阅读说明：本技术 4-苯基-1-（吡啶-4-基甲基）吡咯烷-2-酮衍生物及其制备方法和应用 (4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative and preparation method and application thereof ) 是由 吴泽辉 陈华龙 杨泽群 蒋增 程雪波 于 2021-07-09 设计创作，主要内容包括：本发明属于放射性药物化学与核医学技术领域。本发明提供了一种4-苯基-1-(吡啶-4-基甲基)吡咯烷-2-酮衍生物,其结构式如式Ⅰ所示,本发明还提供了制备该4-苯基-1-(吡啶-4-基甲基)吡咯烷-2-酮衍生物的中间体化合物,以及制备方法和应用。本发明提供的4-苯基-1-(吡啶-4-基甲基)吡咯烷-2-酮衍生物与SV2A具有高亲和力,其放射性标记方法简单,标记产率高,有利于临床大剂量生产和应用,可用于制备SV2A变化相关疾病的诊断的显像剂。(The invention belongs to the technical field of radiopharmaceutical chemistry and nuclear medicine. The invention provides a 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative, a structural formula of which is shown in a formula I, and also provides an intermediate compound for preparing the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative, a preparation method and application thereof. The 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative provided by the invention has high affinity with SV2A, the radioactive labeling method is simple, the labeling yield is high, the clinical large-dose production and application are facilitated, and the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative can be used for preparing an imaging agent for diagnosing SV2A change-related diseases.)

1. A4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative having the formula I:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F。

2. 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivatives according to claim 1 selected from

One kind of (1).

3. An intermediate compound for the preparation of a 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative according to claim 1 having the formula ii:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F；

LG is selected from one of mesylate, p-toluenesulfonyl ester, trifluoromethanesulfonic acid or halogen.

4. A process for the preparation of an intermediate compound as claimed in claim 3, which is carried out by a process comprising the steps of reaction of formula i:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F；

The LG compound is a compound containing one leaving group of mesylate, p-toluenesulfonyl ester, trifluoromethanesulfonic acid or halogen.

5. The method of claim 4, comprising:

1) dissolving a raw material compound in dichloromethane at 0 ℃ under an inert atmosphere, mixing the dichloromethane with 3, 5-difluorobenzaldehyde for normal-temperature reaction, removing a solvent after reaction, adding a complex solution for redissolution, filtering the complex solution to obtain a filtrate, and purifying the filtrate by column chromatography to obtain a first product;

the raw material compound isWherein R is₁、R₂And R₃Each is independently selected from one of H or F;

2) dissolving the first product in acetonitrile, uniformly mixing the first product with DBU and nitromethane at the temperature of 0 ℃, reacting at normal temperature, and extracting and purifying by column chromatography after the reaction to obtain a second product; wherein, the column chromatography developing solvent system petroleum ether: ethyl acetate was 90: 10;

preferably, the volume ratio of the acetonitrile solution of the first product, DBU and nitromethane is 1: 1: 1; preferably, before extraction, the pH value is adjusted to 7 by dilute hydrochloric acid, water is added to dilute the solution after reaction, and then ethyl acetate is used for extraction;

3) dissolving the second product in ethanol, adding a proper amount of palladium carbon, reacting under the condition of hydrogen, filtering to obtain supernatant after the reaction is finished, and removing the solvent to obtain a third product;

4) mixing the third product with isonicotinic aldehyde in a molar ratio of 1: 1, dissolving in ethanol, adding an appropriate amount of acetic acid, performing a primary reaction at 70 ℃ in an inert atmosphere, cooling to 0 ℃ after the primary reaction, adding a reducing agent for a secondary reaction, adjusting the pH to 7 with dilute hydrochloric acid after the secondary reaction is completed, filtering, taking a supernatant, removing the solvent, extracting with ethyl acetate, taking an organic phase, drying with anhydrous sodium sulfate, removing the solvent, adding acetic acid for redissolving, performing a tertiary reaction at 80 ℃, removing the acetic acid after the tertiary reaction, and taking a column chromatography developing agent system which is pure ethyl acetate to obtain a fourth product;

wherein the molar ratio of the third product, isonicotinaldehyde and reducing agent is 1: 1: 3;

5) the fourth product, methyl acrylate, Pd (OAc)₂And triphenylphosphine (PPh)₃) In a molar ratio of 1: 5: 0.1: 0.2 is dissolved in DFM, then triethylamine is added, reaction is carried out at 120 ℃ in an inert atmosphere, DMF is removed by saturated saline after the reaction, and a fifth product is obtained after ethyl acetate extraction and column chromatography purification;

6) dissolving the fifth product in methanol, adding a reducing agent in batches within 3-5min under the ice-water bath condition, fully reacting at normal temperature, removing the methanol after reaction, and purifying by column chromatography to obtain a sixth product; wherein the molar ratio of the fifth product to the reducing agent is 1: 10, the column chromatography developing solvent system is pure ethyl acetate;

