WO2013004092A1 - 3-oxo-3, 4-dihydro-2-pyrazineformamide derivatives, pharmaceutical compositions, preparation methods and uses thereof - Google Patents

Abstract

Disclosed are 3-oxo-3, 4-dihydro-2-pyrazineformamide derivatives, pharmaceutical compositions, preparation methods, and uses thereof. Concretely, disclosed are the compounds shown as the formula Ⅰ, their pharmaceutically acceptable salts, their hydrates, or their solvates, wherein R₁ is H or halogen; R₂ and R₃ are independently selected from H,(C_1-6 alkylacyloxy)-C_1-6 alkyl, 1-(C_1-6 alkylacyloxy)-C_1-6 alkyl, tetrahydrofuranyl, tetrahydropyranyl, and C_1-6 alkyl substituted with OH or halogen, wherein the said halogen is selected from F, Cl, Br, and I; and when both of R₂ and R₃ are H, R₁ cannot be H or F. The compounds of formula Ⅰ may be converted into corresponding 6-R₁-3-oxo-3,4-dihydro-2-pyrazineformamide in vivo for treating virus. Compared with 6-R₁-3-oxo-3,4-dihydro-2-pyrazineformamide, the compounds of formula Ⅰ show higher bioavailability and longer period of effect time in vivo.

Description

 3-oxo-3,4-dihydro-2-pyrazinecarboxamide derivative, pharmaceutical composition thereof, preparation method and use thereof

 The invention belongs to the field of medicine and chemical industry, and relates to a 3-oxo- 3,4-dihydro-2-pyridazine formamide derivative, a pharmaceutical composition thereof, a preparation method thereof and use thereof. Background technique

3-oxo-3,4-dihydro-2-pyrazinecarboxamide (T1105) and 6-fluoro-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (T705), And the nucleoside derivative of T1105 (T1106) (structure is shown below) is an inhibitor of RNA polymerase of a type of virus, which has a good antiviral effect. It has been reported that T705 alone or in combination with a neuraminidase inhibitor has a good anti-influenza virus effect ( Ant imicrobial Agents and Chemotherapy, 2007, Vol. 51 , No. 3 , 845-851 ; Ant imicrobial Agents and Chemotherapy, 2010, 126 - 133, PCT Patent: W02000010569). T1105 exhibits a very good effect against foot-and-mouth disease virus in both in vivo and in vitro models (PCT patent: W020071139081). In addition, T705 and T1106 have a good effect on diseases caused by other RNA viruses. For example, T705 has a therapeutic effect on Western-type equine encephalitis in a mouse model ( Ant iviral Research 82 (2009) 169-171); T705 and T1106 have a therapeutic effect on yellow fever in hamsters (Antipromial Agents and Chemotherapy, 2009, 202 - 209 ); T705 has therapeutic effects in vivo and in vitro against diseases caused by arenavirus and Bunia virus infection (Antipromial Agents and Chemotherapy, 2007, 3168-3176). T705 has a therapeutic effect on rodents infected with West Nile virus (Ant iviral Research 80 (2008) 377 - 379 ); T705 has a therapeutic effect on venous viral infection ( Ant iviral (2010) 121 - 127).

 T705 T1 105 T1 106

The three compounds T1105 and T705, and the nucleoside derivative T1106 of T1105 have a similar mechanism of action, which can be converted into the corresponding nucleoside triphosphate form in vivo, by simulating the guanosine triphosphate (GTP) competition. The viral RNA polymerase is inhibited to exert an antiviral effect (ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 2005, Vol. 49, No. 3, p. 981-986).

 Although Ti 05 and T705 have good antiviral effects in an in vitro model, both compounds have some undesirable pharmacokinetic properties that are not conducive to their efficacy. For example, the oral absorption of T1105 is very poor, and the elimination in vivo is also very fast. Although it exhibits excellent activity against foot-and-mouth disease virus in vitro, IC50 is 1.6 μg/mL, but pigs are administered orally twice a day to achieve a dose of 200 mg/kg to achieve the desired anti-foot-and-mouth disease effect. The elimination of T705 is faster, and there is a problem of short half-life, resulting in a large dosage of the oral dose of 800 mg - 2400 mg per day. Summary of the invention

After intensive research, the inventors obtained a new class of 3-oxo-3, 4 - 2 Hydrogen-2-pyrazinecarboxamide derivative (compound of formula I), and surprisingly found that the derivative is capable of being converted to T705 or T1105 in vivo, exhibits good antiviral effect, and has potential as an antiviral drug. . The following invention is thus provided:

 One aspect of the invention relates to a compound of formula I, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof

 Formula I

 among them,

 Is hydrogen or halogen;

R ₂ and R _{3 are} independently selected from the group consisting of: hydrogen, (d- ₆ alkyl acyloxy)-d- ₆ alkyl, 1-(d- ₆ alkyl acyloxy)-d- ₆ alkyl, tetrahydrofuranyl a tetrahydropyranyl group, and a hydroxy or halogen substituted d- ₆ alkyl group;

 The halogen is selected from the group consisting of fluorine, chlorine, bromine, and iodine, and

When R ₂ and R _{3 are} both hydrogen, they cannot be hydrogen or fluorine.

 The experiments of Examples 17 and 18 demonstrate that the compound of formula I can be converted to T705 or T1105 in mice and monkeys. Example 17 demonstrates that the oral bioavailability of Compound 3 and Compound 12 administered orally by mice is significantly higher than that of Τ705. Example 18 demonstrates that the oral bioavailability of Compound 10 and Compound 12 administered orally by monkeys is significantly higher than that of Τ705. Since the antiviral and antifungal effects of Τ705 or T1105 are known in the art, those skilled in the art will be able to anticipate that the compounds of formula I also have antiviral and activity against foot and mouth disease.

The experimental results of Example 19 demonstrate that Compound 12 has a mortality rate and average life in mice. The inhibitory effects of live, lung lesions and lung index were reproducible statistically significant, and the therapeutic effect was superior to the currently marketed influenza treatment drug oseltamivir phosphate.

 Moreover, it is known to those skilled in the art that the solvate has no change in the structure of the compound, only changes the physical properties of the compound, and therefore should have the same biological activity.

 A compound of the formula I, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, according to any one of the present invention, wherein

The (d- ₆ alkyl acyloxy)-d- ₆ alkyl group is (d- ₆ alkyl acyloxy)-methylene or (d- ₆ alkyl acyloxy)-ethyl;

The 1-(d- ₆ alkylacyloxy)-d- ₆ alkyl group is 1-(d- ₆ alkyl acyloxy)-methylene or 1-(d- ₆ alkyl acyloxy) - Ethyl.

 A compound of the formula I, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, according to any one of the present invention, wherein

 It satisfies the following (1) - (3) any one or more:

 (1) is hydrogen or fluorine;

(2) R ₂ is hydrogen, acetoxy-methylene, or 2-tetrahydrofuranyl;

(3) R ₃ is hydrogen, acetoxy-methylene, hydroxymethyl, 2-tetrahydrofuranyl, pivaloyloxy-methylene, butyryloxy-methylene, isobutyryloxy- Methylene, acetoxy-ethyl.

