CN114380816B

CN114380816B - Nitroimidazole compound, pharmaceutical composition and application

Info

Publication number: CN114380816B
Application number: CN202111213316.5A
Authority: CN
Inventors: 徐华
Original assignee: Wuhan Shengyun Biomedical Technology Co ltd
Current assignee: Wuhan Shengyun Biomedical Technology Co ltd
Priority date: 2020-10-19
Filing date: 2021-10-19
Publication date: 2024-04-26
Anticipated expiration: 2041-10-19
Also published as: CN114380816A; CN118542865A

Abstract

The invention provides a nitroimidazole compound, a pharmaceutical composition and application thereof, wherein the nitroimidazole compound is a compound with a formula I, a stereoisomer or pharmaceutically acceptable salt, solvate or prodrug thereof, and the formula I is as follows:

Description

Nitroimidazole compound, pharmaceutical composition and application

Technical field:

The invention relates to the technical field of pharmaceutical chemistry, in particular to a nitroimidazole compound, a pharmaceutical composition and application.

The background technology is as follows:

Anaerobic bacteria are bacteria that survive and multiply in an anaerobic environment, and can cause serious infections in the event of reduced body resistance. It is common in clinical abdominal infections, pelvic infections, biliary tract infections, complicated skin soft tissue infections and blood flow infections, and commonly causes mixed infections with other pathogenic bacteria. According to the morphology, gram staining, and spore formation, it can be classified into gram-positive cocci, gram-positive bacillus-free bacteria, gram-positive bacillus, gram-negative bacillus, and the like. There are 4 bacteria of the genus Bacteroides, prevotella, she Lin Monomonas and Fusobacterium with a high frequency of clinical isolation at present. In recent years, there have been many changes in the susceptibility spectrum of clinically isolated anaerobic bacteria to antibacterial agents, and there has been a significant increase in the number of resistant bacteria to beta-lactam antibiotics, beta-lactamase inhibitors, metronidazole, and the like. All the drug-resistant strains are formed and developed, so that great difficulty is brought to clinical treatment, and the existing antibacterial drugs can not meet clinical requirements, so that the development of novel antibacterial drugs is particularly important.

After the first 5-nitroimidazole metronidazole in 1957 was developed, the nitroazole (nitroimidazole) was rapidly developed to treat various protozoal and anaerobic infections. The nidazole has the advantages of wide anti-anaerobe spectrum, strong bactericidal effect, low price and good curative effect, and can be widely combined with other antibacterial medicines to be applied to mixed infection of anaerobe and aerobe of various clinical systems. The united states food and drug administration was first approved for the sale of metronidazole tablets in 1963, mainly for the treatment of helicobacter pylori infection, amebiasis, giardiasis, trichomonas, bacterial vaginosis, crohn's disease, as a prophylactic application for abdominal pelvic surgery, etc., and is widely used for the treatment of periodontal diseases. Tinidazole was approved by the FDA as a second generation 5-nitroimidazole drug in 2004 for its marketing as a drug for the treatment of trichomoniasis, giardiasis, amoeba and amoeba liver abscess. Ornidazole is a relatively new 5-nitroimidazole derivative that has been used in some countries to treat specific protozoal infections because of its long half-life and thus better patient compliance. Like tinidazole, ornidazole has good activity against metronidazole resistant strains and shows better tolerance and fewer side effects than metronidazole.

Thus, research and development of new antibacterial compounds is of great importance for the treatment of clinical microbial infections.

Disclosure of Invention

Based on the above, the researchers of the invention design and synthesize a series of nitroazole derivatives on the basis of reference documents, and test the antibacterial activity of the nitroazole derivatives, and the results show that most of the derivatives have antibacterial activity.

In order to achieve the above purpose, the invention adopts the following technical scheme:

A compound having the formula I, a stereoisomer or a pharmaceutically acceptable salt, hydrate, solvate or prodrug thereof,

Wherein,

X is O or S;

r ₁ is selected from hydrogen, (C ₁-C₆) alkyl;

r ₂ and R ₃ are the same or different and are each independently selected from the group consisting of hydrogen, (C ₁-C₁₀) alkyl, (C ₃-C₇) cycloalkyl, (C ₂-C₁₀) alkenyl and (C ₂-C₁₀) alkynyl, which may optionally be substituted with 1 to 3 of the same or different R ₄;

Or R ₂ and R ₃ together with the nitrogen atom to which they are attached form a 4-10 membered heterocyclic group optionally containing, in addition to the nitrogen atom to which R ₂ and R ₃ are attached, 0-4 heteroatoms selected from N, O and S, 0-2 carbon-carbon double or triple bonds, optionally substituted with 1-3 identical or different R ₄;

R ₄ is (C ₁-C₆) alkyl, (C ₃-C₇) cycloalkyl, (C ₁-C₆) alkoxy, hydroxy, (C ₁-C₄) substituted hydroxy, amino, mono-or di (C ₁-C₆) substituted amino, unsubstituted or mono-or di (C ₁-C₆) substituted carbamoyl, unsubstituted or mono-or di (C ₁-C₆) substituted sulfamoyl, (C ₁-C₆) sulfonyl, carboxyl or ester-forming carboxyl.

