JPH05339250A - Isoxazoline derivative and antiviral agent comprising the same as active ingredient - Google Patents

Abstract

PURPOSE:To obtain a new compound, excellent in antiviral activity, especially antiinfluenzal activity and useful as a low toxic antiviral agent. CONSTITUTION:The objective compound of formula I (R1 to R3 are H, alkyl, alkoxy, alkenyl, etc.; R4 is H, alkyl, akoxyalkyl, etc.; R5 is cyano, alkyl or phenyl), e.g. 3-aminomethyl-5-t-butyl-2-isoxazoline. This compound of formula I is obtained by reacting a compound of formula II with an oxime derivative of formula III (Y is halogen or alkoxy) in the presence of a base (e.g. triethylamine) in a solvent (e.g. methanol) at -10 to +100 deg.C) for 0.5 to 100hr. The reaction is carried out by using the compound of formula II in an amount of 1-10 equiv. and the base in an amount of 1-5 equiv. based on 1 equiv. compound of formula II.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel isoxazoline derivative having antiviral activity, an intermediate thereof and an antiviral agent containing the same as an active ingredient.

[0002]

As a compound having antiviral activity,
Conventionally, ribavirin (Japanese Patent Publication No. 55-19
No. 239), Inosuplex (Japanese Patent Publication No. 49-217)
65) and other nucleoside antibiotics; LY-253
963 (Japanese Patent Laid-Open No. 62-148476); FCE-
20028 (JP-A-61-167687); Amantadine (US Pat. No. 3,152,180) and the like are known.

[0003]

[Chemical 3]

[0004]

Although various antiviral agents have been developed as described above, their activity is not yet satisfactory especially against influenza virus.

The present invention is intended to solve the above-mentioned drawbacks, and an object thereof is to provide a novel substance excellent in antiviral activity, particularly in anti-influenza activity.

[0006]

The isoxazoline derivative of the present invention is represented by the following general formula (I), by which the above-mentioned object is achieved:

[0007]

[Chemical 4]

(In the formula, R ₁ , R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, a haloalkyl group or an optionally substituted phenyl group or Represents a phenylalkyl group, R ₄ represents a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkenyl group, a haloalkyl group, a haloalkenyl group, a haloalkynyl group, a cyanoalkyl group,
Represents an optionally substituted phenyl group or phenylalkyl group, or an optionally substituted heterocyclic group or heterocyclic alkyl group, and R ₅ represents a cyano group, an alkyl group or a phenyl group).

The isoxazoline derivative of the present invention is represented by the following general formula (II), by which the above-mentioned object is achieved:

[0010]

[Chemical 5]

(In the formula, R ₁ , R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, a haloalkyl group, or an optionally substituted phenyl group or Represents a phenylalkyl group).

The antiviral agent of the present invention contains the above-mentioned isoxazoline derivative as an active ingredient, thereby achieving the above object.

Next, the present invention will be described in detail.

The isoxazoline derivative of the present invention is a compound represented by the above general formula (I), wherein R ₁ , R ₂ and R ₃ are each preferably a phenyl group or an alkyl group, and among them, C _{1 to} C ₅ are preferred. Alkyl groups are particularly preferred. R ₄ is preferably an alkyl group, an alkenyl group or a benzyl group, and particularly preferably a C ₂ -C ₇ alkenyl group. R ₅
Is preferably a cyano group, a C ₁ -C ₅ alkyl group or a phenyl group, and particularly preferably a cyano group or a methyl group. The configurations of oximes (= N-OR ₄ ) are E and Z.
Any of the above may be used, or a mixture of E and Z may be used, but E is preferable.

The isoxazoline derivative of the present invention is a compound represented by the general formula (II) and an intermediate of the isoxazoline derivative represented by the general formula (I). Each of R ¹ , R ² and R ³ is preferably a C _{1 to} C ₅ alkyl group.

Examples of the isoxazoline derivative of the present invention include compounds having structures (I-1) and (I-2) of the types shown below.