 In a specific embodiment, the compound of formula I of the present invention, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, is selected from the compounds shown in Table 1 below: Table 1: Partial specific compounds of the invention

 Compound number naming structure

N- [(Acetoxy)-methylene 0 Ϊ

1 yl]-3-oxo-3,4-dihydro VIII

 - 2 -pyrazinecarboxamide

H people.

 And a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof. Another aspect of the invention relates to a pharmaceutical composition comprising a compound of formula I according to any of the invention, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof.

 The pharmaceutical composition according to any one of the present invention, further comprising a pharmaceutically acceptable carrier or adjuvant; in particular, the pharmaceutical composition is a solid preparation, an injection, an external preparation, a spray, a liquid preparation, or a combination preparation.

 The pharmaceutical composition usually contains from 0.1 to 90% by weight of the compound of the formula I and/or a pharmaceutically acceptable salt thereof and/or a hydrate thereof and/or a solvate thereof. Pharmaceutical compositions can be prepared according to methods known in the art. When used for this purpose, if desired, a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, may be combined with one or more solid or liquid pharmaceutical excipients and/or adjuvants. It can be used as a suitable administration form or dosage form for mammals.

The compound of formula I or a pharmaceutical composition containing the same may be administered in unit dosage form, either parenterally or parenterally, such as orally, muscle, subcutaneous, nasal, oral mucosa, skin, peritoneum or rectum. Formulations such as tablets, capsules, pills, aerosols, pills, powders, solutions, suspensions, emulsions, granules, liposomes, transdermal agents, buccal tablets, suppositories, lyophilized powders Injection, etc. It may be a general preparation, a sustained release preparation, a controlled release preparation, and various microparticle delivery systems. In order to form a unit dosage form into tablets, various carriers well known in the art can be widely used. Examples of the carrier are, for example, a diluent and an absorbent such as starch, dextrin, calcium sulfate, lactose, mannitol, sucrose, sodium chloride, glucose, urea, calcium carbonate, kaolin, microcrystalline fiber. Wetting agent, aluminum silicate, etc.; wetting agent and binder, such as water, glycerin, polyethylene glycol, ethanol, propanol, starch slurry, dextrin, syrup, honey, glucose solution, gum arabic, gelatin pulp, carboxy Methylcellulose sodium, shellac, methylcellulose, potassium phosphate, polyvinylpyrrolidone, etc.; disintegrating agents, such as dried starch, alginate, agar powder, brown algae starch, sodium bicarbonate and tannic acid, calcium carbonate , polyoxyethylene, sorbitan fatty acid ester, sodium dodecyl sulfate, methyl cellulose, ethyl cellulose, etc.; disintegration inhibitors, such as sucrose, glyceryl tristearate, cocoa butter, hydrogenation Oil or the like; an absorption enhancer such as a quaternary ammonium salt, sodium lauryl sulfate or the like; a lubricant such as talc, silica, corn starch, stearate, boric acid, liquid paraffin, polyethylene glycol or the like. Tablets may also be further formulated into coated tablets, such as sugar coated tablets, film coated tablets, enteric coated tablets, or bilayer tablets and multilayer tablets. In order to prepare the administration unit into a pellet, various carriers known in the art can be widely used. Examples of the carrier are, for example, diluents and absorbents such as glucose, lactose, starch, cocoa butter, hydrogenated vegetable oil, polyvinylpyrrolidone, Gelucire, kaolin, talc, etc.; binders such as acacia, tragacanth, gelatin , ethanol, honey, liquid sugar, rice paste or batter; etc.; disintegrating agents, such as agar powder, dried starch, alginate, sodium dodecyl sulfate, methyl cellulose, ethyl cellulose, and the like. In order to prepare the drug delivery unit as a suppository, various carriers well known in the art can be widely used. Examples of the carrier are, for example, polyethylene glycol, lecithin, cocoa butter, higher alcohols, esters of higher alcohols, gelatin, semi-synthetic glycerides and the like. In order to form the drug delivery unit into a capsule, the active ingredient compound of the formula I or a stereoisomer thereof is mixed with the various carriers described above, and the resulting mixture is placed in a hard gelatin capsule or soft capsule. The active ingredient of the compound of the formula I, or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, may be prepared as a micro-tank, suspended in an aqueous medium to form a suspension, or may be incorporated into a hard gelatin or may be prepared. Injection application. In order to prepare the administration unit into an injectable preparation such as a solution, an emulsion, a lyophilized powder, and a suspension, all diluents conventionally used in the art, for example, water, ethanol, polyethylene glycol, 1, 3 can be used. -propylene glycol, Ethoxylated isostearyl alcohol, polyoxylated isostearyl alcohol, polyoxyethylene sorbitan fatty acid ester, and the like. Further, in order to prepare an isotonic injection, an appropriate amount of sodium chloride, glucose or glycerin may be added to the preparation for injection, and a conventional cosolvent, a buffer, a pH adjuster or the like may be added.

 In addition, coloring agents, preservatives, perfumes, flavoring agents, sweeteners or other materials may also be added to the pharmaceutical preparations as needed. A further aspect of the invention relates to a process for the preparation of a compound of formula I according to any one of the inventions, comprising the steps of any of the following methods (1) to (5)

(1) in an aprotic organic solvent, and in the presence of an organic or inorganic base, 6- 1^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 3⁄4 The carboxylic acid ester gives the corresponding N-[(d- ₆ alkylacyloxy)-methylene)]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide or 4-[ (d- ₆ alkyl acyloxy)-methylene)]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, with 1-halo d- ₆ alkyl carboxylic acid Ester reaction to give the corresponding N-[1-(d- ₆ alkylacyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide or 4-[1 - (d- ₆ alkyl acyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,

其中，

among them,

R is a Cl-alkyl group; R ₅ is hydrogen or d- ₆ alkyl;

 X is fluorine, chlorine, bromine, or iodine;

 (2) reacting 6--3-oxo-3,4-dihydro-2-pyrazinecarboxamide directly with 2,3-dihydrofuran in an aprotic organic solvent; or in PPTS (pair Catalyzed by pyridinium benzenesulfonate) and/or P-TsOH (p-toluenesulfonic acid) to give 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide 2,3-dihydrofuran reaction, preparation of 6-^-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-1^-4 - (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R-[N,4-di-(tetrahydrofuran-2-yl)]- 3-oxo-3,4-dihydro-2-pyrazinecarboxamide,

(3) in the aprotic organic solvent, 6--3-oxo-3,4-dihydro-2-pyrazinecarboxamide is directly reacted with 2-d- ₆ alkoxytetrahydrofuran under heating Reaction, preparation of 6-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-1^-4-(tetrahydrofuran-2-yl)- 3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R-[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3, 4- Dihydro-2-pyrazinecarboxamide,

Wherein R is a d- ₆ alkyl group, preferably a tert-butyl group;

(4) 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 2-acetyl which are etherified in an aprotic organic solvent and in the presence of Lewis acid Preparation of 6--N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6- 1^-4-(tetrahydrofuran-2) by oxytetrahydrofuran -yl)- 3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-Rr[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3 , 4-dihydro-2-pyrazinecarboxamide,

(5) in an aprotic organic solvent, and with the participation of trimethylchlorosilane and triethylamine, 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide 2,3-dihydrofuran reaction to prepare 6--N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6- 1^-4- (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyridylamide, and 6-Rr [N,4-di-(tetrahydrofuran-2-yl)]-3-oxygen Generation - 3,4-dihydro-2-pyrazinecarboxamide,

上述的方法 （1) - (5) 中， 独立地为氢或卤素。

In the above methods (1) to (5), it is independently hydrogen or halogen.

