JPH07173128A - Production of n-cyanoethaneimido ester - Google Patents

Abstract

PURPOSE:To economically and safely obtain an N-cyanoethaneimido ester in a relatively high yield by industrially extremely simple method using cyanogen chloride, ammonia and orthoacetic acid ester as starting raw materials without using anhydrous cyanamide. CONSTITUTION:In producing an N-cyanoethaneimido ester by reaction of cyanogen chloride with ammonia and an orthoacetic acid ester the characteristic of this method for producing the N-cyanoethaneimido ester comprises reacting cyanogen chloride with ammonia and an orthoacetic acid ester in an organic solvent at -20C to 40 deg.C.

Description

Detailed Description of the Invention

[0001]

The invention relates to a process for preparing N-cyanoethaneimidic acid esters, in particular methyl or ethyl esters, starting from cyanogen chloride, ammonia, orthoacetic acid esters.

[0002]

2. Description of the Related Art N-cyanoethaneimidic acid esters are
For example, N-cyano-N '-(2- that is useful as an insecticide
2-amino-4-methoxy-6-methyl-s-triazine, which is an important raw material for producing chloro-5-pyridylmethyl-N'-methylacetamidine, and which is an intermediate of sulfonylurea herbicides, It is an important compound as a raw material for production.

The following three methods are known as methods for producing this N-cyanoethaneimidic acid ester. That is, the first method is acetonitrile in a two-step process,
A method for producing hydrogen chloride gas, alcohol and cyanamide (German Patent No. 3411203), and a second method is to react an ortho acid ester with cyanamide in the presence of acetic anhydride to produce N-cyanoethaneimide. Method for producing acid ester (J. Org. Che
m. 28, 1816), and the third method is a method for producing an N-cyanoethaneimidic acid ester of an orthoacetic acid ester and cyanamide in an alcoholic solvent in the presence of an acidic catalyst (German Patent No. 3815084). Specification).

However, the first method uses an extremely corrosive hydrogen chloride gas and thus requires an expensive apparatus. The second method has a drawback that a large amount of methyl acetate and acetic acid are produced as by-products, and the third method solves the above-mentioned drawbacks of the first and second methods, but it is expensive anhydrous cyanamide. Therefore, N-cyanoethaneimidic acid ester could not be produced at low cost.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to produce an N-cyanoethaneimidic acid ester economically and safely from cyanide chloride, ammonia and orthoacetic acid ester as starting materials without using anhydrous cyanamide. To provide.

[0006]

The method of the present invention is characterized by reacting cyanogen chloride, ammonia and orthoacetic acid ester in an organic solvent under the condition of -20 to 40 ° C. The present invention relates to a method for producing an imidate ester.

The process of the present invention is suitable for the production of N-cyanoethaneimidic acid esters, especially their methyl and ethyl esters.

The organic solvent in the present invention is preferably acetonitrile, ethyl ether, isopropyl ether, methanol or ethanol, and particularly preferably acetonitrile or isopropyl ether for stirring the reaction solution.

Although the amount of the organic solvent used is not limited, the amount of the organic solvent used is preferably 100 to 1000 ml, and particularly preferably 300 to 500 ml per mol of the orthoacetate ester in order to facilitate stirring.

Further, cyan chloride is 0.5 to 2 mol and ammonia is 1 to 4 mol per mol of orthoacetic acid ester, particularly 1.0 to 1.5 mol of cyanogen chloride and 2.0 to 3.0 of ammonia. Molar is preferred. If the amount of cyanogen chloride is 1.0 mol or less, the yield will decrease, and if it is 1.5 mol or more, cyanogen chloride and ammonia will be wasted.

As a method of mixing cyanogen chloride, ammonia and orthoacetate, cyanogen chloride, ammonia and orthoacetate are simultaneously mixed in an organic solvent at -20 to 40.
Even in the method of reacting under the condition of ℃, -20 to 40 ℃
After the reaction of cyanogen chloride and ammonia in an organic solvent under the conditions of 1), orthoacetic acid ester is added under the condition of -20 to 40 ° C, or cyanide chloride and ammonia are added to a mixed solution of the organic solvent and orthoacetic acid ester. -20 to 4
Any of the methods of reacting at 0 ° C. may be used.