Preferably, the compound of formula I, stereoisomers or pharmaceutically acceptable salts, hydrates, solvates or prodrugs thereof,

Wherein,

R ₁ is methyl or ethyl;

R ₂ and R ₃ are identical or different and are each independently selected from the group consisting of hydrogen, (C ₁-C₆) alkyl, (C ₃-C₆) cycloalkyl, (C ₂-C₆) alkenyl and (C ₂-C₆) alkynyl, which may optionally be substituted by 1 to 3 identical or different R ₄,

Or R ₂ and R ₃ together with the nitrogen atom to which they are attached form a 4-6 membered heterocyclic group optionally containing, in addition to the nitrogen atom to which R ₂ and R ₃ are attached, 0-4 heteroatoms selected from N, O and S, 0-2 carbon-carbon double or triple bonds, optionally substituted with 1-3 identical or different R ₄;

More preferably, the compound has the formula II,

Wherein,

R ₂ and R ₃ are identical or different and are each independently selected from hydrogen, (C ₁-C₄) alkyl, (C ₃-C₆) cycloalkyl, which may optionally be substituted by 1 to 3 identical or different R ₄,

Or R ₂ and R ₃ together with the nitrogen atom to which they are attached form a 4-6 membered heterocyclic group optionally containing 0-2 heteroatoms selected from N, O and S, optionally substituted with 1-3 identical or different R ₄ groups, in addition to the nitrogen atom to which R ₂ and R ₃ are attached.

Preferably, the compound of formula II, stereoisomers or pharmaceutically acceptable salts, hydrates, solvates or prodrugs thereof,

Wherein,

R ₂ and R ₃ are identical or different and are each independently selected from

H、

Or R ₂ and R ₃ together with the nitrogen atom to which they are attached form

More preferably, the compound having formula ii, stereoisomers, or pharmaceutically acceptable salts, hydrates, solvates or prodrugs thereof, is selected from the following compounds:

(5Z) -2- (1-piperidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (4-methyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (1-morpholinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (dimethylamino) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (diethylamino) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- [ (2, 3-dihydroxypropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- [ (3-hydroxypropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- [ (2-hydroxyethyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- { [2- (dimethylamino) ethyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- [ (3-amino-2, 2-dimethylpropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- { methyl [3- (methylamino) propyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (3-methyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (1-thiomorpholino) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- { [3- (diethylamino) propyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (4-isopropyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- [4- (3-hydroxypropyl) -1-piperazinyl ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one;

(5Z) -2- (3-amino-1-azetidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one.

Further, the pharmaceutically acceptable salts are according to some of the usual methods in the art to which this invention pertains and may be formed from compounds having formula I with an acid. Preferably, the acid is hydrochloric acid, hydrobromic acid, hydrofluoric acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, picric acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, trifluoroacetic acid, and aspartic acid.

Prodrugs according to the invention are derivatives of the compounds of formula I which may themselves have a relatively weak or even no activity, but are converted to the corresponding biologically active form after administration under physiological conditions (e.g. by metabolism, solvolysis or otherwise).

The term "halogen" as used herein, unless otherwise indicated, refers to fluorine, chlorine or bromine; "alkyl" refers to a straight or branched chain alkyl group; "cycloalkyl" refers to a substituted or unsubstituted cycloalkyl; "alkoxy" refers to straight or branched chain alkoxy; "alkenyl" refers to straight or branched chain alkenyl groups; "alkynyl" refers to straight or branched chain alkynyl groups; "aryl" refers to phenyl groups that are unsubstituted or substituted; "heteroaryl" means a monocyclic or polycyclic ring system containing one or more heteroatoms selected from N, O, S, the ring system being aromatic, such as imidazolyl, pyridyl, pyrazolyl, furanyl, thienyl, pyrrolyl, thiazolyl, benzothiazolyl, oxazolyl, isoxazolyl, naphthyl, quinolinyl, isoquinolinyl, benzimidazolyl, benzoxazolyl, and the like; "saturated or partially saturated heterocyclyl" refers to a monocyclic or polycyclic ring system containing one or more heteroatoms selected from N, O, S, such as pyrrolidinyl, morpholinyl, piperazinyl, piperidinyl, pyrazolidinyl, imidazolidinyl, thiazolinyl, and the like.

The invention also provides a pharmaceutical composition, which comprises the compound with the formula I, stereoisomer or pharmaceutically acceptable salt, hydrate, solvate or prodrug thereof as an active ingredient and pharmaceutically acceptable excipient; the compounds of the invention may be used in combination with other active ingredients as long as they do not produce other adverse effects, such as allergic reactions.

Excipients for use in the pharmaceutical compositions of the present invention are of the usual types available in the pharmaceutical arts, including: binders, lubricants, disintegrants, co-solvents, diluents, stabilizers, suspending agents, non-coloring agents, flavoring agents, and the like, which are useful for oral formulations; a pH regulator, an osmotic pressure regulator, a solubilizer, a stabilizer, etc. for injectable preparations; matrices, diluents, lubricants, preservatives, and the like, which may be used in topical formulations. The pharmaceutical formulations may be administered orally, parenterally (e.g., intravenously, subcutaneously, intraperitoneally, etc.), or topically (e.g., ocular, nasal, sublingual, dermal, etc.), and if some drugs are unstable under gastric conditions, they may be formulated as enteric formulations, such as enteric tablets or enteric capsules, etc.

The use of a compound of formula I, a stereoisomer or a pharmaceutically acceptable salt, hydrate, solvate or prodrug thereof for the manufacture of a medicament for the prophylaxis and/or treatment of a microbial infection. The administration modes include oral administration, parenteral administration, transdermal administration or local administration, etc. The microorganism comprises bacteria or parasites; the parasites include amoeba, trichomonas, giardia, etc. The bacteria may be anaerobic bacteria such as anaerobic streptococcus digestion and clostridium perfringens, etc. Therefore, the compound with the formula I, stereoisomer or pharmaceutically acceptable salt, hydrate and solvate thereof can be used for preparing medicines for treating mammal infection caused by bacteria or parasites and other microorganisms. Mammal means a human or other animal.

