JPS5833230B2 - Oxadiazoline composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a novel method for producing an oxadiazoline derivative having the general formula (wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms) Regarding.

The compound of general formula It is useful as an intermediate in the synthesis of oxadiazoline derivatives having the following groups.

Derivatives of the general formula (III) include halogenated alkyl or alkynyl of the general formula (wherein R1 is the same as defined above and X represents a halogen atom, preferably bromine or chlorine) and an oxadiazoline of the general formula I. (However, R is the same as defined above.)

The reaction is usually carried out in an inert solvent such as acetonitrile.
It is carried out at a temperature between 50 DEG C. and the boiling point of the reaction mixture and optionally in the presence of an alkaline condensing agent such as potassium carbonate.

Oxadiazoline derivatives of the general formula (2) have useful herbicidal activity and are described, for example, in British Patent Specifications Nos. 1063799 and 1345313.

The oxadiazoline derivative of the general formula (1) (wherein R1 represents a linear or branched alkyl group having 1 to 4 carbon atoms) can be prepared using the method described in British Patent Specifications Nos. 1063799 and 1110500. , phosgene and the general formula (wherein R is as defined above and R/1
represents a linear or branched alkyl group having 1 to 4 carbon atoms).

Furthermore, an oxadiazoline derivative of the general formula (1) (however, R
1 represents a straight-chain or branched alkyl group having 1 to 4 carbon atoms) can be obtained by formula (wherein R'1 is Halogenonitrobenzene having the general formula (where R is the same as defined above) (which may be prepared in situ if necessary) ) and react with
It can also be produced by subsequently reducing the nitro group to an amino group and subsequently replacing the amino group with chlorine via a diazonium salt.

British Patent Specification No. 1345313 describes a method for producing an oxadiazoline derivative of the general formula (1) (wherein R1 represents an alkynyl group having 3 or 4 carbon atoms), and the method is as follows: (1 ) the reaction of phosgene with a hydrazide having the general formula (wherein R is as defined above and Rτ represents an alkynyl group having 3 or 4 carbon atoms); or (2) the reaction of phosgene with a hydrazide having the general formula , R1 are the same as defined above and X is...
oxadiazoline derivative of the general formula I, wherein the oxadiazoline derivative of the general formula (same as defined above) with the corresponding hydrazide of the general formula ■
(where ☆☆ R is the same as the above definition, and R1 represents a straight or branched alkyl group having 1 to 4 carbon atoms) by a method known per se. It can be produced by changing an alkoxy group to a hydroxy group without affecting the rest of the molecule.

What was discovered this time and is the subject of the present invention is the general formula ■
The oxadiazoline derivative of nib can be easily prepared by the following diagrammatic process. Compounds of general formula (1) can be prepared by combining 2,5-cyclonitrobenzene with general formula (1) according to the method described in British Patent Specification No. It can be produced by reacting oxadiazoline with an alkali metal salt (2).

A nitro compound of general formula (2) is prepared by reducing its nitro group to a hydroxyamino group with hydrogen in the presence of a catalyst such as palladium supported on charcoal, preferably at ambient temperature (e.g. 15-25°C) and atmospheric pressure. It is done by

The conversion of hydroxylamine derivatives of general formula
berger rearrangement) CC
hem.

Ber, 27.1347 and 1548 (1894)
), preferably at temperatures below 25° C., by treatment with a strong inorganic acid, such as sulfuric acid.

The conversion of the aminophenol of general formula (1) to the oxadiazoline derivative of general formula (2) can be carried out via conversion to the corresponding diazonium salt and reaction of the diazonium salt with, for example, cuprous chloride.

The oxadiazoline derivative of general formula (2) obtained by the method of the present invention can be purified by physical methods such as crystallization or chromatography.

The hydroxylamine derivatives of general formula X, where R is as defined above, are new compounds.

According to another aspect of the invention, the oxadiazoline derivatives having the general formula (wherein R and R'1 are as defined above) are
1 and X are the same as defined above) by a process consisting of the reaction of an alkyl halogenide with an oxadiazoline derivative of the general formula (2).

As used herein, "methods known per se" mean methods conventionally used or methods described in the chemical literature.

The invention is illustrated by the following examples.

Example 1 5(t-butyl)-3-(2-nitro-4-chlorophenyl)-1 in ethyl acetate (800 mO) containing 3% w/w palladium on charcoal (1,5P). 3
- Hydrogenate a solution of 4-oxadiazolin 2-one (iooy) at atmospheric pressure and about 20<0>C.

After absorbing hydrogen (16 liters) for about 4 hours,
Stopped hydrogenation.

After separating the catalyst from P and cooling the solution, the resulting crystals are distributed.

The lachrymal fluid is concentrated and the resulting crystals are distributed door to door.

