(2,5-Dioxopyrrolidin-1-yl)(phenyl)-acetamide derivatives, and their use in the treatment of neurological disorders

Abstract

The first object of the present invention is a compound of general formula (I) or a pharmaceutically acceptable salt thereof. The second object of the present invention is the use of a compound described by general formula (I) as an active ingredient of a pharmaceutical composition for the treatment of epileptic seizures, neuropathic pain, or migraine.

Description

Technical Field

[0001] The present invention relates to (2,5-dioxopyrrolidin-1-yl)(phenyl)-acetamide derivatives and pharmaceutically acceptable salts thereof, which are suitable for the treatment of neurological diseases. The disclosed compounds exhibit a broad range of protective activities in animal models of epileptic seizures and pain models, and thus can find applications in the treatment of neurological diseases, particularly epilepsy and neuropathic pain. Due to the broad therapeutic applicability of anti-epileptic drugs, these compounds may also be useful, for example, in the treatment of migraine, withdrawal syndrome, schizophrenia, schizoaffective disorder, personality and nutritional disorders, and anxiety and post-traumatic stress.

Background Art

[0002] Epilepsy is one of the most common neurological disorders associated with excitability and neurotransmission impairments. This disease affects 1-2% of the human population and significantly reduces the quality of life and the possibility of daily activities of patients (Nadkarni, S.; LaJoie, J.; Devinsky, O., Neurology 2005, 64, S2-S11). Due to its complex pathophysiology, epilepsy is a heterogeneous disease characterized by the onset of various types of seizures (including, for example, tonic-clonic, absence, partial, etc.) and significant drug resistance, reaching 30-40% when diagnosed (Kwan, P.; Schachter, S.C.; Brodie, M.J., N. Engl. J. Med. 2011, 365, 919-926). Neuropathic pain is another severe neurological disorder that is difficult from a therapeutic perspective. Current data indicate that only 50% of patients can achieve a 30-50% reduction in the sensation of neuropathic pain, while the other patients cannot achieve improvement with any of the drugs used (Butera, J.A., J. Med. Chem. 2007, 11, 2543-2546). Therefore, there is a very high need for new AEDs that can control various types of epileptic seizures and are preferably effective against neuropathic pain. Many of the currently used AEDs have a narrow range of therapeutic indications, so they are applicable only to specific types of epileptic seizures. These drugs include, among others, the latest AEDs such as levetiracetam and lacosamide. Investigations conducted in recent years have shown that multi-target compounds, also known as multifunctional compounds, i.e., compounds with complex mechanisms of molecular action, can be particularly beneficial for the treatment of diseases with complex pathophysiological mechanisms (so-called multi-factorial diseases). By combining different synergistic mechanisms, multi-target substances enable a comprehensive treatment process, so they are considered to have high therapeutic efficacy compared to substances that act on a single biological target (Bansal, Y.; Silakari, O., Eur. J. Med. Chem. 2014, 76, 31-42).Another advantage of multifunctional drugs can be the reduction in the number of drugs taken, which can result in fewer and weaker side effects, a lower risk of drug-drug interactions, and better cooperation (compliance) between physicians and patients. It is also hypothesized that multitarget compounds may be useful in the treatment of diseases characterized by high drug resistance (e.g., epilepsy) (Talevi, A., Front. Pharmacol. 2015, 6, 205). Multitarget substances are usually designed as hybrid or chimeric molecules that bind on the structural fragments of a normal chemical backbone involved in a specific pharmacological effect (Morphy, R.; Rankovic, Z., J. Med. Chem. 2005, 48, 6523 - 6543). In particular, intensive research on the development of multitarget compounds as candidates for new drugs is being carried out in the fields of cancer, neurodegeneration, and inflammatory diseases.In particular, as a method enabling the design and development of a novel AED with a wide range of therapeutic indications, the concept of molecular hybridization has been recently proposed by the inventors (Abram, M.; Zagaja, M.; Mogilski, S.; Andres-Mach, M.; Latacz, G.; Bas, S.; Luszczki, J. J.; Kiec-Kononowicz, K.; Kaminski, K., J. Med. Chem. 2017, 60, 8565-8579; Kaminski, K.; Zagaja, M.; Rapacz, A.; Luszczki, J. J.; Andres-Mach, M.; Abram, M.; Obniska, J., Bioorg. Med. Chem. 2016, 24, 606-618; Kaminski, K.; Rapacz, A.; Filipek, B.; Obniska, J., Bioorg. Med. Chem. 2016, 24, 2938-2946; Kaminski, K.; Zagaja, M.; Luszczki, J. J.; Rapacz, A.; Andres-Mach, M.; Latacz, G.; Kiec-Kononowicz, K., J. Med. Chem. 2015, 58, 5274-5286; Kaminski, K.; Rapacz, A.; Luszczki, J. J.; Latacz, G.; Obniska, J.; Kiec-Kononowicz, K.; Filipek, B., Bioorg. Med. Chem. 2015, 23, 2548-2561).

Summary of the Invention

Problems to be Solved by the Invention

[0003] The antispasmodic and / or analgesic activity of the novel compounds is routinely evaluated in animal models (mainly mice and rats). From a clinical perspective, particularly promising candidates for novel broad-spectrum AEDs effective against various types of human epileptic seizures are substances that are active in the maximal electroshock test (MES), subcutaneous pentylenetetrazole seizure test (scPTZ), and the psychomotor 6 Hz seizure model using 6 Hz low-frequency current (at a current intensity of 32 mA and / or 44 mA). Compounds with the aforementioned profile in preclinical in vivo tests may be effective against human tonic-clonic seizures, with or without secondary generalization, absence seizures, myoclonic seizures, partial seizures, and drug-resistant epilepsy. An important added value of the above substances should be their activity in important animal tests / models for evaluating antinociceptive activity, namely, the formalin test, capsaicin-induced pain model, and oxaliplatin-induced neuropathic pain model.

[0004] The technical problem prior to the present invention is to provide such chemical compounds, or pharmaceutically acceptable salts thereof, which can be easily obtained, do not exhibit hepatotoxic effects, and can be used as active substances in pharmaceutical compositions for controlling various types of seizures (tonic-clonic seizures, with or without secondary generalization, absence seizures, myoclonic seizures, partial seizures, and drug-resistant epilepsy). Such compounds should also have analgesic activity in pain caused by neuropathy or migraine.

Means for Solving the Problem

[0005] The first object of the present invention is a compound of general formula (I)

[0006]

Chemical formula

[0007] The term "halogen", when used in the description of the compound according to general formula (I), includes fluorine, chlorine, bromine, and iodine. In another preferred embodiment of the present invention, the halogen atom is fluorine or chlorine.

[0008] Since the compound having general formula (I) has a plurality of chiral centers, it can exist in the form of optical isomers and mixtures thereof. The aforementioned optical isomers and mixtures thereof in various proportions, including racemic mixtures, are included within the scope of the present invention. The individual isomers can be obtained by using the appropriate isomeric form of the starting material (amino acid derivative), or can be separated after preparing the final compound according to known separation methods.

[0009] Preferably, the compound of the present invention has the general formula (II)

[0010]

Chemical formula

[0011] Preferably, the alkyl moiety in the carbon backbone contains 1 to 4 carbon atoms, the alkyl moiety has a straight-chain or branched-chain, and is selected from the group consisting of methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl substituents.

[0012] Compounds having the general formula (II) can exist in the form of optical isomers and mixtures thereof since they have one chiral center. The various optical isomers and mixtures thereof in various ratios, including the racemic mixture, are included within the scope of the present invention. The individual isomers can be obtained by using the appropriate isomeric form of the starting material (amino acid derivative) or can be separated after preparing the final compound according to known separation methods.

[0013] Preferably, k = 0.

[0014] Preferably, the X atom is a nitrogen atom.

[0015] Preferably, the substituent A is selected from the group consisting of 5-benzothiophenyl, 2-naphthyl, 5-benzisoxazolyl substituents.

[0016] Preferably, A is selected from the group consisting of phenyl; phenyl substituted with at least one chlorine or -CF3, -CHF2, -OCF3, -CH3, -SCF3 or phenyl.

[0017] Preferably, the substituent B is selected from the group consisting of phenyl, or phenyl substituted with one or two halogen atoms.

[0018] Preferably, the compounds of the present invention are selected from the group consisting of: 1-(2-oxo-1-phenyl-2-(4-phenylpiperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3-chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3,5-dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-oxo-1-phenyl-2-(4-(m-tolyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3,5-Bis(trifluoromethyl)phenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(difluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethylsulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-([1,1'-Biphenyl]-3-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(1-(4-Fluorophenyl)-2-oxo-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(Naphthalen-2-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(Benzo[b]thiophen-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(1,2-Benzoxazol-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3-chlorophenyl)piperidin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione.

[0019] Preferably, the compound of the present invention is the (R) enantiomer, and is preferably selected from the following compounds: (R)-1-(2-(4-(3-chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, (R)-1-(2-(4-(3,5-dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, (R)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, (R)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, (R)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethylsulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione.

[0020] Preferably, the compound of the present invention is a water-soluble salt, especially a hydrochloride, and is preferably selected from the following compounds: 3-(methylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride, 3-(Dimethylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride 3-(Diethylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride

[0021] A second object of the present invention is a compound according to the present invention as defined above, which is used for the treatment or prevention of epileptic seizures, neuropathic pain, or migraine. In a preferred embodiment, the compound according to the present invention is used as an active substance (only one or one of many) contained in a pharmaceutical composition for the treatment or prevention of at least one of the above medical indications.

[0022] The compounds according to the present invention have antispasmodic and analgesic activities in a wide panel of animal models and can find application as active substances in various dosage forms for the treatment of epilepsy and neuropathic pain.

[0023] The compound of formula (I) according to the present invention can be obtained using a multi-step synthetic procedure, which is illustrated in Figure 2A, where X, A, B, D, and k are as defined above. For the preparation of the compound of formula (I) where D is a halogen, the procedure described for the compound of formula (II) according to Figure 2B is used. In the first step, as a result of a condensation reaction (i) between a suitable piperazine derivative and the corresponding tert-butoxycarbonyl (Boc) amino acid derivative, an intermediate product with an amide structure is obtained, and then a deprotection reaction (ii) is carried out on this to form an amine derivative. In the next step, the aforementioned amine derivative is subjected to a condensation reaction (iii) with maleic anhydride to obtain an unsaturated amide-acid derivative. This derivative forms the corresponding maleimide by applying a cyclization reaction (iv). In the next step (v), the maleimide derivative is subjected to an addition reaction with a suitable primary or secondary amine to obtain a compound having the general formula (I) according to the present invention.

[0024] The compound of formula (II) according to the present invention is of formula (III):

[0025] [Chemical formula] (wherein B and k are as defined for formula (II)) can be obtained starting from the compound of. The compound of formula (III) can be obtained by a two-step procedure using commercially available succinic anhydride and the corresponding amino acid derivative as the substrate. In the first step, as a result of the condensation reaction between succinic anhydride and the appropriate amino acid derivative, an intermediate product of the amide-acid structure (IV) is obtained, which is then subjected to a cyclization reaction to form the desired compound having formula (III). Alternatively, the compound described by formula (III) can be prepared by using a one-step thermal cyclocondensation reaction between succinic anhydride or succinic acid and the corresponding amino acid.

[0026] The desired compound of general formula (II) according to the present invention can be obtained by using an amidation reaction between the compound described by formula (III) and a suitable commercially available secondary aliphatic amine. This reaction can be carried out in the presence of a known coupling agent including CDI, EDCI, DCC, etc. Alternatively, the compound of formula (II) can be obtained by the reaction between the acid chloride obtained by the conversion of the carboxylic acid described by formula (II) and the corresponding commercially available secondary aliphatic amine. The compound described by formula (II) according to the present invention can also be prepared in the reaction between a carboxylic acid and the corresponding aliphatic amine using an activator selected from BOP, HBTU, HATU in the presence of an organic base, especially triethylamine (TEA), N-methylmorpholine (NMM), or N,N-diisopropylethylamine (DIEA).

[0027] The synthetic procedures and reaction conditions are illustrated in Figure 2B, where X, A, B, and k are as defined above.