The amount administered will vary from subject to subject, depending upon the type of subject, the age and general condition of the subject, the severity of the condition being treated, the particular compound used, and the mode of administration, e.g., route and frequency of administration, and the like. One of ordinary skill in the art can determine the appropriate effective amount using only routine experimentation. Generally, the amount to be administered is 0.1 to 100mg/kg body weight/day, preferably 1 to 50mg/kg body weight/day. It will be appreciated that the dosage may vary depending on the patient's needs, the severity of the bacterial infection being treated and the particular compound being used. Moreover, it will be appreciated that the initial dose administered may be increased beyond an upper limit in order to rapidly reach the desired blood level, or the initial dose may be less than optimal, and the daily dose may be gradually increased during treatment, depending on the particular situation. If desired, the daily dose may also be divided into multiple doses, for example 2-4 times per day.

The amount of active ingredient, i.e. the compound according to the invention, in the pharmaceutical composition and unit dosage forms thereof may vary depending on the particular application, the potency of the particular compound and the desired concentration. Generally, the content of active ingredient will be between 0.5% and 90% by total weight of the composition.

In combination therapy, the compound of the invention and the other compound may be administered simultaneously or separately, and in the case of simultaneous administration, the compound of the invention and the other compound may be combined in a single pharmaceutical composition or in separate compositions.

The examples and preparations provided below further illustrate and exemplify the compounds of the invention and methods of preparing the same. It should be understood that the scope of the following examples and preparations is not intended to limit the scope of the present invention in any way.

The following synthetic schemes describe the preparation of the derivatives of formula I of the present invention, all starting materials being prepared by the methods described, by methods well known to those of ordinary skill in the art of organic chemistry, or are commercially available. All of the final compounds of the present invention are prepared by methods described in the synthetic routes or by methods analogous thereto, which are well known to those of ordinary skill in the art of organic chemistry. All variable factors applied in the synthetic route are as defined below or as defined in the claims.

In the compounds of the general formula I according to the invention, in schemes A to C, the substituents R ₂、R₃、R₄ are defined as follows.

In the route A, 1, 2-dimethyl-5-nitroimidazole (A) is taken as a starting material, and is subjected to condensation reaction with DMF-DMA to obtain an intermediate B, and then an oxidation reaction is carried out under the condition of NaIO ₄ to obtain a key intermediate C; taking rhodamine (D) as a starting material, taking NaOH as a base to carry out methylation reaction with methyl iodide to obtain an intermediate E, then carrying out nucleophilic substitution reaction with amine substituted by R ₂,R₃ to generate an intermediate F, and then carrying out a gram brain Wen Geer condensation reaction with the intermediate C under the catalysis of piperidine to obtain the compound I-I of the general formula I.

Synthesis of Compound I-I

In the route B, the intermediate E and N-Boc piperazine undergo nucleophilic substitution reaction to obtain an intermediate G, then undergo Boc protection reaction under the condition of trifluoroacetic acid to obtain an intermediate H, then undergo nucleophilic substitution reaction with R ₄ substituted chloro compound under the condition of triethylamine as base to obtain an intermediate I, and then undergo a Klebsiella Wen Geer condensation reaction with the intermediate C under the catalysis of piperidine to obtain a compound I-ii of the general formula I.

Synthesis of Compound I-ii

In the route B, taking amino-azacycloalkyl-1-carboxylic acid tert-butyl ester (J) as a starting material, taking Na ₂CO₃ as a base, carrying out Fmoc protection reaction with Fmoc-Cl to obtain an intermediate K, and then carrying out Boc removal protection reaction under the condition of trifluoroacetic acid to obtain an intermediate L; intermediate E and intermediate L undergo nucleophilic substitution reaction to obtain intermediate M, and then undergo a kephalic Wen Geer condensation reaction with intermediate C under the catalysis of piperidine to obtain the compound I-iii of the general formula I.

Scheme c Synthesis of Compound I-iii

The specific embodiment is as follows:

In the examples below, the methods of preparing some of the compounds are depicted. It will be appreciated that the following methods, as well as other methods known to those of ordinary skill in the art, may be applicable to the preparation of all compounds described herein. The examples are intended to illustrate, but not limit the scope of the invention. The nuclear magnetic resonance hydrogen spectrum of the compound is measured by BrukerARX-400 or BrukerARX-600, and the mass spectrum is measured by Agilent1100 LC/MSD; the reagents used are analytically pure or chemically pure.

Example 1: (5Z) -2- (1-piperidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

1.1 Synthesis of (E) -N, N-dimethyl-2- (1-methyl-5-nitro-1H-imidazol-2-yl) ethylene-1-amine (B)

50.0G (354.6 mmol) of 1, 2-dimethyl-5-nitroimidazole (A) and 75.9g (638.3 mmol) of DMF are dissolved in DMF (500 mL) at room temperature and the temperature is raised to 145℃for 4h. After the reaction, the reaction solution is cooled to room temperature, petroleum ether (150 mL) is added into the system, purple needle-like crystals are precipitated, suction filtration is carried out, a filter cake is washed by petroleum ether (500 mL) and water (500 mL) in sequence, and 45g of purple solid is obtained after drying, namely the intermediate B. The yield thereof was found to be 65.2%. MS (ESI) m/z 197.1[ M+H ] ⁺.

1.2 Synthesis of 1-methyl-5-nitro-1H-imidazole-2-carbaldehyde (C)

Intermediate b20.0g (102.0 mmol) and NaIO ₄ 65.5.5 g (306.0 mmol) were dissolved in a mixed solvent of THF-H ₂ O (1:1=800 mL) at room temperature and reacted for 2H at room temperature. After the reaction, suction filtration was performed, the filtrate was collected and THF was distilled off under reduced pressure, the reaction solution was extracted with methylene chloride (3×200 mL), the organic phase was collected, washed with saturated brine (200 mL), the organic phase was removed in color by celite, the filtrate was collected and the organic solvent was distilled off under reduced pressure, and dried to obtain 10.5g of orange solid as intermediate C. The yield thereof was found to be 66.1%. MS (ESI) m/z 155.0[ M+H ] ⁺.

