WO2013139206A1 - 3-oxo-3,4-dihydro-2-pyrazine-formamide derivative, pharmaceutical composition of same, method for preparing same, and use thereof - Google Patents

Description

 3-oxo-3,4-dihydro-2-pyrazinecarboxamide derivative,

 Pharmaceutical composition thereof, preparation method and use thereof

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

 3-oxo-3,4-dihydro-2-pyrazinylamide (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 RA polymerase of a kind of virus, which has better antiviral effect. It has been reported that T705 alone or in combination with a neuraminidase inhibitor has a good anti-virulence effect (Antimicrobial Agents and Chemotherapy, 2007, Vol.51, No.3, 845-851; Antimicrobial Agents and Chemotherapy, 2010, 126-133, PCT Patent: WO2000010569). T1 105 exhibits a very good effect against foot-and-mouth disease virus in both in vivo and in vitro models (PCT patent: WO20071139081). In addition, T705 and T1106 have a good effect on diseases caused by other R A viruses. For example, Τ705 has a therapeutic effect on Western-type equine encephalitis in a mouse model (Antiviral Research 82 (2009) 169-171); T705 and T1106 have a therapeutic effect on yellow fever in hamsters (Antimicrobial Agents and Chemotherapy, 2009, 202- 209 ); T705 has therapeutic effects in vivo and in vitro against diseases caused by arenavirus and Bunia virus infection (Antimicrobial Agents and Chemotherapy, 2007, 3168-3176). T705 has a therapeutic effect on rodents infected with West Nile virus (Antiviral Research 80 (2008) 377-379); T705 has a therapeutic effect on venous viral infection (Antiviral Research 86 (2010) 121-127).

^H I O

^H

^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 guanosine triphosphate (GTP). The virus RA polymerase is inhibited to exert an antiviral effect (ANTIMICROBIAL AGENTS AND CHEMOTHERAPY, 2005, Vol. 49, No. 3, p. 981-986).

 Although T1105 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, the IC50 is 1.6 ug/mL, but the oral administration of the pig twice a day to a dose of 200 mg/Kg can 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 larger dosage of the oral dose of 800 mg - 2400 mg per day. Summary of the invention

 The inventors have conducted intensive studies to obtain a new class of 3-oxo-3,4-dihydro-2-pyrazinylamide derivatives (compounds of formula I), and surprisingly found that the derivatives It can be transformed into T705 or T1105 in vivo, showing good antiviral effect and having the 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 1

 among them,

 Is hydrogen or halogen;

And 1 _{3 are} independently selected from the group consisting of: hydrogen, (Cw, alkyl acyloxy) - Cw, alkyl, 1-(C _W , alkyl acyloxy)-(small ₆ alkyl, tetrahydrofuranyl, tetrahydropyridyl a C. pit group substituted with a thiol group and a hydroxyl group or a J) group;

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

When R ₂ and both are hydrogen, R cannot be hydrogen or fluorine.

 EXAMPLES Experiments 7 and 18 demonstrated that the compound of formula T can be converted to T705 or Τί 105 in mice and monkeys. Example 17 confirmed that the oral bioavailability of Compound 3 and Compound 12 administered orally to mice was significantly higher than that of Τ705. Example 18 Confirmation of oral administration of monkeys The oral bioavailability of Compound 10 and Compound 12 was significantly higher than that of '1.705. Since the antiviral and antifungal effects of .05 or T1105 are known in the art, it is expected 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 reproducible statistically significant effect on the inhibition of mortality, mean life, lung lesions, and lung index in mice, and the therapeutic effect is superior to the currently marketed influenza therapeutic drug. Sitavir.

 Furthermore, 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 (Cw, alkyl acyloxy)-C ₁₄ , alkyl group is (Cw, alkyl acyloxy) - methylene or (Ci-6 appearance base listens to ^^;

The l-w,alkylacyloxy)-Cw fluorenyl group is 1-iC^alkyl acyloxy)-methylene or 1-(C ₆ hydroxy 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:

 And a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, and a further aspect of the invention relates to a pharmaceutical composition comprising a compound of the formula I according to any one of the invention, a pharmaceutically acceptable salt thereof, a hydrate, 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 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. The 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, which may be enterally or parenterally, such as sputum, muscle, subcutaneous, nasal cavity, 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 ore, silicon. Aluminum sulphate, etc.; wetting agent and binder, such as water, glycerin, polyethylene glycol, ethanol, propanol, starch slurry, dextrin, syrup, honey, glucose solution, gum arabic, gelatin pulp, carboxymethyl cellulose Sodium, shellac, thiol cellulose, potassium phosphate, polyvinylpyrrolidone, etc.; disintegrating agents, such as dried starch, alginate, agar powder, brown algae starch, sodium bicarbonate and tannic acid, calcium carbonate, polyoxyethylene , sorbitol fatty acid ester, sodium dodecyl sulfate, decyl cellulose, ethyl cellulose, etc.; disintegration inhibitors, such as sucrose, glyceryl tristearate, cocoa butter, hydrogenated oil, etc.; absorption Promoters, such as quaternary ammonium salts, sodium lauryl sulfate, etc.; lubricants such as talc, silica, corn starch, stearates, boric acid, liquid paraffin, polyethylene glycol . 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, a diluent and an absorbent such as glucose, lactose, starch, cocoa butter, hydrogenated vegetable oil, polyvinylpyrrolidone, Gelucire, sorghum, talc, etc.; binders such as gum arabic, gum 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 loaded Into the hard strands or for injection application. In order to prepare the administration unit into an injection preparation such as a solution, an emulsion, a frozen, a dry powder injection and a suspension, all diluents conventionally used in the art, for example, water, ethanol, polyethylene glycol, 1, 3 may 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):