When the crystals are recrystallized from acetonitrile, the melting point is 195
5(t-butyl)-3-(2-hydroxylamino-4-chlorophenyl)-1,3,4-oxadiazolin-2-one (38, IP) at ~196°C is obtained.

5-(t-Butyl)-3-(2-hydroxyl/-4-chlorophenyl)-1,3,4-oxadiazolin-2-one (22,7f) was added little by little to concentrated sulfuric acid (d −
1,83:227 m~, the temperature of the reaction mixture was increased from 13 to 2
Add while keeping at 1℃.

The mixture is stirred for a further 20 minutes at the same temperature.

Pour the orange homogeneous solution onto ice (400F).

The resulting precipitate is separated and then placed in an aqueous solution of potassium bicarbonate.

The resulting suspension is extracted with methylene chloride (2oomO) and the extract is dried and the organic solvent is removed under reduced pressure to give the product (21,1') with a melting point of 131°C.

Recrystallization from carbon tetrachloride (650m7) gives a melting point of 13
5-(t-butyl)-3-(2-amino-4-chloro-5-hydroxyphenyl)-1,3,4 at 1-132°C
-Oxadiazolin-2-one (15,5f) is obtained.

5-(t
butyl)-3-(2-amino-4-chloro-5-hydroxyphenyl)-1,3,4-oxadiazoline-2-
On (14,5f) solution was added with water (13,5f) while cooling.
3mz).

To the resulting suspension, under stirring, a solution of sodium nitrite (3.6 f?) in water (14.5 ml) is added, while maintaining the temperature of the reaction mixture at 5-7°C.

After the addition is complete, the precipitated diazonium sulfate is separated and then dissolved in cuprous chloride (6 ml) in concentrated hydrochloric acid (32, smz).
，! Add to the solution of l).

The mixture is kept at approximately 40° C. until gas evolution ceases.

After cooling, the precipitate is separated and washed with N-hydrochloric acid (200 m) followed by water (6 x lQQm).

The precipitate is dissolved in methylene chloride (150 mA).

The solution is dried and the solvent removed under reduced pressure, melting point 126
A product (13,65f) is obtained at ~129°C.

Cyclohexane (melting point 1 when recrystallized from 4oomO
5-(t-butyl)-3-(2°4-dichloro-5-hydroxyphenyl)-1,3,4-oxadiazolin-2-one (11,2S') at 32°C is obtained.

5-(t-butyl)-3-(2nitro-4, melting point 79°C
-chlorophenyl)-1,3,4-oxadiazoline-
The 2-one is prepared from 2,5-dichloro-nitrobenzene (
382P) and 5(1-butyl)-1,3,4-oxadiazolin-2-one (302f).

Example 2 5(t-butyl)-3-(2,4-dichloro-5hydroxyphenyl)-1,3,4-oxadiazolin-2-one (1,0
Anhydrous potassium carbonate (46i) and sodium iodide (25.4f) are added to the solution of 25P).

Heat the mixture to about 70°C.

Isopropyl bromide (541S') is added to the solution and the reaction mixture is heated under reflux and stirring for 16 hours.

After cooling and filtering out the precipitated inorganic salts, the lachrymal fluid is concentrated under reduced pressure.

The crystallized residue is dissolved in methylene chloride (2.33 liters) and the resulting solution is washed successively with water, a 0.5% aqueous solution of sodium hydroxide and water.

Drying the solution and removing the solvent under reduced pressure gives a melting point of 88~
A product (1,1495') at 89° C. is obtained.

When recrystallized from ethanol (1,149 liters),
5-(t-butyl)=3-(2,4-dichloro-5-isofuropoxyphenyl)-1,3,4-oxadiazolin-2one (1,012P) having a melting point of 89 DEG C. is obtained.

Example 3 Containing 3% w/w palladium on charcoal (1z)
5-isopropyl-3-( in ethyl acetate (130ml)
A solution of 2-nitro-4-70lophenyl)-1,3,4-oxadiazolin-2-one (165') is hydrogenated at atmospheric pressure and about 20<0>C.

After absorption of hydrogen (1,91 Jtutr) (70% of theory), the reaction is stopped and the reaction mixture is filtered.

The p solution was concentrated under reduced pressure, and the residue was dissolved in benzene (50 mJ).
dissolve in

The resulting crystals are separated and washed with benzene (15 mA').

5-isopropyl-3-(2-
Hydroxylamino-4-chlorophenyl) 1, 3, 4
-Oxadiazolin-2-one (7,2'?) is obtained.

Recirculate the benzene sap and subject it to the same operation as above.

5-isopropyl-3-(2
-hydroxylamino-4-chlorophenyl)-1,3
- 4-oxadiazolin-2-one (2,9y) is obtained.