[0028] The solution according to the present invention has several advantages. The disclosed compounds of formula (I), preferably the compounds of formula (II), are characterized by strong and broad antispasmodic activity in various animal models of epilepsy, namely, the maximal electroshock seizure test (MES), the subcutaneous pentylenetetrazole seizure test (scPTZ), and the 6Hz seizure model (32 mA and / or 44 mA). Compounds with the aforementioned profile in preclinical in vivo tests can be effective against various types of human epilepsy, including secondary generalization, generalized seizures (absence), myoclonic seizures, partial seizures, and tonic-clonic seizures with or without important drug-resistant seizures. Another advantage of the compounds of general formula (I), especially those described by formula (II), is their strong analgesic activity in animal models for evaluating anti-nociceptive activity, namely, the formalin test, the capsaicin-induced pain model, and the oxaliplatin-induced neuropathic pain model. Therefore, the compounds of formula (I), preferably the compounds of formula (II), may be useful for the treatment of pain caused by both neurological and inflammatory origins, which is a unique feature among the AEDs available for drug therapy. The compounds according to formula (I), preferably formula (II), have a complex mechanism of molecular action, namely, they interact with voltage-dependent sodium channels, calcium channels, and the TRPV1 receptor. The beneficial antagonist effect observed in the case of the TRPV1 receptor has not yet been demonstrated for known therapeutically relevant AEDs. Importantly, although literature data suggest the possible involvement of TRPV1 in the induction of seizures (Naziroglu, M., Curr. Neuropharmacol. 2015, 13, 239 - 247; Naziroglu, M.; Ovey, I.S., Neuroscience 2015, 293, 55 - 66), its role as a molecular target for substances with anti-nociceptive activity is well-documented (Szallasi, A.; Cortright, D.N.; Blum, C.A.; Eid, S.R., Nat. Rev. Drug. Discov. 2007, 6, 357 - 372).The compounds according to formula (II) may also be potentially useful, inter alia, in the treatment of withdrawal syndromes, schizophrenia, schizoaffective disorders, personality and nutritional disorders, as well as anxiety and post-traumatic stress. Accordingly, the present invention provides compounds for use as medicaments. Furthermore, it discloses the possibility of using TRPV1 receptor antagonists for treating various types of epileptic seizures.

[0029] The compounds according to the invention are applied in pharmaceutically acceptable, effective amounts, together with pharmaceutically acceptable diluents, carriers, and / or excipients known in the art, to prepare pharmaceutical preparations suitable for a given route of administration, containing at least one active compound according to formula (I), preferably formula (II), and can be administered by various routes, including enteral, topical, or parenteral administration. Methodologies for the preparation of such pharmaceutical formulations are known in the art. The therapeutic dosage varies depending on the substance, species, sex, age, disease entity being treated, route, and method of administration, and this needs to be determined by an expert in the field. The proposed dosage of the compounds according to the invention is from 0.1 to about 1000 mg per day, in single or divided doses. The compounds of the present invention can be administered to a patient either by themselves or in combination with one or more active ingredients each present in their own composition, or some or all of the active ingredients combined in a single composition and / or suitable pharmaceutical excipients. Suitable pharmaceutical excipients include conventional support substances necessary for the proper preparation of a given formulation, such as fillers, binders, disintegrants, lubricants, solvents, gel-forming agents, emulsifiers, stabilizers, dyes, and / or preservatives. The compounds of the present invention are formulated into dosage forms using generally known pharmaceutical methods of preparation. The dosage forms can be, for example, tablets, capsules, granules, suppositories, emulsions, suspensions, or solutions. Depending on the method of administration and the galenic form, the amount of the active substance in the formulation can typically range from 0.01 (weight)% to 100 (weight)%.

[0030] Embodiments of the present invention will be described with reference to the drawings shown below.

Brief Description of the Drawings

[0031]

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Figure 2A

Figure 2B

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Figure 14

Mode for Carrying Out the Invention

[0032] Analysis method: Proton nuclear magnetic resonance ( 1 1H NMR) and carbon nuclear magnetic resonance ( 1313C NMR spectra were recorded using a Mercury-300 "Varian" spectrometer (Varian Inc., Palo Alto, CA, USA) at 300 MHz and 75 MHz, respectively, or a JEOL-500 spectrometer (JEOL USA, Inc., MA, USA) operating at 500 MHz and 126 MHz, respectively. Chemical shifts are given as δ (ppm) values relative to TMS δ = 0 (1H) as an internal standard. J values are expressed in Hertz (Hz). Deuterated chloroform (CDCl3) or deuterated dimethyl sulfoxide (DMSO-D6) was used as the solvent. The following signal abbreviations are used in the description of the spectra: s (singlet), br s (broad singlet), d (doublet), dd (doublet of doublets), ddd (doublet of doublets of doublets), t (triplet), td (doublet of triplets), q (quartet), m (multiplet). The UPLC / MS analysis system consisted of a Waters ACQUITY® UPLC® instrument (Waters Corporation, Milford, MA, USA) equipped with a Waters TQD mass spectrometer operating in electrospray ionization (ESI) mode. Chromatographic separation was performed using an Acquity UPLC BEH C18, 1.7 μm (2.1 × 100 mm) column with a VanGuard Acquity UPLC BEH C18, 1.7 μm (2.1 × 5 mm) (Waters, Milford, CT, USA). The column was maintained at 40 °C and eluted at a flow rate of 0.3 mL / min with a gradient of 95% - 0% solvent A over 10 minutes. Solvent A: water / formic acid (0.1%, v / v); Solvent B: acetonitrile / formic acid (0.1%, v / v). Chromatograms were recorded using a Waters eλ PDA detector. Spectra were analyzed at a sampling rate of 20 points / s in the range of 200 - 700 nm with a resolution of 1.2 nm. The UPLC retention time (t R ) is shown in minutes. Thin layer chromatography (TLC) was performed using a developing solvent system with the following composition on silica gel 60 F 254Performed on aluminum sheets coated (Macherey-Nagel, Duren, Germany): DCM:MeOH (9:0.2; v / v), DCM:MeOH (9:0.3; v / v), DCM:MeOH (9:0.5; v / v), DCM:MeOH (9:1; v / v). Spot detection: UV light (λ = 254 nm). The melting point (m.p.) was determined using an open capillary in a Buchi 353 apparatus (Buchi Labortechnik, Flawil, Switzerland). The enantiomeric purity was determined using chiral HPLC technology on Shimadzu Prominence and LC-2030C SD Plus apparatuses (Shimadzu Corporation, Kyoto, Japan) equipped with an Amylose-C (250×4.6 mm) chiral column. The analysis was performed under the following conditions: column temperature: 20 °C, eluent mixture: hexane / i-PrOH = 80 / 20 (v / v), flow rate: 1 mL / min, detection at wavelength λ = 206 nm. The enantiomeric purity is expressed as a percentage.

[0033] The preparation of the compounds of the present invention is shown in the following examples. The syntheses represented in the following examples were not optimized in terms of yield, the amount of reagents used, or the final form of the compounds obtained.

[0034] Abbreviations used: AcOEt: Ethyl acetate CDI: Carbonyldiimidazole DCC: N,N'-Dicyclohexylcarbodiimide DCM: Dichloromethane DMF: Dimethylformamide Et2O: Diethyl ether HCl: Hydrochloric acid HMDS: Hexamethyldisilazane MeOH: Methanol NaCl: Sodium chloride Na2SO4: Sodium sulfate ZnCl2: Zinc chloride

Example

[0035] Synthesis, Physicochemical, and Spectral Data of Intermediates (IV and III According to the Scheme in Figure 2B) Intermediate IV: 4-((Carboxy(phenyl)methyl)amino)-4-oxobutanoic acid Succinic anhydride (3.0 g, 30 mmol, 1 equiv) was dissolved in 15 mL of glacial acetic acid, and then an equimolar amount of DL-phenylglycine (4.53 g) was added. The mixture was heated at 70 °C with stirring for 12 h. After this time, acetic acid was distilled off to dryness. Intermediate IV was washed with Et2O and obtained as a solid.

[0036] White solid. Yield: 87% (6.55 g); m.p. 199.4 - 200.6 °C; TLC: R f = 0.25 (DCM:MeOH (9:1; v / v)); C 12 H 13 NO5 (251.24), monoisotopic mass: 251.08. UPLC (100% purity): t R = 2.77 min. (M + H) + 252.1.

[0037] Intermediate III: 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid ZnCl2 (2.73 g, 20 mmol, 1 equiv) was added to a suspension of 4-((carboxy(phenyl)methyl)amino)-4-oxobutanoic acid (5.0 g, 20 mmol, 1 equiv) (IV) in dry benzene (100 mL), and the mixture was heated to 80 °C. Then, a solution of HMDS (4.84 g, 6.25 mL, 30 mmol, 1.5 equiv) in dry benzene (15 mL) was added dropwise over 30 min. The reaction mixture was stirred under reflux for about 24 h and then concentrated under reduced pressure. After removal of the solvent, the oily residue was dissolved in DCM and extracted with 0.1 M HCl (3 × 50 mL), water (3 × 50 mL), and saturated NaCl solution (3 × 50 mL). The organic layer was dried over anhydrous Na2SO4 and evaporated to dryness. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid was washed with Et2O and obtained as a solid material. Alternatively, 1,4-dioxane can be used instead of benzene in the above procedure.

[0038] White solid. Yield: 90% (4.20 g); m.p. 195.5 - 198.2 °C; TLC: R f = 0.45 (DCM:MeOH (9:1; v / v)); C 12 H 11 NO4 (233.22), monoisotopic mass: 233.07. UPLC (100% purity): t R = 3.41 minutes. (M + H) + 234.1. 1 H NMR (300 MHz, DMSO-D6) δ 2.73 (s, 4H), 5.76 (s, 1H), 7.26 - 7.35 (m, 3H), 7.36 - 7.45 (m, 2H), 13.22 (br s, 1H).

Example

[0039] 1-(2-Oxo-1-phenyl-2-(4-phenylpiperazin-1-yl)ethyl)pyrrolidine-2,5-dione Carbonyl diimidazole (1.17 g, 7.2 mmol, 1.2 eq) was dissolved in 5 mL of dry DMF and then added to a solution of 2-(2,5-dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 eq) dissolved in 10 mL of anhydrous DMF. After stirring for 0.5 h, a solution of 1-phenylpiperazine (0.97 g, 6 mmol, 1 eq) in 5 mL of anhydrous DMF was added dropwise. The reaction mixture was stirred at room temperature for an additional 24 h. After this time, the DMF was removed under reduced pressure. The crude product was purified by column chromatography using a mixture of DCM:MeOH (9:0.3; v / v) as the solvent system. The compound was washed with Et2O and obtained as a solid.

[0040] White solid. Yield: 84% (1.90 g); m.p. 156.7 - 157.4 °C; TLC: R f = 0.35 (DCM:MeOH (9:0.3; v / v)); C 22 H 23 N3O3 (377.44), monoisotopic mass: 377.17. UPLC (100% purity): t R=5.88 minutes. (M+H) + 378.1 1 H NMR (300 MHz, CDCl3) δ 2.58 - 2.81 (m, 5H), 2.95 - 3.15 (m, 2H), 3.17 - 3.42 (m, 3H), 3.63 - 3.76 (m, 1H), 3.92 - 4.05 (m, 1H), 6.12 (s, 1H), 6.80 - 6.91 (m, 3H), 7.19 - 7.28 (m, 2H) 7.29 - 7.47 (m, 5H); 13 C NMR (75 MHz, CDCl3) δ 28.1, 42.4, 45.8, 48.9, 49.2, 56.8, 116.5, 116.6, 120.6, 128.6, 128.6, 128.9, 129.1, 129.2, 129.8, 129.9, 133.0, 150.7, 165.0, 176.3.

Example

[0041] 1-(2-(4-(3-chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(3-chlorophenyl)piperazine (1.40 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.2; v / v) elution system.

[0042] White solid. Yield: 81% (2.00 g); m.p. 128.1 - 129 °C; TLC: R f = 0.51 (DCM:MeOH (9:0.2; v / v)); C 22 H 22 ClN3O3 (411.89), monoisotopic mass: 411.13. UPLC (100% purity): t R = 6.69 minutes, (M+H) + 412.1 11H NMR (300 MHz, CDCl3) δ 2.58 - 2.73 (m, 4H), 3.00 (br s, 1H), 3.27 - 3.53 (m, 3H), 3.54 - 3.86 (m, 2H), 4.17 (br s, 2H), 6.02 (s, 1H), 7.27 - 7.40 (m, 7H), 7.51 - 7.63 (m, 2H); 13 13C NMR (75 MHz, CDCl3) δ 28.0, 40.0, 43.3, 53.3, 53.7, 56.5, 118.9, 120.8, 128.9, 129.1, 129.3, 129.6, 131.4, 132.1, 135.9, 143.8, 165.5, 176.7.

Example

[0043] 1-(2-(4-(3,5-Dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(3,5-dichlorophenyl)piperazine (1.20 g, 6 mmol, 1 equiv). The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system.

[0044] White solid. Yield: 77% (2.06 g); m.p. 163.8 - 165.2 °C; TLC: R f = 0.42 (DCM:MeOH (9:0.2; v / v)); C 22 H 21 Cl2N3O3 (446.33), monoisotopic mass: 446.10. UPLC (99% purity): t R = 7.59 min, (M + H) + 446.1. 11H NMR (500 MHz, CDCl3) δ 2.63 - 2.78 (m, 5H), 2.98 - 3.13 (m, 2H), 3.20 - 3.36 (m, 3H), 3.59 - 3.68 (m, 1H), 3.97 - 4.00 (m, 1H), 6.09 (s, 1H), 6.64 (d, J = 1.7 Hz, 2H), 6.80 (t, J = 1.7 Hz, 1H), 7.33 - 7.38 (m, 3H), 7.42 (d, J = 6.7 Hz, 2H). 13 13C NMR (126 MHz, CDCl3) δ 28.1, 42.2, 45.4, 48.0, 48.2, 56.9, 114.4, 119.8, 128.8, 129.1, 129.9, 132.9, 135.6, 152.1, 165.2, 176.4.

