5,6-dihydroxypyrimidine compound and preparation method and application thereof

Abstract

The present application relates to a kind of 5,6-dihydroxy pyrimidine compounds shown in formula I and its preparation method and its application in antibacterial biofilm formation.The 5,6-dihydroxy pyrimidine compounds involved in the present application are verified by in vivo and in vitro drug efficacy, and most of the obtained compounds have excellent bacterial biofilm and bacterial iron uptake inhibition activity, can be used for preparing broad-spectrum antibiotic synergist, can enhance the antibacterial effect of existing antibiotics.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of medicine, and particularly relates to a 5,6-dihydroxy pyrimidine compound, a preparation method thereof and application thereof in preparing antibacterial drugs. BACKGROUND

[0002] Epidemiological studies have shown that antibiotic resistance is the leading cause of infectious deaths worldwide, with the number of deaths far exceeding that of HIV / AIDS and malaria. According to statistics, hundreds of thousands of people die of antibiotic resistance every year, and children and newborns are particularly vulnerable to drug-resistant bacteria. One-fifth of antibiotic-resistant deaths occur in children under the age of five, and as many as 3 million newborns suffer from severe infections every year, leading to sepsis. The long-term existence of antibiotic resistance leads to prolonged hospitalization of patients and greater economic burden on infected patients. If effective antibiotics are lacking, this will lead to a more serious global public health crisis. Therefore, there is an urgent need to develop new strategies to curb the development of antibiotic resistance.

[0003] Currently, the most difficult to treat hospital infections are caused by gram-negative bacteria, which persistently infect and lead to antibiotic resistance. The formation of bacterial biofilms is one of the main causes of persistent infection, and medical device and tissue-related biofilms can lead to failure of antibiotic therapy and can cause many chronic infections. Biofilms play a key role in the survival and persistence of pathogenic microorganisms, enabling them to escape host immune responses and antibacterial therapy. Biofilm-related bacteria develop resistance to antibacterial drugs due to a variety of mechanisms, including low metabolic rate, protection by biofilm matrix, and development of specific resistance mechanisms in individual cells. Clinical studies have shown that biofilm infections can be treated with traditional antibiotics and biofilm-destroying substances in combination, and have shown excellent prospects for treatment. However, current biofilm inhibitor research is still in the clinical research stage, and cannot be marketed due to reasons such as therapeutic dose and treatment instability. Therefore, the development of new antibiofilm drugs is of great significance in overcoming antibiotic resistance. On the other hand, iron is an essential trace element for bacteria, and in addition to maintaining normal physiological activity, the availability of iron ions has been shown to be involved in the development of bacterial resistance. Inhibiting iron uptake by bacteria and reducing the availability of iron within bacteria can increase the sensitivity of bacteria to traditional antibiotics and curb the development of antibiotic resistance. Current research in this area has made some progress, and the Pasteur Institute's gentamicin and EDTA combination has entered clinical research. However, EDTA as a potent iron chelator has strong toxic side effects, limiting its therapeutic effect.

[0004] Therefore, in the field of anti-biofilm drug resistance, it is still necessary to develop more effective treatment strategies. The present application combines anti-biofilm and iron uptake strategies to develop a dual-effect inhibitor, which is expected to be used to reduce the occurrence of bacterial antibiotic resistance. SUMMARY

[0005] In order to overcome the above-mentioned shortcomings and deficiencies of the prior art, the present application finds a class of 5,6-dihydroxy pyrimidine compounds, which have stable chemical structure, and through activity experiment verification, have the effects of anti-biofilm and anti-iron uptake, and have the potential to become a new type of antibiotic synergist.

[0006] Another object of the present application is to provide a preparation method of the above-mentioned 5,6-dihydroxy pyrimidine compound.

[0007] Still another object of the present application is to provide the application of the above-mentioned 5,6-dihydroxy pyrimidine compound as an anti-biofilm drug, an anti-bacterial iron uptake drug or an antibiotic synergist.

[0008] The object of the present application is achieved by the following scheme:

[0009] In one aspect, the present application provides a class of 5,6-dihydroxy pyrimidine compounds or pharmaceutically acceptable salts, medically acceptable tautomers, meso forms, racemates, stereoisomers, metabolites, metabolic precursors, prodrugs or solvates thereof, characterized by having a chemical structure as shown in formula I:

[0010]

[0011] wherein R1 is selected from one of C1-C4 straight chain or branched chain saturated or unsaturated hydrocarbon group, aryl group, benzyl group, 5-6 membered heteroaryl group;

[0012] R2 is selected from one of C3-C6 straight chain or branched chain saturated or unsaturated hydrocarbon group, C3-C6 cycloalkyl group, 3-6 membered heterocyclic group, aryl group, aryl ethyl group, aryl sulfonyl group, 5-6 membered heteroaryl group, 5-6 membered heteroaryl methyl group.

[0013] R3 is selected from one of halogen, hydroxyl group, amino group, cyano group, C1-C3 straight chain or branched chain saturated or unsaturated hydrocarbon group, C1-C3 straight chain or branched chain saturated or unsaturated alkoxy group, trifluoromethyl group, trifluoromethoxy group, aryl group, aryloxy group.

[0014] In the present application, the "straight chain or branched chain saturated or unsaturated hydrocarbon group" includes C1-C4 alkyl group or C1-C3 alkyl group, such as methyl group, ethyl group, propyl group, butyl group, etc.

[0015] In the present application, the aryl group includes phenyl group, naphthyl group, etc.

[0016] In the present application, the heteroaryl group includes pyrrolyl, imidazolyl, oxazolyl, thiazolyl, thienyl, furanyl, triazolyl, isoxazolyl, isothiazolyl, pyrazolyl, pyridyl, pyrimidyl, triazinyl, and the like.

[0017] In the present application, the heterocyclic group includes tetrahydropyrrolyl, tetrahydrofuranyl, tetrahydrothienyl, piperidyl, piperazinyl, and the like.

