CN107382811B - N-alkyl substituted benzoic acid derivative and preparation method and application thereof - Google Patents

Abstract

The invention provides N-alkyl substituted benzoic acid derivatives, which show stronger activity to influenza A and B virus neuraminidase through in vitro experiments; compared with the active compounds on the market at present, the active compound of the invention has no chiral center and is simpler to synthesize; meanwhile, the raw materials are simple and easy to obtain, the market supply is large, and the price is low. The preparation method is simple and suitable for industrial production.

Description

N-alkyl substituted benzoic acid derivative and preparation method and application thereof

Technical Field

The invention relates to the field of medicines, in particular to N-alkyl substituted benzoic acid derivatives, and a preparation method and application thereof.

Background

Influenza is a global infectious disease caused by influenza virus, and is also a disease with strong infectivity and high transmission speed. It is mainly spread by the spray in the air, the contact between people or the contact with the contaminated articles; typical clinical symptoms are: acute high fever, general pain, marked weakness and mild respiratory symptoms. Generally, the autumn and winter season is the high-incidence period of the disease, and the complications and death phenomena caused by the disease are very serious. The disease is caused by influenza virus and can be divided into three types of A (A), B (B) and C (C). Influenza a viruses are further classified into subtypes, including H1N1, H3N2, and the like, according to the kind of proteins and binding on the surface of the virus. H is called hemagglutinin and N is called neuraminidase, which are glycoproteins distributed on the surface of the virus. H has 1-15 subtypes and N has 1-9 subtypes (in the case of A-type virus). The A-type virus often has antigen variation, is high in infectivity and rapid in transmission, and is very easy to cause pandemic. Type a H1N1 is self-limiting, but is susceptible to death due to severe complications such as pneumonia in infants, the elderly, and patients with cardiopulmonary basic disease.

Vaccination and pharmacotherapy of the target population are the primary measures for the prevention and treatment of influenza. Because the influenza virus subtypes are multiple and are frequently mutated, the prediction accuracy of human beings on influenza outbreaks is greatly reduced, and when a novel highly pathogenic virus subtype appears, the production of a corresponding vaccine before the transmission of the novel highly pathogenic virus subtype is a task which is almost impossible to complete. Therefore, the effective anti-influenza virus medicine can control influenza pandemics and win valuable time for vaccine development. At present, the main means for preventing and treating influenza virus is to use neuraminidase inhibitor medicine, and the medicine takes Neuraminidase (NA) on the surface of influenza virus as a target spot. NA, one of the virus surfaces, is a mushroom-shaped tetramer glycoprotein, has the activity of hydrolyzing sialic acid, and when mature influenza viruses are separated from host cells in a budding mode, hemagglutinin on the virus surface is in contact with host cell membranes through sialic acid receptors, neuraminidase is needed to hydrolyze the sialic acid, the final contact between the virus and the host cells is cut off, and the virus can be smoothly released from the host cells to infect the next host cells. Therefore, inhibition of NA can protect the host from viral infection and delay viral transmission, and neuraminidase also becomes a potent target for influenza therapeutic drugs.

Due to the variable nature of influenza viruses, the difficulty in predicting the pathogenic trend and developing corresponding vaccines is serious, so that drug therapy is still the main means for dealing with the influenza viruses at present; at present, influenza virus neuraminidase inhibitors zanamivir and oseltamivir which are wide in clinical application and obvious in curative effect have higher specificity to influenza viruses, but more and more drug resistance cases are discovered in recent years. Because the chiral center is contained, the synthetic cost is high, the price is high, the economic burden of patients is invisibly increased, and the expensive basic medical institution can not be equipped, which is not beneficial to the prevention and control of influenza outbreak in China. Therefore, the development of novel, high-efficiency and low-cost anti-influenza virus neuraminidase inhibitors has important practical significance.

