CS203971B2 - Process for preparing substituted 2-chlor-4-alkylamino-6-cyanoalkylamino-1,3,5-triazines - Google Patents

Abstract

Cpds. of formula (I) where R1 is H or (1-3)C alkyl R2,R3,R4, is (1-3)C alkyl (pref. cpd. R1=H R2=C2H5 R3,R4=CH3) are prepd. by (a) mixing an aq. soln. of an alkali metal cyanide and an aq. soln. of an ammonium salt, or an aq. soln. of ammonium cyanide, a ketone of formula R3R4CO and cyanuric chloride in any order and neutralising, below 5 degrees C, by the addn. of a base or by (B) dissolving a ketone cyanhydrin of formula R3R4C(OH)CN in a ketone R3R4CO, introducing gaseous NH3 below 30 degrees C, and adding a soln. of cyanuric chloride in a ketone R3R4CO to the mixt. which is then neutralised, below 45 degrees C, by the addn. of a base. An amine of formula R1R2NH is added to the reaction mixt. from (a) or (b), if necessary the excess ketone R3R4CO is removed and the prod. is sepd. This is converted with conventional carriers or adjuvants to a herbicide prepn., pref. an emulsion concentrate.

Description

The invention relates to a novel process for the preparation of herbicidally active, substituted 2-chloro-4-alkylamino-6-cyanoalkylamino-1,3,5-triazines of the formula I,

and at 3 '' NH-C-CN 1 R * (l) <

wherein R 1 is hydrogen or C 1 -C 3 alkyl and R 2, R 3, R 4 are independently C 1 -C 3 alkyl.

The compounds of the formula I obtainable by the process according to the invention are known, for example, from MLR. 156,467. 2-Chloro-4,6-bis-alkylamino-1,3,5-triazines containing a 1-cyanoalkylamino side chain were first described by Ubrizsy and Matolcsy [Acta Agron. Acad. Sci. Hung. 11, 173-182 (1961)]. The authors have recognized that by incorporating a cyano group, the persistence of 2-halo-4,6-bis-alkylamino-1,3,5-triaaines in soil, which is so harmful to crop rotation agriculture, can be eliminated.

The herbicidally active triazine derivatives containing the side cyanoalkylamine chain are completely degraded during the growing season, for example maize, and are therefore no longer in the soil, so that the subsequent sowing is no longer phytotoxic.

Among the triazines containing a cyanoalkylamino group, compounds in which the nitrogen of the amino group is attached to the tertiary carbon atom have the greatest practical significance.

Said compounds are prepared in a known manner by reacting cyanuric chloride in the presence of an acid-binding agent with the appropriate acrylonitrile and reacting the cyanoalkylamino-containing reaction product in the presence of an alkyl or dialkylamino acid-binding agent.

The drawback of this process is that it is based on difficult-to-produce 1-aminonitriles. The 1-aminoisobutylnitrile required for the preparation of 2-chloro-4-alkylamino-6- (1-cyano-1-methylethylamino) -1,3,5-triazine is obtained, for example, by reacting the acetone cyanohydrin obtained by the reaction of acetone with hydrogen cyanide , causes dry ammonia.

Acetone cyanohydride can be prepared according to Cox and Stormont (Organic Syntheses Coll. Vol.

II, 7) adding 40% sulfuric acid to a mixture of aqueous sodium cyanide and acetone under cooling, by separation. the organic phases containing acetone cyanohydrin, separating the precipitated sodium sulphate and washing it with acetone, combining the acetone used to wash the aqueous phase and extracting it with ether, combining the ether extract with the separated acetone cyanohydrin and drying it, then distilling off the ether and acetone and subjecting the residue to vacuum distillation. The yield was 77-78%.

According to Wagner and Baizer (Organic Syntheses Coli. Vol. III, 324), acetone cyanohydrin can be prepared by adding acetone to an aqueous solution of sodium sulphate while cooling, and then the aqueous sodium cyanide solution, the upper phase containing acetone cyanohydrin, is separated and dried sodium sulfate. Yield 70%.

According to Bucherer and Steiner (J. prakt. Chem. 2 140, 308 (1964)), acetone cyanohydrin can be converted to 1-aminoisobutyronitrile by saturating acetone cyanohydrin with dry ammonia, then extracting the aminonitrile with ether, drying and distilling under vacuum. 64%, corresponding to the starting materials acetone and sodium cyanide, gross yield 45-50%.