7) dissolving the sixth product in dichloromethane, adding triethylamine, then adding the LG compound and Dimethylaminopyridine (DMAP) at the temperature of 0 ℃, uniformly mixing, fully reacting at normal temperature, washing with water after reaction, removing the solvent, and purifying by column chromatography to obtain a compound intermediate of the formula II; wherein, the sixth product: LG compounds: triethylamine: molar ratio of DMAP 1:2:2:0.1, column chromatography developer system dichloromethane: methanol: ammonia water is 95: 5: 0.5;

wherein the reducing agent in the steps 4) and 6) is LiAlH₄Or NaBH₄。

6. The method according to claim 4, wherein in the step 1), the double solution is prepared from dichloromethane and n-hexane in a volume ratio of 1: 10 mixing to obtain; column chromatography developer system petroleum ether: ethyl acetate was 90: 10.

7. a process for the preparation of 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivatives according to claim 1 or 2, comprising:

dissolving the intermediate of the compound shown in the formula II in an organic solvent, adding n-butyl ammonium fluoride, carrying out heat preservation reaction at 50 ℃, removing the solvent after the reaction is finished, and carrying out column chromatography purification to obtain the compound;

wherein the organic solvent is selected from any one of tetrahydrofuran, dichloromethane or acetonitrile;

column chromatography developer system dichloromethane: the methanol content is 96: 4;

the concentration of the intermediate of the compound shown in the formula II in the reaction liquid is 10-70mg/mL, and the molar ratio of the intermediate of the compound shown in the formula II to n-butyl ammonium fluoride is 1-2: 1.

8. use of a 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative according to claim 1 or 2 for the preparation of an imaging agent for Positron Emission Tomography (PET).

9. A PET imaging agent for diagnosis of epilepsy or stroke comprising the 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative of claim 1 or 2.

10. The PET imaging agent according to claim 7, wherein the 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative comprises¹⁸And F, marking.

Technical Field

The invention relates to the technical field of radiopharmaceutical chemistry and nuclear medicine, in particular to 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivatives, and a preparation method and application thereof.

Background

Epilepsy (epilepsy) is a chronic disease in which neurons in the brain suddenly discharge abnormally, resulting in transient cerebral dysfunction. In china, epilepsy has become the second largest common disease of neurology, second only to headache, with enormous pain and economic burden on patients and family members. Although the treatment of epilepsy at home and abroad mainly takes drug therapy as the main treatment at present, about 20 to 30 percent of patients still have drug-refractory epilepsy. The surgical treatment of epilepsy provides a new treatment for this group of patients, and the accurate positioning of the lesion before the operation is the key to the success of the operation.

Positron Emission Tomography (PET) is a noninvasive image diagnostic means for exploring the biochemical process of the human brain, and has important significance in the location diagnosis of epilepsy. The current PET imaging agent for the location diagnosis of epileptic lesions, whether metabolic imaging agent: (A)¹⁸F-FDG) is also a neuroreceptor imaging agent (targeting GABA)_Athe/BZ receptor, the opiate receptor and the like) have certain limitations in clinical application research, and can not independently position epileptogenic focuses of all patients. Synaptic vesicular protein 2A (SV 2A) widely distributed in the brain has been proved to be a target molecular site of novel antiepileptic drugs Levetiracetam (LEVeticactam, LEV) and Brivaracetam (BRV), and has extremely high clinical application value in refractory epilepsy animal models and patients. Decreased expression of SV2A in hippocampus in temporal lobe epilepsy and hippocampal sclerosis rat models, Western blot analysis and SV 2A-related imaging agents¹¹PET scanning of C-UCB-J found a significant reduction in temporal cortical SV2A expression in patients with temporal lobe epilepsy and malformations that trigger refractory epilepsy (e.g., cortical dysplasia and cortical nodules). The SV2A is shown to be a very promising new target point for diagnosing epileptic foci.

¹¹C-LEV is an earlier PET imaging agent developed to target SV2A, with higher uptake in many organs and lower affinity (K)_i1.6 μ M) and slow clearance rates, fail to meet the requirements of clinical need, and its in vivo evaluation has not been reported to date.¹¹C-UCB-a was subjected to a series of preclinical studies in minipigs, rats and rhesus monkeys, and the results showed that brain clearance was slow and therefore may not be suitable for PET imaging.¹⁸F-UCB-H is the first to be used for in vivo quantitative determination of SV2A, and shows good kinetic properties in rats and non-human primates and a radiation dose acceptable to human beings; its synthesis has been very challenging, and recently an improved synthesis has been reported, but yields are still low. In addition, its specific binding capacity is relatively low (K)_i40nM) and no studies have been reported on human brain imaging.¹¹C-UCB-J as a PET radiotracer shows excellent properties in rhesus monkeys (K)_i6.3nM) and has been used in diagnostic studies of related clinical diseases. With the development of SV2A imaging agents, related imaging agents have been applied to clinical diagnosis, but the reported imaging agents have complex labeling conditions, low labeling yield and high labeling conditions, and novel PET imaging agents with simple labeling conditions and high yield still need to be further developed.