( ί ) in an aprotic organic solvent, and in the presence of an organic or inorganic base, 6-R,-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 3⁄4 The carboxylic acid ester gives the corresponding N-|(Ci. ₆ alkyl acyloxy)-methylene) 1-3-oxo-3,4-dihydro-2-pyrazinecarboxamide or 4-[ (Alkyl acyloxy)-methylene)]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, reacted with 1-halo(^- ₆ alkylcarboxylate) , corresponding to N- 11-(Phenyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinylamide or 4-[1-(C _1-6 Alkyl acyloxy)-ethyl]-3-oxo-3,4-dihydro-2-pyrazinecarboxamide

其中，

among them,

 R4 is Ci-c

For 氲 or C _1-6 pit base;

 X is fluorine, chlorine, bromine, or floor;

(2) oxo-3,4-dihydro-2-pyrazinecarboxylate in an aprotic organic solvent Ammonia is directly reacted with 2,3-dihydrofuran; or 6-R _t -3 under the catalysis of PPTS (p-toluenesulfonic acid pyridinium salt) and/or p-TsOH (p-methylbenzene cross-acid) -Oxo-3,4-dihydro-2-pyrazinecarboxamide is reacted with 2,3-dihydrofuran to prepare 6-RH-(tetrahydrofuran-2-yl)-3-oxo-3,4- Dihydro-2-pyrazinecarboxamide, 6-R _t -4- (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and G-RrlJN , 4-di-(tetrahydrofuran-2-yl)j-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,

(3) reacting 6--3-oxo-3,4-dihydro-2-pyrazinecarboxamide directly with alkoxytetrahydrofuran under heating in an aprotic organic solvent to prepare 6- Ri-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinylamide, 6-3⁄4-4-(tetrahydrofuran-2-yl)-3-oxo -3,4-dihydro-2-pyrazinecarboxamide, and 6-Ri-lN, 4-di-(tetrahydrofuran-2-yl)]-3-oxo-3,4-dihydro-2- Pyrazine formamide,

其中， R为 烷基， 优选为叔丁基；

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

(4) 6-Ri-3-oxo-3,4-dihydro-2-pyrazinecarboxamide and 2-acetyl which are deuterated in an aprotic organic solvent and in the presence of Lewis acid Oxytetrafuran reaction, preparation 6-T rN- (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-1^-4-(tetrahydrofuran-2-yl)-3- Oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-3⁄4-[, 4-di-(tetrahydrofuran-2-yl) 3-oxo-3,4-dihydro-2- Pyrazine formamide,

(5) 6-oxo-3,4-dihydro-2-pyrazinecarboxamide and 2,3 in an aprotic organic solvent with the participation of a trimethylsilyl chloride furnace and triethylamine -Dihydrofuran reaction, preparation of (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-R _r 4-(tetrahydrofuran-2-yl)-3 -oxo-3,4-dihydro-2-pyrroylformylamide, and 6-RrfN,4-di-(tetrahydrofuran-2-yl)]-3-oxo-3,4-dihydro-2 -pyrazine formamide,

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) - (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, DBLK 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 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-butyl fluorenyl silicon Fluoroformate; preferably SnCl ₄ . 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 Bunyavirus, a Phlebovirus, a foot-and-mouth disease virus ( Foot and Mouth

Disease Virus ) , West Nile virus , Arenavirus , Western Equine Encephalitis

Viru), or Yellow Fever Virus; specifically, the influenza virus is a 1 (H1N1) influenza A virus. 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 in the preparation of a therapeutic And/or use in a medicament for mammalian foot-and-mouth disease; specifically, the mammal is a cloven-hoofed 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 or using 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 subject is a mammal, such as a cloven-hoofed animal (e.g., pig, cow, or sheep).

II A further aspect of the invention relates to a method of treating and/or preventing foot-and-mouth disease 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 comprising A step of a pharmaceutical composition of 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 dosage 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 provide the desired therapeutic response to the particular patient, composition, and mode of administration. 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 a practice in the art to start at a dose lower than that required to achieve the desired therapeutic effect and gradually increase the dosage 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 in 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 the disorder in a reasonable effect/risk ratio suitable for 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. For any particular patient, the specific therapeutically effective dose level will depend on a number of factors, including the disorder being treated and the severity of the disorder. Degree; activity of the particular compound employed; specific composition employed; age, weight, general health, sex and diet of the patient; time of administration, route of administration and excretion rate of the particular compound employed; Time; a drug used in combination with or in combination with a particular compound employed; and similar factors well known in the medical arts. For example, 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. In general, the dose of the compound of the formula I according to the invention for use in mammals, especially humans, may range from 0.001 to 1000 mg/kg body weight per day, for example between 0.01 and 100 mg/kg body weight per day, for example between 0.01 and 10 Mg/kg body weight / day.