 The preparation method according to the present invention, wherein, in the methods (1) to (5): the aprotic organic solvent is selected from one or more of dichloromethane, DMF, acetonitrile, DME, and THF;

 The organic base is selected from one or more of triethylamine, DBU, and diisopropylethylamine;

 The inorganic base is potassium carbonate or cesium carbonate;

 The halo is substituted with fluorine, chlorine, bromine or iodine.

 The preparation method according to any one of the invention, wherein

In the method (3), the 2-d- ₆ alkoxytetrahydrofuran is 2-tert-butoxytetrahydrofuran;

In the method (4), the Lewis acid is selected from the group consisting of SnCl ₄ , TiCl ₄ , and tert-butyldimethylsilyl trifluoromethanesulfonate; and SnCl ₄ is preferred. A further aspect of the invention relates to a compound of formula I according to any one of the invention, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, or a pharmaceutical composition according to any of the inventions for the preparation of an antiviral Use in medicine.

Specifically, the virus in the present invention is an RNA virus; specifically, an influenza virus (Influenza Virus), an HCV virus (Hepatitis C Virus), a Bimyavirus, a Phlebovirus, a foot-and-mouth disease virus ( Foot and Mouth Disease Virus ) , West Ni le virus , Arenavirus , Western Equine Encephalitis Virus , or Yellow Fever Virus ; The influenza virus is a methyl 1 (H1N1) influenza A virus. A further aspect of the invention relates to a compound of formula I according to any one of the inventions, Use of a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, or a pharmaceutical composition according to any of the present invention, for the manufacture of a medicament for the treatment and/or mammalian foot-and-mouth disease; in particular, the mammal is a hoof The animal; specifically, the cloven-hoofed animal is a pig, a cow, or a sheep. A further aspect of the invention relates to a method of antiviral in vivo or in vitro comprising administering to a subject an effective amount of a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, or an effective amount of inclusion A step of a pharmaceutical composition of a compound I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof. Specifically, the subject is a mammal (eg, a human or a monkey), such as a cloven-hoofed animal (eg, pig, cow, or sheep).

 A further aspect of the invention relates to a method of treating and/or preventing foot-and-mouth disease or influenza in a mammal comprising administering to the mammal an effective amount of a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, or an effective amount thereof A step of a pharmaceutical composition comprising a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof. Specifically, the mammal is a cloven-hoofed animal. Specifically, the cloven-hoofed animal is a pig, a cow, or a sheep. A pharmaceutical composition of the compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, or an effective amount of a compound comprising a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, may be used alone or Mix with animal feed or drinking water.

 The dose of a compound of formula I or a pharmaceutically acceptable salt thereof, or a hydrate thereof or a solvate thereof, depends on a number of factors, such as the nature and severity of the disease to be prevented or treated, the sex, age, weight and individual response of the patient or animal. , the specific compound used, the route of administration and the number of administrations, and the like. The above dosages may be administered in a single dosage form or divided into several, for example two, three or four dosage forms.

The actual dosage level of the active ingredient in the pharmaceutical compositions may be varied so that the amount of active compound obtained is effective to the particular patient, composition, and mode of administration Therapeutic response. The dosage level will be selected based on the activity of the compound of formula I, the route of administration, the severity of the condition being treated, and the condition and past medical history of the patient to be treated. However, it is the practice in the art that the dosage of the compound be started from a level lower than that required to achieve the desired therapeutic effect, and the dosage is gradually increased until the desired effect is obtained.

 When used in the above therapeutic and/or prophylactic or adjunctive treatment, a therapeutically and/or prophylactically effective amount of a compound of the invention may be administered in pure form, or in the form of a pharmaceutically acceptable ester or prodrug (in the presence of such forms) B) Application. Alternatively, the compound can be administered as a pharmaceutical composition comprising the compound of interest and one or more pharmaceutically acceptable excipients. The phrase "prophylactically and/or therapeutically effective amount" of a compound of the invention refers to a sufficient amount of a compound to treat a disorder with a reasonable effect/risk ratio applicable to any medical prophylaxis and/or treatment. It will be appreciated, however, that the total daily usage of the compounds and compositions of the present invention will be decided by the attending physician within the scope of sound medical judgment. The specific therapeutically effective dosage level for any particular patient will depend on a number of factors, including the disorder being treated and the severity of the disorder; the activity of the particular compound employed; the particular composition employed; Patient's age, weight, general health, sex and diet; time of administration, route of administration and excretion rate of the particular compound employed; duration of treatment; drug used in combination with or concurrent with the particular compound employed; Similar factors are known in the medical field. For example, it is a practice in the art to start at a dose lower than that required to achieve the desired therapeutic effect, gradually increasing the dosage until the desired effect is achieved. In general, the present invention

011-10100 mg/kg body weight / day, for example, between 0. 01-100 mg / kg body weight / day, for example between 0. 01-10 mg /kg body weight / day.

 The compounds according to the present invention are effective for preventing and/or treating various diseases or conditions described in the present invention.

In the present invention, the term "effective amount" means that treatment can be achieved in a subject, The dosage of the disease or condition of the invention is prevented, alleviated and/or alleviated.

The term "d-C ₆ alkyl" or "d- ₆ alkyl" (including d- ₆ alkyl acyloxy or (d- ₆ alkyl acyloxy)-d- ₆ alkyl or 1-(d- ₆ alkyl acyloxy) _-D-C6 alkyl according to any one D- ₆ alkyl) means a straight-chain or branched alkyl group having 1 to 6 carbon atoms, such as methyl, ethyl, propyl , isopropyl, n-butyl, sec-butyl, tert-butyl, pentyl, 2-pentyl, isopentyl, neopentyl, hexyl, 2-hexyl, 3-hexyl, 3-methylpentyl, etc. . Accordingly, "d- ₆ alkyl oxy group" can be similarly understood. In one embodiment of the present invention, the "d- C ₆ alkyl" or "d- ₆ alkyl" as d- ₃ alkyl or C ₄ - ₆ alkyl. In one embodiment of the present invention, the (Cw of alkyl acyloxy) -d- ₆ is alkyl (d-3-alkyl acyloxy) -d-3 alkyl or (C ₄ - ₆ alkyl Acyloxy)-C _{4 -6} alkyl. In one embodiment of the invention, the 1-(Cw alkylacyloxy)-d- ₆ alkyl group is 1-(da alkylacyloxy)-d-3 alkyl or 1-(C ₄ - ₆ alkyl acyloxy) - C ₄ - ₆ alkyl.