1.3 Synthesis of 2-methylthiothiazol-4 (5H) -one (E)

20G (150.4 mmol) of rhodanine (D) was dissolved in 2% NaOH aqueous (400 mL) at room temperature, and after stirring for 20min, 25.6g (180.5 mmol) of CH ₃ I was slowly added dropwise to the reaction system, and the mixture was reacted at room temperature for 10 hours. After completion of the reaction, the reaction mixture was extracted with methylene chloride (3X 200 mL), and the organic phase was collected, washed successively with saturated aqueous NaHCO ₃ (2X 200 mL), water (200 mL) and saturated brine (200 mL). The organic solvent was distilled off under reduced pressure, slurried with methanol (20 mL), suction filtered, the filter cake washed with a small amount of anhydrous methanol (10 mL), and dried to give 13.0g of an orange-yellow solid as intermediate E. The yield thereof was found to be 59.1%. MS (ESI) m/z 147.9[ M+H ] ⁺.

1.4 Synthesis of 2- (1-piperidinyl) thiazol-4 (5H) -one (F)

Intermediate E10.0g (68.0 mmol) and piperidine 8.7g (102.0 mmol) were dissolved in dry methanol (100 mL) at room temperature and reacted for 1.5h at room temperature. After the reaction, the organic solvent was distilled off under reduced pressure, water (50 mL) was added, the aqueous phase was extracted with methylene chloride (3X 50 mL), the organic phase was collected, the organic phase was washed successively with water (50 mL), saturated brine (50 mL) was washed, the organic solvent was distilled off under reduced pressure, and dried to obtain 11.5g of an orange solid, namely intermediate F. The yield thereof was found to be 92.0%. MS (ESI) m/z 185.0[ M+H ] ⁺.

1.5 Preparation of (5Z) -2- (1-piperidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one (I-I)

At room temperature, 5.0g (27.2 mmol) of intermediate F and 4.6g (29.9 mmol) of intermediate C were dissolved in absolute ethanol (50 mL), and piperidine (7 mL) was added dropwise to the reaction system, and the mixture was warmed to reflux for 4h. After the reaction, filtering, washing the filter cake with a small amount of absolute ethyl alcohol (10 mL), and drying to obtain 7.6g of yellow solid, namely I-I. The yield thereof was found to be 87.0%.

MS(ESI)m/z:322.0[M+H]⁺；

¹H-NMR(600MHz,DMSO-d₆)δ8.31(s,1H),7.51(s,1H),4.04(s,3H),3.92-3.90(m,2H),3.67-3.60(m,2H),1.71-1.66(m,4H),1.65-1.60(m,2H).

Example 2: (5Z) -2- (4-methyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized following the synthesis procedure of 1.4 in example 1 starting from N-methylpiperazine, followed by synthesis of (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (4-methylpiperazin-1-yl) -4 (5H) thiazolone following the synthesis procedure of 1.5 in example 1. The yield thereof was found to be 85.3%.

MS(ESI)m/z:337.1[M+H]⁺；

¹H-NMR(600MHz,CDCl₃)δ8.16(s,1H),7.54(s,1H),4.14-4.11(m,2H),4.10(s,3H),3.75-3.70(m,2H),2.62-2.55(m,4H),2.38(s,3H).

Example 3: (5Z) -2- (1-morpholinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Starting from morpholine, key intermediate F was synthesized according to the synthesis method of 1.4 in example 1, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (morpholin-1-yl) -4 (5H) thiazolone was synthesized according to the synthesis method of 1.5 in example 1. The yield thereof was found to be 86.4%.

MS(ESI)m/z:324.0[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.33(s,1H),7.56(s,1H),4.04(s,3H),3.96–3.91(m,2H),3.77-3.73(m,4H),3.72-3.70(m,2H).

Example 4: (5Z) -2- (dimethylamino) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Key intermediate F was synthesized following the synthesis of 1.4 in example 1 starting with dimethylamine, followed by (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (dimethylamino) -4 (5H) thiazolone following the synthesis of 1.5 in example 1. The yield thereof was found to be 88.5%.

MS(ESI)m/z:282.0[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.33(s,1H),7.52(s,1H),4.04(s,3H),3.28(s,3H),2.49(s,3H)。

Example 5: (5Z) -2- (diethylamino) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Key intermediate F was synthesized following the synthesis of 1.4 in example 1 starting with diethylamine, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (diethylamino) -4 (5H) thiazolone was synthesized following the synthesis of 1.5 in example 1. The yield thereof was found to be 86.7%.

MS(ESI)m/z:310.0[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.34(s,1H),7.52(s,1H),4.04(s,3H),3.74(q,J＝7.1Hz,2H),3.61(q,J＝7.1Hz,2H),1.28(t,J＝7.1Hz,3H),1.22(t,J＝7.1Hz,3H).

Example 6: (5Z) -2- [ (2, 3-dihydroxypropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized according to the synthesis of 1.4 in example 1 starting from 2, 3-dihydroxypropylamine, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- [ (2, 3-dihydroxypropyl) amino ] -4 (5H) thiazolone was synthesized according to the synthesis of 1.5 in example 1. The yield thereof was found to be 82.3%.