[0018] The 5,6-dihydroxypyrimidine compound of the present application can inhibit the formation of Pseudomonas aeruginosa biofilm and disrupt the iron homeostasis of the bacteria, and can be used for the preparation of a biofilm inhibitor and an iron uptake inhibitor, and has the effect of enhancing the efficacy of antibiotics.

[0019] Preferably, the 5,6-dihydroxypyrimidine compound or its pharmaceutically acceptable salt, medically acceptable tautomer, mesomer, racemate, stereoisomer, metabolite, metabolic precursor, prodrug, or solvate is characterized in that the compound is selected from:

[0020]

[0021]

[0022]

[0023]

[0024] Preferably, the pharmaceutically acceptable salt of the 5,6-dihydroxypyrimidine compound is an acid addition salt or a base addition salt of the 5,6-dihydroxypyrimidine compound. It includes but is not limited to: hydrochloride, hydrobromide, hydroiodide, phosphate, sulfate, nitrate, ethanesulfonate, toluenesulfonate, benzenesulfonate, acetate, maleate, tartrate, succinate, citrate, benzoate, ascorbate and salicylate, malonate, adipate, hexanoate, arginate, fumarate, nicotinate, phthalate, oxalate, lithium salt, sodium salt, potassium salt, barium salt, calcium salt, magnesium salt, aluminum salt, iron salt, ferrous salt, copper salt, zinc salt, or a salt of the 5,6-dihydroxypyrimidine compound with morpholine, diethylamine, triethylamine, isopropylamine, trimethylamine, lysine or histidine, or a combination of any one or at least two of the above.

[0025] In another aspect, the present application provides a method for preparing the 5,6-dihydroxypyrimidine compound, characterized in that it comprises the following steps:

[0026] Step (1.1) N-hydroxyacetamidine or N-hydroxyisobutyramidine or N-hydroxybenzamidine and dimethyl acetylenedicarboxylate were dissolved in methanol, the reaction was carried out at 0°C, and then methanol was removed and the reaction was carried out by refluxing in xylene. After the reaction was completed, the reaction solution was purified to obtain compound 1.

[0027] Step (1.2) Compound 1, benzyl bromide and potassium carbonate were placed in acetonitrile solvent and reacted at 80°C to obtain compound 2.

[0028] Step (1.3) Compound 2 and aqueous lithium hydroxide solution were placed in methanol solvent and reacted at 40°C to obtain compound 3.

[0029] Step (1.4) Compound 3, amine compound, benzotriazol-1-yl-oxytris-pyrrolidino-phosphonium hexafluorophosphate (PyBop) and N,N-diisopropylethylamine (DIPEA) were placed in tetrahydrofuran (THF) solvent and reacted at room temperature to obtain compound 4.

[0030] Step (1.5) Compound 4 was dissolved in methanol, and palladium-carbon catalyst was added, and hydrogen was introduced to react at room temperature to obtain compound 5.

[0031] The synthetic route is as follows:

[0032]

[0033] Preferably, the reaction conditions are: (1.1) MeOH, Xylene, 0→135°C, 16h; (1.2) K2CO3, CH3CN, 80°C, 6h; (1.3) LiOH, H2O, MeOH, 40°C, 6h; (1.4) amino compound, PyBop, DIPEA, THF, rt, 4h; (1.5) H2, Pd / C, MeOH, rt, 6h.

[0034] In yet another aspect, the present application provides use of the above-mentioned 5,6-dihydroxypyrimidine compound or a pharmaceutically acceptable salt, a medically acceptable tautomer, a mesomer, a racemate, a stereoisomer, a metabolite, a metabolic precursor, a prodrug or a solvate thereof in the preparation of an anti-biofilm drug, an anti-bacterial iron uptake drug or an antibiotic potentiator.

[0035] Preferably, the biofilm is a bacterial biofilm. More preferably, the bacteria is Pseudomonas aeruginosa.

[0036] Preferably, the antibiotic is used to inhibit Pseudomonas aeruginosa.

[0037] In yet another aspect, the use of the 5,6-dihydroxy pyrimidine compound or its pharmaceutically acceptable salt, medically acceptable tautomer, mesomer, racemate, stereoisomer, metabolite, metabolic precursor, prodrug or solvate in the preparation of an anti-biofilm drug, an anti-bacterial iron uptake drug or an antibiotic potentiator is provided, characterized in that the drug further comprises one or more pharmaceutically acceptable carriers or excipients.

[0038] Preferably, the bacteria is a bacterium, more preferably Pseudomonas aeruginosa.

[0039] In yet another aspect, the present application provides a pharmaceutical composition comprising at least one of the 5,6-dihydroxy pyrimidine compound or its pharmaceutically acceptable salt, medically acceptable tautomer, mesomer, racemate, stereoisomer, metabolite, metabolic precursor, prodrug or solvate according to any one of claims 1-3.

[0040] Preferably, the drug further comprises one or more pharmaceutically acceptable carriers or excipients.

[0041] In yet another aspect, the present application provides a combination drug comprising at least one of the 5,6-dihydroxy pyrimidine compound or its pharmaceutically acceptable salt, medically acceptable tautomer, mesomer, racemate, stereoisomer, metabolite, metabolic precursor, prodrug or solvate and ciprofloxacin.

[0042] Preferably, the mass ratio of the 5,6-dihydroxy pyrimidine compound or its pharmaceutically acceptable salt, medically acceptable tautomer, mesomer, racemate, stereoisomer, metabolite, metabolic precursor, prodrug or solvate to ciprofloxacin is 50:0.5-20, preferably 50:1-10.

[0043] The present application has the following advantages and beneficial effects over the prior art:

[0044] (1) The present application starts from the dihydroxy pyrimidine structure with chelating properties, and invents a 5,6-dihydroxy pyrimidine compound with stable chemical properties through structural modification. The compound is detected by crystal violet staining method to inhibit the biofilm formation of Pseudomonas aeruginosa. Compared with the current clinical research, the compound can significantly inhibit the formation of biofilm at a lower concentration, which is expected to reduce the dosage.