The term "d-C ₆ alkoxy" or "d- ₆ alkoxy" refers to a straight or branched alkoxy group having from 1 to 6 carbon atoms, such as methoxy, ethoxy, propoxy Base, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, 2-oxopentyl, isooxypentyl, neopentyloxy, hexyloxy, 2-hexyloxy Base, 3-oxohexyl, 3-methylpentyloxy and the like. In one embodiment of the present invention, the "C alkoxy" or _"6 D- group" is an alkoxy group or a d- _{3 (4} - ₆ alkoxy beneficial effects of the invention

 The compound of the present invention can be converted into the form of T1105 or T705 in vivo to exert an antiviral effect, and at the same time, the bioavailability of the compound can be remarkably improved, and the action time of the compound T705 or T1105 in vivo can be prolonged. DRAWINGS

Fig. 1: Drugs for T705 after oral administration of compounds 3, 4, 6 and T705, respectively - time curve.

 Fig. 2: The drug-time curve of T705 after oral administration of compounds 10, 11, 12, 13 and T705, respectively.

 Fig. 3: Drug-time curve of T1105 after oral administration of compounds 7, 9 and T1105 in mice (T1105 was not detected in blood after oral administration of T1105).

 Fig. 4: The drug-time curve of the macaques after oral administration of compounds 3, 10, 12, 11, 13 and T705 (in the case of drug testing, 3 monkeys, after giving 1 drug test, after not less than 3 days) During the cleaning period, the next test drug is given). detailed description

 The embodiments of the present invention are described in detail below with reference to the accompanying drawings. Those who do not specify the conditions in the examples are subject to the usual conditions or conditions recommended by the manufacturer. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that are commercially available. Example 1: N-[(Acetoxy)-methylene]-3-oxo-3,4-dihydro-2-pyrazinylamide (Compound 1) and 4-[(Acetoxy) - Preparation of methylene]-3-oxo-3,4-dihydro-2-pyrazinium amide (Compound 2)

Compound 2 Compound 1 Dissolve 1.39 g (l Ommo 1) of T1105 in 10 mL under nitrogen. In anhydrous DMF, after stirring at room temperature for 15 m in, a suspension was added, and 2.20 g (20 mmo 1) of chloromethyl acetate, potassium (2 mmol) and 3.03 g (30 mmol) of triethylamine were added dropwise. The solution is clarified. After stirring at room temperature for 24 hours, the reaction mixture was evaporated to dryness mjjjjjjjjjjjjhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh (Methylene chloride/methanol elution) gave two main products, respectively N-[(acetoxy)-methylene]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 1) and 4-[(Acetoxy)-methylene]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 2).

 Compound 1:

 ^NMRCCCn), δ 2.18 (3Η, s), 5.92(2H, s), 6.42 (1H, brs), 7.66 (1H, d, J=4.0Hz), 7.70 (1H, d, J=4.0Hz), 9, 04 (1H, brs); ESIMS (m/e) 250 (ΜΓ), 234 (MNa+), 221 (MH+)

 Compound 2:

¹匪R(CC13), δ 2.12(3H, s) , , 5.88 (1H, brs) , 6.25 (2H, s) , 7.52(lH, brs), 8.35 (1H, s) , 8.39(1H, s) ; ESIMS (m/e)

250 (ΜΓ), 234 (MNa ⁺ ), 221 (MH+). Example 2: 6-Fluoro-4-[(acetoxy)-methylene]-3-oxo-3,4-dihydro-2-pyrazinylamide (Compound 3) and 6-Fluoro- Preparation of 4-(hydroxyindenyl)-3-oxo-3,4-dihydro-2-pyrazinylamide (Compound 4)

 Compound 4 Compound 3 The same procedure as in Synthesis Example 1, except that T705 was replaced by T705, and 6-fluoro-4-[(acetoxy)-methylene]-3-oxo-3,4-dihydro-2 was mainly obtained. Pyrazinylamide (Compound 3) and 6-fluoro-4-(hydroxymethyl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 4).

 Compound 3:

 ^NMR (CDC 13) δ 2.12 (3Η, s), 5.85 (1H, brs), 6.21(2H, s),

7.38 (1H, s), 8.20(1H, d, J=8.4Hz); ESIMS(m/e), 252 (MNa + ), 230 (MH ⁺ )

 Compound 4:

¹匪R(DMS0-d6) δ 5.77 (3H, s), 7.82 (1H, brs),

8.00 (lH, brs), 8.41 (1H, d, J = 8.4 Hz); ESIMS (m/e), 188 (MH+). Example 3: 4-(Tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinium

Compound 5 ⁴ 000 mg ( 2.87 mmol ) of T110 ^{5 was} suspended in ²⁰ mL of THF, added 2, 3-dihydrofuran l. lg (15. 5 leg ol) and PPTS (9 mg), the reaction was stirred at room temperature for 48 hours, the reaction was filtered, the insoluble material was filtered, concentrated to give an oil, which was solidified and washed with methanol. A powdery solid was obtained as Compound 5.

 Compound 5:

¹匪R ( DMS0-d6 ) , δ 1. 75-1. 85 (lH, m) , 1. 90-2. 10 (2H, m) , 2. 35-2. 45 (1H, m), 3 90-4. 00 (1H, m), 4. 30-4. 40 (1H, m),

6. 04-6. 12 (1H, m), 7. 55 (1H, d, J=4. 0Hz), 7. 72 (1H, brs),

7. 78 (1H, d, J=4. 0Hz), 8. 39 (1H, brs); ESIMS (m/e) , 210 ( MH+ ) , 232 ( MNa ⁺ ). Example 4: Preparation of 6-fluoro-4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 6)

 Compound 6 400 mg ( 2.54 mmol) of T705 was suspended in 20 mL of THF, and 2,3-dihydrofuran 1. lg (15. 5 leg ol) and PPTS (9 mg) were added, and the reaction was stirred at room temperature for 72 hours. The reaction was filtered and the filter cake was washed with THF to give a powdery solid.

 Compound 6:

^NMR (DMS0-d6), δ 1. 78-1. 88 (1H, M), 1· 91-1. 99 (1H, m), 2. 06-2. 14 (1H, m), 2. 34-2. 43 (1H, m), 3. 91-3. 97 (1H, m), 4. 39-6. 08 (1H, m), 7. 93 (1H, brs), 7. 98 ( 1H, d, J=5. 6Hz), 8. 68 (1H, brs); ESIMS (m/e) 228 (MH ⁺ ) , 250 (MNa+). Example 5: N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinium

 Compound 7

In a dry three-necked flask, 1.075 g (7.7 mmol) of T1105 and 1.67 g (11.6 mmol) of 2-tert-butoxytetrahydrofuran were added, dissolved in 5 mL of anhydrous DMF, and heated under N ₂ protection. After reacting at 150 ° C for 12 hours, the temperature was lowered to room temperature, 10 mL of dichloromethane was added, and a solid was precipitated. The solid was collected by filtration, recrystallized twice from methanol, and recrystallized from acetonitrile to give a white solid 250 mg as compound 7 .