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

 In the present invention, the term "effective amount" means a dose which can achieve a treatment, prevention, alleviation and/or alleviation of the disease or condition of the present invention in a subject.

The term "cvc ₆ alkyl," or "d-6 alkyl" (including c _1-6 alkyl acyloxy or (c _1-6 alkyl acyloxy) - C _{t -6} alkyl or l^Cw alkyl acyloxy) -c ^ alkyl with any one of a c _t _ ₆ alkyl with) refers to 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-decylpentyl and the like. Accordingly, "Cw alkyl acyloxy," can be similarly understood. In one embodiment of the invention, the "qialkyl" or "alkyl" is alkyl or alkyl. In one embodiment of the invention, the (Cw alkyl acyloxy)-d The .6 alkyl group is (Cw alkyl acyloxy)-C^alkyl or (C _{4 -6} alkyl acyloxy)-C _{4 -6} alkyl. In one embodiment of the invention, the 1 - (^ _ ₆ alkyl acyloxy) - (: ₁₆ l-fCw alkyl group as acyloxy) -CW acyloxy or alkyl) -C _{4 6} alkyl.

The term "CVC ₆ alkoxy" or "d- ₆ alkoxy" refers to a straight or branched alkoxy group having from 1 to 6 carbon atoms, for example, decyloxy, ethoxy, propoxy, iso Propyloxy, n-butoxy, sec-butoxy, tert-butoxy, pentyloxy, 2-oxopentyl, isooxypentyl, neopentyloxy, hexyloxy, 2-hexyloxy, 3 - Oxyhexyl, 3-methylpentyloxy and the like. In an implementation of the invention Embodiment, the "Ci-Ce alkoxy" or "D. ₆ group" is an alkoxy group or d_ _{3. 6} alkoxy. Advantageous 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.l: Drug-time curve of T705 after oral administration of compounds 3, 4, 6 and T705, respectively.

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

 Fig. 3: The 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 the J! 艮 compounds 3, 10, 12, 11, 13 and T705 (at the time of drug testing, 3 monkeys, after giving a drug test, after a lot of In the 3-day wash period, the next test drug is given). detailed description

The embodiments of the present invention will be described in detail below with reference to the accompanying drawings, however, Those who do not specify the specific parts in the examples are carried out according to the conventional conditions or the manufacturer's recommendations. The reagents or instruments used are not indicated by the manufacturer, and are all conventional products that can be obtained commercially. Example 1: N4 (acetoxy)-indenyl 3-oxo-3,4-dihydro-2-pyrazine indole (compound 1) and 4-Kacetoxymethylene 1- Preparation of 3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 2)

 Compound 2 Compound 1 Under a nitrogen atmosphere, 1.39 g (lOmmo 1) of T1 105 was dissolved in 10 mL of anhydrous DMF, stirred at room temperature for 15 m in a suspension, and chloromethyl acetate (2.12 g) was added dropwise. 20 mmo 1), potassium indole (2 ininol) and triethylamine 03 g (30 mmol), the solution was clarified after the addition. After stirring at room temperature for 24 hours, the reaction mixture was concentrated in vacuo to EtOAc. EtOAc was evaporated. Separation (dichloromethane / methanol elution) gave two major products, respectively, N-|(acetoxy)-methylene-3-oxy-3,4-dihydro-2-pyrazinecarboxamidine Ammonia

1) and 4-[(acetoxy)-methylene 1-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (compound)

2) ₀

 Compound 1:

^INMR ( CCD ) , δ 2.18(3H, _S ), 5.92(2H, s), 6.42(lH,brs), 7.66(lH,d,J=4.0Hz), 7.70(1 H,d,J =4.0Hz), 9,04(lH,brs); ESIMS (m/e) 25 (MK ⁺ ),234 ( : a ⁺ ),221 (MH ⁺ )

 Compound 2:

^ R ( CC13 ) , 6 2.12(3H, s), , 5.88 (lH, brs), 6.25 (2H, s), 7.52 (lM, brs), 8.35 (lH, s), 8.39 (lH, s); ESIMS (m/e) 250 (MK+), 234 (MNa ⁺ ), 221 (MH+).