[0045] (2) The present application identifies the total iron content in bacteria, and the 5,6-dihydroxy pyrimidine compound can effectively reduce the total iron content in bacteria, reduce the availability of bacterial iron, and disturb the iron homeostasis of bacteria.

[0046] (3) The present application uses animal models to determine the optimal antibiotic synergistic effect of the compound, and determines the antibacterial biofilm effect and antibiotic synergistic effect of the 5,6-dihydroxypyrimidine compound described in the present application, and the results show that the compound has good synergistic activity. It is expected to be further developed as an antibacterial synergist.

[0047] The present application will be further described below in conjunction with the specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0048] Figure 1 For the interference of compound W13 on the iron uptake system of Pseudomonas aeruginosa PAO1, the total iron content in the bacteria is reduced due to iron deficiency.

[0049] Figure 2 For the synergistic effect of compound W13 on ciprofloxacin. (A) Bacterial survival rate in the wound infection area of mice. *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001; (B) Monitoring of the wound area of mice, and calculating the wound area using Image J. DETAILED DESCRIPTION

[0050] The present application will be further described below in conjunction with the specific embodiments.

[0051] The reagents used in the examples can be commonly purchased from the market unless otherwise specified.

[0052] Example 1: Preparation of 5,6-bis(benzyloxy)-2-methylpyrimidine-4-carboxylic acid (intermediate 3a-3c)

[0053] Step one: Preparation of 5,6-dihydroxy-2-methylpyrimidine-4-carboxylic acid methyl ester (intermediate 1)

[0054]

[0055] N-hydroxyacetamidine (0.1 mol) was dissolved in methanol, stirred in an ice water bath, then dimethyl acetylenedicarboxylate (0.11 mol) was added dropwise, and the reaction was continued for about 1 h after the solvent was added. The reaction was terminated, and the residual organic solvent in the reaction system was removed. Then the product was dissolved in xylene and stirred at 135℃ for 16 h. The reaction was terminated, then recrystallized with a cold methyl tert-butyl ether / methanol solution (9:1), and filtered under reduced pressure to obtain a light brown solid as intermediate 1 with a yield of 65%. 1 HNMR (400 MHz, DMSO-d6) δ 12.70 (s, 1H), 10.12 (s, 1H), 3.80 (s, 3H), 2.20 (s, 3H). 13C NMR (101 MHz, DMSO) δ 166.75, 159.42, 148.06, 145.29, 128.94, 52.57, 20.88.

[0056] Step two: Preparation of 5,6-bis(benzyloxy)-2-methylpyrimidine-4-carboxylic acid (Intermediate 3a)

[0057]

[0058] Intermediate 1 (0.1 mol) was dissolved in 100 mL of two-necked flask with an appropriate amount of anhydrous acetonitrile, and benzyl bromide (0.24 mol) was added under stirring. The temperature was raised to 80 °C, and the reaction was continued for about 6 h. The reaction was stopped, and the organic phase was extracted with 100 mL x 3 ethyl acetate, and then washed with 100 mL x 3 saturated NH4Cl solution and 100 mL x 3 saturated NaCl solution until the effluent water layer was neutral. After being dried with MgSO4, the solvent was removed by filtration, and the residue was purified by flash chromatography (petroleum ether-ethyl acetate = 80 / 20 v / v) to obtain white solid intermediate 2 with a yield of 60%. 1 H NMR (400 MHz, Chloroform-d) δ 7.45 - 7.40 (m, 2H), 7.29 (h, J = 6.2 Hz, 6H), 7.10 - 7.04 (m, 2H), 5.29 (s, 2H), 5.25 (s, 2H), 3.84 (s, 3H), 2.40 (s, 3H). 13 C NMR (101 MHz, CDCl3) δ 164.53, 160.08, 154.41, 142.40, 140.99, 136.37, 134.49, 129.08, 128.94, 128.43, 128.07, 126.61, 74.37, 52.83, 47.85, 22.97. Intermediate 2 (0.1 mol) was dissolved in methanol solution, and LiOH (0.2 mol) aqueous solution was added, and the reaction was stirred at 40 °C for 6 h. The reaction was stopped, and the pH was adjusted to 5 using hydrochloric acid (6N), and a solid was precipitated, which was filtered to obtain light brown solid intermediate 3a with a yield of 70%. The preparation methods of intermediates 3b and 3c were the same as 3a.

[0059] Example 2: 5,6-Dihydroxy-2-methyl-N-(4-phenylbutan-2-yl)pyrimidine-4-carboxamide (Compound W1)

[0060]

[0061] To a solution of intermediate 3a (1.0 mmol) in tetrahydrofuran, benzotriazole-1- yloxytris-pyrrolidino-phosphonium hexafluorophosphate (PyBop, 1.5 mmol) and N,N- diisopropylethylamine (DIPEA, 2.0 mmol) were added, followed by 4-phenyl-2- butylamine (1.2 mmol). The reaction was stirred for 4 h, then quenched. The reaction mixture was extracted with 30 mL x 3 ethyl acetate, washed with 30 mL x 3 saturated NaHCO3, 30 mL x 3 saturated NH4Cl and 100 mL x 3 saturated NaCl until the water layer was neutral. The organic phase was dried over MgSO4, filtered and the solvent was removed. The residue was purified by flash chromatography (petroleum ether-ethyl acetate = 60 / 40 v / v) to give intermediate 4 as a white solid. Intermediate 4 was dissolved in methanol and 0.02 eq. palladium on carbon was added. The reaction was stirred at room temperature under H2for 6 h, then quenched and filtered to remove the palladium on carbon. The filtrate was concentrated and recrystallized from petroleum ether-ethyl acetate to give compound W1 as a white solid in 58% yield. 1 HNMR (400 MHz, DMSO-d6) δ 12.55 (d, J = 20.2 Hz, 2H), 8.49 (d, J = 8.8 Hz, 1H), 7.21 (dq, J = 18.1, 9.6, 8.6 Hz, 5H), 4.01 (s, 1H), 2.67 - 2.53 (m, 2H), 2.26 (s, 3H), 2.01 - 1.71 (m, 2H), 1.19 (d, J = 6.6 Hz, 3H). 13 C NMR (101 MHz, DMSO) δ 168.37, 158.57, 148.22, 147.70, 142.05, 128.72 (2C), 128.69 (2C), 127.28, 126.17, 44.98, 37.44, 32.47, 20.98, 20.72.