 Compound 7:

¹匪R( DMS0-d6 ), δ 1. 77 (2Η, m), 2. 71 (2H, m) , 3. 42 (1H, m), 4. 56 (1H, brs), 6. 36 ( 2H, dd, J=5. 6Hz), 6. 93 (1H, d, J=6. 0Hz), 9. 72 (1H, d, J=6. 0Hz) , 10. 56 (1H, brs) ESIMS (m/e), 210 (MH ⁺ ), 232 (MNa ⁺ ) „ Example 6: 6-Fluoro-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2 -Pyrazine formylamide (Compound 8) preparation

 Compound 8

In a dry three-necked flask, 377 mg (2.4 mmol) of T705 and 670 mg (4.8 mmol) of 2-tert-butoxytetrahydrofuran were added and dissolved in 5 mL of anhydrous NMP (N-methylpyrrolidone) under N2 protection. Heat to 140. C reaction for 10 hours, add 200 mg (1.4 mmol) of 2-tert-butoxytetrahydrofuran, continue to react at this temperature 10 hours. After the temperature was reduced to room temperature, the solvent was evaporated to dryness crystals crystals crystals crystals

 Compound 8:

 ^NMR (CDC 13 ) , δ (ppm), 1. 90-2. 10 (3Η, m), 2. 40-2. 50 (1H, m), 3. 85-3. 95 (1H, m) , 4. 00-4. 10 (1H, m), 5. 88 (1H, m), 7. 79 (1H, brs) , 8. 28 (1H, d, J=8. 0Hz),

12. 44 (1H, brs). Example 7 Preparation of N,4-di-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 9)

 Compound 9

To a dry three-necked flask with a thermometer and a drying tube, 1.39 g (10 lb) of T1105 and 20 ml of anhydrous DMF were added, and the mixture was stirred well to obtain a suspension. 2.16 g (20 mmol) of trimethyl chloride was added by syringe. Silane and 1. Olg (1 Ommol) of triethylamine, kept at an internal temperature not higher than 33 ^e C, and then reacted at room temperature for 7 hours. The reaction was concentrated to dryness under reduced pressure and then flash column chromatography (dichloromethane / Elution with methanol gave a pale yellow solid as compound 9.

 Compound 9:

ESIMS (m/e, 100) 302 (MNa+, 45), 280 (MH ⁺ , 30), 232 (58), 210 (100), 156 (48). Example 8: Preparation of 6-fluoro-4-(pivaloyloxyarylene)-3-oxo-3,4-dihydro-2-pyrazinylamide (Compound 10)

 The method was the same as in Synthesis Example 1, except that T705 was replaced by T705, and chloromethyl pivalate was replaced by chloromethyl pivalate to obtain 6-fluoro-4-(pivaloyloxymethylene)-3-oxo-3. , 4-dihydro-2-pyrazinecarboxamide (Compound 10).

 Compound 10:

^NMRCCDCn) , δ (ppm), 1.18 (9H, s), 6.21 (2H, s), 6.21 ( 1H, brs ) , 7.42 (lH, brs) , 8.29 (1H, d, J=8.8Hz); ESIMS (m/e) 272 (MH ⁺ ). Example 9: Preparation of 6-fluoro-4-(butyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 11)

 Compound 11

The same procedure as in Synthesis Example 1, except that T705 was replaced by T705, and chloromethyl chloroformate was used instead of chloromethyl acetate to obtain 6-fluoro-4-(n-butyryloxymethylene)-3-oxo. - 3, 4-Dihydro-2-pyrazinecarboxamide (Compound 11).

 Compound 11:

¹ H NMR (CDC13) 50.92 (3H, t, J = 7.2 Hz), 1.66 (2H, m), 2.35 (2H t, J = 7.2 Hz), 6.22 (2H, s ), 6.44 (IH, bs) 7.43 ( IH, brs), 8.19 (IH, d J=8.4 Hz); ESIMS (m/e) 258 (MH+). Example 10: 6-Fluoro-4-(isobutyryloxy fluorenyl)-3-oxo-3,4-dihydro-2-pyrazinyl

 Compound 12 Under a nitrogen atmosphere, 1.57 g (lOmmo 1) of T705 was dissolved in 10 mL of anhydrous DMF. After stirring at room temperature for 15 min, triethylamine 3.03 g (30 ol) was added dropwise, and the temperature was lowered to 0 ° C. Then, add 3.41 g (25 mmo 1) of chloromethyl acetate, add the mixture, and raise to room temperature for 24 hours. Then, the reaction solution is poured into 100 mL of cold water, extracted three times with dichloromethane, and the organic phase is combined. Wash with 1N hydrochloric acid twice, wash with saturated sodium bicarbonate solution, wash with sodium chloride solution, dry over sodium sulfate, and concentrate to dryness. After silica gel chromatography, elute with flash column chromatography (dichloromethane/methanol elution) to obtain 6- Fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 12).

 Compound 12:

¹匪MCDC13) 61.16(6H, d, J=6.8Hz) , 2.59(lH,m) , 6.21 (2H, s) , 6.30(lH,bs), 7.41(lH,brs), 8.19 (IH, d, J = 8.4 Hz); ESIMS (m/e) 258 (MH ⁺ ) Example 11: 6-Fluoro-4-(isobutyryloxy fluorenyl)-3-oxo-3,4-dihydro-2-pyrazinyl Preparation of ammonia (Compound 12) ( 2 )

The compound was dissolved in 10 mL of anhydrous DMF under a nitrogen atmosphere. After stirring at room temperature for 15 min, triethylamine 3.03 g (30 ol) was added dropwise. To 0 ° C, 2, 12 g (20 mmo 1) of bromomethyl acetate was added dropwise, and after stirring for 24 hours at room temperature, the reaction solution was poured into 100 mL of cold water and extracted with dichloromethane three times. The organic phase was combined, washed twice with 1N hydrochloric acid, washed with saturated sodium hydrogen carbonate solution, washed with sodium chloride solution, dried over sodium sulfate, and concentrated to dryness. Mainly, 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 12) was obtained. Example 12: Preparation of 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 12) (3)

 Compound 12 was the same as in Synthesis Example 11, except that diisopropylethylamine was used instead of triethylamine to give 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3, 4- Dihydro-2-pyrazinecarboxamide (Compound 12). Example 13: 6-Fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2 -

Compound 12 Under a nitrogen atmosphere, 1.57 g (1 Ommo 1) of T705 was dissolved in 10 mL of anhydrous DMF, stirred at room temperature for 15 min, then added to a carbonic acid clock (20 mmol), cooled to 0 ° C, and then dripped After adding bromomethyl acetate 2.12 g (20 mmo 1), after adding, after stirring at room temperature for 24 hours, the reaction solution was poured into 100 mL of cold water containing 40 mmol of HCl, extracted three times with dichloromethane, and combined. The organic phase was washed twice with 1N EtOAc (EtOAc) EtOAc. After silica gel was mixed with Flash column chromatography (dichloromethane/methanol elution), 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro- 2-pyrazinecarboxamide (Compound 12). Example 14: 6- 4-(isobutyryloxy fluorenyl)-3-oxo-3,4-dihydro-2-pyrazinyl

 Compound 12

 The method was the same as in Synthesis Example 13, except that cesium carbonate was substituted for the carbonic acid clock, and mainly 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazine was obtained. Formamide (Compound 12). Example 15 Preparation of 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazineformyl (Compound 12) (6)