Disclosure of Invention

In order to overcome the problems of complex labeling conditions and low yield of the existing SV2A developer, the invention introduces a fluoropropyl group on the basis of the reported developer to obtain a series of novel compounds¹⁸F-labeled 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivatives.

The invention aims to provide a 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative with high affinity SV 2A. The compounds have high affinity with SV2A, and belong to brand new compounds for diagnosing and treating SV2A related diseases. A4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative having the formula I:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F。

Preferably, the 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative is selected from

One kind of (1).

The invention also provides an intermediate compound for preparing the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative, which has a structural formula shown in a formula II:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F；

LG is selected from one of mesylate, p-toluenesulfonyl ester, trifluoromethanesulfonic acid or halogen.

In another aspect, the present invention provides a process for the preparation of the above intermediate compound by a process comprising the steps of reacting:

wherein R is₁、R₂And R₃Each is independently selected from one of H or F;

R₄、R₅and R₆Each independently selected from methylene (CH)₂) Or deuterated methylene (CD)₂) One of (1);

f is¹⁹F or¹⁸F；

The LG compound is a compound containing one leaving group of mesylate, p-toluenesulfonyl ester, trifluoromethanesulfonic acid or halogen.

In one embodiment according to the present invention, the process for preparing the intermediate compound comprises:

1) dissolving a raw material compound in dichloromethane at 0 ℃ under an inert atmosphere, mixing the dichloromethane with 3, 5-difluorobenzaldehyde for normal-temperature reaction, removing a solvent after reaction, adding a complex solution for redissolution, filtering the complex solution to obtain a filtrate, and purifying the filtrate by column chromatography to obtain a first product;

the raw material compound isWherein R is₁、R₂And R₃Each is independently selected from one of H or F;

2) dissolving the first product in acetonitrile, uniformly mixing the first product with DBU and nitromethane at the temperature of 0 ℃, reacting at normal temperature, and extracting and purifying by column chromatography after the reaction to obtain a second product; wherein, the column chromatography developing solvent system petroleum ether: ethyl acetate was 90: 10;

3) dissolving the second product in ethanol, adding a proper amount of palladium carbon, reacting under the condition of hydrogen, filtering to obtain supernatant after the reaction is finished, and removing the solvent to obtain a third product;

4) mixing the third product with isonicotinic aldehyde in a molar ratio of 1: 1, dissolving in ethanol, adding an appropriate amount of acetic acid, performing primary reaction at 70 ℃ in an inert atmosphere, cooling to 0 ℃ after the primary reaction, adding a reducing agent for secondary reaction, adjusting the pH to 7 with dilute hydrochloric acid after the secondary reaction is finished, filtering to obtain a supernatant, removing the solvent, extracting with ethyl acetate, drying an organic phase with anhydrous sodium sulfate, removing the solvent, adding acetic acid for redissolving, performing tertiary reaction at 80 ℃, removing the acetic acid after the tertiary reaction, and obtaining a column chromatography developer system of pure ethyl acetate to obtain a fourth product;

wherein the molar ratio of the third product, isonicotinaldehyde and reducing agent is 1: 1: 3;

5) the fourth product, methyl acrylate, Pd (OAc)₂And triphenylphosphine (PPh)₃) In a molar ratio of 1: 5: 0.1: 0.2 is dissolved in DFM, then triethylamine is added, reaction is carried out at 120 ℃ in an inert atmosphere, DMF is removed by saturated saline after the reaction, and a fifth product is obtained after ethyl acetate extraction and column chromatography purification;

6) dissolving the fifth product in methanol, adding a reducing agent in batches within 3-5min under the ice-water bath condition, fully reacting at normal temperature, removing the methanol after reaction, and purifying by column chromatography to obtain a sixth product; wherein the molar ratio of the fifth product to the reducing agent is 1: 10, the column chromatography developing solvent system is pure ethyl acetate;

7) dissolving the sixth product in dichloromethane, adding triethylamine, then adding the LG compound and Dimethylaminopyridine (DMAP) at the temperature of 0 ℃, uniformly mixing, fully reacting at normal temperature, washing with water after reaction, removing the solvent, and purifying by column chromatography to obtain a compound intermediate of the formula II; wherein, the sixth product: LG compounds: triethylamine: molar ratio of DMAP 1:2:2:0.1, column chromatography developer system dichloromethane: methanol: ammonia water is 95: 5: 0.5;

wherein the reducing agent in the steps 4) and 6) is LiAlH₄Or NaBH₄。

In one embodiment according to the present invention, in step 1), the double solution is prepared from dichloromethane and n-hexane in a volume ratio of 1: 10 mixing to obtain; column chromatography developer system petroleum ether: ethyl acetate was 90: 10.