In the case of a method of adding orthoacetic acid ester after reacting cyanogen chloride and ammonia in an organic solvent, the reaction solution is filtered to remove precipitated ammonium chloride, and the reaction solution is further concentrated. It does not matter if the orthoacetic acid ester is reacted.

The reaction temperature at the time of mixing cyanogen chloride, ammonia, and orthoacetic acid ester is -20 to 40 ° C, preferably -5 to 20 ° C. Unnecessarily cooling only requires a high performance refrigerator. At 40 ° C. or higher, ammonia and cyanogen chloride are vaporized to lower the yield, and ammonium chloride adheres to the upper part of the reactor and the vent line, which hinders the reaction.

The aging after the reaction of cyanogen chloride, ammonia and the orthoacetic acid ester is carried out at 20 to 130 ° C., preferably 40 to 90 ° C., and the aging is 0.5 to
It will be completed in 5 hours. The reaction takes a long time at 20 ° C or lower.

The product after the reaction is isolated by concentrating the reaction solution, removing the alcohol produced in the reaction and the organic solvent used in the reaction, extracting with a poorly water-soluble organic solvent, and washing with water. It is carried out by. During this period, the reaction system may be filtered if necessary. The organic solvent used for extraction is preferably toluene, methylene chloride, hexane, isopropyl ether, or butyl acetate.

The crude product thus obtained has such a purity that it can be sufficiently used for the synthesis of pharmaceuticals and agricultural chemicals in the next step, but if necessary, it may be subjected to usual organic chemical reactions such as distillation and chromatography. It can be further purified by the technique.

The present invention will be described in detail below with reference to Examples.
The present invention is not limited to this.

[0018]

【Example】

Example 1 50 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
In a 0 ml four-neck reaction kettle, 280 g of acetonitrile was charged. After cooling the reaction kettle to 0 ° C., 55 ml of cyanogen chloride (specific gravity 1.21 purity 95.5% 1.03 m
ol) was vaporized by a gas generator and introduced into a reaction kettle. At the same time, 35.6 g (2.09 mol) of ammonia gas was introduced into the reaction kettle. During this period, the reaction temperature was kept at -2 to 2 ° C.

After introducing gas, stir at 0 ° C. for 1 hour,
The precipitated ammonium chloride was filtered, and acetonitrile 5
It was washed with 0 g. The filtrate and the washing solution were combined and concentrated under reduced pressure to obtain 64.7 g of a concentrated solution.

Trimethyl orthoacetate 109 was added to this concentrated solution.
After adding g (0.91 mol) and stirring at 65 degreeC for 2 hours, the reaction liquid was distilled and the produced | generated methanol and acetonitrile 58.2g in total were distilled off. 114 g of the obtained concentrated liquid was cooled to 0 ° C, and 95 g of methylene chloride and 7 g of cold water were added.
1 g was added, and the mixture was stirred and separated. The aqueous phase was further extracted with 95 g of methylene chloride.

The methylene chloride solutions obtained were combined and
After placing in a 00 ml distillation pot to distill off methylene chloride, 67.4 g as a fraction at 107 ° C./30 mmHg
N-cyanoethaneimidic acid methyl ester of was obtained. The yield from trimethyl orthoacetate was 75.3%.

Example 2 50 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
In a 0 ml four-neck reaction kettle, 280 g of acetonitrile was charged. After cooling the reaction kettle to 0 ° C., 55 ml of cyanogen chloride (specific gravity 1.21 purity 95.5% 1.03 m
ol) was vaporized by a gas generator and introduced into a reaction kettle. At the same time, 35.6 g (2.09 mol) of ammonia gas was introduced into the reaction kettle. During this period, the reaction temperature was kept at 0 to 6 ° C. After further stirring at 0 ° C. for 1 hour, the reaction solution was concentrated to obtain 136.5 g of a concentrated solution.