[0062] Example 3: 2-(5,6-dihydroxy-2-methylpyrimidine-4-carboxamido)thiazole-4- carboxylic acid ethyl ester (compound W2)

[0063] Using intermediate 3a (1.0 mmol) and 2-aminothiazole-4-carboxylic acid ethyl ester (1.2 mmol) as starting materials, the procedure described for compound W1 was followed to give compound W2 as a light brown solid in 61% yield. 1 H NMR (400 MHz, DMSO-d6) δ 13.66 (d, J = 541.8 Hz, 3H), 8.10 (s, 1H), 4.29 (q, J = 7.1 Hz, 2H), 2.37 (s, 3H), 1.30 (q, J = 5.7, 4.4 Hz, 3H). 13C NMR (101 MHz, DMSO) δ 169.19, 161.37, 158.61, 157.71, 148.38, 147.49, 141.65, 127.32, 123.73, 61.11, 20.90, 14.65.

[0064] Example 4: 5,6-Dihydroxy-2-isopropyl-N-(2-(5-methoxy-lH-indol-3- yl)ethyl)pyrimidine-4-carboxamide (Compound W3)

[0065] Using intermediate 3b (1.0 mmol) and 5-methoxytryptamine (1.2 mmol) as starting materials, the preparation method refers to Compound Wl, Compound W3 was obtained as a white solid in 61% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.48 (d, J = 31.3 Hz, 2H), 10.70 (s, 1H), 8.67 (s, 1H), 7.23 (d, J = 8.7 Hz, 1H), 7.16 (s, 1H), 7.08 (s, 1H), 6.72 (d, J = 8.7 Hz, 1H), 3.74 (s, 3H), 3.56 (s, 2H), 2.94 (s, 2H), 2.75 (s, 1H), 1.17 (d, J = 6.9 Hz, 6H). 13 C NMR (101 MHz, DMSO) δ 168.94, 158.75, 155.76, 153.50, 147.63, 131.90, 127.94, 127.12, 123.92, 112.50, 111.59, 111.49, 100.74, 55.78, 32.97, 25.28, 20.77.

[0066] Example 5: N-(Cyclohexylmethyl)-5,6-dihydroxy-2-methylpyrimidine-4- carboxamide (Compound W4)

[0067] Using intermediate 3a (1.0 mmol) and cyclohexylmethylamine (1.2 mmol) as starting materials, the preparation method refers to Compound Wl, Compound W4 was obtained as a white solid in 69% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.54 (d, J = 22.1 Hz, 2H), 8.71 (t, J = 6.4 Hz, 1H), 3.11 (t, J = 6.7 Hz, 2H), 2.24 (s, 3H), 1.63 (q, J = 15.4, 12.7 Hz, 6H), 1.16 (t, J = 11.4 Hz, 3H), 0.90 (q, J = 11.3 Hz, 2H). 13C NMR (101 MHz, DMSO) δ 168.97, 158.56, 148.25, 147.59, 127.28, 45.09, 37.74, 30.80 (2C), 26.44, 25.77 (2C), 20.98.

[0068] Example 6: 5,6-Dihydroxy-2-methyl-N-(pyridin-3-ylmethyl)pyrimidine-4- carboxamide (Compound W5)

[0069] Using intermediate 3a (1.0 mmol) and 3-aminomethylpyridine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W5 as a white solid in 63% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.58 (d, 2H), 9.51 (t, J = 6.3 Hz, 1H), 8.89 - 8.74 (m, 2H), 8.43 (dt, J = 8.1, 1.7 Hz, 1H), 7.96 (dd, J = 8.1, 5.5 Hz, 1H), 4.64 (d, J = 6.3 Hz, 2H), 2.26 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.30, 158.52, 148.60, 147.69, 144.31, 142.32, 141.99, 138.50, 127.04, 127.00, 40.61, 20.93.

[0070] Example 7: N-(4-Fluorophenethyl)-5,6-dihydroxy-2-methylpyrimidine-4- carboxamide (Compound W6)

[0071] Using intermediate 3a (1.0 mmol) and 4-fluorophenethylamine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W6 as a white solid in 67% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.58 (s, 1H), 12.40 (s, J = 3.4 Hz, 1H), 8.89 - 8.72 (m, 1H), 7.25 (tq, J = 7.8, 4.8, 3.6 Hz, 2H), 7.11 (tp, J = 10.0, 3.5 Hz, 2H), 3.53 - 3.42 (m, 2H), 2.84 (td, J = 7.6, 3.0 Hz, 2H), 2.23 (s, J = 3.2 Hz, 3H). 13 C NMR (101 MHz, DMSO) δ 168.92, 161.35 (d, 1 J C-F= 241.4 Hz), 158.52, 148.29, 147.60, 135.60, 130.90, 130.82, 127.21, 115.65, 115.44, 40.59, 34.35, 20.98.

[0072] Example 8: N-(4-chlorophenethyl)-5,6-dihydroxy-2-phenylpyrimidine-4- carboxamide (Compound W7)

[0073] Using intermediate 3c (1.0 mmol) and 4-chlorophenethylamine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W7 as a white solid in 70% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.72 (d, 2H), 9.08 (s, 1H), 8.20 (d, J = 7.0 Hz, 2H), 7.51 (d, J = 7.6 Hz, 3H), 7.37 (d, J = 7.9 Hz, 2H), 7.30 (d, J = 8.1 Hz, 2H), 3.55 (q, J = 7.1 Hz, 2H), 2.90 (t, J = 7.4 Hz, 2H). 13 C NMR (101 MHz, DMSO) δ 168.94, 159.17, 148.42, 146.54, 138.52, 131.37, 131.02, 129.82, 128.91, 128.83 (2C), 128.56 (2C), 127.88 (2C), 126.68 (2C), 40.61, 34.60.