In one embodiment according to the invention, in step 2), the volume ratio of acetonitrile solution, DBU and nitromethane of the first product is 1: 1: 1; preferably, before extraction, the pH value is adjusted to 7 by dilute hydrochloric acid, water is added to dilute the solution after reaction, and then ethyl acetate is used for extraction;

in a further aspect of the present invention, there is provided a process for producing the above-mentioned 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative, which comprises:

dissolving the intermediate of the compound shown in the formula II in an organic solvent, adding n-butyl ammonium fluoride, carrying out heat preservation reaction at 50 ℃, removing the solvent after the reaction is finished, and carrying out column chromatography purification to obtain the compound; the organic solvent is selected from any one of tetrahydrofuran, dichloromethane or acetonitrile;

wherein, column chromatography developer system dichloromethane: the methanol content is 96: 4;

the concentration of the intermediate of the compound shown in the formula II in the reaction liquid is 10-70mg/mL, and the molar ratio of the intermediate of the compound shown in the formula II to n-butyl ammonium fluoride is 1-2: 1.

the present invention also provides a precursor compound for the preparation of a 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative, said precursor compound being selected from any one of said first, second, third, fourth, fifth or sixth product.

The invention also provides application of the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative in preparation of a Positron Emission Tomography (PET) imaging agent.

The invention further provides a PET imaging agent for diagnosing epilepsy or stroke, which comprises the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative.

Further, the 4-phenyl-1- (pyridin-4-ylmethyl) pyrrolidin-2-one derivative contains¹⁸And F, marking.

The technical scheme of the invention has the following beneficial effects:

the 4-phenyl-1- (pyridine-4-ylmethyl) pyrrolidine-2-ketone derivative provided by the invention has high affinity with SV2A, belongs to a brand new compound for diagnosing and treating SV2A related diseases, and is simple in preparation method, high in preparation interest rate and beneficial to large-scale production and application.

Drawings

FIG. 1 is a PET imaging chart of example 7 of the present invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments.

Example 14- (R) -1- (((3- (3-fluoropropyl) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

The structural formula is as follows:

the synthetic route is as follows:

(E) -methyl 3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) acrylate

A mixture of 1- ((3-bromopyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one (2g, 5.19 mmol), methyl acrylate (2.18g, 25.97mmol), Pd (OAc)₂(0.12g, 0.53mmol) and PPh₃(0.327g, 1.2mmol) was dissolved in 30mL of DMF, and 3mL of triethylamine was added and reacted at 120 ℃ for 5h under nitrogen. DMF was removed with saturated brine, extracted with ethyl acetate, and column-chromatographed with pure ethyl acetate to give 1.6g of the product in 79% yield. HRMS calcd for C20H17F3N2O3390.1191; found, 391.1256.

1- ((3- (3-hydroxypropyl) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

Methyl (E) -3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) acrylate (1.6g, 4.1mmol) was dissolved in 30mL of methanol, cooled in an ice-water bath, LiAlH was added portionwise₄(1.56g, 41mmol), after 5min, reacting at normal temperature for 10h, removing methanol by spinning, and performing column chromatography with a developing agent system dichloromethane: the methanol content is 10: 1, 0.6g of racemic compound is obtained, in a yield of 40%. The mixture was purified by chiral semi-preparative HPLC (ChiralCel OD column (4.6 mm. times.250 mm,10 μm, DAICEL Corporation)) at flow rate: 2min/L, targetingThe peak time of the composition was 12.5min, yielding 0.3 g.¹H NMR(300MHz,CDCl₃)δ8.58–8.17(m,2H),7.03(d,J＝4.9Hz,1H),6.86–6.63(m,2H),4.65(d,J＝15.5Hz,1H),4.42(d,J＝15.5Hz,2H),3.68–3.50(m, 4H),3.32–3.13(m,1H),2.90–2.82(m,1H),2.79–2.65(m,2H),2.57–2.48(m, 1H),1.82–1.73(m,2H).13C NMR(75MHz,CDCl3)δ173.36,153.09,152.95, 152.86,152.72,150.72,149.67,149.54,149.40,147.50,142.72,140.33,138.11, 138.02,137.87,136.05,122.91,111.09,111.00,110.90,110.81,77.57,77.15,76.72, 61.11,53.44,43.07,38.10,36.58,33.58,25.95.HRMS calcd for C19H19F3N2O2 364.1399；found,365.1354[M+H]⁺。

3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) 4-methylbenzenesulfonate propyl ester