1-Aminoisobutyronitrile can also be prepared immediately from acetone, according to Clarke and Bean (Organic Syntheses Coli. Vol. II, 29-30), by adding acetone / ether to an aqueous ammonium chloride solution and then adding the reaction mixture while cooling to temperature. below 10 ° C aqueous sodium cyanide solution. The ethereal acetone cyanohydride solution thus obtained is separated, the aqueous phase is extracted with ether, the ether is distilled off, the residue is dissolved in methanol, the solution is saturated with dry gaseous ammonia and left to stand for 2 to 3 days. distills off.

The methods described are disadvantageous due to their complexity and yield only poor yields. Furthermore, it is disadvantageous that the 1-aminonitriles are readily degradable compounds and are very sensitive to moisture, so they must be handled and stored dry and, if possible, soon to be consumed.

Surprisingly, attempts to overcome the above drawbacks have found that 1,3,5-triazines containing a 1-cyanoalkylamino group as a side chain can be prepared by starting from the corresponding 1-aminonitriles but not from their starting materials - The alkali metal cyanides, ammonium salts as well as the corresponding ketones or also from ketone cyanohydrins and ammonium salts, and the 1-aminonitrile formed in the reaction mixture are reacted in situ without prior isolation with cyanuric chloride.

The substituted 2-chloro-4-alkylamino-6-cyanoalkylamino-1,3,5-triazines of the formula I can therefore be prepared according to the invention in that an aqueous alkali metal cyanide solution and an aqueous ammonium salt solution or optionally an ammonium cyanide prepared in a ketone of the formula R 5 -CO-R 4, wherein R 3 and R 6 are as defined above, and the cyanuric chloride is mixed together in any order, and the mixture is neutralized with a base while maintaining the temperature below 5 ° C; The R 3 R 4 COHCN formed in the above equilibrium reaction isolates, dissolves in the ketone R 3 -CO-R 4, wherein R 3 and R 4 are as defined above, and introduces ammonia gas at temperatures below 30 ° C, then adds to the reaction mixture, a solution of cyanuric chloride in a ketone of the formula R3 — CO — R4, in which R3 and R4 have the same meaning as above, and the reaction mixture is neutralized by addition of a base at p. from 45 ° C and the mixture obtained without separation. of the reaction product is added an amine of the formula R 1 R 2 NH, wherein R 1 and R 2 are as defined above, optionally the excess ketone of the formula R 3 -CO-R 4 is removed and the reaction product is separated.

Surprisingly, the process according to the invention is carried out under conditions in which otherwise the 1-aminonitrile is not formed in sufficient quantity. In the above-cited Clarke and Bean method, for example, by reaction of ammonium chloride, sodium cyanide and acetone, acetone cyanohydrin is formed first, which can only be converted to 1-aminoisobutyronitrile by saturation with gaseous plugs. In the process according to the invention, on the other hand, under reaction conditions otherwise identical to those described by Clark and Bean, 1-aminoisobutyronitrile is formed immediately without treatment with ammonia gas. This can probably be explained by the fact that in an equilibrium system containing ketone cyanohydrin, aminonitrile, ammonia and water, but predominantly ketone cyanohydrin, the equilibrium is shifted in favor of aminonitrile (upper arrow) as the aminonitrile is consumed by reaction with cyanuric chloride:

СНз СНз

HO — C — CN + NH3 - H — N — C — CN + HO

СНз СНз

The process according to the invention makes it possible to eliminate all the above mentioned drawbacks of the known processes, to reduce the number of operations and to reduce the production time required.

According to the process of the invention, the cyanuric chloride is dissolved in the appropriate ketone and an aqueous solution containing alkali cyanide and an ammonium salt is added to the solution with cooling. The ammonium cyanide formed in the solution reacts with the ketone acting as both the solvent and the starting material, while the resulting 1-amino-nitiril reacts with the continuous addition of the acid-binding agent with cyanuric chloride to 2,4-dichloro-6 [1]. (cyanoalkylamino) -1,3,5-triazine. The reaction product can be converted to the desired 2-chloro-4-alkylamino-6- (1-cyanoalkylamino) -1,3,5-triazine by addition of an alkylamine and an acid binding agent.

The process can also be carried out by adding the solutions of the ammonium salt and the alkali cyanide separately to the cyanuric chloride solution.

In another process of the invention, the dissolved alkali cyanide and dissolved ammonium salt are first reacted with the appropriate ketone, and the resulting reaction mixture is added to the cyanuric chloride dissolved in the ketone.

In the process of the invention, an aqueous solution containing the final product is separated. This allows the immediate processing of the active ingredient-containing ketone solution, i.e. without prior separation of the active ingredient, into herbicidal compositions (e.g. emulsion concentrates).