MS(ESI)m/z:328.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ10.27(s,1H),8.34(s,1H),7.47(s,1H),5.18(d,J＝5.1Hz,1H),4.81(d,J＝5.4Hz,1H),4.02(s,3H),3.69-3.66(m,2H),3.45–3.40(m,1H),3.37–3.20(m,2H).

Example 7: (5Z) -2- [ (3-hydroxypropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized following the synthesis procedure of 1.4 in example 1 starting from 3-hydroxypropyl amine, followed by synthesis of (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- [ (3-hydroxypropyl) amino ] -4 (5H) thiazolone following the synthesis procedure of 1.5 in example 1. The yield thereof was found to be 86.4%.

MS(ESI)m/z:312.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ9.73(s,1H),8.33(s,1H),7.49(s,1H),4.59(t,J＝5.0Hz,1H),4.03(s,3H),3.58(t,J＝5.0Hz,2H),3.51–3.44(m,2H),1.78–1.71(m,2H).

Example 8: (5Z) -2- [ (2-hydroxyethyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized following the synthesis procedure of 1.4 in example 1 starting from 2-hydroxyethylamine, followed by synthesis of (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- [ (2-hydroxyethyl) amino ] -4 (5H) thiazolone following the synthesis procedure of 1.5 in example 1. The yield thereof was found to be 84.6%.

MS(ESI)m/z:298.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ9.89(s,1H),8.33(s,1H),7.46(s,1H),4.99(s,1H),4.03(s,3H),3.95-3.85(m,1H),3.57–3.28(m,3H).

Example 9: (5Z) -2- { [2- (dimethylamino) ethyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Key intermediate F was synthesized following the synthesis of 1.4 in example 1 starting with N, N-dimethylethane-1, 2-diamine, followed by (5Z) -5- [ (5-amino-1-methyl-1H-imidazol-2-yl) methylene ] -2- { [2- (dimethylamino) ethyl ] amino } -4 (5H) thiazolone following the synthesis of 1.5 in example 1. The yield thereof was found to be 81.6%.

MS(ESI)m/z:325.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ10.07(s,1H),8.33(s,1H),7.46(s,1H),4.03(s,3H),3.72–3.55(m,3H),2.19(s,7H).

Example 10: (5Z) -2- [ (3-amino-2, 2-dimethylpropyl) amino ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized according to the synthesis of 1.4 in example 1 starting from 2, 2-dimethylpropane-1, 3-diamine, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- [ (3-amino-2, 2-dimethylpropyl) amino ] -4 (5H) thiazolone was synthesized according to the synthesis of 1.5 in example 1. The yield thereof was found to be 87.7%.

MS(ESI)m/z:339.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.33(s,1H),7.47(s,1H),4.04(s,3H),3.53(t,J＝7.0Hz,2H),3.45–3.33(m,1H),2.27(t,J＝6.9Hz,2H),2.14(s,6H),1.79–1.67(m,2H).

Example 11 (5Z) -2- { methyl [3- (methylamino) propyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized following the synthesis of 1.4 in example 1 starting with N, N' -dimethylpropane-1, 3-diamine, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- { methyl [3- (methylamino) propyl ] amino } -4 (5H) thiazolone was synthesized following the synthesis of 1.5 in example 1. The yield thereof was found to be 87.7%.

MS(ESI)m/z:339.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.32(s,1H),7.46(s,1H),4.02(s,3H),3.54(t,J＝6.9Hz,2H),3.46–3.36(m,1H),2.32(t,J＝6.7Hz,2H),2.17(s,6H),1.81–1.68(m,2H).

Example 12: (5Z) -2- (3-methyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Starting from 3-methylpiperazine, key intermediate F was synthesized according to the synthesis method of 1.4 in example 1, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (3-methylpiperazin-1-yl) -4 (5H) thiazolone was synthesized according to the synthesis method of 1.5 in example 1. The yield thereof was found to be 84.6%.

MS(ESI)m/z:337.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.31(s,1H),7.52(s,1H),4.46(d,J＝12.4Hz,1H),4.04(s,3H),3.73(t,J＝10.4Hz,1H),3.19(t,J＝12.2Hz,1H),3.03(dt,J＝21.1,12.6Hz,2H),2.91–2.79(m,1H),2.70(dd,J＝23.9,11.2Hz,2H),1.04(dd,J＝15.0,6.2Hz,3H).

Example 13: (5Z) -2- (1-thiomorpholinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Key intermediate F was synthesized following the synthesis of 1.4 in example 1 starting with thiomorpholine, and (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (thiomorpholin-1-yl) -4 (5H) thiazolone was synthesized following the synthesis of 1.5 in example 1. The yield thereof was found to be 85.5%.

MS(ESI)m/z:340.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.32(s,1H),7.56(s,1H),4.22–4.16(m,2H),4.04(s,3H),3.97–3.91(m,2H),2.85–2.76(m,4H).

Example 14 (5Z) -2- (1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate F was synthesized following the synthesis procedure of 1.4 in example 1 starting from anhydrous piperazine, followed by synthesis of (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- (piperazin-1-yl) -4 (5H) thiazolone following the synthesis procedure of 1.5 in example 1. The yield thereof was found to be 85.0%.

MS(ESI)m/z:323.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.32(s,1H),7.53(s,1H),4.04(s,3H),3.90–3.83(m,2H),3.64–3.57(m,2H),2.85-2.82(m,4H).

Example 15: (5Z) -2- { [3- (diethylamino) propyl ] amino } -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

Starting from N, N-diethylpropane-1, 3-diamine, key intermediate F was synthesized according to the method of synthesis 1.4 in example 1, and (5Z) -5- [ (5-amino-1-methyl-1H-imidazol-2-yl) methylene ] -2- { [3- (diethylamino) propyl ] amino } -4 (5H) thiazolone was synthesized according to the method of synthesis 1.5 in example 1. The yield thereof was found to be 86.2%.