1- ((3- (3-hydroxypropyl) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one (0.6g, 1.65mmol) was dissolved in 30mL of dichloromethane, 2mL of triethylamine was added at 0 ℃, TsCl (1.26g, 0.66mmol) and DMAP (20mg, 0.16mmol) were then added, the reaction was carried out at room temperature for 36 hours, the reaction solution was washed with water, the solvent was removed, and a column chromatography developing reagent system dichloromethane: methanol: ammonia water is 95: 5: 0.5, 0.7g of product is obtained, yield 82%.¹H NMR(300MHz,CDCl₃)δ8.52(s,2H), 7.72-7.59(m,2H),7.36-7.32(m,1H)，7.07(d,J＝7.2Hz,2H),6.89-6.72(m,1H), 3.79-3.55(m,5H),3.26(s,3H),2.74-2.65(m,1H),2.43-2.34(m,2H),2.25(s,3H). HRMS calcd for C26H25F3N2O4S 518.1487；found,519.1568[M+H]⁺。

1- ((3- (3-fluoropropyl) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) 4-methylbenzenesulfonic acid propyl ester (0.7g, 1.35mmol) was dissolved in 10mL of tetrahydrofuran, 1mL of n-butylammonium fluoride (1M) was added, and the reaction was carried out at 50 ℃ for 10 hours, the solvent was removed, and a column chromatography developing solvent system dichloromethane: the methanol content is 96: 4, 0.4g of product is obtained in 80% yield.¹H NMR(300MHz,CDCl₃)δ8.52 (s,2H),7.21(s,1H),6.92–6.72(m,2H),4.75(d,J＝15.6Hz,1H),4.46(d,J＝ 15.7Hz,1H),4.15(t,J＝6.3Hz,2H),3.86–3.49(m,2H),3.25(t,J＝6.9Hz,2H), 3.01–2.69(m,4H),2.68–2.54(m,1H),1.97(dt,J＝12.9,6.3Hz,2H).HRMS calcd for，C19H18F4N2O 366.1355 found,367.1529[M+H]⁺。

Example 2

(R) -1- (((3- (3-fluoropropyl-3, 3-d2) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one of the formula:

the synthetic route is as follows:

1- ((3- (3-hydroxypropyl-3, 3-d2) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

Methyl (E) -3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) acrylate (1g, 2.56mmol) was dissolved in 30mL of methanol, cooled in an ice-water bath and LiAlD was added portionwise₄(0.47g, 12.8mmol), after 5min addition, reacting at normal temperature for 10h, removing methanol by spinning, and performing column chromatography with a developing agent system dichloromethane: the methanol content is 10: 1, 0.25g of racemic compound is obtained, yield 27%. The mixture was purified by chiral semi-preparative HPLC (ChiralCel OD column (4.6 mm. times.250 mm,10 μm, DAICEL Corporation)) at flow rate: 2min/L, the peak-out time of the target compound was 12.5min, yielding 0.15 g. 1H NMR (300MHz, CDCl)₃)δ8.40(d,J＝12.9Hz,2H),7.05(s,1H),6.91– 6.54(m,2H),4.67(d,J＝15.4Hz,1H),4.44(d,J＝15.4Hz,1H),3.31–3.11(m, 1H),3.01–2.67(m,3H),2.58–2.50(m,1H),1.92–1.62(m,2H).13C NMR(75 MHz,CDCl3)δ173.17,153.07,153.02,152.94,152.88,150.99,149.74,149.69, 149.61,149.56,147.71,142.50,140.61,140.41,140.20,138.12,138.02,137.96, 137.87,137.27,137.07,136.87,135.99,123.01,111.06,110.97,110.86,110.77, 61.25,60.89,60.60,60.25,53.80,53.43,43.14,38.36,38.13,36.59,33.72,33.62, 33.52,29.56,29.25,25.94.HRMS calcd for C19H17D2F3N2O2 366.1524 found, 367.2584[M+H]⁺。

(R) -3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) propyl-1, 1-d2 methanesulfonate

1- ((3- (3-hydroxypropyl-3, 3-d2) pyridine-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidine-2-one

(0.2g, 0.54mmol) was dissolved in 30mL of dichloromethane, 2mL of triethylamine was added at 0 ℃ followed by MsCl (0.2g, 0.11mmol), the reaction was carried out at room temperature for 0.5 hour, washed with water, the solvent was removed by spinning, column chromatography developer system dichloromethane: methanol: ammonia water is 95: 5: 0.5, 0.19g of product is obtained, with a yield of 82%.¹H NMR(300MHz,CDCl₃)δ8.47(d,J＝5.8Hz,2H),7.12(d, J＝5.0Hz,1H),6.83(m,2H),4.71(d,J＝15.4Hz,1H),4.42(d,J＝15.4Hz,1H), 3.65–3.54(m,2H),3.24(m,1H),3.06(s,3H),2.83(d,J＝8.1Hz,2H),2.53(d,J ＝8.2Hz,1H),2.04(m,2H).HRMS calcd for，C20H19D2F3N2O4S 444.1300 found,445.2698[M+H]⁺。