Disclosure of Invention

In order to solve the problems of the prior art, according to a first aspect of the present invention, it is an object of the present invention to provide a class of N-alkyl substituted benzoic acid derivatives.

The purpose of the invention is realized as follows:

a N-alkyl substituted benzoic acid derivative has the following structure:

the inventor unexpectedly finds that the N-alkyl substituted benzoic acid derivative has stronger activity of resisting H1N1 influenza, also has stronger activity of resisting H3N2 influenza and even has better treatment effect on B type influenza.

According to a second aspect of the invention, the invention aims to provide a class of N-alkyl substituted benzoic acid derivatives, which can be used as raw materials or pharmaceutical intermediates for preparing the benzoic acid derivatives I-IV.

A benzoic acid derivative has the following structure:

according to a third aspect of the invention, it is an object of the invention to provide a process for the preparation of the above compounds. The invention takes an amino-containing compound L as an initial raw material to prepare an intermediate Ia, and then hydrolyzes the intermediate Ia to obtain a compound I. For similar reasons, the compound L containing amino is used as a starting material to prepare an intermediate IIa, and then the intermediate IIa is hydrolyzed to obtain a compound II; the amino-containing compound L is used as a starting material to prepare an intermediate IIIa, and then is hydrolyzed to obtain a compound III; the amino-containing compound L is used as an initial raw material to prepare an intermediate IVa, and then the intermediate IVa is hydrolyzed to obtain a compound IV.

The specific preparation route is as follows:

according to a fourth aspect of the present invention, there is provided a use of the above-mentioned N-alkyl-substituted benzoic acid derivative for the preparation of an anti-influenza drug; especially in the application of the medicine for resisting highly pathogenic H1N1 influenza, H3N2 influenza and B influenza.

According to a fifth aspect of the present invention, it is an object of the present invention to provide use of the benzoic acid derivative (Ia-IVa) as a raw material or an intermediate for producing the N-alkyl substituted benzoic acid derivative (I-IV).

According to a sixth aspect of the present invention, it is an object of the present invention to provide the use of benzoic acid derivatives (Ia-IVa) as reference impurities for N-alkyl substituted benzoic acid derivatives (I-IV).

Has the advantages that:

the invention provides N-alkyl substituted benzoic acid derivatives I-IV which have stronger activity on influenza A and B virus neuraminidase; compared with the active compounds on the market at present, the active compound of the invention has no chiral center and is simpler to synthesize; meanwhile, the raw materials are simple and easy to obtain, the market supply is large, and the price is low. The compounds I-IV of the invention have stronger selectivity to influenza A H1N1, influenza H3N2 and influenza B virus (influenza A virus has stronger pathogenicity to human beings), and have nM activity to two types of A neuraminidase subtypes (note: N1, N4, N5 and N8 are one group of subtypes, N2, N3, N6, N7 and N9 are the other group of subtypes according to whether the active center of the enzyme has a cavity, and the active centers of the same subtype have similar structures). The invention can develop the anti-influenza virus medicine with high efficiency and low price, which serves the health of people; has stronger activity to influenza B virus neuraminidase. The compound has wide coverage on influenza viruses, and is not only suitable for treating influenza, but also can be used for preventing the influenza. The preparation method is simple and suitable for industrial production.

Detailed Description

The present invention is described in detail below with reference to specific examples, which are given for the purpose of further illustrating the invention and are not to be construed as limiting the scope of the invention, and the invention may be modified and adapted by those skilled in the art in light of the above disclosure. All the raw materials and reagents of the invention are commercial products.