Example 2: 6-Fluoro-4-liacetoxy)-methylene-3-oxy-3-,4-dihydro-2-pyrazinecarboxamide (Compound 3) and 6-Fluoro-4- Preparation of (methyl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 4)

方法同合成实施例 1 , 只是以 T705代替 T1 105, 主要得到 6-氟 -4-[(乙酰氧基) - 亚甲基] -3-氧代 -3，4-二氢 -2-吡嗪甲酰氨 (化合物 3 )和 6-氟 -4- (羟甲基) -3-氧代 -3,4-二氢 -2-吡嗪甲酰氨（化合物 4 ) 。

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

 Compound 3:

¹ Li (CDC13) 62.12 (3H, s), 5.85 (1 H, brs), 6.21 (2H, s), 7.38 (1 H, s), 8.20 (lH, d, J = 8.4 Hz); ESIMS ( Ra/e), 252(MNa ), 230(MH ⁺ )

 Compound 4:

¹ H NMR (DMSO-d6) 65.77 (3H, s), 7.82 (1H, brs), 8.00 (lH, brs), 8.41 (lH, d, J = 8.4 Hz); ESIMS (m/e), 188 (MH) ⁺ ). Example 3: Preparation of 4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 5)

 400 mg (2.87 mmoI) of Til 05 was suspended in 20 ml of THF, and 2,3-dihydrofuran (15.5 mmol) and PPTS (9 mg) were added, and the reaction was stirred at room temperature for 48 hours, and the reaction was filtered. The insoluble material was filtered off, concentrated to give an oil, which was solidified and washed with methanol to give a powdery solid.

 Compound 5:

¹ H NMR ( DMSO-d6 ) , δ 1.75-1.85 (1 H, m), 1.90-2.10 (2H, m), 2.35-2.45 (1 H, m), 3.90-4.00 (1 H, m), 4.30- 4.40(1 H,m), 6.04-6.12(1 H,m), 7,55(lH,d, J=4.0Hz), 7.72(lH, rs), 7.78(lH,d,J=4.0Hz), 8.39(lH,brs); ESIMS(m/e), 210 ( MH ), 232 (MNa ⁺ ). Example 4: 6-Fluoro-4-indolyltetrahydrofuran-2-yl)-3-methoxy-3,4-dihydro-2-pyridinylamide

(Compound 6)

 Compound 6 400 mg (2.54 mmol) of hydrazine 705 was suspended in 20 mL of THF, and 2, 3-dihydrofuran (15.5 mmol) and PPTS (9 mg) were added, and the reaction was stirred at room temperature for 72 hours, and the reaction was filtered. The filter cake was washed with THF to give a powdery solid as Compound 6.

 Compound 6:

¹ H NMR (DMSO-d6 ) , δ 1.78-1.88 (1 Η, Μ), 1.91-1.99 (lH, m), 2.06-2.14 (1 H, m), 2.34-2.43 (1 H, m), 3.91 - 3.97(1 H,m), 4.39-6.08(1 H,m), 7.93(1 H.brs), 7.98(lH,d,J=5,6Hz), 8.68(lH,brs); ESIMS(m/ e) 228(MH ⁺ ), 250(MNa ⁺ ) _o Example 5: N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 7 Preparation

 Compound 7

In a dry three-necked flask, 1.075 g (7.7 mmol) of hydrazine 05 and 1.67 g (ll, 6 mmol) of 2-tert-butoxytetrahydrofuran were added, dissolved in 5 mL of anhydrous DMF, and heated to 150 ° under N ₂ protection. After reacting for 12 hours, after dropping to room temperature, lOmJL dichloromethane was added, and a solid precipitated. The solid was collected by filtration and recrystallized twice from methanol with acetonitrile. Recrystallization once gave 250 mg of a white solid as Compound 7.

 Compound 7:

¹ Li legs (DMSO-d6), δ 1.77 (2H, m), 2.71 (2H, m), 3.42 (1 H, m) 4.56 (lH, brs), 6.36 (2H, dd, J=5, 6 Hz) , 6.93 (lH, d = 6.0 Hz), 9.72 (1H d, J = 6.0 Hz), 10.56 (lH, brs). ESlMS (m/e), 210 (MH), 232 (MNa). Example 6: 6-Fluoro-N-(tetrahydrofuran-2-yl 3-oxo-3,4-dihydro-2-pyrrolidine gas

Preparation of (Compound 8)

 In a dry three-necked flask, add 377rag (2.4mmoI) of 1705 and 670mg (4.8mmol) of 2-tert-butoxytetrahydrofuran, and dissolve with 5mL of anhydrous]\1?(1-methylpyrrolidone), N2 protection Heat to 14 (TC reaction for 10 hours, add 200 mg (1.4ramoI) of 2-tert-butoxytetrahydrofuran, continue to react at this temperature for 10 hours. Then, after cooling to room temperature, the solvent is evaporated under reduced pressure, and the residue is used. The preparative TLC was isolated and purified (dichloromethane/methanol) to afford a white solid 100 s.

 Compound 8:

12.44(lH,brs)。 实施例 7: N, 4-二 -i四氢呋喃 -2-基) -3-氧代 -3,4-二氢 -2-吡嗪甲酰 氨（化合物 9 ) 的制备

^ MRiCDClS ) , 6 (ppm), 1.90-2.10 (3H, ra), 2.40-2.50 (lH, m), 3.85-3.95 (lH, m) _? 4.00-4.10(lH,m), 5.88(lH,m ), 7.79(lH,brs),

12.44 (lH, brs). Example 7 Preparation of N,4-di-itetrahydrofuran-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, add 1.39 g (10 mmo) of II 105 and 20 mL of anhydrous DMF, stir well to obtain a suspension, and add 2.16 g (20 minol) of trimethylchlorosilane by syringe. And l.Olg (10 mmol) of triethylamine, keep the internal temperature not higher than 33 C, and then react at room temperature for 7 hours, the reaction is concentrated to dryness under reduced pressure, and then flash column chromatography (dichloromethane / methanol wash) Remove) to give a pale yellow solid as compound 9.