[0017]

[Chemical 6]

The isoxazoline derivative of the present invention will be described.

The compound represented by the above general formula (I-1), which is one of the preferred types of the isoxazoline derivative of the present invention, is produced by the following method.

[0020]

[Chemical 7]

First, J. Org. Chem, 48 336-372 (1983)
In accordance with the method described in, the oxime derivative represented by the general formula (III) is reacted with the compound represented by the general formula (IV) to give the isoxazoline represented by the general formula (V). A derivative is obtained (step 1).

In the above general formula (III), R ⁶
Represents an alkyl group, and among them, a methyl group or an ethyl group is preferable. In the general formula (IV), R ¹ , R ²
And R ³ are respectively R ¹ in the above general formula (I),
It has the same meaning as R ² and R ^3, and in the general formula (V), R ¹ , R ² , R ³ and R ⁶ are respectively R ¹ , R ² , R ³ and R in the general formula (I). Represents the same meaning as ⁶ . The resulting isoxazoline derivative represented by the above general formula (V) may be directly used in the next step,
You may isolate and refine by usual methods, such as column chromatography.

Next, the isoxazoline derivative represented by the general formula (V) is reduced with a reducing agent in a suitable solvent to give the isoxazoline derivative represented by the general formula (VI). Obtain (Step 2).

Here, in the above general formula (VI),
R ¹ , R ² and R ³ have the same meanings as described above.

In this reaction, sodium borohydride is preferably used as the reducing agent, and the amount used is 1 to 20 equivalents relative to 1 equivalent of the isoxazoline derivative represented by the general formula (V). Preferably, 1 to 10 equivalents are more preferable. As the solvent, alcohols such as methanol, ethanol and isopropanol are preferably used. The reaction temperature is preferably -10 to 130 ° C, 0 to
100 ° C. is more preferable. The reaction time is 0.5 to 2
4 hours are preferable, and 1 to 8 hours are more preferable.

The isoxazoline derivative represented by the above general formula (VI) can also be produced by the method described in Angew. Chem., 93 576-578 (1981). The isoxazoline derivative represented by the above general formula (VI) thus obtained may be directly used in the next step, or may be isolated and purified by a usual method such as column chromatography. ..

Next, the isoxazoline derivative represented by the general formula (VI) is halogenated in a suitable solvent with a halogenating agent to give the isoxazoline derivative represented by the general formula (VII). A derivative is obtained (step 3).

Here, in the above general formula (VII),
R ¹ , R ² and R ³ have the same meanings as described above, and X
Represents a halogen atom, and among them, a chlorine atom or a bromine atom is preferable.

In this reaction, thionyl chloride, phosphorus oxychloride, thionyl bromide and the like are preferably used as the halogenating agent, and the amount of the halogenating agent used is 1 equivalent of the isoxazoline derivative represented by the general formula (VI). 1 to 5 equivalents are preferable, and 1 to 2 equivalents are more preferable. As the solvent, benzene, toluene, dichloroethane, dichloromethane or the like is preferably used. Reaction temperature is -10 to 13
0 degreeC is preferable and 0-100 degreeC is more preferable. The reaction time is preferably 0.5 to 20 hours, more preferably 1 to 8 hours. The isoxazoline derivative represented by the above general formula (VII) thus obtained may be directly used in the next step, or may be isolated and purified by a usual method such as column chromatography. ..

Next, the isoxazoline derivative represented by the general formula (VII) is reacted with the imide derivative metal salt in a suitable solvent to give the isoxazoline derivative represented by the general formula (VIII). Obtain (step 4).

In the above general formula (VIII), R
¹ , R ² and R ³ have the same meanings as described above.

In this reaction, potassium phthalimide is preferably used as the imide derivative metal salt, and the amount thereof is preferably 1 to 5 equivalents relative to 1 equivalent of the isoxazoline derivative represented by the general formula (VII). , 1-2
An equivalent amount is more preferable. As the solvent, dimethylformamide, dimethylsulfoxide, acetonitrile, acetone and the like are preferably used. The reaction temperature is preferably 0 to 150 ° C, more preferably 15 to 80 ° C. The reaction time is preferably 1 to 100 hours, more preferably 3 to 24 hours. The above general formula (VIII) thus obtained
The isoxazoline derivative represented by may be directly used in the next step, or may be isolated and purified by a usual method such as column chromatography.