在氮气保护下， 将 1.57 g (lOmmo 1)的 T705溶于 10 mL无 水 DMF中， 室温搅拌 15 m in 后， 滴加三乙胺 3.03g (30腿 ol) , 降温至 - 30°C, 再滴入碘甲基乙酸酯 2.12 g (20腿 0 1)的乙腈溶 液， 加毕， 在- 30。C 下反应 24小时后， 逐渐升至 0 。C反应 8小 时， 将反应液冲入 lOOmL冷水中， 用二氯甲烷萃取三次， 合并有 机相， 用 1N盐酸洗涤两次， 饱和碳酸氢钠溶液洗涤， 氯化钠溶液 洗涤， 硫酸钠干燥， 浓缩至干， 硅胶拌样后用 Flash柱层析分离 (二氯甲烷 /甲醇洗脱） 主要得到 6-氟- 4- (异丁酰氧基亚甲 基)- 3-氧代- 3,4-二氢- 2-吡嗪甲酰氨（化合物 12) 。 实施例 16: 6-氟- 4- [1- (乙酰氧基） -乙基 ]-3-氧代- 3， 4-二氢 - 2 -吡嗪曱酰氨（化合物 13) 的制备

Under nitrogen protection, 1.57 g (lOmmo 1) of T705 was dissolved in 10 mL of anhydrous DMF. After stirring at room temperature for 15 min, triethylamine 3.03 g (30 leg ol) was added dropwise, and the temperature was lowered to - 30 °C. A solution of 2.12 g (20 leg 0 1) of iodine methyl acetate in acetonitrile was added dropwise, at -30. After 24 hours of reaction at C, it gradually rose to 0. C reaction for 8 hours, the reaction solution was flushed into 100 mL of cold water, extracted three times with dichloromethane, the organic phase was combined, washed twice with 1N hydrochloric acid, washed with saturated sodium hydrogen carbonate solution, washed with sodium chloride solution, dried over sodium sulfate, concentrated To the dry, silica gel was used for separation by flash column chromatography (dichloromethane/methanol elution) to give 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4- Dihydro-2-pyrazinecarboxamide (Compound 12). Example 16: Preparation of 6-fluoro-4-[1-(acetoxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinylamide (Compound 13)

 The method was the same as in Synthesis Example 1, except that T705 was replaced by T705, and chloromethyl acetate was replaced by 1-chloromethyl acetate to obtain 6-fluoro-4-[1-(acetoxy)-ethyl]-3- Oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 13).

 Compound 13:

¹匪M CDC13 ) δ 1.73(3H,d, J=5.6Hz), 2.08 (3H, s ) 6· 50 ( 1H , brs ) , 7.22(1H, q, J=5.6Hz), 7.35 (1H, brs ), 8.17 (1H, d, J = 8.4 Hz); ESIMS (m/e) 244 (MH ⁺ ). Example 17: Metabolism experiment in mice

 Experimental drugs: Compounds 1-13, T1105, Τ705.

 Subjects: KM mice (male, 27 ± 2 g) were randomly divided into 15 groups according to body weight, with 3 rats in each group.

 experimental method:

 Test compounds were administered orally in a dose of 0.0637 mmol/10 ml/kg (corresponding to 10 mg/10 ml/kg for T705 or T1105) (one group for each compound, i.e., 3 mice). 20 μΐ of blood was collected from the eyelids at different time points, 20 cation internal standard acetonitrile solution, 20 anion internal standard acetonitrile solution, 40 μΐ acetonitrile, shaking, 18000 g centrifugation for 10 min, and the supernatant was taken by LC/MS/MS. Corresponding test compound and concentration of T705 or T1105. Bioavailability [AUC (μΜ*ή)] value calculated by T1105 when metabolized in mice.

 Experimental results:

 As shown in Fig.1-3 and Table 2-3.

Table 2: Bioavailability of T705 calculated by T705 and its derivative compounds 3, 4, 6, 10, 11, 12, 13 and the like when metabolized in mice and monkeys [AUC ( μΜ*ή) ]

 And half-life [Tl/2 (h) 〗 value

化合物 13 244.2 ±83.4 2.0 ±0.5

Compound 13 244.2 ±83.4 2.0 ±0.5

 T705 36.64 ±2.91 1.09 ±0.714 Compound 3 36.65 ±12.37 1.639 ±0.807 Compound 10 86.12 ±31.96 0·6±0.066 Monkey

 Compound 11 59.13 ±26.00 1.189 ±0.149 Compound 12 105·20±30·86 0.965 ±0.489 Compound 13 55.23 ±25.39 1.263 ±0.522 Table 3: T1105 and its derivative compounds 7 and 9 are metabolized in mice with T1105

 Calculated bioavailability [AUC ( μΜ*ή) ] value

结果显示， 化合物 3、 10、 11、 12、 13在小鼠口服给药的条 件下能够有效改善 Τ705的药代动力学性质。其中化合物 3可明显 提高小鼠体内以 Τ705计算的血药浓度和口服生物利用度 [ AUC( μΜ *h) ]。 化合物 12能明显提高以 T705计算的血药浓度和口服生物 利用度， 并延长半衰期。 化合物 10、 11、 13虽然不能提高以 T705 计算的口服生物利用度， 但能延长以 T705计算的半衰期。 T1105 衍生物化合物 7和 9在小鼠口服给药的条件下， 其以 T1105计算 的口服生物利用度明显高于 T1105口服给药的口服生物利用度。 实际上， T1105在 0.0637 mmol/10ml/kg剂量下口服给药时, 在 在小鼠血浆中没有检测出 T1105, 说明 T1105的口服生物利用度 很低。 实施例 18: 猴子体内代谢试验

The results showed that Compounds 3, 10, 11, 12, 13 were effective in improving the pharmacokinetic properties of Τ705 under conditions of oral administration to mice. Among them, compound 3 can significantly increase the blood concentration and oral bioavailability [AUC(μΜ*h)] calculated by Τ705 in mice. Compound 12 significantly increased the plasma concentration and oral bioavailability calculated as T705 and prolonged the half-life. Compounds 10, 11, and 13 did not increase the oral bioavailability calculated as T705, but extended the half-life calculated as T705. The oral bioavailability of T1105 derivative compounds 7 and 9 calculated by oral administration of T1105 was significantly higher than the oral bioavailability of T1105 oral administration. In fact, when T1105 was orally administered at a dose of 0.0637 mmol/10 ml/kg, no T1105 was detected in mouse plasma, indicating that the oral bioavailability of T1105 was very low. Example 18: Metabolic test in monkeys

 Experimental drugs: Compounds 3, 10, 12, 11, 13 and T705.

 Experimental subjects: 3 macaques.

 Experimental method: 3 macaques, according to 0. 0637 legs ol / lml / kg respectively, orally administered a drug. 50 μΙ of monkey plasma was administered at different time points for administration. 50 different concentrations of Τ acetonitrile acetonitrile standard solution were added, 50 anion internal standard acetonitrile solution, 100 μΐ acetonitrile were added, and the analytical sample was equivalent to plasma concentrations of 100, 500, 1000, 5000, 10000. Ng/ml. Oscillate, centrifuge at 18000 g for 10 min, and take the supernatant LC/MS/MS for injection to determine the T705 concentration. The theoretical concentration was linearly fitted to the ratio of the detected peak area of T705 to the internal standard peak area in the plasma sample.

 After a cleaning period of not less than 3 days, the next test drug is administered.

 Experimental results: as shown in Fig. 4 and Table 2-3.