 Compound 9:

ESIMS (m/e, 1 0) 302 (MNa ⁺ , 45), 280 (MH ⁺ , 30), 232 (58), 210 (100), 156 (48). Example 8: Preparation of 6-fluoro-4-(pivaloyloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (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-(pivaloyloxymethyleneoxy-3,4-di). Hydrogen-2-pyrazinecarboxamide (Compound 10).

 Compound 10:

¹ Lirang (CDC13), S (ppm), 1.l8 (9H, s), 6.21 (2H, s), 6.21 (III, brs), 7.42 (lH, brs), 8.29 (lH, d, J = 8.8Hz); ESIMS(m/e ) 272(MH ⁺ ) ₀ Example 9: 6-Fluoro-4-(butyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 11)

 The method was the same as in the synthesis of Example 1, except that Τ 705 was substituted for T110S, and chloromethyl butyrate was used instead of chloromethyl acetate to obtain 6-fluoro-4-(n-butyryloxymethylene)-3-oxo-3. 4-Dihydro-2-pyrazinecarboxamide (Compound 11).

 Compound 11:

^INMR ( DC13 ) 60.92(3H,t,J=7.2Hz) _i 1.66(2H,m), 2,35(2H, t,J=7.2Hz),6.22( 2H, s ) ,6.44(lH,bs 7.43 (lH, brs), 8.19 (lH, d, J = 8.4 Hz); ESIMS (m/e) 258 (MH ⁺ ) ₀ Example 10: 6-fluoro-4-{isobutyryloxy- -3-oxo-3,4-dihydro-2-pyrazine

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 mmo0) was added dropwise, and the temperature was lowered to 0. Add 3,41 g (25 mmo l) of chloromethyl acetate. After adding to room temperature for 24 hours, the reaction solution is poured into 100 mL of cold water, extracted three times with dichloromethane, and the organic phase is combined with IN. Wash twice with hydrochloric acid, wash with saturated sodium citrate solution, wash with sodium chloride solution, The sodium salt is dried and concentrated to a thousand. After the silicon strands are mixed, the column is separated by flash column chromatography (dichloromethane/methanol elution) to obtain 6-fluoro-4-(isobutyryloxymethylene)-3. - Oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound Ί2).

 Compound 12:

¹ H NMR ( CDC13 ) ai.l6 (6H, d, J = 6.8 Hz), 2.59 (lH, m), 6.21 (2H, s), 6.30 (lH, bs), 7.41 (lH, brs), 8.19 (lH) , d, J = 8.4 Hz); ESIMS (m/e) 258 (MH ⁺ ). Example 11: 6-Fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 1

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 mmol) was added dropwise and cooled to 0. C, 2,12 g (20 mmo I) 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 three times with dichlorohydrazine to combine organic The phase was washed twice with 1N hydrochloric acid, washed with saturated sodium bicarbonate solution, washed with sodium chloride solution, dried over sodium sulfate, and concentrated to dryness. After silica gel chromatography, it was separated by flash column chromatography (dichloromethane/methanol wash) Mainly, 6-fluoro-4-(isobutyryloxy fluorenyl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 12) was obtained. Example 12: Preparation of 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-diar-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-pyrazin decanoylamide (Compound 12). Example 13: Preparation of 6-fluoro-4-(isobutyryloxymethylene fluoren-3-oxo-3,4-dihydro-2-pyrazinium amide (Compound 12) (4)

Compound 12 Under a nitrogen atmosphere, 1.57 g (U) mmo I) of T705 was dissolved in 10 mL of anhydrous DMF. After stirring at room temperature for 15 min, potassium sulphate (20 mm oi) was added and the temperature was lowered to 0. C, 2.12 g (20 mmol) of bromomethyl acetate was added dropwise, and after completion, stirring at room temperature for 24 hours, the reaction solution was poured into 100 mL of cold water containing 40 mmol of HCl, and extracted three times with dichloromethane. The organic phase was washed twice with li hydrochloric acid, washed with saturated sodium carbonate solution, washed with sodium chloride solution, dried over sodium sulfate and concentrated to dryness. Methanol elution) mainly gave 6-fluoro-4-(isobutyryloxymethylene)-3-oxo- 3,4-dihydro-2-pyrolecarboxamide (Compound 12). Example 14: Preparation of 6-fluoro-4-ί isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 12) (S)

 The compound 12 method was the same as in the synthesis of Example 13, except that potassium carbonate was used instead of potassium carbonate, and mainly 6-fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-diindole-2- Pyrazine formylamide (compound 12). Example 15: 6-Fluoro-4-(isobutyryloxymethylene)-3-oxo-3,4-dihydro-2-pyranyl