(R) -1- (((3- (3-fluoropropyl-3, 3-d2) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

((R) -3- (4- ((2-oxo-4- (3,4, 5-trifluorophenyl) pyrrolidin-1-yl) methyl) pyridin-3-yl) propyl-1, 1-d2 methanesulfonate (0.1g, 0.27mmol) was dissolved in 10mL of tetrahydrofuran, 1mL of n-butylammonium fluoride (1M) was added, and the reaction was carried out at 50 ℃ for 10h, with the solvent removed, and the column chromatography developer system dichloromethane: methanol 96: 4, to give 66mg of the product in 65.7% yield.¹H NMR(300MHz,CDCl₃) δ8.48(s,2H),7.11(d,J＝4.8Hz,1H),6.82(m,2H),4.67(s,1H),4.45(d,J＝15.6 Hz,1H),3.62(d,J＝8.8Hz,2H),3.24(m,1H),2.87(m,3H),2.57(dd,J＝17.0, 8.1Hz,1H),2.00(m,2H).HRMS calcd for，C19H16D2F4N2O 368.1481 found, 369.2458[M+H]⁺。

Example 3

(R) -4- (3, 5-difluorophenyl) -1- ((3- (3-fluoropropyl) pyridin-4-yl) methyl) pyrrolidin-2-one

The structural formula is as follows:

the synthetic route is as follows:

(E) -3- (3, 5-difluorophenyl) acrylic acid methyl ester

Ethoxyformylmethylenetriphenylphosphine (8.8g, 25.2mmol) was dissolved in 40mL of dichloromethane, stirred at 0 ℃ under nitrogen protection, and 3, 5-difluorobenzaldehyde (3g, 21mmol) was dissolved in 10mL of dichloromethane and injected into the previous system, and reacted at room temperature for 0.5 hour. Spin-drying and dissolving, adding 3mL of dichloromethane and 30mL of n-hexane, filtering triphenylphosphine oxide solid, and performing column chromatography developer system petroleum ether: ethyl acetate was 90: 10, 3.8g of product is obtained, with a yield of 91%. HRMS calcd for, C10H8F2O2198.0492 found,199.2456[ M + H [ ]]⁺

3- (3, 5-difluorophenyl) -4-nitrobutanoic acid methyl ester

Dissolving (E) -3- (3, 5-difluorophenyl) methyl acrylate into 15mL of acetonitrile, adding 15mL of DBU and 15mL of nitromethane at the temperature of 0 ℃, reacting for 16 hours at normal temperature, adjusting the pH value to 7 by using dilute hydrochloric acid, adding 30mL of water, extracting by using ethyl acetate, performing spin-drying, and performing column chromatography by using a developing agent system petroleum ether: ethyl acetate was 90: 10, 3g of product is obtained with a yield of 60%. HRMS calcd for C11H11F2NO4259.0656 found,260.0489[ M + H ]]⁺。

4-amino-3- (3, 5-difluorophenyl) butanoic acid methyl ester

Methyl 3- (3, 5-difluorophenyl) -4-nitrobutanoate was dissolved in 20mL of ethanol, 0.3g of palladium on carbon was added, the reaction was carried out under hydrogen conditions for 10 hours, filtration was carried out, and the solvent was removed by rotation to give 2.69g of a product with a yield of 100%. HRMS calcd for, C11H13F2NO2229.0914 found,230.0159[ M + H [ ]]⁺。

1- ((3-bromopyridin-4-yl) methyl) -4- (3, 5-difluorophenyl) pyrrolidin-2-one

Methyl 3- (3, 5-difluorophenyl) -4-nitrobutanoate (3g, 11.6mmol) and isonicotinal (2.15g, 11.6mmol) were dissolved in 40mL of ethanol and 0.5mL of acetic acid was added. Nitrogen is present inGas protection, reacting for 5 hours at 70 ℃, cooling to 0 ℃, and adding LiAlH₄(1.32g, 34.8mmol), reacting for 0.5 hour, adding diluted hydrochloric acid to adjust the pH to 7, filtering, removing ethanol by rotation, extracting with ethyl acetate, drying with anhydrous sodium sulfate, removing the solvent by rotation, adding 15mL of acetic acid, reacting at 80 ℃ for 6 hours, removing the acetic acid by rotation, and obtaining 2g of a product with the yield of 47% by pure ethyl acetate as a column chromatography developing solvent system. HRMS calcd for, C16H13BrF2N2O 366.0179 found,367.1128[ M + H ]]⁺。