Next, the isoxazoline derivative represented by the general formula (VIII) is hydrolyzed in a suitable solvent to obtain the isoxazoline derivative represented by the general formula (II) (step 5). ).

In this reaction, hydrazine, potassium hydroxide and sodium hydroxide are preferably used as the base used for the above hydrolysis, and hydrazine is particularly preferably used. The amount used is as shown in the general formula (VII
1-10 equivalents are preferable with respect to 1 equivalent of the isoxazoline derivative represented by I), and 1-3 equivalents are more preferable. Further, the above hydrolysis may be carried out using an acid such as hydrochloric acid, and the amount thereof used is 1 to 1 with respect to 1 equivalent of the isoxazoline derivative represented by the general formula (VIII).
0 equivalent is preferable and 1 to 3 equivalent is more preferable. As the solvent, alcohol such as methanol and ethanol and water are preferably used. The reaction temperature is 0 to 10
0 degreeC is preferable and 0-70 degreeC is more preferable. The reaction time is preferably 0.5 to 100 hours, more preferably 1 to 24 hours. The isoxazoline derivative represented by the above general formula (II) thus obtained may be directly used in the next step, or may be isolated and purified by a usual method such as column chromatography. ..

Finally, the isoxazoline derivative represented by the general formula (II) is reacted with the oxime derivative represented by the general formula (IX) in a suitable solvent to give the general formula (I). -1) to obtain the isoxazoline derivative of the present invention (step 6).

In the above general formula (IX), R ⁴
And R ⁵ have the same meanings as described above, and Y represents a halogen atom or an alkoxy group, and among them, a chlorine atom, a methoxy group or an ethoxy group is preferable. Further, in the oxime derivative represented by the general formula (IX), compounds in which R ⁵ is cyano include compounds disclosed in JP-A-63-35553, JP-A-63-35554, and J. Goto et al., J. Anti
It can be produced by the method described in biot., 37, 557 (1884).

In this reaction, the amount of the oxime derivative represented by the general formula (IX) used is 1 to 1 equivalent of the isoxazoline derivative represented by the general formula (II).
10 equivalents are preferable, and 1 to 5 equivalents are more preferable. If necessary, the reaction can be carried out in the presence of a base, and as the base, triethylamine, pyridine and the like are preferably used, and the amount thereof is 1 equivalent of the isoxazoline derivative represented by the general formula (II). On the other hand, 1 to 5 equivalents are preferable, and 1 to 2 equivalents are more preferable. As the solvent, alcohols such as methanol and ethanol, acetonitrile, tetrahydrofuran and the like are preferably used. The reaction temperature is preferably -10 to 100 ° C, 0 to 80 ° C
Is more preferable. The reaction time is preferably 0.5 to 100 hours, more preferably 1 to 24 hours. The isoxazoline derivative represented by the above general formula (I-1) thus obtained may be isolated and purified by a usual method such as column chromatography.

The isoxazoline derivative represented by the general formula (I-1) can also be produced by the following method.

[0039]

[Chemical 8]

By reacting the isoxazoline derivative represented by the general formula (VII) with the oxime derivative represented by the general formula (X) in the presence of a base in a suitable solvent, the above general formula An isoxazoline derivative of the present invention represented by (I-1) is obtained (step 7).

Here, in the general formula (X), R ⁴ and R ⁵ have the same meanings as described above.