Example

[0045] 1-(2-Oxo-1-phenyl-2-(4-(m-tolyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(3-methylphenyl)piperazine (1.18 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system.

[0046] White solid. Yield: 86% (2.02 g); m.p. 188.7 - 192.1 °C; TLC: R f = 0.45 (DCM:MeOH (9:0.3; v / v)); C 23 H 25 N3O3 (391.47), monoisotopic mass: 391.19. UPLC (98.9% purity): t R = 6.35 min, (M + H) + 392.2. 11H NMR (300 MHz, CDCl3) δ 2.36 (s, 3H), 2.57 - 2.78 (m, 5H), 2.91 - 3.54 (m, 3H), 3.63 - 4.55 (m, 4H), 6.06 (s, 1H), 7.22 (d, 1H, J = 7.5 Hz), 7.27 - 7.62 (m, 8H); 13 13C NMR (75 MHz, CDCl3) δ 21.4, 28.1, 39.7, 43.0, 54.1, 54.6, 56.5, 117.9, 121.7, 128.9, 129.3, 129.7, 130.2, 130.8, 132.3, 141.0, 141.8, 165.4, 176.3.

Example

[0047] 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equivalent), and 1-[3-(trifluoromethyl)phenyl]piperazine (1.38 g, 6 mmol, 1 equivalent) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.2; v / v) elution system.

[0048] White solid. Yield: 82% (2.19 g); m.p. 150.3 - 151.4 °C; TLC: R f = 0.34 (DCM:MeOH (9:0.2; v / v)); C 23 H 22 F3N3O3 (445.44), monoisotopic mass: 445.16. UPLC (100% purity): t R = 6.94 minutes, (M + H) + 446.2. 11H NMR (300 MHz, CDCl3) δ 2.60 - 2.86 (m, 5H), 3.00 - 3.20 (m, 2H), 3.23 - 3.44 (m, 3H), 3.62 - 3.76 (m, 1H), 3.93 - 4.06 (m, 1H), 6.12 (s, 1H), 6.94 - 7.04 (m, 2H), 7.09 (d, 1H, J = 7.7 Hz), 7.28 - 7.51 (m, 6H); 13 13C NMR (75 MHz, CDCl3) δ 28.0, 42.2, 45.6, 48.4, 48.6, 56.8, 112.7 (q, J = 4.6 Hz), 116.7 (q, J = 4.6 Hz), 119.2, 123.4 (q, J = 271.8 Hz), 128.7, 128.9, 129.7, 129.8, 131.5 (q, J = 31.8 Hz), 132.9, 150.8, 165.1, 176.3.

Example

[0049] 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-[4-(trifluoromethyl)phenyl]piperazine (1.38 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system.

[0050] White solid. Yield: 62% (1.66 g); m.p. 173.2 - 174.3 °C; TLC: R f = 0.49 (DCM:MeOH (9:0.3; v / v)); C 23 H 22 F3N3O3 (445.44), monoisotopic mass: 445.16. UPLC (100% purity): t R = 6.89 min, (M + H) +446.2。 1 1H NMR (300 MHz, CDCl3) δ 2.61 - 2.85 (m, 5H), 3.04 - 3.43 (m, 5H), 3.63 - 3.77 (m, 1H), 3.91 - 4.05 (m, 1H), 6.12 (s, 1H), 6.83 (d, 2H, J = 8.6 Hz), 7.30 - 7.40 (m, 3H), 7.40 - 7.50 (m, 4H); 13 13C NMR (75 MHz, CDCl3) δ 28.0, 42.1, 45.4, 47.6, 47.9, 56.8, 115.0, 124.5 (q, J = 270.6 Hz), 126.5 (q, J = 4.6 Hz), 128.7, 128.8, 128.9, 129.8, 132.8, 152.7, 165.1, 176.3.

Example

[0051] 1-(2-(4-(3,5-Bis(trifluoromethyl)phenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-[3,5-bis(trifluoromethyl)phenyl]piperazine (1.18 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0052] White solid. Yield: 69% (2.12 g); m.p. 228.1 - 229.4 °C; TLC: R f = 0.47 (DCM:MeOH (9:0.5; v / v)); C 24 H 21 F6N3O3 (513.44), monoisotopic mass: 513.13. UPLC (100% purity): t R = 6.58 minutes, (M + H) + 514.1。 11H NMR (300 MHz, CDCl3) δ 2.52 - 2.75 (m, 4H), 2.82 - 3.07 (m, 4H), 3.12 - 3.86 (m, 4H), 6.11 (s, 1H), 6.97 - 7.05 (m, 3H), 7.22 - 7.61 (m, 5H).

Example

[0053] 1-(2-Oxo-1-phenyl-2-(4-(3-(difluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(3-difluoromethylphenyl)piperazine (1.27 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.2; v / v) elution system.

[0054] White solid. Yield: 83% (2.13 g); m.p. 156.4 - 157.6 °C; TLC: R f = 0.55 (DCM:MeOH (9:0.2; v / v)); C 23 H 23 F2N3O3 (427.45), monoisotopic mass: 427.17. UPLC (100% purity): t R = 6.36 minutes, (M + H) + 428.2. 1 1H NMR (300 MHz, CDCl3) δ 2.58 - 2.78 (m, 5H), 3.02 - 3.18 (m, 2H), 3.24 - 3.46 (m, 3H), 3.62 - 4.08 (m, 2H), 6.12 (s, 1H), 6.44 - 7.62 (m, 1H), 6.94 - 7.04 (m, 2H), 7.28 - 7.51 (m, 7H).

Example

[0055] 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equivalent) and 1-[3-(trifluoromethoxy)phenyl]piperazine (1.48 g, 6 mmol, 1 equivalent) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system.

[0056] White solid. Yield: 89% (2.46 g); m.p. 100.3 - 101.6 °C; TLC: R f = 0.42 (DCM:MeOH (9:0.3; v / v)); C 23 H 22 F3N3O4 (461.44), monoisotopic mass: 461.16. UPLC (100% purity): t R = 7.15 minutes, (M + H) + 462.2. 1 H NMR (300 MHz, CDCl3) δ 2.63 - 2.79 (m, 5H), 3.00 - 3.16 (m, 2H), 3.22 - 3.39 (m, 3H), 3.93 - 4.05 (m, 1H), 3.63 - 3.75 (m, 1H), 6.12 (s, 1H), 6.62 (s, 1H), 6.66 - 6.78 (m, 2H), 7.16 - 7.28 (m, 1H), 7.32 - 7.48 (m, 5H); 13 C NMR (75 MHz, CDCl3) δ 28.0, 42.2, 45.5, 48.3, 48.5, 56.8, 108.8, 112.1, 114.2, 120.4 (q, J = 256.8 Hz), 128.7, 128.9, 129.8, 130.2, 132.8, 150.2, 151.9, 165.1, 176.3.

Example

[0057] 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 eq), and 1-[4-(trifluoromethoxy)phenyl]piperazine (1.48 g, 6 mmol, 1 eq) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system.

[0058] White solid. Yield: 83% (2.29 g); m.p. 102.3 - 103.5 °C; TLC: R f = 0.43 (DCM:MeOH (9:0.3; v / v)); C 23 H 22 F3N3O4 (461.44), monoisotopic mass: 461.16. UPLC (100% purity): t R = 7.17 minutes, (M+H) + 462.2. 1 H NMR (300 MHz, CDCl3) δ 2.61 - 2.73 (m, 5H), 2.98 - 3.13 (m, 2H), 3.20 - 3.37 (m, 3H), 3.91 - 4.08 (m, 1H), 3.63 - 3.75 (m, 1H), 6.13 (s, 1H), 6.60 (s, 1H), 6.63 - 6.79 (m, 2H), 7.14 - 7.28 (m, 1H), 7.29 - 7.51 (m, 5H).

Example

[0059] 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl(sulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 eq), and 1-[3-(trifluoromethylthio)phenyl]piperazine (1.57 g, 6 mmol, 1 eq) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0060] White solid. Yield: 64% (1.83 g); m.p. 97.8 - 99.2 °C; TLC: R f = 0.48 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 F3N3O3S (477.50), monoisotopic mass: 478.13. UPLC (99% purity): t R = 7.55 minutes, (M+H) + 478.1. 1 H NMR (500 MHz, CDCl3) δ 2.64 - 2.78 (m, 5H), 3.01 - 3.07 (m, 1H), 3.09 - 3.15 (m, 1H), 3.24 - 3.32 (m, 2H), 3.34 (dd, J = 7.7, 3.2 Hz, 1H), 3.62 - 3.75 (m, 1H), 3.99 (ddd, J = 13.2, 5.7, 3.4 Hz, 1H), 6.11 (s, 1H), 6.92 (dd, J = 8.0, 2.3 Hz, 1H), 7.06 (s, 1H), 7.12 (d, J = 7.4 Hz, 1H), 7.24 - 7.29 (m, 1H), 7.33 - 7.38 (m, 3H), 7.43 (d, J = 6.8 Hz, 2H). 13 C NMR (126 MHz, CDCl3) δ 28.1, 45.6, 48.4, 48.7, 56.9, 118.5, 123.7, 125.3, 127.8, 128.5, 129.4 (d, J = 141.2 Hz), 129.6 (d, J = 137.0 Hz), 130.9, 132.9, 151.4, 165.2, 176.4.

Example

[0061] 1-(2-(4-([1,1'-Biphenyl]-3-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(biphen-3-yl)piperazine (1.43 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0062] White solid. Yield: 82% (2.23 g); m.p. 114.1~115.4 °C; TLC: R f = 0.4 (DCM:MeOH (9:0.5; v / v)); C 28 H 27 N3O3 (453.54), monoisotopic mass: 453.20. UPLC (100% purity): t R = 7.43 minutes, (M+H) + 454.2. 1 H NMR (300 MHz, CDCl3) δ 2.56 - 2.81 (m, 5H), 3.00 - 3.21 (m, 2H), 3.23 - 3.56 (m, 3H), 3.65 - 3.79 (m, 1H), 3.94 - 4.11 (m, 1H), 6.14 (s, 1H), 6.83 (dd, 1H, J = 8.1, 2.0 Hz), 7.00 - 7.17 (m, 2H), 7.27 - 7.62 (m, 11H); 13 C NMR (75 MHz, CDCl3) δ 28.1, 42.5, 45.8, 49.0, 49.2, 56.8, 115.4, 115.6, 119.7, 127.2, 127.4, 128.7, 128.8, 129.6, 129.9, 132.9, 141.4, 142.5, 151.1, 165.0, 176.4.

Example

[0063] 1-(1-(4-Fluorophenyl)-2-oxo-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-(4-fluorophenyl)acetic acid (1.51 g, 6 mmol, 1 eq), and 1-[3-(trifluoromethoxy)phenyl]piperazine (1.38 g, 6 mmol, 1 eq) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0064] White solid. Yield: 73% (2.03 g); m.p. 88.8 - 90.7 °C; TLC: R f = 0.63 (DCM:MeOH (9:0.5; v / v)); C 23 H 21 F4N3O3 (463.43), monoisotopic mass: 463.15. UPLC (100% purity): t R = 7.05 minutes, (M+H) + 464.2. 1 H NMR (300 MHz, CDCl3) δ 2.61 - 2.89 (m, 5H), 3.02 - 3.46 (m, 5H), 3.67 - 3.80 (m, 1H), 3.88 - 4.04 (m, 1H), 6.09 (s, 1H), 6.94 - 7.27 (m, 6H), 7.29 - 7.40 (m, 2H). 13 C NMR (75 MHz, CDCl3) δ 28.0, 42.3, 45.6, 48.5, 48.6, 56.0, 112.7 (q, J = 3.4 Hz), 115.9, 116.2, 116.7 (q, J = 3.4 Hz), 117.0, 119.3, 124.1 (q, J = 272.9 Hz), 125.5 (d, J = 3.4 Hz), 129.7, 130.2, 130.3, 131.5 (q, J = 31.1 Hz), 135.1 (d, J = 6.9 Hz), 150.7, 160.9, 164.2, 164.5, 176.23.

Example

[0065] 1-(2-(4-(Naphthalen-2-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(naphthalen-2-yl)piperazine (1.27 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0066] White solid. Yield: 79% (2.02 g); m.p. 197.1 - 198.5 °C; TLC: R f = 0.71 ((DCM:MeOH (9:0.5; v / v)); C 26 H 25 H3N3O3 (427.50), monoisotopic mass: 427.19. UPLC (100% purity): t R = 6.97 minutes (M+H) + 428.2. 1 H NMR (300 MHz, CDCl3) δ 2.58 - 2.87 (m, 5H), 3.03 - 3.25 (m, 2H), 3.29 - 3.60 (m, 3H), 3.69 - 3.89 (m, 1H), 3.96 - 4.17 (m, 1H), 6.12 - 6.18 (m, 1H), 7.00 - 7.24 (m, 2H), 7.28 - 7.54 (m, 7H), 7.61 - 7.80 (m, 3H).