(E) -methyl 3- (4- (((4- (3, 5-difluorophenyl) -2-oxopyrrolidin-1-yl) methyl) pyridin-3-yl) acrylate

A mixture of 1- ((3-bromopyridin-4-yl) methyl) -4- (3, 5-difluorophenyl) pyrrolidin-2-one (2g, 2.59mmol), methyl acrylate (1.09g, 12.8mmol), Pd (OAc)₂(0.06g, 0.26mmol) and PPh₃(0.16g) was dissolved in 20mL of DMF, and 3mL of triethylamine was added and reacted at 120 ℃ for 5 hours under nitrogen. DMF was removed with saturated brine, extracted with ethyl acetate, and column-chromatographed with pure ethyl acetate to give 0.79g of the product in 79% yield. HRMS calcd for, C20H18F2N2O3372.1285 found, 373.2589[ M + H]⁺。

4- (3, 5-difluorophenyl) -1- ((3- (3-hydroxypropyl) pyridin-4-yl) methyl) pyrrolidin-2-one

1- ((3-Bromopyridin-4-yl) methyl) -4- (3, 5-difluorophenyl) pyrrolidin-2-one (1g, 2.68mmol) was dissolved in 30mL methanol in an ice-water bath and LiAlH was added portionwise₄(1g, 26.8mmol), reacting for 5min at normal temperature for 10h, removing methanol by spinning, and obtaining 0.61g of product with 65.3% yield by using pure ethyl acetate as column chromatography developing agent system. HRMS calcd for, C19H20F2N2O2346.1493 found, 347.6852[ M + H]⁺。

3- (4- ((4- (3, 5-difluorophenyl) -2-oxopyrrolidin-1-yl) methyl) pyridin-3-yl) 4-methylbenzenesulfonic acid propyl ester

4- (3, 5-difluorophenyl) -1- ((3- (3-hydroxypropyl) pyridin-4-yl) methyl) pyrrolidin-2-one (0.2g, 0.57mmol) was dissolved in 20mL of dichloromethane, 1mL of triethylamine was added at 0 ℃, TsCl (0.22g, 1.1mmol) and DMAP (2mg) were added, and the mixture was reacted at room temperature for 12 hours, washed with water, the solvent was removed by spinning, and a column chromatography developer was appliedIs dichloromethane: methanol: ammonia water is 95: 5: 0.5, 0.24 g of product is obtained, with a yield of 82.1%. HRMS calcd for C26H26F2N2O4S 500.1581 found 501.4267[ M + H ]]⁺。

4- (3, 5-difluorophenyl) -1- ((3- (3-fluoropropyl) pyridin-4-yl) methyl) pyrrolidin-2-one

Dissolving 3- (4- ((4- (3, 5-difluorophenyl) -2-oxopyrrolidin-1-yl) methyl) pyridin-3-yl) 4-methylbenzenesulfonic acid propyl ester (0.1g, 0.2mmol) in 10mL of tetrahydrofuran, adding 1mL of n-butylammonium fluoride (1M), reacting at 50 ℃ for 10h, removing the solvent by rotation, and performing column chromatography using a developing solvent system dichloromethane: the methanol content is 96: 4, 43mg of product are obtained in 62.1% yield.¹H NMR(300MHz,CDCl₃)δ8.42(s,1H), 8.05(t,J＝5.2Hz,1H),6.92–6.72(m,4H),5.19(s,2H),4.31-4.18(m,4H),3.25(t, J＝4.2Hz,1H),2.65–2.32(m,4H),1.97–1.85(m,2H).HRMS calcd for，HRMS calcd for C19H19F3N2O 348.1449 found,349.1459[M+H]⁺。

Example 4(R) -4- (3, 5-difluorophenyl) -1- ((3- (3-fluoropropyl-3, 3-d2) pyridin-4-yl) methyl) pyrrolidin-2-one

The structural formula is as follows:

the synthetic route is as follows:

example 4 following the above synthetic route, with reference to example 2, the title compound was obtained in approximately 15% overall yield.¹H NMR(300MHz,CDCl₃)δ8.41(s,1H),8.04(t,J＝5.2Hz,1H),6.91– 6.72(m,4H),5.19(s,2H),4.31-4.16(m,2H),3.24(t,J＝4.2Hz,1H),2.65–2.32 (m,4H),1.96–1.83(m,2H).HRMS calcd for，C19H17D2F3N2O 350.1575 found,351.2578[M+H]⁺

Example 5

(R) -4- (3-fluorophenyl) -1- ((3- (3-fluoropropyl) pyridin-4-yl) methyl) pyrrolidin-2-one

The structural formula is as follows:

the synthetic route is as follows:

example 5 according to the above synthetic route, with reference to example 3, the desired compound is obtained in approximately 12% overall yield.