In this reaction, the amount of the oxime derivative represented by the general formula (VII) used is the same as the general formula (X).
With respect to 1 equivalent of the isoxazoline derivative represented by
~ 1.5 equivalents are preferred, and 1.0-1.1 equivalents are more preferred. Sodium hydride is preferably used as the base, and the amount thereof is preferably 1 to 5 equivalents, and 1 to 1.2 equivalents relative to 1 equivalent of the isoxazoline derivative represented by the general formula (X). More preferable. As the solvent, dimethylformamide, dimethylsulfoxide and the like are preferably used. The reaction temperature is preferably 10 to 50 ° C, more preferably 10 to 24 ° C. The reaction time is preferably 1 to 5 hours, more preferably 1 hour.
The isoxazoline derivative of the present invention represented by the above general formula (I-1) thus obtained may be isolated and purified by a usual method such as column chromatography.

The compound represented by the above general formula (I-2), which is another suitable type of the isoxazoline derivative of the present invention, is produced by the following method.

[0044]

[Chemical 9]

First, the oxime derivative represented by the above general formula (IX) and the amine derivative represented by the above general formula (XI) are mixed with an amide derivative represented by the above general formula (XII) in a suitable solvent. Is obtained (step 8).

Here, R ² and R ³ in the general formula (XI), and R ² , R ³ in the general formula (XII),
R ⁴ and R ⁵ have the same meanings as described above.

In the reaction, the amount of the amine derivative represented by the general formula (XI) used is preferably 1 to 10 equivalents, and preferably 1 to 5 equivalents, relative to 1 equivalent of the oxime derivative represented by the general formula (IX). An equivalent amount is more preferable. If necessary, the reaction may be carried out in the presence of a base, and triethylamine, pyridine, etc. are suitably used as the base, and the amount thereof is 1 equivalent of the oxime derivative represented by the general formula (IX). 1-5 equivalents are preferable, and 1-2 equivalents are more preferable. As the solvent, methanol, ethanol, acetonitrile, tetrahydrofuran, etc. are preferably used. The reaction temperature is preferably -10 to 100 ° C, more preferably 0 to 80 ° C. The reaction time is preferably 0.5 to 100 hours, more preferably 1 to 24 hours. The above general formula (XI
In the amide derivative represented by I), a compound in which R ⁵ is cyano can also be produced by the method described in JP-A-61-243057. The amide derivative represented by the above general formula (XII) thus obtained may be directly used in the next step, or may be isolated and purified by a usual method such as column chromatography.

Finally, the amide derivative represented by the above general formula (XII) and the hydroxamic acid chloride represented by the above general formula (XIII) are added to the above general formula (I- An isoxazoline derivative of the present invention represented by 2) is obtained (step 9).

In the above general formula (XIII), R
¹ has the same meaning as described above.

In the reaction, the amount of the hydroxamic acid chloride represented by the general formula (XIII) used is 1-2 with respect to 1 equivalent of the amide derivative represented by the general formula (XII).
0 equivalent is preferable and 1-5 equivalent is more preferable. As the base, inorganic bases such as sodium hydrogen carbonate, sodium carbonate and potassium carbonate and organic bases such as triethylamine and pyridine are preferably used, and the amount thereof is 1 equivalent of the amide derivative represented by the general formula (XII). 1 to 5 equivalents are preferable, and 1 to 2 equivalents are more preferable. As the solvent, alcohols such as methanol, ethanol, propanol, isopropanol and butanol are preferably used. The reaction temperature is preferably -10 to 120 ° C, more preferably 0 to 80 ° C. The reaction time is 1
-200 hours are preferable, and 3-48 hours are more preferable. The isoxazoline derivative of the present invention represented by the above general formula (I-2) thus obtained may be isolated and purified by a usual method such as column chromatography.