Example

[0067] 1-(2-(4-(Benzo[b]thiophen-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 1-(benzo[b]thiophen-5-yl)piperazine (1.30 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0068] White solid. Yield: 79% (2.05 g); m.p. 164.1 - 165.3 °C; TLC: R f = 0.66 ((DCM:MeOH (9:0.5; v / v)); C 24 H 23 N3O3S (433.53), monoisotopic mass: 433.15. UPLC (100% purity): t R = 6.62 minutes, (M+H) + 434.1. 1 H NMR (300 MHz, CDCl3) δ 2.56 - 2.85 (m, 5H), 2.96 - 3.17 (m, 2H), 3.20 - 3.54 (m, 3H), 3.66 - 3.87 (m, 1H), 3.96 - 4.12 (m, 1H), 6.14 (s, 1H), 6.99 (dd, J = 8.7, 1.9 Hz, 1H), 7.15 - 7.25 (m, 1H), 7.30 - 7.55 (m, 7H), 7.72 (d, J = 8.8 Hz, 1H).

Example

[0069] 1-(2-(4-(1,2-Benzoxazol-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 5-(piperazin-1-yl)benzo[d]isoxazole (1.22 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0070] White solid. Yield: 57% (1.43 g); m.p. 186.4 - 187.8 °C; TLC: R f = 0.58 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 N4O4 (418.45), monoisotopic mass: 418.16. UPLC (98% purity): t R = 7.25 min, (M+H) + 419.1. 1 H NMR (300 MHz, CDCl3) δ 2.57 - 2.86 (m, 5H), 2.95 - 3.19 (m, 3H), 3.22 - 3.53 (m, 2H), 3.62 - 3.84 (m, 2H), 3.94 - 4.11 (m, 1H), 6.14 (s, 1H), 7.05 - 7.32 (m, 1H), 7.29 - 7.54 (m, 6H), 7.98 (d, J = 8.8 Hz, 1H).

Example

[0071] 1-(2-(4-(3-Chlorophenyl)piperidin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 4-(3-chlorophenyl)piperidine (1.17 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0072] White solid. Yield: 74% (1.83 g); m.p. 111.8 - 113.4 °C; TLC: R f = 0.43 (DCM:MeOH (9:0.5; v / v)); C 23 H 23 ClN2O3 (410.90), monoisotopic mass: 410.14. UPLC (100% purity): t R = 7.05 minutes, (M + H) + 411.1. 1 H NMR (300 MHz, CDCl3) δ 1.52 - 2.05 (m, 4H), 2.33 - 2.84 (m, 8H), 2.96 - 3.34 (m, 1H), 6.15 (s, 1H), 7.05 - 7.28 (m, 6H), 7.32 - 7.66 (m, 3H).

Example

[0073] 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equivalent), and 1-[3-(trifluoromethyl)phenyl]piperidine (1.37 g, 6 mmol, 1 equivalent) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0074] White solid. Yield: 85% (2.26 g); m.p. 100.1 - 101.5 °C; TLC: R f = 0.45 (DCM:MeOH (9:0.5; v / v)); C 24 H 23 F3N2O3 (444.45), monoisotopic mass: 444.17. UPLC (100% purity): t R = 7.26 minutes, (M + H) + 445.1. 11H NMR (300 MHz, CDCl3) δ 1.49 - 2.00 (m, 3H), 2.54 - 2.83 (m, 8H), 2.94 - 3.77 (m, 2H), 6.14 (s, 1H), 7.09 - 7.60 (m, 9H).

Example

[0075] 1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-dioxopyrrolidin-1-yl)-2-phenylacetic acid (1.40 g, 6 mmol, 1 equiv), and 4-[3-(trifluoromethoxy)phenyl]piperidine (1.45 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0076] White solid. Yield: 79% (2.18 g); m.p. 112.1 - 113.2 °C; TLC: R f = 0.47 (DCM:MeOH (9:0.5; v / v)); C 24 H 23 F3N2O4 (460.45), monoisotopic mass: 460.16. UPLC (100% purity): t R = 7.12 min, (M + H) + 461.1. 1 1H NMR (300 MHz, CDCl3) δ 1.38 - 2.15 (m, 3H), 2.49 - 2.92 (m, 8H), 2.99 - 3.85 (m, 2H), 6.15 (s, 1H), 7.11 - 7.64 (m, 9H).

Example

[0077] 1-(1-oxo-3-phenyl-1-(4-phenylpiperazin-1-yl)propan-2-yl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-3-phenylpropanoic acid (1.48 g, 6 mmol, 1 eq), and 1-phenylpiperazine (0.97 g, 6 mmol, 1 eq) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0078] White solid. Yield: 87% (1.13 g); m.p. 121.7 - 123.2 °C; TLC: R f = 0.62 (DCM:MeOH (9:0.5; v / v)); C 23 H 25 N3O3 (391.47), monoisotopic mass: 392.19. UPLC (100% purity): t R = 6.22 minutes, (M+H) + 392.1. 1 H NMR (300 MHz, CDCl3) δ 2.49 - 2.61 (m, 4H), 3.08 (d, J = 16.4 Hz, 4H), 3.31 - 3.89 (m, 6H), 5.19 (dd, J = 10.3, 6.1 Hz, 1H), 6.83 - 6.96 (m, 3H), 7.13 - 7.33 (m, 7H). 13 C NMR (75 MHz, CDCl3) δ 27.8, 34.2, 42.5, 45.4, 49.3, 49.6, 52.9, 116.6, 120.7, 127.1, 128.6, 129.1, 129.3, 136.7, 150.7, 166.4, 176.5.

Example

[0079] 1-(1-(4-(3-Chlorophenyl)piperazin-1-yl)-1-oxo-3-phenylpropan-2-yl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-3-phenylpropanoic acid (1.48 g, 6 mmol, 1 equiv), and 1-(3-chlorophenyl)piperazine (1.40 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0080] White solid. Yield: 87% (1.23 g); m.p. 114.3 - 116.2 °C; TLC: R f = 0.80 (DCM:MeOH (9:0.5; v / v)); C 23 H 24 ClN3O3 (425.91), monoisotopic mass: 426.15. UPLC (100% purity): t R = 6.97 minutes, (M+H) + 426.1. 1 H NMR (300 MHz, CDCl3) δ 2.49 - 2.64 (m, 4H), 3.07 (d, J = 15.3 Hz, 4H), 3.30 - 3.86 (m, 6H), 5.17 (dd, J = 10.1, 6.2 Hz, 1H), 6.73 (ddd, J = 8.3, 2.2, 0.9 Hz, 1H), 6.79 - 6.88 (m, 2H), 7.06 - 7.35 (m, 6H). 13 C NMR (75 MHz, CDCl3) δ 27.8, 34.2, 42.2, 45.2, 48.7, 49.0, 52.9, 114.4, 116.3, 120.2, 127.1, 128.6, 129.1, 130.2, 135.0, 136.6, 151.7, 166.4, 176.5.

Example

[0081] 1-(1-Oxo-3-phenyl-1-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)propan-2-yl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-3-phenylpropanoic acid (1.48 g, 6 mmol, 1 equiv), and 1-[3-(trifluoromethyl)phenyl]piperazine (1.38 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0082] White solid. Yield: 84% (1.59 g); m.p. 126.1 - 127.2 °C; TLC: R f = 0.72 (DCM:MeOH (9:0.5; v / v)); C 24 H 24 F3N3O3 (459.47), monoisotopic mass: 460.18. UPLC (100% purity): t R = 7.22 min, (M+H) + 460.1. 1H NMR (300 MHz, CDCl3) δ 2.50 - 2.64 (m, 4H) 3.12 (d, J = 14.8 Hz, 4H), 3.32 - 3.89 (m, 6H) 5.18 (dd, J = 9.9, 6.2 Hz, 1H), 6.94 - 7.42 (m, 9H).

Example

[0083] 1-(1-(4-([1,1'-Biphenyl]-3-yl)piperazin-1-yl)-1-oxo-3-phenylpropan-2-yl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-3-phenylpropanoic acid (1.48 g, 6 mmol, 1 equiv), and 1-(biphenyl-3)piperazine (1.43 g, 6 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0084] White solid. Yield: 88% (1.46 g); m.p. 119.1 - 120.0 °C; TLC: R f= 0.77 (DCM:MeOH (9:0.5; v / v)); C 29 H 29 N3O3 (467.57), monoisotopic mass: 467.22. UPLC (100% purity): t R = 7.63 minutes, (M+H) + 468.2 1 H NMR (300 MHz, CDCl3) δ 2.50 - 2.63 (m, 4H) 3.16 (d, J = 18.9 Hz, 4H), 3.32 - 3.91 (m, 6H), 5.20 (dd, J = 10.2, 6.0 Hz, 1H) 6.88 (dd, J = 8.1, 1.8 Hz, 1H), 7.06 - 7.38 (m, 9H), 7.39 - 7.48 (m, 2H), 7.51 - 7.62 (m, 2H). 13 C NMR (75 MHz, CDCl3) δ 27.8, 34.2, 42.5, 45.4, 49.4, 49.7, 53.0, 115.5, 115.7, 119.7, 127.1, 127.2, 127.4, 128.6, 128.7, 129.1, 129.6, 136.7, 141.4, 142.5, 151.1, 166.4, 176.5.

Example

[0085] 1-(1-Oxo-3-phenyl-1-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)propan-2-yl)pyrrolidine-2,5-dione The compound was prepared according to the procedure described in Example 2. 2-(2,5-Dioxopyrrolidin-1-yl)-3-phenylpropanoic acid (1.48 g, 6 mmol, 1 equivalent), and 1-[3-(trifluoromethoxy)phenyl]piperazine (1.48 g, 6 mmol, 1 equivalent) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0086] White solid. Yield: 83% (1.32 g); m.p. 104.4 - 105.5 °C; TLC: R f= 0.71 (DCM:MeOH (9:0.5; v / v)); C 24 H 24 F3N3O4 (475.47), monoisotopic mass: 475.17. UPLC (100% purity): t R = 7.40 minutes, (M+H) + 476.1. 1 H NMR (300 MHz, CDCl3) δ 2.50 - 2.63 (m, 4H, 3.10 (d, J = 16.4 Hz, 4H), 3.31 - 3.86 (m, 6H), 5.18 (dd, J = 9.9, 6.2 Hz, 1H), 6.62 - 6.85 (m, 3H), 7.11 - 7.36 (m, 6H).

Example

[0087] Determination of the in vivo anticonvulsant activity in mice Male Swiss albino mice (CD-1) weighing 18 - 26 g were used. All procedures were carried out in accordance with the applicable Polish and international guidelines on the ethics of animal testing, after receiving approval from the appropriate facility. The substance was administered intraperitoneally (i.p.) as a single injection at a volume of 10 ml / kg, 30 minutes before a given test, in a 1% aqueous solution of Tween. Screening was performed in groups of 4 mice. The mean effective dose (ED 50 ), and the toxic dose (TD 50 ) in the rotarod test were estimated based on the results obtained from 3 - 4 groups of 6 animals. All tests were carried out based on procedures described in the specialist literature.

Example

[0088] Maximal electroshock seizure test (MES) In the MES test, seizures were induced by an electrical stimulus lasting for 0.2 s at a voltage of 500 V and an intensity of 25 mA. The electrical stimulus was generated using an electrical shock generator (Rodent shocker, Type 221, Hugo Sachs Elektronik, Germany) and delivered to the animals using electrodes placed on the auricles. The test was performed 30 min after the intraperitoneal administration of the compound at various doses. During the experiment, the number of animals that experienced seizure episodes in the form of tonic extension of the hindlimbs was counted (Kaminski, K.; Rapacz, A.; Luszczki, J.J.; Latacz, G.; Obniska, J.; Kiec-Kononowicz, K.; Filipek, B., Bioorg. Med. Chem. 2015, 23, 2548 - 2561; Castel-Branco, M.M.; Alves, G.L.; Figueiredo, I.V.; Falcao, A.C.; Caramona, M.M., Methods Find. Exp. Clin. Pharmacol. 2009, 31, 101 - 106).

Example

[0089] Psychomotor seizure test (6 Hz test) In the 6 Hz test, seizures were induced by electrical stimulation at 32 mA and / or 44 mA, and at a frequency of 6 pulses per second. Electrical pulses were generated using an electrical shock generator (ECT Unit 57800; Ugo Basile, Gemonio, Italy) and delivered to the animals using eye electrodes. Before starting the test, the surface of the eye was gently moistened with a solution of a local anesthetic (1% lidocaine solution). The test was performed 30 minutes after intraperitoneal administration of the compound at various doses. Electrical pulses were delivered continuously for 3 seconds, after which the animals were observed for 10 seconds. During this period, immobility or apnea related to breeding, forelimb clonus, contraction of the sensory hairs, and Straub’s tail reaction were observed. These symptoms persisted during the observation period and indicated the occurrence of psychomotor seizures in the mice. Mice that resumed normal movement within 10 seconds after stimulation were considered protected (Barton, M.E.; Klein, B.D.; Wolf, H.H.; White, H.S., Epilepsy Res. 2001, 47, 217 - 227; Wojda, E.; Wlaz, A.; Patsalos, P.N.; Luszczki, J.J., Epilepsy Res. 2009, 86, 163 - 174).