MS(ESI)m/z:367.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.32(s,1H),7.49(s,1H),4.04(s,3H),3.54(t,J＝7.0Hz,2H),3.42(t,J＝6.9Hz,1H),2.49–2.41(m,6H),1.76–1.66(m,2H),0.94(t,J＝7.1Hz,6H).

Example 16: (5Z) -2- (4-isopropyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

16.1 Synthesis of tert-butyl 4- (4-oxo-4, 5-dihydrothiazol-2-yl) piperazine-1-carboxylate (G)

Intermediate E10.0g (68.0 mmol) and N-Boc piperazine 19.0g (102.0 mmol) were dissolved in dry methanol (100 mL) at room temperature and reacted for 1.5h at room temperature. After the reaction, the organic solvent was distilled off under reduced pressure, water (50 mL) was added, the aqueous phase was extracted with methylene chloride (3X 50 mL), the organic phase was collected, the organic phase was washed with water (50 mL) successively, saturated brine (50 mL) was washed, the organic solvent was distilled off under reduced pressure, and dried to obtain 17.5G of an orange solid, namely intermediate G. The yield thereof was found to be 90.2%.

MS(ESI)m/z:286.0[M+H]⁺。

16.2 Synthesis of 2- (1-piperazinyl) thiazol-4 (5H) -one (H)

15.0G (52.6 mmol) of the intermediate G was dissolved in methylene chloride (75 mL) at room temperature, and trifluoroacetic acid (75 mL) was added to the reaction mixture under an ice bath to react at room temperature for 2h. After the reaction, the reaction mixture was concentrated, water (50 mL) was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, and the mixture was suction-filtered and dried to give 8.37g of a yellow solid as intermediate H. The yield thereof was found to be 86.0%.

MS(ESI)m/z:186.0[M+H]⁺。

16.3 Synthesis of 2- (4-isopropyl-1-piperazinyl) thiazol-4 (5H) -one (I)

Intermediate H8.0g (43.2 mmol), ethyl chloride 4.2g (65.6 mmol) were dissolved in acetonitrile (80 mL) at room temperature, triethylamine 8.7g (86.4 mmol) was added and the temperature was raised to 80℃for 4h. After the reaction, the organic solvent was distilled off under reduced pressure, water (50 mL) was added, the aqueous phase was extracted with methylene chloride (3X 50 mL), the organic phase was collected, the organic phase was washed successively with water (50 mL), saturated brine (50 mL) was washed, the organic solvent was distilled off under reduced pressure, and dried to obtain 6.8g of an orange solid, namely intermediate I. The yield thereof was found to be 73.4%.

MS(ESI)m/z:214.0[M+H]⁺。

16.4 Preparation of (5Z) -2- (4-isopropyl-1-piperazinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one (I-ii)

At room temperature, 5.0g (23.4 mmol) of intermediate I and 4.4g (28.0 mmol) of intermediate C were dissolved in absolute ethanol (50 mL), and piperidine (7 mL) was added dropwise to the reaction system, and the mixture was heated to reflux for 4h. After the reaction, the filter cake was washed with a small amount of absolute ethanol (10 mL) and dried to give 6.9g of a yellow solid, i.e., I-ii. The yield thereof was found to be 87.2%.

MS(ESI)m/z:365.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.32(s,1H),7.53(s,1H),4.04(s,3H),3.91(s,2H),3.65(s,2H),2.81–2.69(m,1H),2.59(s,4H),0.99(d,J＝5.8Hz,6H).

Example 17: (5Z) -2- [4- (3-hydroxypropyl) -1-piperazinyl ] -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

The key intermediate I was synthesized following the synthesis of 16.3 in example 16 starting from 3-chloropropanol, followed by synthesis of (5Z) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] -2- [4- (3-hydroxypropyl) piperazin-1-yl ] -4 (5H) thiazolone following the synthesis of 16.4 in example 16. The yield thereof was found to be 85.2%.

MS(ESI)m/z:381.1[M+H]⁺；

¹H-NMR(400MHz,DMSO-d₆)δ8.33(s,1H),7.55(s,1H),4.50-4.40(m,1H),4.04(s,3H),3.95-3.87(m,2H),3.74-3.66(m,2H),3.46(t,J＝11.3Hz,4H),2.43-2.33(m,2H),1.63-1.60(m,2H),1.25-1.21(m,2H).

Example 18: (5Z) -2- (3-amino-1-azetidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one

18.1 Synthesis of tert-butyl 3- ({ [ (9H-fluoren-9-yl) methoxy ] carbonyl } amino) azetidine-1-carboxylate (K)

Intermediate J1g (5.8 mmol), fmoc-cl1.7g (6.4 mmol) and Na ₂CO₃ 3.1.1 g (29.1 mmol) were dissolved in a mixed solvent of 1, 4-dioxane-water (2:1=30 mL) at room temperature and reacted for 8h at room temperature. After the reaction, suction filtration is carried out, a filter cake is washed by a small amount of water (20 mL), an organic solvent is distilled off under reduced pressure, a white solid crude product is obtained, and column chromatography [ silica gel, V (petroleum ether)/V (ethyl acetate) =10:1 ] is purified, and 1.8g of white solid is obtained, namely an intermediate K. The yield thereof was found to be 78.3%. MS (ESI) m/z 395.2[ M+H ] ⁺.

