KR950007920B1 - Novel 4-ethoxycarbonyl-1-methylpyrazol-5-sulphon carbarmate derivatives and process for preparing thereof - Google Patents

Abstract

4-Ethoxycarbonyl-1-methyl pyrazole-5-sulfone carbamate derivatives of formula (I) are prepared by reacting sulfoneamide in the presence of a solvent and an alkali. In the formulas, R is C1-8 alkyl, alkylether, allyl or phenyl. The alkyl chloroformate is pref. ethyl chloroformate; and the alkali is selected from NaOH, NaHCO3, KOH, KHCO3, K2CO3, Ca(OH)2, triethylamine or pyrimidine. The cpds. of formula (I) are useful as an intermediate in the prodn. of sulfonyl urea herbicides.

Description

Novel 4-ethoxycarbonyl-1-methylpyrazole-5-sulfone carbamate derivatives and preparation method thereof

The present invention relates to novel 4-ethoxycarbonyl-1-methylpyrazole-5-sulfon carbamate derivatives of the following general formula (I) useful as intermediates of sulfonyl urea herbicides and methods for their preparation.

[Formula 1]

In the formula, R represents a C ₁ -C ′ alkyl group, alkyl ether group, allyl group or phenyl group (except for methyl group).

The compound of formula (I) according to the present invention can be usefully used in the preparation of the sulfonyl urea derivative represented by the following formula (A) having excellent herbicidal efficacy. Further preferred embodiments for the use of the compound (I) according to the invention for this purpose are those in which the substituent R is a C ₂ -C ₄ alkyl group, particularly preferably an ethyl group.

[Formula 1a]

Wherein X and Y are independently a hydrogen atom, a halogen atom, a C ₁ -C ₈ alkyl group, a C ₁ -C ₈ alkoxy group, a C ₁ -C ₈ alkoxyalkyl group, a -CF ₃ group, a C ₁ -C ₈ haloalkyl group , Alkylamino group, dialkylamino group, May each represent a hydrogen atom or a C ₁ -C ₈ alkyl group, or X or Y together with Z may form a five-membered ring containing one hydrogen atom, where Z is a nitrogen atom, CR ″ ″ (where R Represents a hydrogen atom, a haloalkyl group, or a 5-membered ring containing one oxygen atom together with X or Y), and R 'represents a hydrogen atom or a C ₁ -C ₈ alkyl group.

As a compound similar to the compound of the general formula (I) according to the present invention, N-methoxycarbonyl-4-ethoxycarbonyl-1-methylpyrazole-5-sulfonamide represented by the following structural formula (B) is Published Patent Publication No. 3-200742 by Yoshioka et al.

[Formula 1b]

However, the patent publication only describes the inter compound only, and there is no mention or suggestion of various substituents that the compound according to the present invention may have. Furthermore, according to this patent specification, in order to prepare the sulfonylurea derivative of formula (A) using the compound of formula (B) as a starting material, the compound of formula (B) is reacted with a hydrogen-containing compound under reduced pressure. Although it can be described that the target compound can be produced in a yield of about 97%, methanol produced as a by-product in this reaction is a highly toxic substance and requires great care in its handling and removal. There is a disadvantage that a reactor is required.

On the other hand, the compound of the general formula (I) according to the present invention, in particular, the compound having a substituent R is an ethyl group is toxic even when the sulfonyl urea derivative of the general formula (A) is prepared by applying the method of Japanese Patent Application by Yoshioka et al. The sulfonyl urea derivatives of general formula (A) have been found to be very useful compounds as sulfonyl urea herbicide intermediates because there is no risk of generating toxic by-products and the reaction is appropriate.

The target compound (I) according to the present invention can be prepared by reacting a sulfonamide compound represented by the following general formula (II) with an alkyl chloroformate in the presence of a solvent and a base.

[Formula 2]

Wherein R is the same as described above.

In the present invention, the compound of formula (II) used as a starting material is a known material, and can be synthesized by the method described in Korean Patent Publication No. 89-1546. Alkylchloroformate is a commercially available compound, preferably ethylchloroformate, and its amount is preferably used in an amount of 1.1 to 1.3 equivalents based on compound (II).

In the reaction according to the method of the present invention, the base is an inorganic salt such as sodium hydroxide, sodium hydrogen carbonate, potassium hydroxide, potassium hydrogen carbonate, potassium carbonate, potassium hydroxide, lithium hydroxide, or a tertiary amine such as triethylamine or pyrimidine. The same organic base can be used. In the case of using an inorganic base, the reaction is completed when the reaction is performed at room temperature for about 24 hours. However, when the organic base is used, the reaction is completed for about 1 hour under the same conditions. Therefore, it is particularly preferable to use organic bases of tertiary amines. The amount used is suitably 1 to 3 equivalents based on the compound of formula (II) as a starting material.