Example

[0090] Subcutaneous pentylenetetrazole seizure test (scPTZ) In the scPTZ test, seizures were induced by subcutaneous administration of pentylenetetrazole (PTZ) at a dose of 100 mg / kg. This caused subconvulsions accompanied by the loss of the righting reflex. The test compound was administered 30 minutes before the experiment. After PTZ administration, the animals were placed individually in transparent containers and observed for 30 minutes for the onset of subconvulsions. During this period, the latency to the first onset of subconvulsions, defined as generalized clonus lasting at least 3 seconds accompanied by the loss of the righting reflex and the number of seizure episodes during the test period, was observed and compared with the control group. The absence of subconvulsive seizures during the observed period was interpreted as the ability of the compound to protect against PTZ-induced seizures (Ferreri, G.; Chimirri, A.; Russo, E.; Gitto, R.; Gareri, P.; De Sarro, A.; De Sarro, G., Pharmacol. Biochem. Behav. 2004, 77, 85-94; Laczkowski, K.; Salat, K.; Misiura, K.; Podkowa, A.; Malikowska, N., J. Enzyme Inhib. Med. Chem. 2016, 31, 1576-82).

Example

[0091] Effect on the motor coordination of mice in the rotarod test The effect of the tested compound on motor coordination was evaluated by the rotarod test (apparatus used: May Commat, RR 0711 Rota Rod, Turkey). Mice were trained the day before the actual experiment. They were individually placed on a rod with a diameter of 2 cm rotating at 10 revolutions per minute (rpm). During each training session, the animals remained on the rod for 3 minutes. The experiment was carried out 30 minutes after the administration of the compound. Motor coordination was tested for 60 seconds at a rod rotation speed of 10 rpm. Motor impairment was defined as the inability to stay on the rotating rod for 1 minute. The average time spent on the rod was counted in each experimental group (Dunham, N.W.; Miya, T.A.; Edwards, L.D., J. Am. Pharm. Assoc. 1957, 46, 64 - 66; Laczkowski, K.; Salat, K.; Misiura, K.; Podkowa, A.; Malikowska, N., J. Enzyme Inhib. Med. Chem. 2016, 31, 1576 - 82).

Example

[0092] Statistical analysis ED along the corresponding 95% confidence interval 50 (Effective dose) and TD 50 (Toxic dose) values were calculated based on the Litchfield and Wilcoxon method (Litchfield, J.T., Wilcoxon, F., 1949, A simplified method of evaluating dose - effect experiments. J. Pharmacol. Exp. Ther. 96, 99 - 113). To perform a statistical evaluation of the results, one - way ANOVA analysis of variance and Dunnett's post hoc test (multiple comparison test) were used. Values with a significant level of p < 0.05 were considered statistically significant.

Example

[0093] Results of the antispasmodic activity test The compounds of the present invention showed broad antispasmodic activity by effectively acting in the MES test, 6 Hz (32 mA and / or 44 mA), and scPTZ at a dose of 100 mg / kg. At the 30-minute time point, these protected 50 - 100% of the animals tested. The most potent protection was revealed for compounds containing an electron-withdrawing substituent at position 3 of the aromatic ring attached to the piperazine moiety, preferably Cl, CF3, OCF3, SCF3, CHF2, or a phenyl substituent, where k is preferably 0. Table 1 shows the pharmacological screening data for the selected substances.

[0094]

Table 1

[0095] The above tests were carried out with the racemic mixtures of the compounds according to the invention.

[0096] Table 2 presents quantitative pharmacological data for the selected compounds according to general formula (II), in particular for the selected active compound: 1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione (6), which protected 100% of the mice in the MES test, 6 Hz (32 mA and 44 mA) tests, and scPTZ test (at the 0.5-hour time point) during the screening tests.

[0097]

Table 2

[0098] The results obtained confirmed that the compounds of the present invention, especially compound 6, have a strong protective effect and a clearly better protection index compared to the model AED - valproic acid. In particular, valproic acid is known to have a broad spectrum of therapeutic indications.

Example

[0099] Determination of antinociceptive activity in in vivo tests in mice The tests were performed using male white Swiss mice (CD-1) weighing 18 - 25 g. All procedures were carried out in accordance with Polish and international guidelines on the ethics of animal testing, after receiving approval from the appropriate facilities. The test groups consisted of 8 - 10 animals. The test substance and the reference substance were administered intraperitoneally as a suspension in a 1% aqueous solution of Tween 30 minutes before the given test. All tests / models were performed based on the procedures described in the expert literature: formalin test (Beirith, A.; Santos, A.R.; Calixto, J.B.; Rodrigues, A.L.; Creczynski-Pasa, T.B., Eur. J. Pharmacol. 1998, 345, 233 - 245), model of capsaicin-induced pain (Mogilski, S.; Kubacka, M.; Redzicka, A.; Kazek, G.; Dudek, M.; Malinka, W.; Filipek, B., Pharmacol. Biochem. Behav. 2015, 133, 99 - 110), model of oxaliplatin-induced neuropathic pain - von Frey test (Salat, K.; Cios, A.; Wyska, E.; Salat, R.; Mogilski, S.; Filipek, B.; Wieckowski, K.; Malawska, B., Pharmacol. Biochem. Behav. 2014, 122, 173 - 181).

Example

[0100] Determination of analgesic activity in the formalin test Pain was induced by plantar injection of 20 μL of 2.5% formalin solution into the right hind limb of the mice. The animals were placed in separate transparent observation chambers for 30 minutes. The measurements were the total time spent licking or biting the limb injected with the formalin solution. The nociceptive response time was calculated at 5 minutes after the first injection of formalin (first phase of the test: acute pain), as well as at time intervals of 15 - 20 minutes, 20 - 25 minutes, and 25 - 30 minutes after administration (second phase of the test: inflammatory pain). The observed inhibition of the nociceptive response - reduction in the time spent licking or biting the limb was interpreted as the analgesic effect of the tested compound. Based on the results obtained, the ED 50 dose (dose reducing the nociceptive response time by 50%) was calculated. The reference compound for this test was valproic acid, which was administered intraperitoneally at doses of 100 mg / kg, 150 mg / kg, and 200 mg / kg. Compound 6 was administered at doses of 10 mg / kg, 20 mg / kg, and 30 mg / kg.

[0101] Compound 6 showed different analgesic activities in both phases of the test. The mean nociceptive response time in the control group was 90.0 ± 4.97 seconds and 212.70 ± 10.16 seconds in the first and second phases of the test, respectively. Compound 6 reduced the nociceptive response time in the first phase of the formalin test corresponding to acute pain at all doses tested, and a statistically significant effect was observed at the two highest doses. The ED 50 value of Compound 6 in the first phase of the test was 28.50 mg / kg. In the second phase of the test corresponding to persistent inflammatory pain, Compound 6 significantly shortened the time of the nociceptive response statistically at all doses used. The ED 50 value for this compound in the second phase of the test was 12.40 mg / kg (Figure 3).

[0102] Valproic acid (VPA) did not show analgesic activity in the first phase of the test at any of the doses tested. In the second phase of the VPA test, the nociceptive response time was reduced at all doses used, and the ED 50 value for this phase of the test was 132.90 mg / kg (Figure 3).

Example

[0103] Determination of Analgesic Activity in a Capsaicin Pain Model In this test, the time that mice licked and / or bit the hind limb injected subplantarly with 1.6 μg of capsaicin dissolved in a 20 μl mixture containing 0.9% saline and ethanol (5% final volume) was evaluated. Observations were made for 5 minutes after capsaicin administration. The test compound was administered intraperitoneally 30 minutes before capsaicin administration. Inhibition of the nociceptive response - shortening of the time of licking or biting the limb - was a measure of the antinociceptive activity of the tested compound.

[0104] Valproic acid (VPA) was the reference compound in this test. VPA was administered intraperitoneally at doses of 100 mg / kg, 150 mg / kg, and 200 mg / kg. Compound 6 was administered at 20 mg / kg, 30 mg / kg, and 40 mg / kg. The test compounds were administered as suspensions in a 1.0% Tween 80 solution. The control group consisted of mice treated with vehicle alone (1% Tween 80 solution). The nociceptive response time in this group was 43.29 ± 3.21 seconds.

[0105] Compound 6 significantly reduced the nociceptive response time statistically at 20 mg / kg and 30 mg / kg, and the ED 50 was 17.9 mg / kg (Figure 4).

[0106] The reference compound (valproic acid) significantly reduced the nociceptive response time statistically only after administration at 200 mg / kg to 25.00 ± 4.57 seconds (corresponding to 42.25% analgesic activity) (Figure 4).

Example

[0107] Model of Oxaliplatin - Induced Neuropathic Pain - Determination of Analgesic Activity by von Frey Test Oxaliplatin (OXPT) was dissolved in a 5% glucose solution and then administered intraperitoneally to mice. A single dose of 10 mg / kg was used. Tactile and thermal (cold sensation) allodynia associated with oxaliplatin-induced neuropathy is characterized in two phases. The initial phase is acute and develops immediately after the administration of OXPT, while the symptoms of the late (chronic) phase (associated with neuronal damage) develop several days later. Behavioral tests in mice with OXPT-induced neuropathy were performed 7 days after administration, i.e., in the late phase of neuropathy.

[0108] The effect of the test compound on tactile allodynia was determined by the von Frey test. Animals were individually placed in cages with a mesh bottom 60 minutes before the start of the experiment to adapt to the new environment. An electronic Von Frey apparatus (Electronic Von Frey, Bioseb, France) was used to evaluate the pain threshold to mechanical stimuli. The von Frey filament was applied to the underside of the right limb of the mouse while increasing the pressure. At the intersection of the pain threshold, the limb was withdrawn, and the mechanical pressure that subsequently induced a nocifensive response was recorded. The measurements were performed 3 times on each mouse at least 30 seconds between measurements, and the results obtained were averaged. The entire test was performed 3 times: before OXPT administration to determine the baseline pain threshold; before administration of the test compound 7 days after OXPT administration to evaluate the onset of neuropathy by setting a new pain threshold; 30 minutes after administration of the compound to determine the effect of developing neuropathy.

[0109] The effect of the test compound on thermal allodynia was evaluated by the cold plate test using a special device: Cold / Hot Plate, Bioseb, France. Animals were individually placed on a metal plate cooled to 2°C using a thermostat-equipped device. The observed nocifensive responses in the animals included licking and / or characteristic raising or jumping of the hind limbs. The observation time was set to 60 seconds to remove the potential risk of tissue damage and minimize the discomfort of the animals. Similar to the von Frey test, the measurements were performed 3 times.

[0110] Compound 6 and valproic acid as a reference AED were administered intraperitoneally as suspensions in a 1% solution of Tween 80. Compound 6 was administered at doses of 10, 20, and 30 mg / kg. The reference compound (valproic acid) was given at doses of 50, 100, and 150 mg / kg.

[0111] Injection of OXPT in mice caused the development of neuropathy, resulting in a significant and statistically significant reduction in pain threshold measured by the von Frey method. The pain sensitivity threshold decreased in OXPT-administered mice from 3.18 ± 0.06 - 3.36 ± 0.10 g in healthy mice to levels in the range of 1.89 ± 0.04 - 1.94 ± 0.14 g. The results obtained indicate a statistically significant analgesic effect of the tested Compound 6. The mean pain sensitivity threshold of the control group was 3.36 ± 0.10 g, while after administration of OXPT, it decreased to 1.89 ± 0.04 g (56.25% of the initial value). Administration of Compound 6 at a dose of 10 mg / kg increased the pain threshold to 2.87 ± 0.12 g (85.41% of the initial value), which already shows an inhibitory effect on the development of mechanical allodynia at a low dose. Compound 6 at a dose of 20 mg / kg increased the pain sensitivity threshold up to 3.83 ± 0.13 g, which is 113.98% of the initial value. The 30 mg / kg dose resulted in an increase in the pain threshold up to 4.17 ± 0.17 g, which is 124.10% of the initial value. The results obtained indicate that Compound 6 is highly effective in suppressing the development of mechanical allodynia, which is a result of neuronal damage caused by the chemotherapeutic agent - OXPT (Figure 5A).

[0112] The mean pain sensitivity threshold in the control group for the reference compound (valproic acid, VPA) was 2.62 ± 0.06 g, and it decreased to 1.78 ± 0.04 g after administration of OXPT. Administration of VPA at a dose of 150 mg / kg caused an increase in the pain threshold up to a maximum of 3.97 ± 0.30 g, while doses of 100 mg / kg and 50 mg / kg body weight enabled an increase in the mean pain threshold up to 3.18 ± 0.14 g and 2.75 ± 0.06 g, respectively (Figure 5B).

[0113] Compound 6 also significantly enhanced thermal allodynia sensitivity in the cold plate test (Figure 5C).

Example

[0114] In vitro affinity and functionality tests The affinity and functionality tests performed in vitro on the most active substance 6, which represents the compounds according to formula (II), showed that its mechanism of action is related to the effect on nerve conductivity through interaction with voltage-dependent sodium channels (site 2) and calcium channels (dihydropyridine, diltiazem, and verapamil binding sites). A unique feature of compound 6, which represents the compounds of formula (II) according to the present invention, is the inhibition of calcium current by blocking the transient receptor potential vanilloid type 1 (TRPV1). This effect is not disclosed for known AEDs. TRPV1 receptor antagonism can determine the anti-nociceptive effect of the compounds disclosed herein. The role of the TRPV1 receptor in the transmission of pain stimuli is well documented in the specialist literature (Szallasi, A.; Cortright, D.N.; Blum, C.A.; Eid, S.R., Nat. Rev. Drug. Discov. 2007, 6, 357 - 372). The compounds according to the present invention are characterized by a complex mechanism of action, which is not described for known anticonvulsants. However, it should be emphasized that further in vitro tests can reveal additional molecular targets involved in the pharmacological action of the substances which are the subject of the claims. The results of the binding tests (sodium channels, calcium channels) and functionality tests (TRPV1 receptor) for compound 6 are shown in Table 3.