[0074] Example 9: 5,6-dihydroxy-N-(3-methoxybenzyl)-2-methylpyrimidine-4- carboxamide (Compound W8)

[0075] Using intermediate 3a (1.0 mmol) and 3-methoxybenzylamine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W8 as a white solid in 71% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.59 (s, 1H), 12.32 (s, 1H), 9.28 (t, J = 6.3 Hz, 1H), 7.24 (t, J = 8.0 Hz, 1H), 6.93 - 6.78 (m, 3H), 4.43 (d, J = 6.2 Hz, 2H), 3.73 (s, 3H), 2.25 (s, 3H). 13C NMR (101 MHz, DMSO) δ 169.01, 159.74, 158.53, 148.38, 147.68, 140.61, 129.91, 127.30, 120.10, 113.85, 112.71, 55.46, 42.57, 20.99.

[0076] Example 10: 5,6-Dihydroxy-N-(4-(2-hydroxyethyl)phenyl)-2-methylpyrimidine-4- carboxamide (Compound W9)

[0077] Using intermediate 3a (1.0 mmol) and 2-(4-aminophenyl)-1-ethanol (1.2 mmol) as starting materials, the procedure described for Compound W1 was followed to give Compound W9 as a white solid in 62% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.78 (d, 2H), 10.39 (s, 1H), 7.64 (dd, J = 8.8, 2.4 Hz, 2H), 7.21 (dd, J = 8.7, 2.4 Hz, 2H), 5.31 (s, 1H), 3.59 (t, J = 7.0 Hz, 2H), 2.70 (t, J = 7.0 Hz, 2H), 2.33 (d, J = 2.3 Hz, 3H). 13 C NMR (101 MHz, DMSO) δ 166.59, 158.78, 148.59, 148.09, 136.70, 135.33, 129.60 (2C), 126.92, 121.46 (2C), 62.56, 38.94, 20.67.

[0078] Example 11: 5,6-Dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W10)

[0079] Using intermediate 3a (1.0 mmol) and L-tyrosine methyl ester (1.2 mmol) as starting materials, the procedure described for Compound W1 was followed to give Compound W10 as a white solid in 55% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.20 (d, 2H), 9.25 (d, J = 8.1 Hz, 1H), 7.28 (s, 1H), 6.99 (d, J = 8.0 Hz, 2H), 6.66 (d, J = 7.9 Hz, 2H), 4.69 (q, J = 7.3 Hz, 1H), 3.66 (s, 3H), 3.09 (d, J = 6.8 Hz, 2H), 2.26 (s, 3H). 13C NMR (101 MHz, DMSO) 5 171.49, 158.58, 156.59, 149.15, 147.55, 131.37, 130.50 (2C), 127.08, 126.06, 115.69 (2C), 53.83, 52.68, 35.74, 20.70.

[0080] Example 12: N-(2-(benzo[d][l,3]dioxol-5-yl)ethyl)-5,6-dihydroxy-2- isopropylpyrimidine-4-carboxamide (Compound Wl l)

[0081] Using intermediate 3a (1.0 mmol) and piperonylamine (1.2 mmol) as starting materials, the preparation method refers to Compound Wl, Compound Wl l was obtained as a white solid in 63% yield. 1 H NMR (400 MHz, DMSO-d6) 5 12.57 (s, 1H), 12.37 (s, 1H), 8.83 - 8.69 (m, 1H), 6.93 - 6.74 (m, 2H), 6.67 (dt, J = 7.8, 2.0 Hz, 1H), 5.96 (d, J = 2.0 Hz, 2H), 3.45 (q, J = 8.2, 7.3 Hz, 2H), 2.82 - 2.69 (m, 2H), 2.23 (d, J = 2.2 Hz, 3H). 13 C NMR (101 MHz, DMSO) 5 168.88, 158.53, 148.30, 147.71, 147.59, 146.08, 133.21, 127.22, 121.97, 109.42, 108.64, 101.16, 40.75, 34.89, 20.99.

[0082] Example 13: N-(4-benzoylphenyl)-5,6-dihydroxy-2-isopropylpyrimidine-4- carboxamide (Compound Wl 2)

[0083] Using intermediate 3b (1.0 mmol) and 4-aminobenzophenone (1.2 mmol) as starting materials, the preparation method refers to Compound Wl, Compound Wl 2 was obtained as a white solid in 65% yield. 1 H NMR (400 MHz, DMSO-d6) 5 12.63 (s, 1H), 11.77 (s, 1H), 10.10 (s, 1H), 7.64 (d, J = 8.4 Hz, 2H), 7.31 - 7.17 (m, 7H), 2.83 (p, J = 6.9 Hz, 1H), 1.30 - 1.20 (m, 6H). 13C NMR (101 MHz, DMSO) δ 167.17, 158.79, 156.00, 147.68, 141.72, 138.59, 135.12, 129.45, 129.11, 128.90, 127.52, 126.45, 122.07, 33.20, 21.07, 20.74.

[0084] Example 14: N-(3-fluorobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W13)

[0085] Using intermediate 3a (1.0 mmol) and 3-fluorobenzylamine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W13 as a light brown solid in 71% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.60 (s, 1H), 12.23 (s, 1H), 9.38 (t, J = 6.4 Hz, 1H), 7.38 (td, J = 7.9, 6.2 Hz, 1H), 7.19 - 7.04 (m, 3H), 4.47 (d, J = 6.5 Hz, 2H), 2.25 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.15, 162.61 (d, 1 J C-F = 243.6 Hz), 158.52, 148.41, 147.69, 142.04 (d, 3 J C-F = 7.2 Hz), 130.79 (d, 5 J C-F = 8.4 Hz), 127.26, 123.95 (d, 4 J C-F = 2.7 Hz), 114.65 (d, 6 J C-F = 21.7 Hz), 114.26 (d, 2 J C-F = 21.0 Hz), 42.17, 21.00.