Trimethyl orthoacetate 118
g (0.98 mol) was added, the mixture was stirred at 65 ° C. for 90 minutes, and distilled under reduced pressure to distill off the produced methanol and acetonitrile 83.3 g to obtain 167 g of a concentrated liquid containing N-cyanoethaneimidic acid methyl ester. It was

120 g of butyl acetate and 23 g of cold water were added to the concentrated liquid.
0 g was added, and the mixture was stirred and separated. 60g of butyl acetate in the aqueous phase
It was further extracted with. The obtained butyl acetate solution containing N-cyanoethaneimidic acid methyl ester was concentrated and distilled under reduced pressure to obtain 68.4 g of a fraction at 97 ° C / 20 mmHg.
The purity of N-cyanoethaneimidic acid methyl ester of this fraction was 98.0%, and the yield from trimethyl orthoacetate was 70.0%.

Example 3 10 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
Trimethyl orthoacetate 12 in a 00 ml 4-neck reaction kettle
0g (1.00mol) and acetonitrile 280.9g
Was charged. After cooling the reaction kettle to 10 ° C., 53.1 ml of cyanogen chloride (specific gravity 1.21 purity 95.5%
(1.00 mol) was vaporized by a gas generator and introduced into a reaction kettle. At the same time, 34.0 g of ammonia gas (2.00 m
ol) was introduced into the reaction kettle. During this time, the reaction temperature is 8 to 1
It was kept at 8 ° C.

Then, after stirring at 64 ° C. for 1 hour, the reaction solution was concentrated to distill off 299.0 g, cooled to 20 ° C. and filtered. The filtered product was washed with 120 g of methylene chloride, and the filtrate and the washing liquid were combined. 120 g of methylene chloride solution
After that, methylene chloride was distilled off, and the residue was distilled under reduced pressure to obtain 66.1 g of a fraction at 107 ° C./30 mmHg. The purity of N-cyanoethaneimidic acid methyl ester in this fraction was 98.0%, and the yield from trimethyl orthoacetate was 6%.
It was 6.0%.

Example 4 50 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
In a 0 ml 4-neck reaction kettle, 80 g of trimethyl orthoacetate
(0.67 mol) and 188.3 g of acetonitrile were charged. After cooling the reaction kettle to 5 ° C., 35.4 ml (0.67 mol) of cyanogen chloride was vaporized by a gas generator and introduced into the reaction kettle. Simultaneously with the start of the introduction of cyanogen chloride, 22.7 g (1.33 mol) of ammonia gas was introduced into the reaction kettle. During this period, the reaction temperature was kept at 6 to 15 ° C.

After standing at 17 ° C. for 19 hours, methanol and acetonitrile were distilled off, the mixture was cooled to 20 ° C. and filtered, and the filtered product was washed with 80 g of methylene chloride. The filtrate and the washing solution were combined, washed with 80 g of water, the solvent was distilled off, and then the fraction of 113 to 117 ° C./40 mmHg was 43.6.
g was obtained. The purity of N-cyanoethaneimidic acid methyl ester of this fraction was 99.1%, and the yield from trimethyl orthoacetate was 68.4%.

Example 5 30 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
Triethyl orthoacetate 53.
5 g (0.33 mol) and isopropyl ether 13
1.1 g was charged. After cooling this reaction kettle to 5 ° C., 17.7 ml (0.33 mol) of cyanogen chloride was vaporized by a gas generator and introduced into the reaction kettle. At the same time when the introduction of cyanogen chloride was started, 11.3 g of ammonia gas (0.67 m
ol) was introduced into the reaction kettle. During this time, the reaction temperature is 5 to 2
It was kept at 1 ° C. The mixture was further stirred at 30 ° C. for 30 minutes and then filtered.

The filtrate is refluxed at 65 ° C. for 3 hours to give a reaction solution 14
The concentration of N-cyanoethaneimidic acid ether ester in 9.6 g was 15.6%, and the yield of N-cyanoethaneimidic acid thisyl ester was 62.9%.