The composition containing the isoxazoline derivative of the present invention as an active ingredient is administered as an antiviral agent, particularly a drug having antiinfluenza activity. The dosage form is oral or parenteral. Dosage forms include injections (intravenous injection, intramuscular injection, infusion, ampoule for subcutaneous injection, vials, solutions, suspensions, etc.), external preparations, topical preparations (ear drops, nasal drops, eye drops) Agents, ointments, sprays, suppositories, etc.), orally administered agents, etc. Administration by injection,
Transdermal, transmucosal administration and the like are preferable. The above formulation contains an isoxazoline derivative in a proportion of 0.1% by weight or more,
It contains appropriate excipients, auxiliaries, stabilizers, wetting agents, emulsifiers, other additives, etc. depending on the dosage form. They are,
It must be a substance that can be used pharmaceutically and pharmacologically and that does not affect the carbapenem derivative. For example, oral formulations include lactose, stearic acid,
Magnesium stearate, clay, sucrose, corn starch, talc, gelatin, agar, pectin, peanut oil, olive oil, cacao oil, ethylene glycol,
It contains tartaric acid, citric acid, fumaric acid and the like. Parenteral formulations include solvents (alcohol, buffer, methyl oleate, water, etc.), buffers, dispersants, solubilizers, stabilizers (methyl p-hydroxybenzoate or ethyl p-hydroxybenzoate). , Sorbic acid, etc.), absorption promoters (mono or dioctanoic acid ester of glycerin, etc.), antioxidants, fragrances, analgesics, suspensions, side effect inhibitors, action enhancers (absorption / excretion regulators, enzymatic degradation prevention) Agents, β-lactamase inhibitors, other kinds of antibacterial agents, etc.) and the like.

The dose of the isoxazoline derivative of the present invention varies depending on the age of the patient, the type and condition of the disease, the type of compound used, and the like. Generally, the patient will be administered in an amount of 50 to 5000 mg / individual per day, and higher doses may be administered as needed.

[0053]

EXAMPLES Next, the present invention will be described with reference to Examples and Comparative Examples.

In the present invention, ¹ H-NMR is 270M.
It was measured at Hz, and was expressed in δ value (ppm) with tetramethylsilane as an internal standard in deuterated chloroform, and the binding constant (J) was expressed in Hz. s is a singlet, d is a doublet, t is a triplet, q is a quartet, sept is a septet, brs is a wide singlet, and m is a multiplet.

(Example 1) 5-t-butyl-2-isoxazoline-3-carvone
Preparation of ethyl acidate (Step 1) Ethyl 2-chloro-2-hydroxyiminoacetate 6.06
g (0.04 mol), isopropanol 40 ml,
6.33 g (0.08 m) of 3,3-dimethyl-1-butene
ol) and sodium hydrogen carbonate 4.03 g (0.048 m
ol) was added and the mixture was stirred at 40 ° C. for 22 hours. After the reaction
250 ml of water was added, followed by extraction with methylene chloride, the extract was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to obtain 7.81 g of ethyl 5-t-butyl-2-isooxozoline-3-carboxylate as a colorless liquid. (Yield 98.0%). ¹ H-NMR of this compound is shown below.

¹ H-NMR (CDCl ₃ ) δppm: 0.94 (9H, s),
1.37 (3H, t, J = 6.8), 2.96 (1H, dd, J = 17.6, 9.8),
3.09 (1H, dd, J = 17.6, 11.7), 4.34 (2H, q, J = 6.8),
4.52 (1H, dd, J = 11.7, 9.8).

5-t-butyl-2-hydroxymethyl-
Preparation of 2-isoxazoline (Step 2) 25.91 g (0.13 mol) of ethyl 5-t-butyl-2-isoxazoline-3-carboxylate was dissolved in 260 ml of methanol. To this solution was added sodium borohydride (29.51 g, 0.75) under ice cooling for 15 minutes.
(8 mol) was added, and the mixture was heated under reflux for 1 hour. After the reaction, 1000 ml of water was added, followed by extraction with methylene chloride, the extract was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure to give colorless crystals of 5-t-butyl-2.
-Hydroxymethyl-2-isoxazoline 19.5 g
Was obtained (yield 95.5%). ¹ H-NMR of this compound
Is shown below.

¹ H-NMR (CDCl ₃ ) δppm: 0.92 (9H, s),
2.04 (1H, brs), 2.79 (1H, dd, J = 17.6, 9.8), 2.93
(1H, dd, J = 17.6, 10.7), 4.35 (1H, dd, J = 10.7, 9.
8), 4.39 (2H, s).