Compound 12 Under a nitrogen atmosphere, 1.57 g (10 mmol) of T705 was dissolved in 10 mL of anhydrous DMF. After stirring at room temperature for 15 min, triethylamine 3.03 g (30 mmol) was added dropwise, and then cooled to -30. C, then add iodine methyl acetate 2.12 g (20 mmo) in acetonitrile solution, add, at -30. After reacting for 24 hours at C, gradually increase to 0 C for 8 hours. The reaction solution was flushed into 100 mL of cold water, extracted three times with dichloromethane, and the organic phase was combined and washed twice with 1N hydrochloric acid, saturated sodium hydrogen hydride solution. Washing, washing with sodium chloride solution, drying with sodium afuate, concentrating to a thousand, and mixing the silicon strands with Flash column chromatography (dichloromethane/methanol elution) to obtain 6-fluoro-4-(isobutyryloxy) Benzylmethyl)-3-oxo-3,4-diindole-2-pyrazinecarboxamide (Compound 12). Example 16: Preparation of 6-fluoro-4-11-(acetoxy)-ethyl 1-3-oxo-3,4-dihydro-2-pyrazinecarboxamide (Compound 13)

 The method was the same as in Synthesis Example 1, except that T705 was used instead of T1 10S, and 1-chloromethyl acetate was used instead of chloromethyl acetate to obtain 6-fluoro-4-[1-(ethylideneoxy)-ethyl]- 3-oxo-3,4-diindole-2-pyrazinecarboxamide (Compound 13).

 Compound 13:

¹ HNMR ( CDC13 ) S1.73 (3H, d, J = 5.6 Hz), 2.08 (3H, s ) 6.50 ( 1H, brs ) , 7.22 (1H, q, J = 5.6 Hz), 7.35 (lH, brs) , 8.17 (lH, d, J = 8.4 Hz); ESIMS (m/e) 244 (MH+). Example 17: Metabolism experiment in mice

Experimental drug: Compound 1-13, ΤΠ05, T705 _o

 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 by gavage at a dose of 0.0637 mmol/10 ml/kg (corresponding to 10 mg/10 ml/k for T705 or ΊΊ105) (a group of 3 mice per compound). 20 L of blood was collected from the eyelids at different time points, 20 μL of cation internal standard acetonitrile solution, 20 jiL anion internal standard acetonitrile solution, 40 L acetonitrile, shaking, 18000 g centrifugation for 10 min, and the supernatant LC S/MS was injected. The concentration of the corresponding test compound and T70S or T1105 was determined separately. Bioavailability calculated by T110S when metabolized in mice. [AUG (M*h)] value.

 Experimental results:

 As shown in Fig.l - 3 and Table 2-3.

Table 2: Bioavailability of T705 and its derivative compounds 3, 4, 6, 10, 11, 12, 13 and the like in the metabolism of mice and monkeys [AUC (μΜ*1ι)] and half-life fTl/2 (h)〗 value

Bioavailability calculated by ΤΊ105 when T1105 and its derivative compounds 7 and 9 are metabolized in mice IALJC (μΜ )

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 can significantly increase the plasma concentration and oral bioavailability calculated by T705, and Increase 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 orally administered in mice 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 methods: Three macaques were orally administered with 0.0637 mmol/l ml/kg orally to give a test drug. 50 μΙ of monkey plasma was taken at different time points, 50 L different concentrations of T705 acetonitrile standard solution were added, 50 L anion internal standard acetonitrile solution, 100 acetonitrile was added, and the analytical sample was equivalent to plasma concentrations of 100, 500, 1000, 5000. The 10000 ng/mU was shaken, centrifuged at 18000 g for 10 min, and the supernatant was taken for LC/MS/MS 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, 1 1, 12, 13 and other four compounds can significantly improve the blood concentration and oral bioavailability in terms of T705, compounds 12 and 10 in increasing the blood concentration and oral life in T705 The effect of these two aspects is most obvious. Example 19: Pharmacodynamic study of compound 12 in a mouse influenza virus alpha 1 (H1N1) subtype (FM1 strain) infection model

Experimental drug: Compound 12 was formulated into a colorless transparent solution using physiological saline. Experimental time 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, with a health certificate.

Virus used: Influenza virus A (H1N1) subtype (FM1 strain) Mouse lung adaptation forest (provided by the Institute of Medical Biotechnology, Chinese Academy of Medical Sciences, other H1N1 influenza strains can also be purchased or used). Toxic to mice LD50 of about ^10.5.

 Control drug: oseltamivir phosphate, provided by the Institute of Pharmacology and Toxicology, Academy of Military Medical Sciences. experimental method:

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

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

 The first batch of experiments: Compound 12 dose: 30 mg/kg, 100 mg/kg, 300 mg/k Three dose groups of the administration group, 20 mice per group. Dosing is about 1 hour after infection. Infected controls were treated with the same amount of physiological saline. The positive control drug oseltamivir (5 mg/kg) was administered 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 groups of the drug group, 20 mice per group. Dosing is about 1 hour after infection. Infected controls were treated in the same amount as normal saline. The positive control drug oseltamivir (10 mg/kg) was administered once a day, and the administration time was the same as that of the treatment group.

 The administration time qdx5, the virus LD50 was simultaneously titrated in each batch of experiments.