The process according to the invention can also be carried out without using a substantial excess of ketone as solvent. In this case, however, the yield is considerably lower. For example, if 2-chloro-4-ethylamino-6- (1-cyano-1-methylethylamino) -1,3,5-triazine is used instead of an acetone solution of cyanuric chloride with an aqueous suspension of cyanuric chloride with the addition of an equivalent amount of acetone instead of 86%, the yield is only 48%.

The 2-chloro-4-alkylamino-6-cyanoalkylamino-1,3,5-triazines of the formula I prepared according to the process of the invention can be formulated in a known manner into herbicidal preparations. Conventional carriers and excipients are used in the preparation of these preparations. Of the preparations, liquid, especially emulsion concentrates are preferred, since the active substances produced in the process according to the invention need not be isolated.

The process according to the invention is illustrated in more detail by the following examples

Example 1

Choi-2 ^{^,} 4-el; hylamino-6- (1-cyano-l-methylethylaminopi ^^ - triazine:

18.4 g (0.1 mol) of cyanuric chloride are dissolved in 180 ml of acetone cooled below 5 ° C. 4.9 g (0.1 mol) of sodium cyanide and 4.8 g (0.11 mol) of ammonium chloride dissolved in 28 ml of water are added to this solution with cooling and stirring. 4 g (0.1 mol) of sodium hydroxide in the form of a 10% solution are then added while stirring and cooling, taking care to keep the temperature between 0 and 5 ° C. The mixture was stirred at a temperature below 5 ° C for an additional half hour and then without cooling for an additional hour. During this time, the pH is checked and, if necessary, kept between 7 and 8 by adding 10% aqueous sodium hydroxide (if necessary, 6 to 8 g of 10% sodium hydroxide are usually required). 95 g (0.11 mol) of ethylamine as a 70% aqueous solution while maintaining the temperature below 35 ° C by cooling. The reaction mixture was further stirred without cooling for an additional hour and then the acetone was distilled off at 55 to 56 ° C with stirring. Finally, the reaction mixture is cooled, the solid product is collected, washed with water and dried. 19 g (78%) of a snow-white product are obtained having a melting point of 163-164 ° C.

Example 1 a d 2

2-Chloro-4-ethylamino-6- (1-cyano-1-methylethylamino) -1,3,5-triazine:

4.9 g (0.1 mole) of sodium cyanide and 4.4 g (0.1 mole) of ammonium chloride are dissolved in 15 ml of water and 60 ml of acetone are added to the solution while cooling to a temperature below 20 ° C. The mixture was stirred for 2 hours. 18.4 g (0.1 · mol) of cyanuric chloride are dissolved in 180 ml of acetone cooled below 5 ° C and this solution is added under stirring at a temperature below 5 ° C to the first continuously stirred solution consisting of two phases. 4 g (0.1 mol) of sodium hydroxide is then added to the reaction mixture as a 10% solution. It is then stirred at a temperature below 5 DEG C. for a further half hour and then for a further hour without cooling. Then, 4.95 g (0.11 mol) of ethylamine as a 70% aqueous solution and 4.4 g (0.11 mol) of sodium hydroxide are added as a 10% solution while keeping the temperature below 35 ° C by cooling. The reaction mixture is stirred for an additional hour and then 140 ml of water are added. The acetone is separated off either at 50 to 60 degrees Celsius at atmospheric pressure or at room temperature under vacuum. The residue is cooled, the solid product is collected, washed with water and finally dried. 21 g (86%) of a snow-white product are obtained, m.p. 163-164 ° C.

The crude product was recrystallized from acetone / water 1: 2 to give a melting point of 166 ° C.

Analysis:

% C, 45.2; H, 5.45. Cl 14.75,

N, 34.90;

Found%: C 45.2, H 5.59, Cl 14.53

N, 35.10.

NMR Spectrum: CDCl3 (ethyl), triplet (J = 7.5 Hz); 1.25 ppm; (3H), OCH 3 (i-pnp, singlet: 1.85 ppm; (6H), OCH 2: 3.55 ppm; (2H), ONH; 3.08 and 7.2 ppm.

Example 3

2-Chloro-4-ethalamino-6- (1-cyano-1-methyl-ethylamino) -1,3,5-triazine as an acetone solution:

The procedure described in Example 2 is followed except that after the reaction of the upper phase of the biphasic reaction mixture consisting of the acetone solution containing the product is separated, dried with a desiccant and emulsion concentrate is prepared from the solution by addition of the usual auxiliaries.