1- (5-t-butyl-2-isoxazo
Preparation of phosphorus-3-ylmethyl) phthalimide (steps 3 and 4) 5-tert-butyl-3-hydroxymethyl-2-isoxazoline 19.53 g (0.124 mol) in dry benzene 200 ml and thionyl chloride 19.04 g (0 .1m
ol) was added, the mixture was stirred at room temperature for 1 hour, and then heated under reflux for 1 hour. The reaction solution was concentrated under reduced pressure, 200 ml of dried N, N-dimethylformamide and 29.91 g (0.16 mol) of potassium phthalimide were added, and the mixture was allowed to stand at room temperature for 19 hours.
Stir for hours. After the reaction, 700 ml of ethyl ether was added, the organic layer was washed with water, and concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography to obtain 20.00 g of light brown crystals of 1- (5-t-butyl-2-isoxazolin-3-ylmethyl) phthalimide (yield 56.3%. ). ¹ H-NMR of this compound is shown below.

¹ H-NMR (CDCl ₃ ) δppm: 0.88 (9H, s),
2.71 (1H, dd, J = 17.6, 9.8), 2.86 (1H, dd, J = 17.6, 1
0.7), 4.33 (1H, dd, J = 10.7, 8.8), 4.57 (2H, s), 7.
71-7.90 (4H, m).

3-aminomethyl-5-t-butyl-2-
Production of isoxazoline (step 5) 1- (5-t-butyl-2-isoxazolin-3-ylmethyl) phthalimide 10.32 g (0.036mo)
72 ml of methanol and 2.74 g (0.0432 mol) of 80% hydrazine monohydrate were added to l), and the mixture was stirred at 60 ° C. for 15 hours. After the reaction, 200 ml of a 1N aqueous solution of sodium hydroxide was added to this solution, which was then extracted with methylene chloride. The extract was dried over anhydrous magnesium sulfate and concentrated under reduced pressure to give a brown oily substance, 3-aminomethyl-5.
-T-Butyl-2-isoxazoline (Compound No. 1)
4.53 g was obtained (yield 80.5%).

¹ H-NM of the isoxazoline derivative represented by the general formula (II) prepared according to Example 1 above.
R is shown in Table 1.

[0063]

[Table 1]

(E) -2-Allyloxyimino-2-si
Ano-N- (5-t-butyl-2-isoxazoline-
Preparation of 3-ylmethyl) acetamide (Step 6) 0.31 g (2.0 mmol) of 3-aminomethyl-5-t-butyl-2-isoxazoline and 4 m of methanol
1, ethyl (E) -2-allyloxyimino-2-cyanoacetate 0.40 g (2.2 mmol) and triethylamine 0.24 g (2.4 mmol) were added, and the mixture was stirred at room temperature for 15 hours. After the reaction, 80 ml of water was added to this solution, and then concentrated hydrochloric acid was added to adjust the pH to 2. Then
Ether was added to this solution for extraction. The extract was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography to give (E) -2-allyloxyimino-2 as light brown crystals.
-Cyano-N- (5-t-butyl-2-isoxazolin-3-ylmethyl) acetamide (Compound No. 13)
0.38 g was obtained (yield 65.0%).

Physical properties of the isoxazoline derivative (Compound Nos. 5 to 18) represented by the general formula (I) prepared according to the above Example 1 are shown in Table 2, and ¹ H-NMR data are shown in Table 3. ..

Example 2 (E) -2-allyloxyimino-2-phenyl-N-
(5-t-butyl-2-isoxazolin-3-ylme
Preparation of ( Cyl) acetamide (Step 6) To 3-aminomethyl-5-t-butyl-2-isoxazoline 160 mg (1 mmol), (E) -2-allyloxyimino-2-phenyl-ethyl acetate 293 mg
(1.3 mmol) was added, and the mixture was stirred at 150 ° C. for 2 hours. After the reaction, this mixture was purified by silica gel chromatography to give an oily substance (E) -2-allyloxyimino-2-phenyl-N- (5-t-butyl-2).
60 mg of -isoxazolin-3-ylmethyl) acetamide (Compound No. 19) was obtained (yield 17%). Physical properties of this compound are shown in Table 2, and ¹ H-NMR data are shown in Table 3.