18.2 Synthesis of (9H-fluoren-9-yl) -3-azetidinylcarbamate (L)

Intermediate K1.5g (3.8 mmol) was dissolved in methylene chloride (15 mL) at room temperature, trifluoroacetic acid (15 mL) was added to the reaction mixture under ice-bath, and the mixture was reacted at room temperature for 2h. After the reaction, the reaction mixture was concentrated, water (20 mL) was added, the pH was adjusted to 8 with saturated sodium bicarbonate solution, and the mixture was suction-filtered and dried to obtain 0.8g of a white solid, intermediate L. The yield thereof was found to be 72.7%. MS (ESI) m/z 295.1[ M+H ] ⁺.

18.3 Synthesis of (9H-fluoren-9-yl) methyl [1- (4-oxo-4, 5-dihydrothiazol-2-yl) -3-azetidinyl ] carbamate (M)

Intermediate E0.2g (1.4 mmol) and intermediate L0.6g (2.0 mmol) were dissolved in anhydrous methanol (2 mL) at room temperature and reacted for 1.5h at room temperature. After the reaction, the organic solvent was distilled off under reduced pressure, water (10 mL) was added, the aqueous phase was extracted with methylene chloride (3X 10 mL), the organic phase was collected, the organic phase was washed with water (30 mL) successively, saturated brine (30 mL) was washed, the organic solvent was distilled off under reduced pressure, and dried to obtain 0.43g of a white solid, namely intermediate M. The yield thereof was found to be 82.0%. MS (ESI) m/z 394.1[ M+H ] ⁺.

18.4 Preparation of (5Z) -2- (3-amino-1-azetidinyl) -5- [ (1-methyl-5-nitro-1H-imidazol-2-yl) methylene ] thiazol-4 (5H) -one (I-iii)

At room temperature, 0.2g (0.5 mmol) of intermediate M and 0.09g (0.58 mmol) of intermediate C were dissolved in absolute ethanol (2 mL), and piperidine (5 drops) was added dropwise to the reaction system, and the mixture was warmed to reflux for 8h. After the reaction, the filter cake is washed by pumping filtration and a small amount of absolute ethyl alcohol (2 mL) and dried to obtain 0.12g of yellow solid, namely I-iii. The yield thereof was found to be 72.0%. MS (ESI) m/z 309.1[ M+H ] ⁺.

The specific structures of the compounds prepared in examples 1-18 are shown in Table 1.

TABLE 1

Experimental example 1 in vitro antibacterial Activity study

1.1 Process for increasing bacterial growth

(1) A suitable amount of sterile defibrinated sheep blood was added to a sterile BrainHeartInfusion broth agar medium to a 5% level, and 4mL of the mixture was added to each tube to form a slant.

(2) Igniting the alcohol lamp, burning all inoculating loops on the outer flame, then slowly passing the inoculating rod in the outer flame, and repeating the steps for three times; after the inoculating loop is cooled, picking a colony of the flat plate stored at 4 ℃ for one loop, and scribing on an inclined plane to finish subculture inoculation.

1.2 Test procedure

(1) The positive control ornidazole standard and the test compounds of examples 1-18 were dissolved with 100% dimethyl sulfoxide to 2560 μg/mL concentration, and filtered for sterilization.

(2) 180 Mu L of broth culture solution and 20 mu L of the compound stock solution prepared in the step (1) are added into a 1# hole in a 96-well plate, and the mixture is uniformly mixed; 100 mu L of broth culture solution is respectively added into the 2-11# holes, then 100 mu L of liquid in the 1# holes is taken into the 2# holes by a liquid-transferring gun, the mixture is uniformly mixed, 100 mu L of liquid in the previous hole is sequentially sucked into the next hole by the 3-10# holes by the liquid-transferring gun until the last 100 mu L is discarded after the 10 th hole, the 11# holes are used as strain growth condition control, and 200 mu L of broth culture solution is added into the 12# holes to be used as blank control.

(3) The cultured thalli is diluted by 3-5mL of physiological saline to ensure that the correction concentration reaches the standard of the Mitsubishi turbidimetry, and then diluted by 1:100 (the bacteria content is about 10 ⁶ cfu/mL) by 10 percent of defibrinated sheep blood meat soup, and the mixture is uniformly mixed by vortex. Then 100. Mu.L of bacterial liquid is added into 1-11# holes of a 96-well plate, and the final concentration of the compound to be tested is 128. Mu.g/mL, 64. Mu.g/mL, 32. Mu.g/mL, 16. Mu.g/mL, 8. Mu.g/mL, 4. Mu.g/mL, 2. Mu.g/mL, 1. Mu.g/mL, 0.5. Mu.g/mL and 0.25. Mu.g/mL respectively by adopting a double dilution method. Well 11 was used to detect if bacteria were growing and well 12 was used to detect if the broth was contaminated.

(4) All compounds tested were diluted as above. The 96-well plate was sealed in an anaerobic bag and incubated at 37℃for 24 hours, and absorbance was measured with an enzyme-labeled instrument, and the results are shown in Table 2.

TABLE 2 Activity of test Compounds against Streptococcus anaerobic digestion and Clostridium perfringens MIC

As can be seen from Table 2, the compounds prepared in examples 1 to 18 have more excellent antibacterial activity than the positive controls tinidazole, ornidazole and metronidazole.

Experimental example 2 study of the Activity of clinically isolated strains

The experimental method comprises the following steps: the clinical isolated bacteroides fragilis, the anaerobic streptococcus digest and the clostridium difficile were inoculated into blood agar plates and cultured in an anaerobic incubator (H ₂10％,N₂80％,CO₂, 37 ℃). And (3) carrying out passage for 2-3 times, flushing the agar surface with normal saline, and collecting colonies to prepare bacterial liquid until the OD value is 1.708 for later use.

The specific experimental method is the same as 1.1, and the results are shown in tables 3-5.