 Virus isolation experiment: Mice were infected with appropriate amount of influenza virus FM-1, and the infected mice were divided into three groups, which were treated with lOOmg/k compound 12, oseltamivir 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. Weigh and store in an ice bath at -85 °C. The lung tissue was added to 10 volumes of MEM and an appropriate amount of glass powder, and thoroughly ground into a homogenate. The supernatant was collected by centrifugation at 12,000 rpm for 1 minute at 4 °C. The supernatant was diluted in equal portions, CPE was observed on MDCK cells at 24 and 48 hours, and TC1D50 of each lung was titrated.

Observation and judgment indicators: Experimental observation of mortality, average life day, lung disease, lung index To evaluate the efficacy.

 Lung lesions, lung index: The 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 indicates no lung disease, and 1-4 is 25% lung lesions per grade. The weight and lung weight of each mouse were weighed. The lung index of each mouse was calculated, and the average lung index of each group was obtained for comparison and statistical processing. 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 Ridit 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 of the compound 12 against the mouse influenza virus 曱 1 (H1N1 ) subtype (FM1 strain) infection and the average life day test results are shown in Table 4. The experimental results of lung lesions and lung index are shown in Table 5. Table 4: Compound 12 vs. influenza virus 曱 1 (H1N1) subtype A (FM1 strain) Infected mouse model efficacy test survival and average life day results

病毒对照 10/10 0 8.4

Virus control 10/10 0 8.4

 Normal control 0/10 100 14.0

 Compound 12

 0/10 100 ≥14.(Γ

 300mg/kg

 Compound 12

 0/10 100 ≥14.(Γ

 100mg/kg

 Compound 12

 The second batch 2 times LDso 5/10 50 11.10*

 30mg/kg

 Oseltamivir phosphate

 3/10 70 12.5

 10mg/kg

 Virus control 10/10 0 8.6 Normal control 0/10 100 14.0

 Kaplan-Meier test was performed in comparison with virus, *p<0.05, **p<0.05. Table 5: Compound 12 against influenza virus A (H1 1 ) subtype A (FM1 strain) in a mouse model of drug efficacy test lung lesions, lung index results

化合物 12

Compound 12

 ο.ΐίΓ 0.010"

 300mg/kg

 Compound 12

 0.014"

 100mg/kg

 2 times

 Second batch of compounds 12

LD ₅ „ 3.0 0.019

 30mg/kg

 Oseltamivir phosphate

 2. 0.012"

 10mg/kg

 Virus control 3.8 0.021

 T test was performed in comparison with virus, *p<0.05; **p<0.01.

 Compound 12 showed reproducible statistical significance in the inhibition of mouse mortality, mean daily life, lung disease, and lung index in both batches of experiments. This indicates that the compound 12 has a reproducible therapeutic effect on the experimental infection of the 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 alterations may be made to those details in accordance with the teachings of the invention, which are within the scope of the invention. The full scope of the invention is indicated by the appended claims and any equivalents thereof.

Claims

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

 Formula I  among them,  Is hydrogen or halogen; 3⁄4 and independently selected from: hydrogen, (Cw, alkyl acyloxy)-Cw, alkyl, alkyl acyloxy)-(: j. ₆ alkyl, tetrahydrofuranyl, tetrahydropyranyl, and hydroxy Or a halogen-substituted C ₆ group;  The halogen is selected from the group consisting of fluorine, chlorine, bromine, and hydrazine, and When R ₂ and R _{3 are} both hydrogen, they cannot be hydrogen or fluorine.  The compound of the formula T according to claim 1, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, wherein  The (C^alkylacyloxy)alkyl group is (Cw,alkylacyloxy)-methylene or ((;alkylacyloxy)-ethyl;  The i-(Cw alkyl acyloxy)alkyl group is a (C^alkyl acyloxy)-indenylene group or a 1-((small fluorenyloxy)-ethyl group.  The compound of the formula I according to claim 1, a pharmaceutically acceptable salt thereof, a hydrate thereof, or a solvate thereof, wherein  It satisfies the following (1) - (3) any one or more of:  (1) R, which 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-arylene, butyryloxy-hydrazolyl, 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)-indenyl j -3-oxo-3,4-dihydro-2-pyrazine decanoylamide,  6-fluoro-4-[(acetoxy)-methylene-3-oxy-3,4-dihydro-2-pyrazinecarboxamide,  6-fluoro-4-(hydroxyindenyl)-3-oxo-3,4-dihydro-2-pyrazinenonanoylamine,  N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamidine,  N, 4-di-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazine decanoylamide,  6-fluoro(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide,  6-fluoro-4-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazine decanoylamide,  6-fluoro-4-(neopentyloxymethylene)-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-pyrazinylamide, and 6-fluoro-4-11-(acetoxy)-ethylpyr-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, and pharmaceutically acceptable salts thereof, hydrates thereof, or Solvate.  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 ) In an aprotic organic solvent, and in the presence of an organic or inorganic base, 6-1^-3- Oxo-3,4-dihydro-2-pyrazinylamide and halomethylcarboxylate give the corresponding N-KC^alkylacyloxy)-methylene)]-3-oxo- 3,4-Dihydro-2-pyrazinecarboxamide or 4-[(alkyloxy)-methylene) 1-3-oxo-3,4-dihydro-2-pyrazinecarboxamide Ammonia, reacting with 1-halo (: alkylalkyl carboxylate to give the corresponding (w, alkyl acyloxy)-ethyl 1-3-oxo-3,4-dihydro-2-pyridyl Pyrazinamide or 4-[1-(( ₆ -alkylacyloxy)-ethyloxo-3,4-dihydro-2-pyrazinylamide,