5-isopropyl-3-(2-hydroxylamino-4
-chlorophenyl)-1,3,4-, oxadiazolin-2-one (13P) was added little by little to concentrated sulfuric acid (d = 1.8
3; to 130 mQ, reduce the temperature of the reaction mixture to 12-16
Add while keeping at ℃.

The mixture is stirred for 30 minutes at the same temperature.

Pour the brown homogeneous solution onto ice (240?).

The resulting precipitate is separated, then placed in an aqueous solution of potassium bicarbonate and extracted with ethyl acetate (ioomz).

Drying the ethyl acetate solution and removing the organic solvent under reduced pressure yields 5-isopropyl-3-(2-amino-4-chloro-5-hydroxyphenyl)-1.3. with a melting point of 129°C.
4-oxadiazolin-2-one (10,8 g) is obtained.

Acetone (5-isopropyl-3-(2) in 50 rIl
-amino-4-chloro-5-hydroxyphenyl)-1
- To a solution of 3,4-oxadiazolin-2-one (5 g) add a 2N solution of raw hydrogen chloride in acetone (10 ml).

The precipitate thus obtained is separated and washed three times with acetone (total amount of acetone 30 m).

The resulting hydrochloride salt is dissolved in hydrochloric acid (d=1.19; 50 m0) and then a solution of sodium nitrite (1,35 P) in water (6 m0) is added, keeping the temperature of the reaction mixture at 5-10°C.

After stirring for 15 minutes, a solution of raw cupric chloride (2,41) in concentrated hydrochloric acid (15 mA') is added.

The reaction mixture was heated at 30-40°C until gas evolution stopped.
Keep it.

After cooling, the resulting precipitate is separated and treated with N-hydrochloric acid (1
00m and then 3 times with water (total amount 300fflQ).

Dissolve some of the precipitate in methylene chloride.

Drying the methylene chloride solution and removing the solution under reduced pressure gives the product (4,2f) with a melting point of 122°C.

Benzene (melting point 126 when recrystallized from 201rL)
5-isopropyl 3-(2,4-dichloro-5-hydroxyphenyl)-1,3,4-oxadiazolin- at °C
2-one (3,5f) is obtained.

5-isopropyl-3-(2-nitro-4) with a melting point of 68°C
-chlorophenyl)-1,3,4-oxadiazoline-
The 2-one is prepared from 2,5-dichloro-nitrobenzene (
115,5P) and 5-isopropyl-1,3,4-oxadiazolin-2-one (100f).

Example 4 5-isopropyl-3 in acetonitrile (15oml)
-(2,4-cyclo-5-hydroxyphenyl)-1
・3,4-oxadiazolin-2-one (2s, 9f)
Add potassium carbonate (13,81) to the solution and heat the mixture to about 70°C.

Isopropyl bromide (14, sP) is added and the mixture is heated under reflux for 13 hours.

After cooling the mixture and removing the inorganic salts, the solution is concentrated under reduced pressure.

The residue is dissolved in methylene chloride (150 mO) and the resulting solution is washed successively with water, a 0.5% aqueous solution of sodium hydroxide and water.

Drying the methylene chloride solution and removing the organic solvent under reduced pressure gives the product (33s') with a melting point of 90°C.

When recrystallized from cyclohexane (100TL0, 5=isopropyl-3-(2,4-Sifoo-5-isopropoxyphenyl)-1,3,4-oxadiazolin-2-one (26 , 5f) are obtained.

Claims (1)

[Claims] 1. The nitro group of a nitro compound having the general formula (wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms) is hydrogenated in the presence of a catalyst. A hydroxylamine derivative having the general formula (wherein R is the same as defined above) obtained by converting it into a hydroxylamino group is converted into a hydroxylamine derivative having the general formula (wherein R is the same as defined above) by Bamberger rearrangement including acid treatment. ), and the amino group of the aminophenol is converted into a chlorine atom by diazotization and treatment of the resulting diazonium salt with cuprous chloride. A method for producing an oxadiazoline derivative having the general formula (wherein R is the same as defined above). 2 The nitro group of a nitro compound having the general formula (wherein R represents a linear or branched alkyl group having 1 to 4 carbon atoms) is converted into a hydroxylamino group by hydrogenation in the presence of a catalyst, The thus obtained hydroxylamine derivative having the general formula (wherein R is as defined above) is subjected to Mpanberger rearrangement including acid treatment to have the general formula (wherein R is as defined above) and converting the amino group of the aminophenol into a chlorine atom by diazotization and treating the resulting diazonium salt with cuprous chloride, thus giving the general formula (wherein R is as defined above). The oxadiazoline derivative having the general formula (in which R'1
represents a linear or branched alkyl group having 1 to 4 carbon atoms, and X represents a halogen atom). A method for producing oxadiazoline derivatives which is the same as defined above.