TABLE 3 drug sensitivity test on Bacteroides fragilis (mg/L)

TABLE 4 drug sensitivity test on Streptococcus mutans (mg/L)

TABLE 5 drug sensitivity test on Clostridium difficile (mg/L)

As is clear from tables 3 to 5, the compounds prepared in examples 1 to 4 have a certain inhibitory effect on the clinically isolated Bacteroides fragilis, streptococcus anaerobic digestion and Clostridium difficile, and have more excellent antibacterial activity than the positive controls tinidazole and metronidazole.

Experimental example 3 in vivo pharmacodynamic test

50 Healthy Balb/c mice were randomly divided into a control group, a metronidazole (0.6 g/kg) group, an example 1.8g/kg group, a 0.6g/kg group and a 0.2g/kg group, 10 animals/males each. A solution of Bacteroides fragilis bacteria (OD=1.708) was prepared according to the method of experimental example 2, and 90% of the bacterial load of the 9MLD strain was injected intraperitoneally, 0.2 mL/dose, immediately after infection, by gastric lavage, administration of an equal volume of deionized water to a control group, administration volume of 20mL/kg, and continuous administration for 3 days. On day 1, 24-48h, 2, and so on, 72-96h, 4 days are prescribed. The status and death number of each group of mice were recorded for 4 days, and the results are shown in Table 6.

Mortality/% = number of dead animals/total number of animals in the group x 100%.

TABLE 6 effects of example 1 on mortality and mortality in mice

As can be seen from Table 6, the compound prepared in example 1 has a certain antibacterial activity in vivo within 24 hours, and the activity is superior to that of the positive control metronidazole.

The compounds of formula I of the present invention may be used alone, but are typically administered in admixture with a pharmaceutically acceptable carrier selected according to the desired route of administration and standard pharmaceutical practice, the novel use of which in the pharmaceutical field is exemplified below by tablets, capsules, injectables and suppositories.

Example 19: tablet formulation

10G of the compound of the formula I (example 2) are granulated by a wet method, 20g of auxiliary materials are added according to a common tabletting method in pharmacy, and after being uniformly mixed, 150 tablets are pressed, and each tablet weighs 200mg.

Example 20: capsule preparation

10G of the compound of the formula I (example 3) are added with 20g of auxiliary materials according to the requirements of pharmaceutical capsules, and the mixture is uniformly mixed and filled into 100 hollow capsules, wherein each capsule weighs 300mg.

Example 21: injection preparation

2G of the compound of the formula I (example 4) was filtered through a microporous membrane of 0.25 μm according to the general pharmaceutical method, and then filled into nitrogen tanks to prepare water needle preparations each of which was 0.4mL and filled into a total of 100 bottles.

Example 22: suppository

1G of the compound of the formula I (example 4) was ground, added with an appropriate amount of glycerin, ground uniformly, added with melted glycerogelatin, ground uniformly, and poured into a lubricant-applied mold to prepare 5g of suppositories.

The above examples illustrate only a few embodiments of the invention, which are described in detail and are not to be construed as limiting the scope of the invention. It should be noted that it will be apparent to those skilled in the art that several variations and modifications can be made without departing from the spirit of the invention, which are all within the scope of the invention. Accordingly, the scope of protection of the present invention is to be determined by the appended claims.

Claims

1. A compound having formula I, stereoisomers or pharmaceutically acceptable salts thereof,

Wherein,

X is O;

R ₁ is methyl or ethyl;

R ₄ is (C ₁-C₆) alkyl, (C ₁-C₆) alkoxy, hydroxy, (C ₁-C₄) substituted hydroxy, amino, mono or di (C ₁-C₆) substituted amino;

Or R ₂ and R ₃ together with the nitrogen atom to which they are attached form a 4-6 membered heterocyclic group optionally containing 0-4 heteroatoms selected from N, O and S, containing 0 carbon-carbon double or triple bonds, in addition to the nitrogen atom to which R ₂ and R ₃ are attached, said heterocyclic group optionally being substituted with 1-3 identical or different R ₄.

2. The compound, stereoisomer or pharmaceutically acceptable salt thereof according to claim 1, wherein the compound has a structural formula as shown in formula II,

R ₂ and R ₃ are identical or different and are each independently selected from (C ₁-C₄) alkyl, (C ₃-C₆) cycloalkyl, which may optionally be substituted by 1 to 3 identical or different R ₄,

3. A compound, stereoisomer or pharmaceutically acceptable salt thereof according to claim 1,

R ₂ and R ₃ are the same or different and are each independently selected from:

H、

4. A compound, stereoisomer, or pharmaceutically acceptable salt thereof, wherein the compound is selected from the group consisting of:

5. The compound, stereoisomer, or pharmaceutically acceptable salt thereof according to any one of claims 1-4, wherein the pharmaceutically acceptable salt is a salt of the compound with an acid selected from the group consisting of hydrochloric acid, hydrobromic acid, sulfuric acid, phosphoric acid, nitric acid, formic acid, acetic acid, propionic acid, oxalic acid, malonic acid, succinic acid, fumaric acid, maleic acid, lactic acid, malic acid, tartaric acid, citric acid, methanesulfonic acid, ethanesulfonic acid, toluenesulfonic acid, benzenesulfonic acid, naphthalenesulfonic acid, trifluoroacetic acid, and aspartic acid.

6. A pharmaceutical composition comprising a compound, stereoisomer or pharmaceutically acceptable salt thereof according to any one of claims 1 to 4 as active ingredient and a pharmaceutically acceptable excipient.

7. Use of a compound, stereoisomer or a pharmaceutically acceptable salt thereof according to any one of claims 1 to 4 in the manufacture of a medicament for the prevention and/or treatment of an infection by a microorganism which is anaerobic streptococcus mutans or clostridium perfringens.