[0115]

Table 3A

Example

[0116] In vitro electrophysiological tests The experiments were carried out in accordance with the institutional and international guidelines on the ethics of animal research. Rats (3 weeks old) were anesthetized with ethyl chloride and decapitated. The brain was then removed and placed in ice-cold extracellular fluid. The methodology for section preparation and preincubation has been described previously (Szulczyk, B.; Nurowska, E., Biochem. Biophys. Res. Commun. 2017, 491, 291 - 295). Sections containing the prefrontal cortex were dispersed enzymatically and mechanically. Single prefrontal cortical pyramidal neurons were visualized using an inverted microscope (Nikon). Sodium currents were evoked by rectangular depolarizing stimuli. The potential between depolarizing stimuli was maintained at -65 mV.

[0117] The intracellular solution in the pipette contained CsF (110), NaCl (7), EGTA (3), HEPES-Cl (10), MgCl2 (2), Na2ATP (4) (pH 7.4 and osmolarity 290 mOsm) (in mM units).

[0118] The extracellular solution for washing the neurons contained NaCl (30), choline chloride (90), TEA-Cl (30), CaCl2 (2), MgCl2 (2), glucose (15), HEPES (10), LaCl3 (0.001), and CdCl2 (0.4) (pH 7.4) (in mM units). Currents were recorded using an Axopatch 1D amplifier and analyzed using pClamp software (Axon Instruments and Molecular Devices, USA). The pipette resistance was between 4 - 5 MΩ. After gigaseal formation, the pipette capacitance was compensated by the amplifier.

[0119] After the patch membrane was destroyed by suction or electrical stimulation, the membrane capacitance was compensated. The access resistance was between 5 and 7 MΩ. 80% series resistance compensation was used. The leakage current was subtracted from the recorded current. The recording was performed at room temperature. The voltage-dependent potassium current was blocked by TEA-Cl in the extracellular solution. The voltage-dependent calcium current was blocked by cadmium and lanthanum ions in the extracellular solution. The membrane potential of the neuron was maintained at -65 mV. Substance 6 was administered from the outside (to the entire bath).

[0120] From the results obtained, the inhibitory effect of Compound 6 was confirmed by rapidly activating and then rapidly inactivating voltage-dependent sodium channels in prefrontal cortical pyramidal neurons (the test was performed at a concentration of 100 μM). The maximum current was induced by a rectangular depolarizing stimulus lasting 20 milliseconds. The potential between depolarizing stimuli was maintained at -65 mV. Control recordings were performed for 2 minutes, the test substance was administered for 3 minutes, and the current after washout was recorded for 5 minutes. The recorded current was normalized to the value of the control current. Substance 6 blocked the maximum amplitude of the sodium current by up to 0.59 ± 0.08 compared to the control (1.0, p < 0.001). After washout, the current amplitude partially recovered to the control value (0.79 ± 0.07, n = 5). An example of the recording and averaged results of the sodium current is shown in Figure 6.

Example

[0121] Evaluation of ADMETox parameters in in vitro tests The ADME-Tox parameters of Compound 6 were evaluated by in vitro methods using recombinant enzymes, human and mouse liver microsomes, and eukaryotic cell lines.

[0122] Metabolic stability. The metabolic stability of Compound 6 was evaluated using human liver microsomes (HLM). The internal clearance value CL intwas calculated by monitoring the change with compound concentration in the presence of microsomes per unit time according to the procedure proposed by Obach R.S. (Obach, R.S., Drug Metab. Dispos. 1999, 27, 1350 - 1359). Based on the obtained data, a very low clearance value of Compound 6 after incubation with HLM was found, and CL int reached 5.8 ml / min / kg, indicating high predicted stability in humans. UPLC analysis of the metabolism of Compound 6 after incubation with HLM revealed that it was metabolized to three metabolites M1 - M3 (Figure 7). Based on the UPLC / MS data, metabolite M1 was formed by dehydrogenation of the piperazine ring, M2 was formed by hydroxylation of the phenyl substituent linked to the piperazine, while M3 was found to be formed with high certainty as a result of hydroxylation of the lateral phenyl group simultaneously with the reduction of the ketone group in the imide fragment to a hydroxyl group (Figure 7).

[0123] Metabolic stability study - Methodology. The metabolic stability study for Compound 6 was performed using HLM (Promega, Madison, WI, USA). For this purpose, 10 μL of Compound 6 at a concentration of 1000 μM was diluted with 132 μL of Tris - HCl buffer (100 mM, pH 7.4), and then 8 μL of appropriate microsomes was added. The reaction mixture was pre - incubated at 37 °C for 5 minutes, and then 50 μL of NADPH Regeneration System supplied by Promega (Madison, WI, USA) was added. After mixing, the entire mixture was incubated at 37 °C for 120 minutes. To complete the reaction, 200 μL of cold methanol was added to the tube and centrifuged. The supernatant was subjected to UPLC / MS analysis including fragmentation analysis. Four mixtures of 6 and HLM were prepared to determine the intrinsic clearance CL intIt was determined. Each of these reactants was completed at different time points after 5, 15, 30, and 45 minutes by adding cold methanol containing 50 μM of the internal standard. Then, according to the guidelines in the literature (Obach, R.S., Drug Metab. Dispos. 1999, 27, 1350 - 1359), a regression equation was determined based on the plot of the relationship between the height of the peak from 6 and the height of the internal standard, and the reaction rate constant k was calculated. Then, the constant k was substituted into Equation (1).

[0124]

Number

[0125] Then, the calculated t 1 / 2 value was substituted into Equation (2).

[0126]

Number

[0127] Effect on Pgp activity. P-glycoprotein (Pgp) is an endogenous plasma membrane protein that can actively remove xenobiotics as an ATP-dependent efflux pump and can cause drug-drug interactions. Pgp plays an important role in drug absorption in the gastrointestinal tract and also through the blood-brain barrier. The effect of Compound 6 on Pgp activity was tested using a commercial bioluminescent Pgp-Glo™ assay system (Promega, Madison, WI, USA). The assay procedure is based on measuring the change in the level of ATP consumed by a membrane containing recombinant Pgp protein in the presence of the test compound. The results are presented as % of baseline activity and were compared to the reference compounds: the selective Pgp inhibitor Na3VO4 and the verapamil stimulant. Compound 6 showed a statistically significant (p < 0.01) inhibitory effect on Pgp of up to 38% of the baseline activity at 100 μM, while no effect on Pgp activity was observed at 50 μM (Figure 8).

[0128] Effect on Pgp activity - Methodology. The tests were carried out according to the protocol of the Bioluminescence Pgp-Glo™ assay system test provided by Promega (Madison, WI, USA). The enzyme reaction was carried out in Nunc™ MicroWell™ 96-well white plates manufactured by Thermo Scientific (Waltham, MA, USA). Bioluminescence was measured with a PerkinElmer multispecific EnSpire plate reader (Waltham, MA, USA). After using the Na3VO4 Pgp inhibitor (which induced 100% inhibition), the signal increased for the control samples, indicating inhibition of ATP consumption by Pgp, the so-called basal activity. The calculated difference in luminescence values between the inhibitor-treated samples and the control samples was obtained as 100% of Pgp basal activity and was treated as a negative control in the test. The reference compounds Na3VO4 and verapamil were used at 100 μM and 200 μM, respectively, according to the manufacturer's instructions. Compound 6 was tested at concentrations of 50 and 100 μM, obtained after dilution in DMSO in the reaction buffer from a concentrated stock solution (10 mM). Incubation of the compounds with Pgp-containing membranes was carried out at 37 °C for 40 minutes, after which bioluminescence measurements were performed to determine the extent of ATP consumption by Pgp. Statistical significance was calculated by one-way ANOVA with Bonferroni post-test using GraphPad Prism5. The compounds were tested in triplicate.

[0129] Effect of Compound 6 on cytochrome P-450 3A4 and 2D6 activities. The investigation was conducted using commercially available luminescence assays CYP3A4 P450-Glo™ and CYP2D6 P450-Glo™ from Promega (Madison, WI, USA) based on the methodology described in the literature (Socala, K.; Mogilski, S.; Pierog, M.; Nieoczym, D.; Abram, M.; Szulczyk, B.; Lubelska, A.; Latacz, G.; Doboszewska, U.; Wlaz, P.; Kaminski, K., ACS Chem. Neurosci. 2018, doi: 10.1021 / acschemneuro.8b00476; Latacz, G.; Lubelska, A.; Jastrzebska-Wiesek, M.; Partyka, A.; Sobalo, A.; Olejarz, A.; Kucwaj-Brysz, K.; Satala, G.; Bojarski, A.J.; Wesolowska, A.; Kiec-Kononowicz, K.; Handzlik, J., Chem. Biol. Drug Des. 2017, 90, 1295-1306). The CYP isoforms selected for the tests are involved in the metabolism of approximately 40-50% of commercially available drugs, and these stimulations or inhibitions determine most metabolic drug-drug interactions. The results obtained show that at a concentration of 10 μM, there is no effect of Compound 6 on CYP3A4 activity (Figure 9A), and the stimulatory effect on CYP2D6 is very weak (Figure 9B). In summary, the results obtained indicate a low potential for metabolic interactions caused by 6.

[0130] In vitro hepatotoxicity evaluation. The test was conducted using the hepatocellular carcinoma HepG2 liver cancer cell line, and this was used to evaluate the hepatotoxicity of substances in vitro. The classical MTS colorimetric assay manufactured by Promega (Madison, WI, USA) was used to investigate the effects of 6 on HepG2 cell viability and proliferation. The compound was tested at four concentrations within the range (0.1 - 100 μM). Doxorubicin at a concentration of 1 μM was used as a reference cell growth inhibitor. In addition, the reference mitochondrial toxin carbonyl cyanide m-chlorophenyl hydrazone (CCCP) at a concentration of 10 μM was also used (Figure 10). The hepatotoxicity test of the HepG2 strain after 72-hour incubation with compound 6 showed a statistically significant (p < 0.05) reduction in cell viability only at the maximum concentration of 100 μM used in the test (Figure 10). In addition, the cell viability decreased to only 84% of the control, indicating a slight toxic effect of this compound on the HepG2 cell line. Due to the potential toxic effects of foreign substances on hepatocytes being particularly exposed, after a short 3-hour exposure to compound 6 at concentrations in the range of 1 - 100 μM, additional tests were performed on the HepG2 strain in the form of luminescence measurement of ATP levels in the cells. For this purpose, the commercial CellTiter-Glo Luminescent Cell Viability Assay manufactured by Promega (Madison, WI, USA) was used. The purpose of the test was to examine the effect of the compound on the mitochondrial respiration of hepatocellular carcinoma cells. The reference point was the CCCP reference mitochondrial toxin at a concentration of 10 μM. Even at the maximum concentration of 100 μM used, there was no statistically significant effect of compound 6 on the ATP level of HepG2 cells. This indicates a very low risk of hepatotoxic effects of compound 6 (Figure 11).

[0131] In Vitro Hepatotoxicity Evaluation - Methodology. The HepG2 hepatocellular carcinoma cell line (ATCC HB - 8065) was used for the test. The HepG2 cell line was incubated in "Modified Eagle’s Medium" (MEM) culture medium supplemented with 2 mM glutamine and 10% FBS, manufactured by Gibco (Carlsbad, CA, USA). The cells were incubated at 37 °C in an atmosphere containing 5% CO2. The cell viability was tested using the CellTiter96® AQueous Non - Radioactive Cell Proliferation Assay (MTS) supplied by Promega (Madison, WI, USA). Before the test, the cells were seeded at a concentration of 1.5×10 4 cells per well in a Thermo Scientific Nunc™ 96 - well clear culture plate (Waltham, MA, USA) and incubated for 24 hours. Then, a 10 mM stock solution of Compound 6 was diluted in the appropriate culture medium and added to the cells at a final concentration in the range of 0.1 - 100 μM (the DMSO concentration in all wells was 1%). The reference compounds CCCP and DX were applied at final concentrations of 10 μM and 1 μM, respectively. After 72 - hour incubation at 37 °C in an atmosphere containing 5% CO2, the medium containing the compounds was removed, and then fresh medium containing the diluted MTS reagent was added. After the plate was incubated for an additional 2 - 3 hours, absorbance measurements were taken at 490 nm using an EnSpire PerkinElmer (Waltham, MA, USA) reader. Statistical significance was calculated by one - way ANOVA and the Bonferroni method. The compounds were tested in quadruplicate.