 The results showed that under the conditions of oral administration of monkeys, five compounds such as compounds 3, 10, 11, 12, 13 can effectively improve the pharmacokinetic properties of T705, and compounds 3, 11, and 13 can be significantly improved with T705. The half-life of the compound, compound 10, 11, 12, 13 and other four compounds can significantly improve the blood concentration and oral bioavailability in T705, compounds 12 and 10 in increasing the blood concentration and oral bioavailability in T705 The effect of these two aspects is most obvious. Example 19: Pharmacodynamic study of compound 12 in a mouse influenza virus 曱H1N1) subtype (FM1 strain) infection model

 Experimental drug: Compound 12 was formulated into a colorless transparent solution using physiological saline. At the time of the experiment, the compound 12 was formulated into solutions of different concentrations and administered orally.

Experimental animals: Kunming mice, the first and second batches of male and female, the third batch of females, 16-18 grams, provided by the rodent culture center of the Chinese Academy of Medical Sciences, Health certificate.

Virus used: Influenza virus A (H1N1) subtype A (FM1 strain) rat lung adaptor strain (provided by the Institute of Medical Biotechnology of Chinese Academy of Medical Sciences, other H1N1 influenza strains can also be purchased or used). Toxicity LD50 to mice is about ^10-5.

 Control drug: oseltamivir phosphate, Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences.

 experimental method:

 Influenza virus A (H1N1) subtype A (FM1 strain) infection method: After anesthetizing the mice with ether, a 40 μl appropriately diluted virus solution was intranasally dropped by a pipette.

 Mode of administration: Both the experimental sample and the control drug were administered intragastrically.

 The first batch of experiments: Compound 12 dose: 30 mg/kg, 100 mg/kg, 300 mg/kg Three dose groups of the drug-administered group, 20 mice per group. Dosing is about 1 hour after infection. The infection control was treated with the same amount of physiological saline. The positive control drug oseltamivir phosphate (5 mg/kg) was given to the stomach once a day, and the administration time was the same as that of the treatment group.

 The second batch of experiments: Compound 12 dose: 30 mg / kg, 100 mg / kg, 300 mg / kg Three dose groups of the drug-administered group, 20 mice per group. Dosing is about 1 hour after infection. The infection control was treated with the same amount of physiological saline. The positive control drug oseltamivir phosphate (10 mg/kg) was given to the stomach once a day, and the administration time was the same as that of the treatment group.

 The administration time was qd x 5 , and the virus LD50 was simultaneously titrated in each batch of experiments.

Virus isolation experiment: The mice were infected with the appropriate amount of influenza virus FM-1, and the infected mice were divided into three groups, which were treated with 100 mg/kg of compound 12, oseltamivir phosphate 10 mg/kg, and physiological saline. 20 animals per group. Five rats from each group were sacrificed at 24 hours, 48 hours, 72 hours, and 96 hours after infection, and the lungs were aseptically taken. Weighed and stored in a -85 water tank. The lung tissue taken was added to 10 volumes of MEM and an appropriate amount of glass powder, and fully ground into a homogenate. The mixture was centrifuged at 12,000 rpm for 1 minute, and the supernatant was collected. The supernatant was diluted in equal proportions, and CPE was observed on MDCK cells at 24 and 48 hours. Titrate the TCID50 of each lung.

 Observation and judgment indicators: The mortality, average life, lung lesions, and lung index were observed experimentally to evaluate the efficacy.

 Lung lesions, lung index: mice were fasted on the 4th day after infection, and the next day, the 5th day after infection, the mice were sacrificed in groups, and the lungs of the rats were taken out, and the degree of lung lesions was visually judged. 0 means no lung lesions, 1-4 is 25% lung lesions per grade. The weight and lung weight of each mouse were weighed, and the lung index of each mouse was calculated, and the average lung index of each group was determined, and compared and statistically processed. The lung index is the ratio of lung weight to rat weight.

 Mortality, mean life day: Daily observation, record the number of deaths per group for 2 weeks, calculate mortality and average life expectancy.

 Statistical methods: Statistical procedures were used to test drug toxicity results and lung index lesions by t-test analysis; lung lesions were examined by Ridi t test; Kaplan-Meier method was used to compare mortality and mean life days.

 Experimental results:

 The average daily life index was observed experimentally. The survival rate and average life-day test results of Compound 12 against mouse influenza A (H1N1) subtype A (FM1 strain) are shown in Table 4. The experimental results of lung lesions and lung index are shown in Table 5.

Table ⁴ : Pharmacodynamic test survival and average life-day results of compound I ² against mouse model of influenza virus alpha 1 (H1N1) subtype A (FM1 strain) infection

化合物 12

Compound 12

 3/10 70 11. 11* 30mg/kg

 Oseltamivir phosphate

 4/10 60 11. 70" 5mg/kg

 Virus control 10/10 0 8. 4 Normal control 0/10 100 14. 0 Compound 12

 0/10 100 > 14. 0" 300mg/kg

 Compound 12

 0/10 100 > 14. 0" 100mg/kg

 Compound 12

 Second batch 5/10 50 11. 10*

 2 times 30mg/kg

LD ₅ . Osalvaline

 3/10 70 12. 5" 10mg/kg

 Virus control 10/10 0 8. 6 Normal control 0/10 100 14. 0 Kaplan-Meier test with virus control, *p<0.05, **p<0.05. Table 5: Compound 12 against influenza virus A 1 (H1N1 ) subtype A (FM1 strain) Infected mouse model Efficacy test Lung lesions, lung index results

化合物 12

Compound 12

 1. 9 0. 016 30mg/kg

 Ossar phosphate

 2. 6 0. 017 Wei 5mg/kg

 Virus control 3. 5 0. 021 Compound 12

 0. 10" 0. 010" 300mg/kg

 Compound 12

 1. 30"

 100mg/kg

 Second batch of compounds 12

 2 times 3. 0 0. 019

 30mg/kg

LD ₅

 Ossar phosphate

 2. Γ

 Wei 10mg/kg

 Virus control 3. 8 0. 021 Check with virus for t test, *p<0. 05; **p<0. 01

Compound 12 showed reproducible statistical significance in the inhibition of mouse mortality, mean daily life, lung lesions, and lung index in both batches of experiments. This indicates that compound I ² has a reproducible therapeutic effect on experimental infection of mouse influenza A (H1N1) subtype (FM1 strain), and the therapeutic effect is superior to the currently marketed influenza treatment drug oseltamivir phosphate. Although specific embodiments of the invention have been described in detail, those skilled in the art will understand. Various modifications and substitutions may be made to those details in light of the teachings of the invention, which are within the scope of the invention. The full scope of the invention is given by the appended claims and any equivalents thereof.