(Example 3) 5-t-butyl-3-chloromethyl-2-isoxazo
Preparation of phosphorus (step 3) 300 mg (1.9 mmol) of 5-t-butyl-3-hydroxymethyl-2-isoxazoline in 3 ml of dry dichloromethane and 680 mg of thionyl chloride (5.7 mm)
ol) was added and the mixture was heated at 50 ° C. for 1 hour. The reaction mixture was concentrated under reduced pressure, and the obtained residue was mixed with sodium hydrogen carbonate (1).
g was added for neutralization, and then diethyl ether was added for extraction. The obtained extract was washed with water, dried over anhydrous sodium sulfate, and concentrated under reduced pressure to give 5-t-butyl-3-chloromethyl-2-isoxazoline 301m.
g was obtained (yield 90%).

(E) -2-Allyloxyimino-N-
(5-t-butyl-2-isoxazolin-3-ylme
Preparation of ( Cyl) propionamide (Step 7) (E) -2-allyloxyimino-propionamide 2
71 mg (1.9 mmol), dry dimethylformamide 2.7 ml, and sodium hydride 92 mg (2.3
mmol, 60% oil dispersion) was added to the solution, and 301 mg (1.71 mmol) of 5-t-butyl-3-chloromethyl-2-isoxazoline was added, and the mixture was reacted at room temperature for 15 minutes. Then, ice water was added to this solution, and the mixture was extracted with diethyl ether. The extract was washed with water, dried over anhydrous sodium sulfate, and concentrated under reduced pressure. The obtained residue was purified by column chromatography to give an oily substance (E) -2-allyloxyimino-N-
50 mg of (5-t-butyl-2-isoxazolin-3-ylmethyl) propionamide (Compound No. 20) was obtained (yield 10%). The physical properties of this compound are shown in Table 2, ¹ H
-NMR data are shown in Table 3 or Table 4.

[0069]

[Table 2]

[0070]

[Table 3]

[0071]

[Table 4]

Example 4 (E) -2-Methoxyimino-2-cyano-N-allyl
Preparation of acetamide (step 8) (E) -2-Methoxyimino-2-cyanoacetate (1.56 g, 10 mmol) and allylamine (0.69)
g (12 mmol), methanol 20 ml, and triethylamine 1.21 g (12 mmol) were added, and the mixture was stirred at room temperature for 24 hours. After the reaction, add 200 ml of water to this solution.
Was added, and the pH was adjusted to 2 with concentrated hydrochloric acid. Then, it was extracted with methylene chloride, the extract was dried over anhydrous magnesium sulfate, and concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography to obtain 1.21 g of (E) -2-methoxyimino-2-cyano-N-allylacetamide as a pale yellow oily substance (yield 72.5%). ..
¹ H-NMR of this compound is shown below.

¹ H-NMR (CDCl ₃ ) δppm: 4.01 (2H, t, J =
5.9), 4.25 (3H, s), 5.20-5.28 (1H, m), 5.79-5.94
(1H, m), 6.87 (1H, brs).

(E) -2-Methoxyimino-2-cyano
-N- (3-t-butyl-2-isoxazolyl-5-
Preparation of Ilmethyl) acetamide (Step 9) 0.5 g (3 mmol) of (E) -2-methoxyimino-2-cyano-N-allylacetamide was added to 1-chloro-
2,2-Dimethylpropionaldehyde oxime
76 g (5.6 mmol) and 5 ml isopropanol
And 0.5 g (6 mmol) of sodium hydrogen carbonate were added, and the mixture was stirred at room temperature for 65 hours. After the reaction, 150 ml of water was added to this solution and the mixture was extracted with ether. The extract was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. The obtained residue was purified by silica gel chromatography to give a colorless oily substance (E) -2-methoxyimino-2-cyano-N- (3-t-butyl-2-isoxazoline-
5-ylmethyl) acetamide (Compound No. 21)
19 g was obtained (yield 23.8%). ¹ H-N of this compound
The MR is shown below.