[0132] The ATP level in HepG2 cells was tested using the CellTiter - Glo Luminescent Cell Viability Assay manufactured by Promega (Madison, WI, USA). Before the test, the cells were seeded in a white 96 - well clear - bottom culture plate manufactured by Corning (Tewksbury, MA, USA) at a concentration of 1.5×10 4The concentration of individual cells was adjusted for luminescence measurement. The cells were then incubated at 37 °C in an atmosphere containing 5% CO2. Compound 6 was applied to the plate in amounts of 100 μL at three final concentrations of 1, 10, and 100 μM, CCCP at 10 μM, and DX at 1 μM. The plate was incubated at 37 °C for 3 hours with 5% CO2. After adding the CellTiter-Glo Luminescent Cell Viability Assay in an amount of 100 μl to the culture, luminescence measurements were performed with an EnSpire PerkinElmer (Waltham, MA, USA) reader. Statistical significance was calculated by one-way ANOVA and Bonferroni analysis using GraphPad Prism5. All substances were tested in quadruplicate.

Example

[0133] Preparation of Selected Enantiomers of Compounds According to the Invention The enantiomers of the compounds according to formula (II) of the invention can be obtained by applying a four-step procedure using commercially available tert-butoxycarbonyl (Boc) D- or L-amino acid derivatives (R or S absolute configuration, respectively) as starting materials. The enantiomers are obtained for the selected compounds described by formula (II), where k = 0 and A and B have the same meaning as in the racemic mixture of formula (II).

[0134] A general scheme for the synthesis of the enantiomers of the compounds according to formula (II) is shown in Figure 12.

[0135] In the first step, an intermediate product of formula (VII) is obtained by a condensation reaction of a given piperazine derivative with the corresponding Boc-D- or Boc-L-amino acid derivative, followed by formation of the amine derivative (VI) in a deprotection reaction. In the next step, compound (VI) is condensed with succinic anhydride to obtain an intermediate having an amide-acid structure (V), which is then subjected to a cyclization reaction to form compound R-(II) or S-(II). Asymmetric synthesis proceeds while maintaining the absolute configuration confirmed by applying X-ray crystallographic analysis.

[0136] Synthesis of the selected intermediates (VII, VI, and V according to Figure 12), as well as examples of physicochemical and spectral data, are described below.

Example

[0137] tert-Butyl-(R)-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)carbamate (VII) Boc-D-phenylglycine (1.25 g, 5 mmol, 1 equivalent) was dissolved in 20 mL of DCM, and then DCC (1.55 g, 7.5 mmol, 1.5 equivalents) was added. Next, after 30 minutes, 1-(3-(trifluoromethyl)phenyl)piperazine (1.15 g, 5 mmol, 1 equivalent) dissolved in 5 mL of DCM was added. The reaction mixture was continuously stirred at room temperature for 4 hours. After this time, DCM was distilled off to dryness. Intermediate VII was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0138] Light oil. Yield: 78% (1.81 g); TLC: R f = 0.62 (DCM:MeOH (9:0.5; v / v)); C 24 H 28 F3N3O3 (463.50), monoisotopic mass: 463.21. UPLC (100% purity): t R = 8.40 minutes. (M + H) + 464.2.

Example

[0139] (R)-2-Amino-2-phenyl-1-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethan-1-one (VI) 5 mL of TFA was added to a solution of tert-butyl-(R)-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)carbamate (VII, 1.39 g, 3 mmol, 1 equiv) in DCM (50 mL), and the mixture was stirred for 2 h. The reaction mixture was then neutralized with 25% NH4OH solution and extracted with DCM (3 × 50 mL). The organic layer was dried over anhydrous Na2SO4 and evaporated to dryness. (R)-2-Amino-2-phenyl-1-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethan-1-one was obtained as a yellow oil.

[0140] Yellow oil. Yield: 95% (1.03 g); C 19 H 20 F3N3O (363.38), monoisotopic mass: 363.16. UPLC (purity >99.9%): t R = 4.96 min. (M+H) + 364.1.

Example

[0141] (R)-4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)amino)butanoic acid (V) Succinic anhydride (0.28 g, 2.8 mmol, 1 equiv) was added to a solution of (R)-2-amino-2-phenyl-1-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethan-1-one (VI, 1.02 g, 2.8 mmol, 1 equiv) in AcOEt (50 mL), and the mixture was stirred for 30 min. After this time, the solvent was evaporated to dryness. The compound was washed with Et2O and obtained in solid form.

[0142] White solid. Yield: 87% (1.13 g); C 23 H 24 F3N3O4 (463.46), monoisotopic mass: 463.17. UPLC (purity >99.9%): t R = 6.40 min. (M+H) + 464.2.

Example

[0143] (R)-1-(2-(4-(3-Chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione ((R)-3) ZnCl2 (0.27 g, 2.0 mmol, 1 equiv) was added to a suspension of (R)-4-((2-(4-(3-chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)amino)-4-oxobutanoic acid (V, 0.86 g, 2.0 mmol, 1 equiv) in dry benzene (50 mL). After heating the whole mixture to 80 °C, a solution of HMDS in dry benzene (5 ml) (0.48 g, 0.62 ml, 3.0 mmol, 1.5 equiv) was added dropwise over 30 minutes. The reaction mixture was continuously stirred under reflux for about 24 hours and then concentrated under reduced pressure. After evaporation of the solvent, the oily residue was dissolved in DCM and extracted with 0.1 M HCl (3 × 50 mL), water (3 × 50 mL), and saturated NaCl solution (3 × 50 mL). The organic layer was dried over anhydrous Na2SO4 and then evaporated to dryness. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) elution system. The compound was washed with Et2O and obtained as a solid.

[0144] White solid. Yield: 82% (0.67 g); m.p. 167.3–168.1 °C; TLC: Rf = 0.41 (DCM:MeOH (9:0.3; v / v)); C 22 H 22 ClN3O3 (411.89), monoisotopic mass: 411.13. UPLC (purity >99.9%): t R = 6.70 minutes, (M+H) + 412.4. 11H NMR (500 MHz, CDCl3) δ 2.64 - 2.75 (m, 5H), 2.96 - 3.12 (m, 2H), 3.21 - 3.37 (m, 3H), 3.60 - 3.72 (m, 1H), 3.92 - 4.03 (m, 1H), 6.10 (s, 1H), 6.68 (dd, J = 8.0, 2.3 Hz, 1H), 6.77 (t, J = 2.0 Hz, 1H), 6.81 (d, J = 7.6 Hz, 1H), 7.13 (t, J = 7.9 Hz, 1H), 7.32 - 7.37 (m, 3H), 7.42 (d, J = 6.8 Hz, 2H). 13 13C NMR (126 MHz, CDCl3) δ 28.1, 42.3, 45.6, 48.5, 48.8, 56.9, 114.5, 116.4, 120.3, 128.8, 129.0, 129.9, 130.2, 133.0, 135.1, 151.8, 165.1, 176.4. Enantiomeric purity >99% (t R = 40.25 minutes).

Example

[0145] (R)-1-(2-(4-(3,5-Dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione ((R)-4) The compound was prepared according to the procedure described in Example 44. (R)-4-((2-(4-(3,5-Dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)amino)-4-oxobutanoic acid (0.93 g, 2 mmol, 1 equivalent) was used as the starting material for the cyclization reaction. The crude product was purified by column chromatography using a DCM:MeOH (9:0.2; v / v) elution system.

[0146] White solid. Yield: 79% (0.70 g); m.p. 174.3 - 175.5 °C; TLC: R f = 0.43 (DCM:MeOH (9:0.2; v / v)); C 22 H 21Cl2N3O3 (446.33), monoisotopic mass: 445.10. UPLC (purity > 99.9%): t R = 7.59 minutes, (M+H) + 446.1. 1 H NMR (500 MHz, CDCl3) δ 2.64 - 2.74 (m, 5H,), 2.99 - 3.03 (m, 1H), 3.06 - 3.11 (m, 1H), 3.23 - 3.31 (m, 2H), 3.43 - 3.47 (m, 1H), 3.60 - 3.64 (m, 1H), 3.95 - 3.99 (m, 1H), 6.08 (s, 1H), 6.63 (d, J = 1.7 Hz, 2H), 6.79 (t, J = 1.4 Hz, 1H), 7.32 - 7.37 (m, 3H), 7.41 (d, J = 6.7 Hz, 2H). 13 C NMR (126 MHz, CDCl3) δ 28.1, 42.1, 45.4, 47.9, 48.2, 56.8, 114.3, 119.8, 128.8, 129.1, 129.9, 132.9, 135.6, 152.1, 165.2, 176.4. Enantiomeric purity > 99% (t R = 43.23 minutes).

Example

[0147] (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione ((R)-6) The compound was prepared according to the procedure described in Example 44. (R)-4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)amino)-butanoic acid (0.93 g, 2.0 mmol, 1 equivalent) was used as the starting material for the cyclization reaction. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0148] White solid. Yield: 80% (0.71 g); m.p. 189.1~190.5 °C; TLC: Rf = 0.35 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 F3N3O3 (445.44), monoisotopic mass: 445.16. UPLC (purity > 99.9%): t R = 6.93 minutes, (M+H) + 446.2. 1 H NMR (300 MHz, CDCl3) δ 2.52 - 2.85 (m, 5H), 2.99 - 3.19 (m, 2H), 3.22 - 3.45 (m, 3H), 3.62 - 3.76 (m, 1H), 3.93 - 4.07 (m, 1H), 6.12 (s, 1H), 6.90 - 7.15 (m, 3H), 7.11 (d, 1H, J = 7.7 Hz), 7.28 - 7.55 (m, 6H); 13 C NMR (75 MHz, CDCl3) δ 28.0, 42.3, 45.5, 48.4, 48.6, 56.8, 112.7 (d, J = 3.4 Hz), 116.7 (d, J = 3.4 Hz), 119.2, 124.1 (q, J = 272.9 Hz), 128.7, 128.9, 129.7, 129.8, 130.9, 131.5 (q, J = 32.2 Hz), 132.8, 150.8, 165.1, 176.4. Enantiomeric purity > 99% (t R = 39.97 minutes).

Example

[0149] (S)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione ((S)-6) The compound was prepared according to the procedure described in Example 44. (S)-4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)amino)-butanoic acid (0.93 g, 2.0 mmol, 1 equivalent) was used as the substrate for the cyclization reaction. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0150] White solid. Yield: 78% (0.69 g); m.p. 188.9 - 190.5 °C; TLC: R f = 0.36 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 F3N3O3 (445.44), monoisotopic mass: 445.16. UPLC (purity > 99.9%): t R = 6.94 minutes, (M + H) + 446.2. 1 H NMR (300 MHz, CDCl3) δ 2.56 - 2.83 (m, 5H), 3.00 - 3.20 (m, 2H), 3.23 - 3.43 (m, 3H), 3.62 - 3.76 (m, 1H), 3.94 - 4.08 (m, 1H), 6.12 (s, 1H), 6.89 - 6.99 (m, 2H), 7.10 (d, 1H, J = 7.7 Hz), 7.28 - 7.53 (m, 6H); 13 C NMR (75 MHz, CDCl3) δ 28.0, 42.2, 45.5, 48.4, 48.6, 56.8, 112.7 (d, J = 4.6 Hz), 116.7 (d, J = 4.6 Hz), 124.1 (q, J = 272.9 Hz), 128.7, 129.0, 129.7, 129.8, 131.6 (q, J = 32.2 Hz), 132.8, 150.8, 165.1, 176.3. Enantiomeric purity > 99% (t R = 26.21 minutes).

Example

[0151] (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione ((R)-10) The compound was prepared according to the procedure described in Example 44. (R)-4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)amino)butanoic acid (0.96 g, 2.0 mmol, 1 equivalent) was used as the starting material for the cyclization reaction. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0152] White solid. Yield: 77% (0.70 g); m.p. 168.2 - 169.1 °C; TLC: R f = 0.46 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 F3N3O4 (461.44), monoisotopic mass: 461.16. UPLC (purity > 99.9%): t R = 7.18 minutes, (M + H) + 462.1. 1 H NMR (500 MHz, CDCl3) δ 2.60 - 2.78 (m, 5H), 2.98 - 3.16 (m, 2H), 3.23 - 3.38 (m, 3H), 3.63 - 3.72 (m, 1H), 3.98 (ddd, J = 12.89, 6.01, 2.86 Hz, 1H), 6.11 (s, 1H), 6.61 (s, 1H), 6.69 - 6.73 (m, 2H), 7.21 (t, J = 8.0 Hz, 1H), 7.32 - 7.38 (m, 3H), 7.42 - 7.44 (m, 2H). 13 C NMR (126 MHz, CDCl3) δ 28.1, 42.3, 45.6, 48.4, 48.6, 56.9, 108.9, 112.2, 114.3, 120.5 (q, J = 256.7 Hz), 129.4 (d, J = 143.7 Hz), 129.6 (d, J = 151.5 Hz), 132.9, 150.3, 152.0, 165.2, 176.4. Enantiomeric purity > 99% (t R = 35.08 minutes).

Example

[0153] (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)sulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione ((R)-12) The compound was prepared according to the procedure described in Example 44. (R)-4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-((trifluoromethyl)thio)phenyl)piperazin-1-yl)ethyl)amino)butanoic acid (0.99 g, 2.0 mmol, 1 equivalent) was used as the starting material for the cyclization reaction. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system.