Example 1:

preparation route of compound (I)

The specific process is as follows:

preparation of methyl 4- (5- (2, 2-diacetylhydroxymethyl) pyrrolidin-1-one) -3- (2- (1-ethyl-propylamino) -ethyl) benzoate (Ia):

l (0.34mmol) was dissolved in 1ml of 1, 2-dichloroethane and 0.5ml of acetic acid, 3-pentanone (2.30mmol) and NaBH were added₃CN (1.2mmol), the mixture was stirred at room temperature for 6 hours, the reaction mixture was diluted with ethyl acetate 10mL, and then the organic layer was washed with saturated sodium bicarbonate (3X 5mL), water (2X 5mL) and saturated brine (2X 5mL), dried over anhydrous sodium sulfate, filtered, concentrated, and the residue was chromatographed on a silica gel column to give Ia (colorless oil, 86% yield):¹H NMR(300MHz，CDCl₃)δ0.87(m，6H)，1.52(m，4H)，1.82(s，3H)，2.17(s，3H)，2.36(m，2H)，2.75(m，2H)，2.90(m，1H)，3.00(m，1H)，3.18(m，2H)，3.39(m，1H)，3.95(d，J＝12Hz，1H)，3.96(s，3H)，4.24(d，J＝12.0Hz，1H)，4.25(d，J＝12.0Hz，1H)，4.34(d，J＝11.6Hz，1H)，7.12(d，J＝8.3Hz，1H)，8.02(d，J＝8.3Hz，1H)，8.10(s，1H)；MS(ES)m/z 476(M+1).

preparation of 4- (5- (2, 2-dimethylol) pyrrolidin-1-one) -3- (2- (1-ethyl-propylamino) -ethyl) benzoic acid (I):

ia (0.2mmol) was dissolved in 2ml of methanol, 2ml of 1Mol/L sodium hydroxide were added, the mixture was stirred at room temperature for half an hour and the pH was then adjusted to 2 with 1Mol/L hydrochloric acid. The mixture was evaporated to dryness, the residual solid was dissolved in 3ml of methanol, filtered, the filtrate was concentrated, and the obtained residue was chromatographed on a column to give I (white solid, 74% yield): m.p. > 300 ℃;¹H NMR(400MHz，D₂O)δ0.90(m，6H)，1.65(m，4H)，2.25(t，J＝8.0Hz，2H)，2.66(t，J＝8Hz，2H)，3.13-3.07(m，2H)，3.24(m，2H)，3.40(d，J＝12.4Hz，1H)，3.50(d，J＝12.4Hz，1H)，3.66(d，J＝12.0Hz，1H)，3.72(d，J＝12.0Hz，1H)，3.99(m，1H)，7.29(d，J＝8.2Hz，1H)，7.84(d，J＝8.2Hz，1H)，7.94(s，1H)；MS(ES)m/z 379(M+1).

example 2:

route to compound (II):

the specific process is as follows:

preparation of methyl 4- (5- (2, 2-diacetylhydroxymethyl) pyrrolidin-1-one) -3- (2-isopropylamino-ethyl) benzoate (IIa):

l (0.34mmol) was dissolved in 1ml of 1, 2-dichloroethane and 0.5ml of acetic acid, acetone (2.30mmol) and NaBH were added₃CN (1.2mmol), the mixture was stirred at room temperature for 6 hours, the reaction mixture was diluted with ethyl acetate 10mL, then with saturated sodium bicarbonate (3X 5mL), water (2X 5mL)The organic layer was washed with saturated brine (2X 5mL), dried over anhydrous sodium sulfate, filtered, concentrated, and the residue was subjected to silica gel column chromatography to obtain IIa (colorless oil, 88% yield):¹H NMR(400MHz，CDCl₃)δ1.24(d，J＝6.5Hz，3H)，1.31(d，J＝6.5Hz，3H)，1.79(s，3H)，2.17(s，3H)，2.27(m，1H)，2.37(m，1H)，2.71(m，1H)，2.80(m，1H)，2.97(m，1H)，3.11(m，1H)，3.23(m，2H)，3.44(m，1H)，3.90(d，J＝12Hz，1H)，3.92(s，3H)，4.21(t，J＝11.7Hz，2H)，4.31(d，J＝12Hz，1H)，7.09(d，J＝8.2Hz，1H)，7.97(d，J＝8.2Hz，1H)，8.05(s，1H)；MS(ES)m/z 448(M+1).