HRMS calcd for C19H20F2N2O 330.1544 found,331.2549[M+H]⁺。

Example 6

(R) -4- (3-fluorophenyl) -1- ((3- (3-fluoropropyl-3, 3-d2) pyridin-4-yl) methyl) pyrrolidin-2-one

The structural formula is as follows:

the synthetic route is as follows:

example 5 according to the above synthetic route, with reference to example 2, the desired compound is obtained in approximately 14% overall yield. HRMS calcd for C19H18D2F2N2O 332.1669 found,333.2675[ M + H ]]⁺。

Example 7

(R) -1- (((3- (3- (fluoro-18F) propyl) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

The structural formula is as follows:

the reaction equation is as follows:

the experimental steps are as follows:

a) will be provided with¹⁸F^-Use 1mL K from QMA column₂₂₂/K₂CO₃Solution (160mg K)₂₂₂ in 18.6mL acetonitrile/29mg K₂CO₃in 3.4mL water) into a reaction tube;

b) at 110 ℃ and N₂Blowing and evaporating the above K₂₂₂/K₂CO₃Eluting the solution; adding 1mL of anhydrous acetonitrile to the evaporation residue and evaporating to dryness again, repeating the above process three times to obtain a dried product¹⁸F^-/ K₂₂₂/K₂CO₃A complex compound;

c) cooling the reaction solution to dry¹⁸F^-/K₂₂₂/K₂CO₃Adding 1mg of labeled precursor solution (dissolved in 1mL of acetonitrile) into the complex, and reacting at 110 ℃ for 10 min;

d) adding 8mL of water into the reaction tube, and then passing the diluted reaction solution through an Oasis HLB solid-phase extraction column;

e) washing the Oasis HLB solid phase extraction column with 10mL water;

f) the solid phase extraction column was rinsed with 1mL of methanol solution and then purified by semi-preparative HPLC (Phenomenex Gemini-Nx C18110A (250 × 4.6mm × 5 μ, acetonitrile/0.1% formic acid water 4/6) with a peak time of 11.5min and a purity of greater than 95%. Compared with the literature, the alkoxy labeling condition of the invention is simpler than the aryl labeling condition reported in the literature.

Example 8(R) -1- (((3- (3- (fluoro-18F) propyl-3, 3-d2) pyridin-4-yl) methyl) -4- (3,4, 5-trifluorophenyl) pyrrolidin-2-one

The structural formula is as follows:

the reaction equation is as follows:

experimental procedure referring to example 7, purification by semi-preparative HPLC (Phenomenex Gemini-Nx C18110A (250 × 4.6mm × 5 μ, acetonitrile/0.1% formic acid water 4/6) gave a peak time of 12.1min and a purity of greater than 95%.

Example 9 brain uptake and inhibition experiments

20 rats (30min) with the same week age, sex and body weight in the same interval are selected, 5 groups are repeated, 10mCi of probe is taken, dried by nitrogen, dissolved in physiological saline, and prepared into 2 mu Ci/100 mu L. Rats were sacrificed by injecting 100. mu.L (100. mu. Ci) of test compound probe salt solution into the tail vein and phase-wise. The eyeball is removed and blood is taken in a gamma counting tube with the pre-weighed weight, and the rat is quickly dissected to respectively take the brain tissue. The selected viscera are respectively put into plastic small bags with pre-weighed weights, the gamma counting tube and the plastic bags are weighed, and the samples are put into the counting tube for detection. The injection is diluted 100 times, 100 mul is taken out to measure cpm, the obtained cpm value is recorded as one percent of injection measurement of the experiment, 3 times of background measurement is carried out, and the data is shown as% ID/mL. Specific values are shown in table 1. Inhibition experiments: after UCB-H tail vein is injected into rat body, brain, volume and dose are taken and counted to test radioactive dose 10min later.

Table 1: brain uptake and inhibition assay

As can be seen from the results in Table 1, the brain entry amounts of the compounds examples 1-6 are comparable to the reported PET imaging agent targeting SV2A¹⁸F-UCB-H is close to that of the compound, and simultaneously, through UCB-H inhibition experiments, the brain-entering amount of the compounds in examples 1-6 is obviously reduced, which shows that the compounds provided by the patent have similar target points with UCB-H, and further proves that the compounds target SV 2A.

Example 10 SD rats were anesthetized, fixed on a rat plate, and after anesthesia, a radioactive compound was injected via the tail vein, and 2 hours of micro PET/CT dynamic scan was performed after administration, and the acquired and reconstructed PET/CT images were transferred to a workstation for image fusion and display, and the radioactivity distribution of the probe and the binding to SV2A were determined. As can be seen from fig. 1, example 7 is consistent with the specific imaging agent imaging site reported in the literature as targeting SV2A, and therefore, the inventive compounds of this patent have SV2A specificity.

While the foregoing is directed to the preferred embodiment of the present invention, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.