¹ H-NMR (CDCl ₃ ) δppm: 1.19 (9H, s),
2.72 (1H, dd, J = 17.6, 5.9), 3.10 (1H, dd, J = 17.6, 1
0.7), 3.39-3.48 (1H, m), 3.58-3.67 (1H, m), 4.25
(3H, s), 4.67-4.76 (1H, m), 6.87 (1H, brs).

(Experimental Example) Compound 5 obtained in the above Example
~ 14 and compounds 19-21 were subjected to the following biological tests. The results are shown in Table 5.

Antiviral activity The influenza AO / WSN strain was propagated in embryonated chicken eggs, and the infectious titer was measured and stored. Separately, place MDBK cells (derived from bovine kidney) cells in a 96-well microtest plate, and
0% fetal bovine serum was added, and then cultured in E-MEM medium at 37 ° C. in 5% carbon dioxide overnight. Then, 10 mg of the isoxazoline compound obtained in each example was dissolved in 0.5 ml of dimethyl sulfoxide, and E-ME was further added.
50 in M (Eagle's mimimum essential medium) medium
The 5000-fold diluted solution was added to each well of the plate in an amount of 50 μl. Then the E-MEM of the virus
50 μl of dilution with medium (1 × 10 ⁴ plaque forming
unit) was added to each well of the above plate and cultured in 5% carbon dioxide at 37 ° C. for 48 hours. Virus causes M
The concentration of the isoxazoline compound that inhibits DBK cell damage by 50% was defined as EC50.

The anti-virus activity was evaluated in the same manner as above except that 50 μl of E-MEM medium was added instead of 50 μl of the diluted solution of cytotoxic virus in E-MEM medium. CC50 is the concentration at which cells are killed by an isoxazoline compound by 50%.
And

[0079]

[Table 5]

From Table 5, it can be seen that the compounds obtained in Examples have high anti-influenza activity and low toxicity.

[0081]

INDUSTRIAL APPLICABILITY As is apparent from the above description, according to the present invention, a novel isoxazoline derivative having excellent antiviral activity, particularly, anti-influenza activity and low toxicity, and an antivirus containing this isoxazoline derivative are obtained. An agent can be provided.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Tamio Fujiwara 2-2-1-1017 Aoki, Higashinada-ku, Kobe-shi, Hyogo (72) Inventor Hide Ogata 8-20-8 Sumiyoshi Yamate, Higashinada-ku, Kobe-shi, Hyogo (72) ) Inventor Hiroshi Matsumoto 5-10-25 Yamatedai, Ibaraki City, Osaka Prefecture

Claims (3)

[Claims] 1. An isoxazoline derivative represented by the following general formula (I): (In the formula, R ₁ , R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, a haloalkyl group, or an optionally substituted phenyl group or a phenylalkyl group. Represents
R ₄ is a hydrogen atom, an alkyl group, an alkoxyalkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group,
Represents a cycloalkenyl group, a haloalkyl group, a haloalkenyl group, a haloalkynyl group, a cyanoalkyl group, an optionally substituted phenyl group or a phenylalkyl group, or an optionally substituted heterocyclic group or a heterocyclic alkyl group, R ₅ represents a cyano group, an alkyl group or a phenyl group). 2. An isoxazoline derivative represented by the following general formula (II): (In the formula, R ₁ , R ₂ and R ₃ are each independently a hydrogen atom, an alkyl group, an alkoxy group, an alkenyl group, a cycloalkyl group, a haloalkyl group, or an optionally substituted phenyl group or a phenylalkyl group. Represents) 3. An antiviral agent containing the isoxazoline derivative according to claim 1 as an active ingredient.