[0086] Example 15: 5,6-dihydroxy-2-methyl-N-(3-(trifluoromethyl)benzyl)pyrimidine-4- carboxamide (Compound W14)

[0087] Using intermediate 3a (1.0 mmol) and 3-trifluoromethylbenzylamine (1.2 mmol) as starting materials, the procedure of Compound W1 was followed to give Compound W14 as a white solid in 77% yield. 1H NMR (400 MHz, DMSO-d6) δ 12.60 (s, 1H), 12.20 (s, 1H), 9.45 (t, J = 6.4 Hz, 1H), 7.68 (s, 1H), 7.63 (d, J = 7.9 Hz, 2H), 7.58 (d, J = 7.4 Hz, 1H), 4.54 (d, J = 6.3 Hz, 2H), 2.25 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.23, 158.51, 148.45, 147.71, 140.60, 132.20, 129.93, 129.64, 129.33, 127.22, 126.05, 124.62, 124.58, 124.28, 124.24, 123.34, 42.28, 21.00.

[0088] Example 16: N-(2-fluorobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W15)

[0089] The starting material was intermediate 3a (1.0 mmol) and 2-fluorobenzylamine (1.2 mmol), and the preparation method referred to Compound W1 to obtain Compound W15 as a white solid in a yield of 67%. 1 H NMR (400 MHz, DMSO-d6) δ 12.61 (s, 1H), 12.20 (s, 1H), 9.27 (t, J = 6.4 Hz, 1H), 7.33 (dt, J = 11.5, 6.4 Hz, 2H), 7.22 - 7.14 (m, 2H), 4.52 (d, J = 6.2 Hz, 2H), 2.25 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.16, 160.41 (d, 1 J C-F = 244.7 Hz), 158.52, 148.45, 147.66, 129.95 (d, 3 J C-F = 4.2 Hz), 129.56 (d, 5 J C-F = 8.2 Hz), 127.22, 125.61 (d, 2 J C-F = 14.6 Hz), 124.85 (d, 4 J C-F = 3.4 Hz), 115.60 (d, 6 J C-F = 21.2 Hz), 36.46 (d, J = 4.8 Hz), 21.00.

[0090] Example 17: N-(4-chlorobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W16)

[0091] Using intermediate 3a (1.0 mmol) and 4-chlorobenzylamine (1.2 mmol) as starting materials, the procedure of compound W1 was followed to give compound W16 as a white solid in 69% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.41 (d, J = 90.6 Hz, 2H), 9.37 (t, J = 6.4 Hz, 1H), 7.45 - 7.27 (m, 4H), 4.44 (d, J = 6.5 Hz, 2H), 2.25 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.10, 158.52, 148.39, 147.72, 138.14, 132.05, 129.87 (2C), 128.76 (2C), 127.23, 42.01, 20.98.

[0092] Example 18: N-(4-bromobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W17)

[0093] Using intermediate 3a (1.0 mmol) and 4-bromobenzylamine (1.2 mmol) as starting materials, the procedure of compound W1 was followed to give compound W17 as a white solid in 68% yield. 1 H NMR (400 MHz, DMSO-d6) δ 12.60 (s, 1H), 12.26 (s, 1H), 9.37 (t, J = 6.5 Hz, 1H), 7.52 (d, J = 8.0 Hz, 2H), 7.28 (d, J = 8.0 Hz, 2H), 4.42 (d, J = 6.4 Hz, 2H), 2.25 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.12, 158.51, 148.41, 147.71, 138.56, 131.68 (2C), 130.23 (2C), 127.24, 120.53, 42.07, 21.00.

[0094] Example 19: N-(4-cyanobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W18)

[0095] Using intermediate 3a (1.0 mmol) and 4-cyanobenzylamine (1.2 mmol) as starting materials, the procedure of compound W1 was followed to give compound W18 as a white solid in 58% yield. 1H NMR (400 MHz, DMSO-d6) δ 12.62 (s, 1H), 12.16 (s, 1H), 9.45 (t, J = 6.4 Hz, 1H), 7.80 (d, J = 7.9 Hz, 2H), 7.50 (d, J = 7.9 Hz, 2H), 4.53 (d, J = 6.3 Hz, 2H), 2.26 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.31, 158.51, 148.47, 147.70, 144.91, 132.80 (2C), 128.72 (2C), 127.21, 119.31, 110.22, 42.45, 21.01.

[0096] Example 20: N-(3-chlorobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W19)

[0097] Using intermediate 3a (1.0 mmol) and 3-chlorobenzylamine (1.2 mmol) as starting materials, the preparation method refers to Compound W1, Compound W20 was obtained as a white solid in a yield of 63%. 1 H NMR (400 MHz, DMSO-d6) δ 12.62 (s, 1H), 12.16 (s, 1H), 9.45 (t, J = 6.4 Hz, 1H), 7.80 (d, J = 7.9 Hz, 2H), 7.50 (d, J = 7.9 Hz, 2H), 4.53 (d, J = 6.3 Hz, 2H), 2.26 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.31, 158.51, 148.47, 147.70, 144.91, 132.80 (2C), 128.72 (2C), 127.21, 119.31, 110.22, 42.45, 21.01.

[0098] Example 21: 5,6-dihydroxy-N-(4-isopropylbenzyl)-2-methylpyrimidine-4-carboxamide (Compound W20)

[0099] Using intermediate 3a (1.0 mmol) and 4-isopropylbenzylamine (1.2 mmol) as starting materials, the preparation method refers to Compound W1, Compound W22 was obtained as a white solid in a yield of 75%. 1H NMR (400 MHz, DMSO-d6) δ 12.59 (s, 1H), 12.35 (s, 1H), 9.26 (t, J = 6.4 Hz, 1H), 7.27 - 7.15 (m, 4H), 4.41 (d, J = 6.4 Hz, 2H), 2.85 (p, J = 6.9 Hz, 1H), 2.24 (s, 3H), 1.18 (d, J = 6.9 Hz, 6H). 13 C NMR (101 MHz, DMSO) δ 168.92, 13 C NMR (101 MHz, DMSO) δ 168.92, 167.17, 158.53, 148.35, 147.69, 136.45, 128.09 (2C), 127.31, 126.71 (2C), 42.37, 33.59, 24.38 (2C), 20.98.

