecane A substitution reaction is carried out to form a compound K, and the chemical structural formula of the compound K is (v) subjecting the compound K to a substitution reaction with a sulfonium chloride compound to form a compound L having a chemical structural formula of Wherein R 'is acyl methanesulfonamide or toluenesulfonamide acyl; and (vi) reacting the compound with tetrabutylammonium fluoride L amine to de silicon, to form compound M, compound of formula M is of the And (vii) subjecting the compound M to a ring closure reaction to form the compound D, wherein the step (iv) is carried out under the action of a base comprising triethylamine, tributylamine, 1,8- Diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; the step (v) is carried out under the action of a base comprising triethylamine, tributylamine, 1,8- Diazabicycloundec-7-ene, pyridine, imidazole or a combination thereof; the step (vii) is carried out under the action of a base, which is potassium hydroxide, sodium hydroxide, potassium carbonate, carbonic acid Sodium, potassium bicarbonate, sodium bicarbonate or a combination thereof. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 13, wherein in the step (iv), the compound E and the tert-butyl dimethyl group are obtained. The chloropurane is subjected to the substitution reaction in a solvent, which is dichloromethane, dichloroethane or a combination thereof; in the step (vii), the The compound M is subjected to the ring closure reaction in an alcohol under the action of the base, and the base is the potassium carbonate, the sodium carbonate or a combination thereof. The process for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine as described in claim 13, wherein in the step (iv), the compound E, the base and the t-butyl group The molar ratio of dimethylchlorodecane is 1: (1~1.5): (1~2), the reaction temperature is 0-30 ° C, and the reaction time is 1~12 hours; in the step (v), the compound K The molar ratio of the base to the sulfonium chloride compound is 1: (1~1.2): (1~1.5), the reaction temperature is 0-35 ° C, and the reaction time is 1-8 hours; in the step (vi) The compound L is reacted with the tetrabutylfluorinated amine in tetrahydrofuran at room temperature; in the step (vii), the molar ratio of the compound M to the base is 1: (1~10), the reaction temperature It is 0~50 °C, and the reaction time is 1~8 hours. The process for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 15, wherein in the step (iv), the compound E, the base and the tert-butyl group The molar ratio of dimethylchloromethane is 1:1.2:1.0, the reaction temperature is 0 ° C, and the reaction time is 6 hours; in the step (v), the compound K, the base and the sulfonium chloride compound The molar ratio is 1:1.0:1.0, the reaction temperature is 0 ° C, and the reaction time is 6 hours; in the step (vii), the molar ratio of the compound M to the base is 1:3. The reaction temperature was 0 ° C and the reaction time was 2 hours. The method for producing (1R,2S)-2-(3,4-difluorophenyl)cyclopropylamine according to claim 13, wherein the step (v) comprises: after the reaction is completed, adding water to the reaction solution, stirring To the layering; the layered aqueous layer is extracted with dichloromethane, and the organic layer is further combined; and the organic layer is steamed and dried to obtain the compound L; the step (vi) comprises: adding water after the reaction is completed To the reaction liquid, stirring to the layer; the layered aqueous layer is extracted with dichloromethane, and the organic layer is further combined; and the organic layer is steamed and dried to obtain the compound M; the step (vii) comprises After the reaction was completed, the reaction mixture was filtered to give a filtrate. The filtrate was concentrated, and then water and ethyl acetate were added to the mixture. The layered aqueous layer was extracted with ethyl acetate. The organic layer was dried and concentrated; calcium hydrogen was added to the organic layer; and the organic layer was distilled under reduced pressure to give the compound D.