As the solvent used in the reaction according to the present invention, it is preferable to use a hydrophilic solvent such as acetone, dimethylformamide, dimethyl sulfoxide, acetonitrile when using an inorganic base, and alcohol when using an organic base such as tertiary amine. All hydrophilic or non-hydrophilic solvents can be used.

Example 1

Synthesis of N- (ethoxycarbonyl) -4-ethoxycarbonyl-1-methylpyrazole-5-sulfonamide

23.32 g (0.1 mol) dml 4-ethoxycanyl-1-methylpyrazole-5-sulfonamine and 100 ml of acetone and 16.59 g (0.12 mol) of potassium carbonate (K ₂ CO ₃ ) were added to the flask and stirred with ethyl chloro 13.02 g (0.12 mol) of formate is added dropwise and stirred for 24 hours at room temperature under a nitrogen atmosphere. When the reaction was completed, 20 ml of 10% sulfuric acid solution was added to the reaction flask, the reaction product was extracted with ethyl ether, dried over magnesium sulfate, and the solvent was removed to obtain 25.59 g of the crude product of the title compound.

This crude product was recrystallized from 50 g of ethanol to give 20.20 g of pure title compound.

¹ H NMR (270 MHz, CDCl ₃ / TMS); δ 1.14 (3H, t), 1.31 (3H, t), 4.00 (2H, q), 4.24 (3H, s), 4.28 (2H, q), 7.86 (1H, s)

Example 2

Synthesis of N- (ethoxycarbonyl) -4-ethoxycarbonyl-1-methylpyrazole-5-sulfonamide

23.32 g (0.1 mole) of 4-ethoxycarbonyl-1-methylpyrazole-5-sulfonamine and 100 ml of toluene and 16.35 g (0.15 mole) of triethylamine were added to the flask and 13.02 g of ethylchloroformate was stirred. (0.12 mol) is added dropwise, followed by stirring for 24 hours at room temperature under a nitrogen atmosphere. Upon completion of the reaction, 20 ml of 10% sulfuric acid solution was added to the reaction flask and stirred for 5 minutes to separate the toluene layer, dried over magnesium sulfate, and the solvent was removed to obtain 25.59 g of the crude product of the title compound.

This crude product was recrystallized from 50 g of ethanol to give 20.20 g of pure title compound.

[Reference Example]

Synthesis of N-[(4,6-dimethoxypyrimidin-2-yl) aminocarbonyl] -4-ethoxycarbonyl-1-methylpyrazole-5-sulfonamide

30.5 g (0.1 mol) of the compound obtained in the example, 41.6 g (0.2 mol) of phosphorus pollutant, and 200 ml of toluene were added to the flask, and the mixture was stirred under reflux under nitrogen atmosphere for about 6 hours to extinguish the starting material. 15.5 g (0.1 mol) of 2-amino-4,6-dimethoxypyrimidine was added thereto, followed by stirring at room temperature for about 1 hour to complete the reaction.

After completion of the reaction, 30 ml of dichloromethane and 10 ml of water were added, and the layers were separated. The organic layer was dried over magnesium sulfate, and the solvent was removed under reduced pressure to obtain 41.0 g of the title compound.

Claims (6)

Novel 4-ethoxycarbonyl-1-methylpyrazole-5-sulfoncarbamate derivatives of the general formula (I) In the formula, R represents a C ₁ -C ₈ alkyl group, alkyl ether group, allyl group or phenyl group (except for methyl group). The compound of formula (I) according to claim 1, wherein R is an ethyl group. 4-ethoxycarbonyl-1-methylpyrazole-5 of formula (I) characterized by reacting a sulfonamide compound represented by formula (II) with alkylchloroformate in the presence of a solvent and a base: Preparation of sulfone carbamate derivatives. In the above formula, R represents a C ₁ -C ₈ alkyl group, alkyl ether group, allyl group or phenyl group (except for methyl group). 4. The process according to claim 3, wherein the alkyl chloroformate is ethyl chloroformate and its amount is 1.1 to 1.3 equivalents based on the compound of formula (II). The method of claim 3 wherein the base is sodium hydroxide, sodium bicarbonate, potassium hydroxide, potassium bicarbonate, potassium carbonate, calcium hydroxide, triethylamine or pyrimidine. A process according to claim 5, wherein the amount of base used is 1 to 3 equivalents relative to the compound of formula (II).