[0100] Example 22: N-([1,1'-Biphenyl]-4-ylmethyl)-5,6-dihydroxy-2-methylpyrimidine-4- carboxamide (Compound W21)

[0101] Using intermediate 3a (1.0 mmol) and 4-phenylbenzylamine (1.2 mmol) as starting materials, the preparation method refers to Compound W1, Compound W23 was obtained as a white solid in a yield of 73%. 1 H NMR (400 MHz, DMSO-d6) δ 12.48 (d, J = 99.0 Hz, 2H), 9.37 (t, J = 6.6 Hz, 1H), 7.63 (t, J = 6.6 Hz, 4H), 7.48 - 7.40 (m, 4H), 7.35 (t, J = 7.3 Hz, 1H), 4.51 (d, J = 6.2 Hz, 2H), 2.26 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.07, 158.54, 148.40, 147.72, 140.40, 139.47, 138.30, 129.37 (2C), 128.61 (2C), 127.82, 127.60, 127.15 (2C), 127.06 (2C), 42.37, 20.99.

[0102] Example 23: N-(3,5-Dichlorobenzyl)-5,6-dihydroxy-2-methylpyrimidine-4-carboxamide (Compound W22)

[0103] Using intermediate 3a (1.0 mmol) and 3,5-dichlorobenzylamine (1.2 mmol) as starting materials, the preparation method refers to Compound W1, Compound W24 was obtained as a light brown solid in a yield of 69%. 1H NMR (400 MHz, DMSO-d6) δ 12.61 (s, 1H), 12.24 - 12.00 (m, 1H), 9.41 (t, J = 6.5 Hz, 1H), 7.49 (t, J = 1.9 Hz, 1H), 7.37 (d, J = 1.9 Hz, 2H), 4.45 (d, J = 6.2 Hz, 2H), 2.26 (s, 3H). 13 C NMR (101 MHz, DMSO) δ 169.26, 158.50, 148.46, 147.70, 143.46, 134.40 (2C), 127.21, 127.15, 126.80 (2C), 41.81, 21.01.

[0104] Example 24: Inhibition of Pseudomonas aeruginosa biofilm by compounds

[0105] Experimental method: First, prepare a compound premix solution with cell-grade DMSO, then dilute it with ABTGC medium to a certain concentration for standby. Dilute the Pseudomonas aeruginosa PAOl strain to OD 600 = 0.05 with ABTGC medium and add it to a 96-well plate, each well containing 75 μL of medium containing the compound and 75 μL of diluted bacteria solution. At the same time, set up a blank group (only medium) and a control group (only bacteria and a positive control group), with azithromycin as the positive control drug, and 6 replicate wells for each group of data. Place the plate in an incubator at 37°C for 24 hours, then wash each well with PBS 3 times to remove planktonic bacteria. Next, fix the 96-well plate with 160 μL of methanol at room temperature for 30 minutes, then air dry and dry. Then stain with 150 μL of 0.1% crystal violet for 30 min, dry, and wash with PBS buffer and dry. Then add 150 μL of 33% glacial acetic acid to each well to dissolve the crystal violet, shake well on a microshaker, and measure the absorbance at 570 nm using a microplate reader. All experiments were performed in triplicate, and compounds with biofilm inhibition activity were selected. The results of the biofilm inhibition activity experiment are shown in Table 1.

[0106] Biofilm inhibition rate calculation method:

[0107] Biofilm inhibition rate = [(control group OD值 - blank group OD值 ) - (sensitivity group OD值 - blank OD值 )] / (control group OD值 - blank group OD值 ) x 100%. The IC 50 of the compound is greater than 10 μM, marked as +; between 10 μM and 1 μM, marked as ++; between 1 μM and 0.1 μM, marked as +++.

[0108] Table 1 Inhibition of P. aeruginosa biofilm by all compounds

[0109]

[0110] a IC 50 = Concentration of inhibitor required to inhibit 50% biofilm formation. b IC 50 The screening concentration was 0.001-10 μM.

[0111] Experimental results: Most of the 5,6-dihydroxy pyrimidine compounds described in the present application can inhibit biofilm formation at a lower concentration, and the IC 50 of some compounds is less than 1 μM, which is better than the IC 50 value of the positive control drug azithromycin. Among them, compound W13 has the best activity, and the inhibition of biofilm IC 50 is 0.1 μM.

[0112] Example 25: Inhibition activity of compound W13 on total iron in P. aeruginosa

[0113] Experimental method: In this example, the total iron content of bacteria was detected by a microplate reader. PAOl was incubated overnight, then diluted to OD 600 0.05 in a 50 mL conical flask. Experimental and control groups (only bacteria and positive control group) were set up. The experimental group added a compound premix solution prepared by adding cell-level DMSO to the diluted bacterial solution, and the sample was incubated at 37°C with shaking (200 rpm) for 24 hours. A commercially available deferiprone (DFP) was used as a positive control drug, which is an oral iron chelator that has been marketed and has good iron chelation effect. Then, each group of bacterial cultures was centrifuged at 4000 rpm for 10 min, the precipitate was washed twice with 5 mL of HEPES buffer solution (Biosharp, China), and then centrifuged at 4000 rpm for 10 min. 5 mL (50 mM) of HEPES buffer solution was added to the precipitate, shaken well, and 800 μL of bacterial suspension was taken, 200 μL of lysozyme was added, vortexed, placed in an ice box for 10 min, and then centrifuged at 15000 rpm for 10 min. 80 μL of supernatant was taken to the corresponding well of the microplate, and 80 μL of reagent three reaction solution was added. Incubate at 37°C for 40 min, and measure the OD value of each well at 593 nm on the microplate reader.

[0114] Experimental results: As Figure 1 shown, compared with the commercially available iron chelator DFP, compound W13 can significantly reduce the total iron content in bacteria at a low concentration, indicating that the compound can effectively inhibit bacterial iron uptake and reduce the availability of iron in bacteria, and is expected to be used in antibacterial iron uptake drugs.