Claims

 A compound of the formula I, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof

among them,  Is hydrogen or halogen; R ₂ and R _{3 are} independently selected from the group consisting of: hydrogen, (d- ₆ alkyl acyloxy)-d- ₆ alkyl, 1-(d- ₆ alkyl acyloxy)-d- ₆ alkyl, tetrahydrofuranyl a tetrahydropyranyl group, and a hydroxy or halogen substituted d- ₆ alkyl group;  The halogen is selected from the group consisting of fluorine, chlorine, bromine, and iodine, and When R ₂ and R _{3 are} both hydrogen, they cannot be hydrogen or fluorine.  2. A compound of formula I, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, according to claim 1, wherein The (d- ₆ alkyl acyloxy)-d- ₆ alkyl group is (d- ₆ alkyl acyloxy)-methylene or (d- ₆ alkyl acyloxy)-ethyl; The 1-(d- ₆ alkylacyloxy)-d- ₆ alkyl group is 1-(d- ₆ alkyl acyloxy)-methylene or 1-(d- ₆ alkyl acyloxy) - Ethyl.  The compound of the formula I according to claim 1, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, It satisfies one or more of (1) - (3) as follows: (1) is hydrogen or fluorine; (2) R ₂ is hydrogen, acetoxy-methylene, or 2-tetrahydrofuranyl; (3) R ₃ is hydrogen, acetoxy-methylene, hydroxymethyl, 2-tetrahydrofuranyl, pivaloyloxy-methylene, butyryloxy-methylene, isobutyryloxy- Methylene, acetoxy-methylene.  4. A compound of formula I according to claim 1, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, selected from the group consisting of:  N-[(Acetoxy)-methylene]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 4-[(acetoxy)-methylene -3- Oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-fluoro-4-[(acetoxy)-methylene]-3-oxo-3,4-dihydro-2- Pyrazine formamide,  6-fluoro-4-(hydroxymethyl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  N,4-di-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-fluoro-N-(tetrahydrofuran-2-yl)- 3- Oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-fluoro-4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarbonyl Ammonia, 6-fluoro-4-(pivaloyloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  6-fluoro-4-(n-butyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and  6-fluoro-4-[1-(acetoxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, And a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof. A pharmaceutical composition comprising the compound of the formula I according to any one of claims 1 to 4, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof.  The pharmaceutical composition according to claim 5, further comprising a pharmaceutically acceptable carrier or adjuvant; in particular, the pharmaceutical composition is a solid preparation, an injection, a external preparation, a spray, a liquid preparation, or a combination preparation.  7. A process for the preparation of a compound of formula I according to any one of claims 1 to 4, comprising the steps of any of the following methods (1) to (5):  method 1 ) 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 3⁄4 methylcarboxylate in an aprotic organic solvent and in the presence of an organic or inorganic base The corresponding N-[(d- ₆ alkylacyloxy)-methylene)]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide or 4-[(d- ₆₎ Alkyl acyloxy)-methylene)]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, reacted with 1-3⁄4 generation d- ₆ alkyl carboxylate to give Corresponding N-[l-(d- ₆ alkylacyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide or 4-[1-(d- ₆ -alkylacyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,

among them,  R4 is a Cl-6 group; R ₅ is hydrogen or ( ₆ alkyl; X is fluorine, chlorine, bromine, or iodine; Method (2)  In a aprotic organic solvent, 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide is directly reacted with 2,3-dihydrofuran; or in PPTS (p-methylbenzene) Catalyzed by pyridinium sulfonate) and/or P-TsOH (p-toluenesulfonic acid) to give 6-^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide to 2 3-Dihydrofuran reaction to prepare 6-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-^-4-(tetrahydrofuran-2 -yl)- 3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo- 3, 4-dihydro-2-pyrazinecarboxamide,

Method (3) In an aprotic organic solvent, 6--3-oxo-3,4-dihydro-2-pyrazinecarboxamide is directly reacted with 2-d- ₆ alkoxytetrahydrofuran under heating to prepare 6-Id-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-1^-4-(tetrahydrofuran-2-yl)-3 -oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R-[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3, 4-di Hydrogen- 2-pyrazinecarboxamide,

Wherein R is a d- ₆ alkyl group, preferably a tert-butyl group;  Method (4) In a aprotic organic solvent, and in the presence of Lewis acid, the silicon etherified 6-1^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 2-acetoxy group Preparation of 6-RrN-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6--4-(tetrahydrofuran-2-yl)- 3 by tetrahydrofuran -oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R-[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3,4-di Hydrogen- 2-pyrazinecarboxamide,

Method (5) In an aprotic organic solvent, and with the participation of trimethylchlorosilane and triethylamine, 6- 1^-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 2, 3-Dihydrofuran reaction to prepare 6-RrN-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6- - ⁴ - (tetrahydrofuran-2- 3-)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R-[N,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3 , 4-dihydro-2-pyrazinecarboxamide,

In the above methods (1) to (5), it is independently hydrogen or halogen.  8. The preparation method according to claim 7, wherein in the methods (1) to (5):  The aprotic organic solvent is selected from one or more of dichloromethane, DMF, acetonitrile, DME, and THF;  The organic base is selected from one or more of triethylamine, DBU, and diisopropylethylamine;  The inorganic base is potassium carbonate or cesium carbonate;  The halo is substituted with fluorine, chlorine, bromine or iodine.  The preparation method according to claim 7 or 8, wherein In the method (3), the 2-d- ₆ alkoxytetrahydrofuran is 2-tert-butoxytetrahydrofuran; In the method (4), the Lewis acid is selected from the group consisting of SnCl ₄ , TiCl ₄ , and tert-butyldimethylsilyl trifluoromethanesulfonate; and SnCl ₄ is preferred.  The compound of the formula I according to any one of claims 1 to 4, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, or the pharmaceutical composition according to claim 5 or 6 in the preparation of an antiviral drug the use of.  The use according to claim 10, wherein the virus is an RNA virus; specifically, Influenza Virus, Hepatitis C Virus, Bunyavirus, Bering virus ( Phlebovirus ), Foot and Mouth Disease Virus , West Nile virus , Arenavirus , Western Equine Encephalitis Virus , or Yellow Fever Virus ( Yellow Specifically, the influenza virus is a gamma 1 (H1N1) influenza A virus. 12. A compound of formula I according to any one of claims 1 to 4, a pharmaceutically acceptable salt thereof, Use of the hydrate thereof, or a solvate thereof, or the pharmaceutical composition according to claim 5 or 6 for the preparation of a medicament for treating and/or mammalian foot-and-mouth disease; in particular, the mammal is a cloven-hoofed animal; The cloven-hoofed animals are pigs, cows, or sheep.  13. A method of antiviral in vivo or in vitro comprising administering to a subject an effective amount of a compound of formula I according to any one of claims 1 to 4, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvent thereof Or a step of the pharmaceutical composition according to claim 5 or 6, wherein the subject is a mammal; specifically, the cloven-hoofed animal is a pig, a cow, or a sheep.  14. The method according to claim 13, wherein the virus is an RNA virus; specifically, Influenza Virus, Hepatitis C Virus, Bunyavirus, Bering virus ( Phlebovirus ), Foot and Mouth Disease Virus , West Nile virus , Arenavirus , Western Equine Encephalitis Virus , or Yellow Fever Virus ( Yellow Specifically, the influenza virus is a gamma 1 (H1N1) influenza A virus.  A method of treating and/or preventing a foot-and-mouth disease or an influenza in a mammal, comprising administering to a mammal an effective amount of a compound of the formula I according to any one of claims 1 to 4, a pharmaceutically acceptable salt thereof, a hydrate thereof, Or a solvate thereof, or a step of the pharmaceutical composition according to claim 5 or 6, wherein the mammal is a cloven-hoofed animal; specifically, the cloven-hoofed animal is a pig, a cow, or a sheep.