preparation of 4- (5- (2, 2-hydroxymethyl) pyrrolidin-1-one) -3- (2-isopropylamino-ethyl) benzoic acid (II):

IIa (0.2mmol) is dissolved in 2ml of methanol, 2ml of 1Mol/L sodium hydroxide are added, the mixture is stirred at room temperature for half an hour and the pH is then adjusted to 2 with 1Mol/L hydrochloric acid. The mixture was evaporated to dryness, the residual solid was dissolved in 3ml of methanol, filtered, the filtrate was concentrated, and the obtained residue was chromatographed on a column to give II (white solid, 58% yield): m.p. > 300 ℃;¹H NMR(400MHz，D₂O)δ1.27(d，J＝5.8Hz，3H)，1.29(d，J＝5.8Hz，3H)，2.28(t，J＝8.0Hz，2H)，2.69(t，J＝8.0Hz，2H)，3.00(m，1H)，3.10(m，1H)，3.32-3.25(m，2H)，3.40(m，1H)，3.43(d，J＝12.1Hz，1H)，3.52(d，J＝12.1Hz，1H)，3.70(d，J＝12.2Hz，1H)，3.75(d，J＝12.2Hz，1H)，7.30(d，J＝8.3Hz，1H)，7.85(d，J＝8.3Hz，1H)，7.95(s，1H)；MS(ES)m/z 351(M+1).

example 3:

route to compound (III):

the specific process is as follows:

preparation of methyl 4- (5- (2, 2-diacetylhydroxymethyl) pyrrolidin-1-one) -3- (2-diethylamino-ethyl) benzoate (IIIa):

mixing L: (0.34mmol) was dissolved in 1ml of 1, 2-dichloroethane and 0.5ml of acetic acid, after addition of acetaldehyde (2.30mmol) and NaBH₃CN (1.2mmol), the mixture was stirred at room temperature for 6 hours, and acetaldehyde (2.30mmol) and NaBH were added to the system₃CN (1.2mmol) was stirred for a further 15 h. The reaction mixture was diluted with 10mL of ethyl acetate, and the organic layer was washed with saturated sodium bicarbonate (3 × 5mL), water (2 × 5mL) and saturated brine (2 × 5mL), respectively, dried over anhydrous sodium sulfate, filtered, concentrated, and the residue was subjected to silica gel column chromatography to obtain IIIa (colorless oil, 68% yield):¹HNMR(400MHz，CDCl₃)δ7.98-7.96(m，2H)，7.14(d，J＝7.8Hz，1H)，4.23(d，J＝12.0Hz，1H)，4.33(d，J＝12.1Hz，1H)，4.27(d，J＝12.1Hz，1H)，4.05(d，J＝12.0Hz，1H)，3.94(s，3H)，3.54-3.47(m，2H)，3.21(m，2H)，3.12(m，2H)，3.02-2.94(m，3H)，2.66-2.59(m，2H)，2.21(m，1H)，2.16(s，3H)，1.71(s，3H)，1.40(t，J＝7.2Hz，6H)；MS(ES)m/z 463(M+1).

preparation of 4- (5- (2, 2-hydroxymethyl) pyrrolidin-1-one) -3- (2-diethylamino-ethyl) benzoic acid (III):