[0154] White solid. Yield: 86% (0.82 g); m.p. 155.1 - 155.8 °C; TLC: R f = 0.48 (DCM:MeOH (9:0.5; v / v)); C 23 H 22 F3N3O3S (477.50), monoisotopic mass: 477.13. UPLC (purity > 99.9%): t R = 7.54 minutes, (M+H) + 478.1. 1 H NMR (500 MHz, CDCl3) δ 2.68 - 2.75 (m, 5H), 2.96 - 3.19 (m, 2H), 3.22 - 3.43 (m, 3H), 3.62 - 3.76 (m, 1H), 3.99 (ddd, J = 13.17, 5.73, 2.8 Hz, 1H), 6.11 (s, 1H), 6.91 (dd, J = 8.3, 2.6 Hz, 1H), 7.06 (s, 1H), 7.12 (d, J = 8.0 Hz, 1H), 7.24 - 7.28 (m, 1H), 7.33 - 7.38 (m, 3H), 7.42 - 7.44 (m, 2H). 1313C NMR (126 MHz, CDCl3) δ 28.1, 42.3, 45.6, 48.4, 48.7, 56.9, 123.7, 125.3, 129.6 (q, J = 307, 8 Hz), 127.8, 129.4 (d, J = 142.4 Hz), 129.1, 130.1, 132.9, 151.4, 165.2, 176.4. Enantiomeric purity >99% (t R = 34.82 minutes).

Example

[0155] Special properties of enantiomers. The effect of the stereochemistry of the compounds according to the invention on these antispasmodic activities was investigated. The antispasmodic properties were evaluated according to the method described above, and the results are summarized in Tables 3 and 4.

[0156]

Table 3B

[0157]

Table 4

[0158] Based on the results obtained, it was unexpectedly found that the R enantiomer exhibits high biological activity with the desired profile compared to the S enantiomer.

[0159] In particular, for the R enantiomer, the following were found: - Weaker acute neurotoxicity in the rotarod test for the racemate (see TD in Tables 2 and 4 respectively 50 for reference), - It was also unexpectedly found that the antispasmodic effect was stereospecific. The enantiomer with the R configuration is characterized by stronger biological activity.

[0160] Metabolic stability. The metabolic stability of (R)-6 was evaluated according to the above methodology. Based on the data obtained, very low values of the intrinsic clearance of compound (R)-6 after incubation with HLM were found, with CL int reaching = 2.4 mL / min / kg, indicating high predicted stability in humans. Additionally, surprisingly, preferably, the determined clearance value was lower than that determined for the racemate, compound 6 (CL int = 5.6), which indicates a lower susceptibility of the enantiomer to metabolic changes. In addition, the results of UPLC analysis revealed that the (R)-6 enantiomer was preferably metabolized to two metabolites: the M1 metabolite formed by dehydrogenation of the piperazine ring, and the M2 metabolite formed by hydroxylation of the phenyl substituent linked to the piperazine (Figure 13). In the case of the racemate, an additional M3 metabolite was observed, most likely obtained by hydroxylation of the lateral phenyl moiety and reduction of the keto group in the imide ring to hydroxyl (Figure 7).

Example

[0161] Preparation of water-soluble salts of the compounds according to the invention. The water-soluble salts of the compounds according to formula (I) of the present invention can be obtained by applying a 6-step procedure using commercially available tert-butoxycarbonyl (Boc) amino acid derivatives as starting materials. The water-soluble salts are obtained for the selected compounds described by formula (I), where k = 0, and D is a substituent selected from the group consisting of H, an amino group (-NH2), an amino group substituted with one or two aliphatic substituents (especially -CH3 and / or -C2H5), or an amino group that is part of a heterocycle, and A and B have the same meaning as in the case of the compounds described by formula (II).

[0162] The general scheme for the synthesis of the water-soluble salts of the compounds described by formula (I) according to the present invention is shown in Figure 14. In the case of the preparation of the compounds of formula (I) where D is a halogen, the procedure described for the compounds of formula (II) according to Figure 2B is used, and then the resulting compound is converted to the water-soluble salt (preferably the hydrochloride salt) using the methods described in the literature.

[0163] Steps i and ii are similar to the procedures described for the synthesis of enantiomers. The amine derivative (VI) is condensed with maleic anhydride to obtain a compound having an unsaturated amide-acid structure (VIII). Next, compound VIII cyclizes to compound IX. In the next step, the compound of formula IX is subjected to an addition reaction with a suitable primary or secondary amine. Then, the desired compound according to formula (I) is converted to the water-soluble salt (preferably the hydrochloride salt) using the methods described in the literature.

[0164] Examples of the synthesis of the selected intermediates (VIII, IX), and the final product according to Figure 14, as well as the physico-chemical and spectral data, are described below.

Example

[0165] 4-Oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)amino)but-2-enoic acid (VIII) Maleic anhydride (0.98 g, 10.0 mmol, 1 eq) was added to a solution of 2-amino-2-phenyl-1-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethan-1-one (4.61 g, 10.0 mmol, 1 eq) in AcOEt (50 mL) and stirred for 30 minutes. After this time, the solvent was evaporated to dryness. The compound was washed with Et2O and obtained as a solid.

[0166] White solid. Yield: 85% (3.76 g); C 23 H 22 F3N3O4 (461.44), monoisotopic mass: 461.16. UPLC (purity = 96%): t R= 6.94 minutes. (M+H) + 462.2

Example

[0167] 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)-1H-pyrrole-2,5-dione (IX) ZnCl2 (1.36 g, 10.0 mmol, 1 equivalent) was added to a suspension of 4-oxo-4-((2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)amino)but-2-enoic acid (4.40 g, 10.0 mmol, 1 equivalent) in dry benzene (100 mL), and the mixture was heated to 80 °C. Then, a solution of HMDS (2.42 g, 3.14 mL, 15.0 mmol, 1.5 equivalents) in dry benzene (10 mL) was added dropwise over 30 minutes. The reaction was continued to stir under reflux for about 24 hours, then cooled and concentrated under reduced pressure. After evaporation of the solvent, the oily residue was dissolved in DCM and extracted with 0.1 M HCl (3 × 50 mL), water (3 × 50 mL), and saturated NaCl solution (3 × 50 mL). The organic layer was dehydrated with anhydrous Na2SO4 and then evaporated to dryness. The crude product was purified by column chromatography using a DCM:MeOH (9:0.3; v / v) mixture as the eluent system. The compound was washed with Et2O and obtained as a solid.

[0168] White solid. Yield: 79% (3.34 g); C 23 H 22 F3N3O4 (443.43), monoisotopic mass: 443.15. UPLC (purity = 99%): t R = 7.45 minutes. (M+H) + 444.1

Example

[0169] 3-(Methylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride A 2 M solution of methylamine in THF (0.07 g, 2.2 mmol, 1 equiv) was added to a solution of 1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)-1H-pyrrole-2,5-dione (0.98 g, 2.2 mmol, 1 equiv) in dry benzene (50 mL). The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system. The compound was then converted to the hydrochloride salt by treating the compound with 2 M methanolic hydrochloric acid solution.

[0170] White solid. Yield: 87% (0.91 g); m.p. 161.2 - 163.4 °C; C 24 H 25 F3N4O3 (474.48), monoisotopic mass: 474.19. UPLC (purity > 99.9%): t R = 5.53 minutes, (M + H) + 475.3. 1 H NMR (500 MHz, CDCl3) δ 2.76 (br s, 3H), 2.90 (br s, 1H), 3.22 (br s, 2H), 3.38 - 3.54 (m, 4H), 3.55 - 3.66 (m, 1H), 3.70 (br s, 1H), 3.84 - 4.23 (m, 2H), 4.53 (br s, 1H), 6.20 (br s, 1H), 7.18 - 7.24 (m, 3H), 7.29 - 7.51 (m, 5H), 7.71 (br s, 1H), 9.98 (br s, 1H).

Example

[0171] 3-(Dimethylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride The compound was prepared according to the procedure described in Example 54. 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)-1H-pyrrole-2,5-dione (0.98 g, 2.2 mmol, 1 equiv), and dimethylamine (0.10 g, 2.2 mmol, 1 equiv) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system. The compound was converted to the hydrochloride salt by treating the compound with 2 M methanolic hydrochloric acid solution.

[0172] White solid. Yield: 83% (0.90 g); m.p. 157.8~159.2 °C; C 25 H 27 F3N4O3 (488.51), monoisotopic mass: 488.20. UPLC (purity >99.9%): t R = 5.53 minutes, (M+H) + 489.3. 1 H NMR (500 MHz, CDCl3) δ 2.76 (d, J = 8.6 Hz, 1H), 2.93 (br s, 2H), 3.06 - 3.18 (m, 5H), 3.25 - 3.33 (m, 3H), 3.36 - 3.41 (m, 2H), 3.41 - 3.45 (m, 2H), 3.71 (br s, 1H), 3.94 - 3.98 (m, 1H), 6.14 (s, 1H), 7.01 (d, J = 7.4 Hz, 1H), 7.04 (br s, 1H), 7.12 (d, J = 7.4 Hz, 1H), 7.34 (t, J = 7.7 Hz, 1H), 7.39 (s, 5H), 13.02 (br s, 1H). 1313C NMR (126 MHz, CDCl3) δ 31.4, 42.5 45.7, 48.7, 48.9, 57.7, 60.1, 65.9, 113.1, 117.5, 119.3, 119.9, 119.7, 124.1 (d, J = 272.2 Hz), 129.1, 129.8, 129.9, 131.1, 131.7 (d, J = 32.0 Hz), 150.5, 164.4, 169.8, 171.7.

Example

[0173] 3-(Diethylamino)-1-(2-oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione hydrochloride The compound was prepared according to the procedure described in Example 54. 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)-1H-pyrrolo-2,5-dione (0.98 g, 2.2 mmol, 1 equivalent) and diethylamine (0.16 g, 2.2 mmol, 1 equivalent) were used as starting materials. The crude product was purified by column chromatography using a DCM:MeOH (9:0.5; v / v) elution system. The compound was converted to the hydrochloride salt by treating the compound with 2M methanolic hydrochloric acid solution.

[0174] White solid. Yield: 88% (1.00 g); m.p. 142.2 - 143.1 °C; TLC: R f = 0.52 (DCM:MeOH (9:0.5; v / v)); C 27 H 31 F3N4O3 (516.57), monoisotopic mass: 516.23. UPLC (purity > 99.9%): t R = 5.79 minutes, (M + H) + 517.2. 11H NMR (500 MHz, DMSO-d6) δ 1.17-1.27 (m, 6H), 2.79-2.89 (m, 1H), 3.05-3.36 (m, 9H), 3.54-3.78 (m, 3H), 4.79 (dd, J = 9.2, 5.7 Hz, 1H), 4.92 (dd, J = 9.2, 5.7 Hz, 1H), 6.20 (s, 1H), 7.04 (d, J = 7.4 Hz, 1H), 7.10 (s, 2H), 7.14 (d, J = 8.0 Hz, 1H), 7.31-7.37 (m, 5H), 12.88 (br s, 1H).

Example

[0175] Special properties of the water-soluble salts of the compounds according to the invention. The effect of the improved water solubility (i.e., salts) of the compounds according to the invention on these antispasmodic activities was investigated. The antispasmodic properties were evaluated according to the method described above, and the results are summarized in Tables 3 and 4.

[0176]

Table 5

[0177]

Table 6

[0178] Based on the results obtained, it was found that the salts of the compounds according to the invention clearly exhibit improved water solubility. This has a positive impact on their pharmacokinetic and / or pharmaceutical properties and is particularly advantageous in the case of intravenous administration of the compounds according to the invention.

Claims

1. 1-(2-Oxo-1-phenyl-2-(4-phenylpiperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3-Chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3,5-Dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(m-tolyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3,5-Bis(trifluoromethyl)phenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(difluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(4-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethylsulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-([1,1'-Biphenyl]-3-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(1-(4-Fluorophenyl)-2-oxo-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-(4-(Naphthalen-2-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(Benzo[b]thiophen-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(1,2-Benzoxazol-5-yl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-(4-(3-Chlorophenyl)piperidin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione, 1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperidin-1-yl)ethyl)pyrrolidine-2,5-dione, A compound selected from the group consisting of.

2. The compound according to claim 1, which is the (R) enantiomer.

3. The following compounds: (R)-1-(2-(4-(3-Chlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, (R)-1-(2-(4-(3,5-Dichlorophenyl)piperazin-1-yl)-2-oxo-1-phenylethyl)pyrrolidine-2,5-dione, (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione, (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethoxy)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione (R)-1-(2-Oxo-1-phenyl-2-(4-(3-(trifluoromethylsulfanyl)phenyl)piperazin-1-yl)ethyl)pyrrolidine-2,5-dione The compound according to claim 2, characterized in that it is selected from

4. The compound according to any one of claims 1 to 3, which is a water-soluble salt.

5. The compound according to claim 4, wherein the water-soluble salt is a hydrochloride.

6. A medicament for use in the treatment or prevention of epileptic seizures, neuropathic pain, or migraine, which contains, as an active ingredient, the compound according to any one of claims 1 to 5.

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