[0115] Example 26: Synergistic effect of compound W13 on ciprofloxacin (CIP) in a mouse wound infection model

[0116] Experimental method: 3-5 weeks old healthy female balb / c mice were purchased from SPF (Beijing) Biotechnology.co.Ltd. The animal experiment was conducted in accordance with the national animal experiment management regulations. Compound W13 was mixed with 0.1% Tween 80 and saline to the required concentration, and antibiotics (ciprofloxacin) were prepared in saline. First, 30 mice (5 in each group) were anesthetized with 4% chloral hydrate (intraperitoneal injection, 0.15 mL) and the back hair was shaved. A wound about 5 mm was made on the back of the mouse, and then 30 μL of PAOl (5 x 10 8 CFU, prepared with 0.9% saline solution) was inoculated on the wound surface. After 24 h of establishing the wound infection model, the wound was treated with 30 μL of normal saline, antibiotics alone or antibiotics combined with compound W13, and the drug was administered once every 24 h. After 3 days of continuous administration, the mice were sacrificed with isoflurane. Next, the skin about 7 mm in diameter at the wound site was taken and placed in a centrifuge tube containing 4 mm grinding beads and 1 mL of normal saline, homogenized with a grinder, and then CFU counting was performed on agar plates. The wound area of the mice was monitored by photography every day, and the wound area was calculated by ImageJ.

[0117] Experimental results: As shown in Figure 2 , after 3 days of continuous administration of mice, the bacteria in the wound of the combined administration treatment group mice were significantly reduced compared with the bacteria treated by normal saline (Control). By calculating the survival rate of bacteria at the wound site, the bacteria survival rate of the normal saline group was counted as 100%, and after 3 days of treatment with 1 mg / ml CIP, the bacteria were basically completely cleared. After treatment with 0.002 mg / ml CIP + 0.5 μM W13, there were very few surviving bacteria, indicating that the synergistic effect of W13 on CIP reached 500 times. The bacterial survival rate of the 0.001 mg / ml CIP + 0.5 μM W13 combined administration group was also relatively low compared with the Control group, only about 1%. Subsequently, the monitoring of the wound area of the mice also obtained consistent experimental results. After 3 days of combined administration of W13 and diluted CIP, the wound area was basically the same as that of the CIP administration group alone, and both were much smaller than that of the Control group. On the 9th day, the wound healing degree reached about 80%.

[0118] The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be noted that for those skilled in the art of the art, without departing from the principles of the present application, the present application can be improved and modified, and these improvements and modifications also fall within the scope of the claims of the present application.

Claims

1. A class of 5,6-dihydroxy pyrimidine compounds or pharmaceutically acceptable salts thereof, characterized in that, The compound is selected from the group consisting of:

2. The 5,6-dihydroxy pyrimidine compound or pharmaceutically acceptable salt thereof according to claim 1, characterized by, The pharmaceutically acceptable salt of the 5,6-dihydroxy pyrimidine compound is an acid addition salt or a base addition salt of the 5,6-dihydroxy pyrimidine compound, including: hydrochloride, hydrobromide, hydroiodide, phosphate, sulfate, nitrate, ethanesulfonate, toluenesulfonate, benzenesulfonate, acetate, maleate, tartrate, succinate, citrate, benzoate, ascorbate and salicylate, malonate, adipate, hexanoate, arginate, fumarate, nicotinate, phthalate, oxalate, lithium salt, sodium salt, potassium salt, barium salt, calcium salt, magnesium salt, aluminum salt, iron salt, ferrous salt, copper salt, zinc salt, or any one of the salts of the 5,6-dihydroxy pyrimidine compound with morpholine, diethylamine, triethylamine, isopropylamine, trimethylamine, lysine or histamine acid or a combination of at least two of them.

3. A process for the preparation of 5,6-dihydroxy pyrimidine compounds according to claim 1 or 2, characterized in that The method comprises the following steps: Step (1.1) dissolving N - hydroxyacetamidine or N - hydroxyisobutyramidine or N - hydroxybenzamidine and dimethyl acetylenedicarboxylate in methanol, reacting at 0°C, then removing methanol and refluxing in xylene, and purifying the reaction solution obtained after the reaction to obtain compound 1. Step (1.2) Compound 1, benzyl bromide and potassium carbonate are placed in acetonitrile solvent to react at 80°C, and the obtained reaction solution is purified to obtain Compound 2; Step (1.3) Compound 2 and aqueous lithium hydroxide solution are placed in methanol solvent to react at 50°C, and the obtained reaction solution is purified to obtain Compound 3; Step (1.4) Compound 3, amine compound, benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBop) and N,N-diisopropylethylamine (DIPEA) are placed in tetrahydrofuran (THF) solvent to react at room temperature, and the obtained reaction solution is purified to obtain Compound 4; Step (1.5) Compound 4 is dissolved in methanol, and then palladium-carbon catalyst is added, and then hydrogen is introduced to react at room temperature, and the obtained reaction solution is purified to obtain Compound 5; The synthetic route is as follows: 。 4. The 5,6-dihydroxy pyrimidine compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-2, for use in the preparation of a drug for resisting Pseudomonas aeruginosa biofilm, or a synergist of ciprofloxacin antibiotic.

5. Use according to claim 4, characterized in that: The drug further comprises one or more pharmaceutically acceptable carriers or excipients.

6. A pharmaceutical composition comprising the 5,6-dihydroxy pyrimidine compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-2, and further comprising one or more pharmaceutically acceptable carriers or excipients.

7. A combination drug comprising the 5,6-dihydroxy pyrimidine compound or a pharmaceutically acceptable salt thereof according to any one of claims 1-2, and the antibiotic ciprofloxacin.

8. The combination drug according to claim 7, wherein the mass ratio of the 5,6-dihydroxy pyrimidine compound or a pharmaceutically acceptable salt thereof to ciprofloxacin is 50:0.5-20.

9. The combination drug according to claim 7, wherein the mass ratio of the 5,6-dihydroxy pyrimidine compound or a pharmaceutically acceptable salt thereof to ciprofloxacin is 50:1-10.

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