IIIa (0.2mmol) was dissolved in 2ml of methanol, 2ml of 1Mol/L sodium hydroxide were added, the mixture was stirred at room temperature for half an hour and the pH was then adjusted to 2 with 1Mol/L hydrochloric acid. The mixture was evaporated to dryness, the residual solid was dissolved in 3ml of methanol, filtered, the filtrate was concentrated, and the obtained residue was chromatographed on a column to give III (white solid, 61% yield): m.p. > 300 ℃;¹H NMR(400MHz，D₂O)δ0.97(t，J＝7.2Hz，3H)，0.99(t，J＝7.2Hz，3H)，2.00(m，2H)，2.39(m，2H)，3.00-2.70(m，8H)，3.10(d，J＝12.1Hz，1H)，3.21(d，J＝12.1Hz，1H)，3.25(d，J＝12.1Hz，1H)，3.44(d，J＝12.1Hz，1H)，7.04(d，J＝8.4Hz，1H)，7.60(d，J＝8.4Hz，1H)，7.68(s，1H)；MS(ES)m/z 345(M+1).

example 4:

route to compound (IV):

the specific process is as follows:

preparation of methyl 4- (5- (2, 2-diacetylhydroxymethyl) pyrrolidin-1-one) -3- (2-di-n-propylamino-ethyl) benzoate (IVa):

l (0.34mmol) was dissolved in 1ml of 1, 2-dichloroethane and 0.5ml of acetic acid, and propionaldehyde (2.30mmol) and NaBH were added₃CN (1.2mmol), the mixture was stirred at room temperature for 6 hours, and propionaldehyde (2.30mmol) and NaBH were added to the system₃CN (1.2mmol) was stirred for a further 15 h. The reaction mixture was diluted with 10mL of ethyl acetate, and the organic layer was washed with saturated sodium bicarbonate (3 × 5mL), water (2 × 5mL) and saturated brine (2 × 5mL), respectively, dried over anhydrous sodium sulfate, filtered, concentrated, and the residue was subjected to silica gel column chromatography to obtain IVa (colorless oil, 61% yield):¹HNMR(300MHz，CDCl₃)δ1.00(m，6H)，1.73(s，3H)，1.82(m，4H)，2.17(s，3H)，2.23(m，1H)，2.44(m，1H)，2.80-2.60(m，3H)，3.20-2.94(m，6H)，3.54-3.47(m，1H)，3.95(s，3H)，4.00(d，J＝12.1Hz，1H)，4.36-4.26(m，3H)，7.15(d，J＝8.2Hz，1H)，8.02-7.98(m，2H)；MS(ES)m/z 463(M+1).

preparation of 4- (5- (2, 2-dimethylol) pyrrolidin-1-one) -3- (2-di-n-propylamino-ethyl) benzoic acid (IV):

IVa (0.2mmol) is dissolved in 2ml of methanol, 2ml of 1Mol/L sodium hydroxide are added, the mixture is stirred at room temperature for half an hour and the pH is then adjusted to 2 with 1Mol/L hydrochloric acid. The mixture was evaporated to dryness, the residual solid was dissolved in 3ml of methanol, filtered, the filtrate was concentrated, and the obtained residue was chromatographed on a column to give IV (white solid, 65% yield): mp is more than 300 ℃;¹H NMR(400MHz，CDCl₃)δ0.84(t，J＝7.2Hz，6H)，1.59(m，4H)，2.22-2.16(m，2H)，2.60-2.53(m，2H)，2.87(m，1H)，3.21-2.98(m，7H)，3.27(d，J＝12.3Hz，1H)，3.30(d，J＝12.3Hz，1H)，3.54(d，J＝12.3Hz，1H)，3.59(d，J＝12.3Hz，1H)，7.21(d，J＝8.3Hz，1H)，7.74(d，J＝8.3Hz，1H)，8.81(s，1H)；MS(ES)m/z 393(M+1).