among them, R ₅ is hydrogen or Cw, an alkyl group;  X is fluorine, chlorine, bromine, or angstrom;  Method ( 2 )  In an aprotic organic solvent, oxo-3,4-dihydro-2-pyrazinylamide is directly reacted with 2,3-dihydrofuran; or in PPTS (pyridyl p-toluenesulfonate) and / or P-TsOH (p-toluenesulfonic acid) catalyzed reaction of 6--3-oxo-3,4-dihydro-2-pyrazinecarboxamide with 2,3-dihydrofuran, Preparation of 6-Ri-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6-3⁄4-4-(tetrahydrofuran-2-yl)-3 -oxo-3,4-dihydro-2-pyrazinecarboxamide, and 6-R |N,4-di-(tetrahydrofuran-2-yl)bu 3-oxo-3,4-dihydro- 2-pyrazinecarboxamide,

Fang's method (3) In a aprotic organic solvent, 3-oxo-3,4-dihydro-2-pyrazinecarboxamide is directly reacted with 2-d- ₆ alkoxytetrahydrofuran under heating to prepare 6-TRrN. - (tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6--4-(tetrahydrofuran-2-yl)-3-oxo-3,4 -dihydro-2-pyrazinecarboxamide, and 6--, 4-di-(tetrahydrofuran-2-yl) j-3-oxo-3,4-diin-2-pyrazinecarboxamide ,

Wherein R is a C _1-6 aryl group, preferably a tert-butyl group;  Method ( 4 )  Silanated 6-11,-3-oxo-3,4-dihydro-2-pyrazinecarboxylic acid and 2-acetoxy group in an aprotic organic solvent and in the presence of Lewis acid Preparation of 6-R4-N-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6--4-(tetrahydrofuran-2-yl) by tetrahydrofuran 3-oxo-3,4-diin-2-pyrene formyl, and 6-R,-f\,4-di-(tetrahydrofuran-2-yl)-3-oxy-3,4 - dihydro-2-pyrazinecarboxamide,

Method (5)  Oxy-3,4-dihydro-2-pyrazinecarboxamide is reacted with 2,3-dihydrofuran in an aprotic organic solvent with the participation of trimethylchlorosilane and triethylamine. Preparation of 6--indole-(tetrahydrofuran-2-yl)-3-oxo-3,4-dihydro-2-pyrazinecarboxamide, 6--4-(tetrahydrofuran-2-yl)-3-oxo 3,4-dihydro-2-pyrazinecarboxamide, and 6- -[Ν, 4-di-(tetrahydrofuran-2-yl) 3-oxo-3,4-dihydro-2 -pyrazine formamide,

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 non-shield organic solvent is selected from the group consisting of dichloromethane, DMF, acetonitrile, DME, and One or more of THF;  The organic base is selected from one or more of triethylamine, DBU, and diisopropylethylamine;  The inorganic base is potassium complex or carbonated gauze;  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-butyl dimethyl Silyl-based triflate; preferably Sna ₄ .  10. The compound of 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 for the preparation of an antiviral drug Use in. 11. The use according to claim 10, wherein the virus is a RiNA virus; Specifically, it is Tnfluenza Virus, Hepatitis C Virus, Bunyavirus, Phlebovirus, Foot and Mouth Disease Virus, West Nile Virus (West) Nile virus ), Arenavirus, Western Equine Encephalitis Virus, or Yellow Fever Virus; specifically, the influenza virus is A 1 ( H1N1 ) subtype flu virus.  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 a treatment and/or Use in a medicament for mammalian foot-and-mouth disease; specifically, the mammal is a cloven-hoofed animal; specifically, the cloven-hoofed animal is a pig, a cow, or a sheep.  13. A method of antiviral in vivo or in vitro, comprising administering to a subject or using 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 solvate thereof or a step of the pharmaceutical composition according to claim 5 or 6; specifically, the virus is an RNA virus; specifically, an influenza virus (Influenza Virus), an HCV virus (Hepatitis C Virus), Bunia Bunyavirus, Phlebovirus, Foot and Mouth Disease Virus, West Nile virus, Arenavirus, Western Equine Encephalitis Virus Or Yellow Fever Virus; specifically, the influenza virus is a 1 ( ΤΠΝ 1 ) influenza A virus.  A method for treating and/or preventing foot-and-mouth disease 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 or a step of the pharmaceutical composition according to claim 5 or 6; specifically, the mammal is a cloven-hoofed animal; specifically, the cloven-hoofed animal is a pig, a cow, or a sheep.