Example 6 10 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
Trimethyl orthoacetate 12 in a 00 ml 4-neck reaction kettle
0 g (1.00 mol) and methanol 278.4 g were charged. After cooling this reaction kettle to 10 ° C., 53.1 ml (1.00 mol) of cyanogen chloride was vaporized by a gas generator and introduced into the reaction kettle. At the same time ammonia gas 34.1
g (2.00 mol) was introduced into the reaction vessel at the same time as cyanogen chloride. During this period, the reaction temperature was kept at 10 to 20 ° C.

After stirring at 60 ° C. for 2 hours, the reaction solution was concentrated, cooled to 20 ° C. and filtered.
Washed with 20 g. Combine the filtrate and the washing solution and wash with water 120
After washing with g, 282.6 g of a methylene chloride solution containing 12.7% of N-cyanoethaneimidic acid methyl ester was obtained. The yield of N-cyanoethaneimidic acid methyl ester was 36.7%.

Comparative Example 30 equipped with a stirrer, a cooler, a thermometer, and two gas introduction pipes
In a 0 ml four-neck reaction kettle, 40 g of trimethyl orthoacetate
(0.33 mol) and 180 ml of toluene were charged.
The reaction kettle was cooled to 5 ° C. and then cyanide chloride 17.7.
ml (0.33 mol) was vaporized with a gas generator and introduced into a reaction kettle. Ammonia gas 11.3g (0.67m
ol) was introduced into the reaction vessel simultaneously with cyanogen chloride in 65 minutes. During this period, the reaction temperature was kept at 5 to 16 ° C. After reacting at 30 ° C. for 30 minutes, the mixture was filtered. The filtrate was stirred at 70 ° C. for 4 hours. Thereafter, the reaction solution was cooled to 20 ° C. and filtered. The concentration of N-cyanoethaneimidic acid methyl ester in the filtered solution 182.1 g was 1.38%, and the reaction yield was 7.
It was 7%.

[0034]

As described above, according to the present invention, when N-cyanoethaneimidic acid ester is produced by the reaction with cyanogen chloride, ammonia and orthoacetic acid ester, cyanide chloride and ammonia are mixed with each other in an organic solvent. A method for producing an N-cyanoethaneimidic acid ester, which comprises reacting an orthoacetic acid ester under the condition of -20 to 40 ° C. According to the present invention, cyanide chloride and ammonia are used without using anhydrous cyanamide. There is an advantage that N-cyanoethaneimidic acid ester can be obtained in relatively high yield economically, safely and industrially by a very simple method using orthoacetic acid ester as a starting material.

Claims (6)

[Claims] 1. When producing N-cyanoethaneimidic acid ester by reaction with cyanogen chloride, ammonia and orthoacetic acid ester, cyanide chloride, ammonia and orthoacetic acid ester are mixed in an organic solvent at -20 to 40.
A method for producing an N-cyanoethaneimidic acid ester, which comprises reacting at a temperature of ° C. 2. The orthoacetic acid ester is added after reacting cyanogen chloride and ammonia in an organic solvent.
A method for producing the described N-cyanoethaneimidic acid ester. 3. When producing N-cyanoethaneimidic acid ester by reaction with cyanogen chloride, ammonia and orthoacetic acid ester, cyanide chloride and ammonia are added to a mixed solution of an organic solvent and orthoacetic acid ester.
N- characterized by reacting under the condition of 20-40 ° C
Method for producing cyanoethaneimidic acid ester. 4. The production of N-cyanoethaneimidic acid ester according to claim 1, wherein 0.6 to 1.4 mol of cyanogen chloride and 1.2 to 2.8 mol of ammonia are used per mol of orthoacetic acid ester. Method. 5. The method for producing an N-cyanoethaneimidic acid ester according to claim 1, wherein the organic solvent is one kind or two or more kinds of methanol, ethanol, ethyl ether, isopropyl ether and acetonitrile. 6. The orthoacetic acid ester is trimethyl orthoacetate or triethyl orthoacetate.
A method for producing the described N-cyanoethaneimidic acid ester.