example 5:

route to 1- (4-carbonyl-2-guanidino) -5, 5-dimethylol-pyrrolidin-2-one (V):

the specific process is as follows:

compound Va (350mg, 0.57mmol) was dissolved in 1mL of methanol, then 2.5mL of 1Mol/L NaOH was added, and the mixture was stirred at room temperature for 16 hours. The reaction solution was adjusted to pH 3 with 1Mol/L HCl, the solution was evaporated to dryness, and the residue obtained was subjected to ion exchange chromatography (ion exchange resin; 1.4N NH4OH) to give V (110mg, 59.0% yield): MS 323(M + 1);¹HNMR(300MHz，D₂O)δ7.95(d，1H，J＝1.8Hz)，7.93(dd，1H，J＝1.9&8.2Hz)，7.45(d，1H，J＝8.2Hz)，3.7(dd，2H，J＝8.1&12.0Hz)，3.55(d，1H，J＝12.0Hz)，3.29(d，1H，J＝12Hz)，2.7(m，2H)，2.35(m，2H).

example 6:

the virus experimental method comprises the following steps:

influenza strains were grown in embryonated chicken eggs. Adding a neuraminidase specific fluorescent substrate 2 '-4-methylumbelliferyl-a-N-acetylneuraminic acid (2' - (4-methylumbelliferyl) a-D-N-acetylneuraminic acid) into a 96 fluorescent enzyme label plate to determine IC₅₀Numerical values. Reactions using intact purified virions of neuraminidase, two-fold dilutions of the inhibitor were placed in 50mM sodium acetate, 100uM calcium chloride, 320uM magnesium chloride and 60uM sodium chloride (pH 6.0) before addition of 100uM fluorogenic substrate; preincubation was performed at room temperature for 30 minutes. After the reaction mixture was incubated at 37 ℃ for 15 minutes, the reaction was stopped with five times the volume of 0.2M glycine-sodium hydroxide mixture (pH 11). IC (integrated circuit)₅₀The values are determined by prism software by response selectivity normalized to the logarithm of the inhibitor concentration; the values were cross-checked using a plot of the partial inhibitory activity of the enzyme versus the concentration of the inhibitor, IC₅₀Determined by the dose-response curve of the linear region. IC (integrated circuit)₅₀The values are shown in the following table:

a: activity data against influenza virus subtype N9 (N1 and N9 are of the same group)

Through in vitro activity experiments, the compounds I to IV of the invention all show the activity of resisting influenza virus neuraminidase N1, N2 and B. Wherein, I and II have strong neuraminidase resistance, have obvious activity on influenza virus neuraminidase of two different subtypes (H1N1 and H3N2), and have strong activity on influenza virus neuraminidase of type B; the activity of the compounds I, II, III and IV on the influenza A virus is remarkably enhanced by hundreds of times compared with the activity of the compound V; the activity of the compounds I, II, III and IV on the B type influenza virus is stronger than that of the compound V. The compounds I, II, III and IV also have stronger inhibitory activity to N1 subtype, and the compound V has no activity to N1 subtype; this indicates that the compounds of the present invention have a wide coverage of influenza viruses, and are suitable for the treatment of various types of influenza as well as the prevention of influenza. In conclusion, the invention has important practical significance.

Claims (9)

1. An N-alkyl substituted benzoic acid derivative having the structure:

   
2. 2. a benzoic acid derivative has the following structure:

   
3. 3. the process for the preparation of the derivatives according to claim 1, by the following route:

   
4. 4. use of the derivative of claim 1 for the preparation of a medicament for the prophylaxis or treatment of influenza.
5. 5. The use of the derivative of claim 1 for the preparation of a medicament for the prophylaxis or treatment of H1N1 influenza.
6. 6. The use of the derivative of claim 1 for the preparation of a medicament for the prophylaxis or treatment of H3N2 influenza.
7. 7. The use of a derivative according to claim 1 for the preparation of a medicament for the prophylaxis or treatment of influenza B.
8. 8. Use of the benzoic acid derivatives Ia to IVa according to claim 2 as starting materials or intermediates for the preparation of the benzoic acid derivatives I to IV according to claim 1.
9. 9. Use of benzoic acid derivatives Ia-IVa as defined in claim 2 as reference substances for impurities of benzoic acid derivatives I-IV as defined in claim 1.