Example 4

2-Chloro-4-ethylamino-O- (1-cyano-1-methylethylamino) -1,3,5-triazine:

I. Dissolve 85 g of acetone cyanohydrin at room temperature in 150 g of acetone. 17 g of ammonia gas are introduced into the solution while cooling, and the gas stream is metered in. so that the temperature of the reaction mixture. did not exceed 30 ° C. The acetone cyanohydrin solution thus obtained is cooled to room temperature with stirring.

II. 184 g of cyanuric chloride are suspended in 1500 g of acetone with stirring and cooling. The suspension is cooled. to 0 ° C.

Solution I is now added to solution II, taking care to:. to maintain the temperature of the mixture between 0 and 5 ° C. 80 g of aqueous sodium hydroxide solution are added slowly to the mixture. Without cooling, 90 g of a 50% aqueous solution of ethylamine and 80 g of a 50% aqueous solution of sodium hydroxide are now added to the reaction mixture, taking care that the temperature is not allowed to stand at 40 to 45 ° C for one hour and then poured into 10 liters of water. It increased to 45 ° C. The weakly alkaline reaction black crystals are filtered off, washed on the filter with water and then dried. 212 g of product are obtained, melting at 103-104 ° C.

Example 5

The procedure is as described in Example 4 except that the sodium chloride precipitated from the weakly alkaline solution is filtered off and 3 liters of water are added to the acetone solution. The acetone is then distilled off. The product precipitated from water is washed, filtered and dried. 225 g of product are obtained, m.p. 103-104 ° C.

Example 1 and d 0

2-Chloro-4-isopropyl ^| mino-O- (1-cyano-1-methylethylamino) -AS-triazine:

The procedure is as described in Example 2 except that an aqueous solution of 0.2 g (0.105 mol) is used instead of an aqueous solution of ethylamine. isopropylamine. 21.0 g (84%) of a pale pink color are obtained. After recrystallization from acetone. and water 2: 3, mp 192-193 ° C.

Analysis:

Calculated%: N 33.00, Cl 13.95;

Found%: N 33.40, Cl 13.77.

Example 7

2-Chloro-4-dimethylamino-O- (1-cyano-1-methylethylamino) -1,3,5-triazine:

The procedure described in Example 2 was followed except that an aqueous solution of 4.95 (0.11 mol) of dimethylamine was used instead of ethylamine. 10.2 g (07%) of a white product are obtained. Recrystallization from 2: 3 acetone / water gave a melting point of 123 ° C.

Analysis:

Calculated%: N 35.80, Cl 15.10;

Found%: N 35.11, Cl 14.51.

Example8

2-Chloro-4-ethylamino-O- (1-cyano-1-methylpropylamino) -1,3,5-triazine:

The procedure is as described in Example 2 except that an equal amount of methyl ethyl ketone is taken instead of acetone. Excess ketone was removed from the reaction mixture under low vacuum. 23 g (90%) of product are obtained, which, after recrystallization from acetone / water 2: 3, melts at 142-144 ° C.

Analysis:

Calculated%: N 33.00, Cl 13.95;

Found%: N 33.37, Cl 13.91.

Example 9

The active compounds can be prepared in the form of various preparations. The composition of the emulsifiable concentrate is as follows:

wt. % 2-chloro (1-chloro-O-ethylaminos-triazin-2-ylamino) -2-propionylnitrile, wt. % N-methyl-4-pyrrolidone, 40 wt.

percent xylene, 5 wt. % of a mixture of calcium salt of dodecylbenzenic acid, nonylphenol-ethylene oxide condensate.

This concentrate can be used immediately after dilution with water.

The active ingredient can also be formulated in powder form, and the active ingredient content can be increased up to 80% by weight. The powders contain the sodium salt of ligninsulfonic acid and olein methyltauride as a surfactant and can be diluted with synthetic silicic acid or kaolin.

Claims (5)

I will invent it A process for the preparation of substituted 2-chloro-4-alkylamino-6-cyanoalkylamino-1,3,5-triazines of the general formula I, C1 wherein R1 is hydrogen or C1-C3 alkyl and R2, R3, R4 are independently C1-C3 alkyl, characterized in that the aqueous alkali cyanide solution and the aqueous ammonium salt solution or optionally ammonium cyanide prepared in situ in aqueous solution, a ketone of the formula R3-CO-R4, wherein R3 and R4 are as defined above, and the cyanuric chloride is mixed together in any order and the mixture is neutralized with a base while maintaining the temperature below 5 ° C, optionally, the ketone cyanohydrin of the formula R3R4COHCN formed in the above equilibrium reaction is isolated, dissolved in a ketone of the formula R3-CO-R1, wherein R3 and R4 are as defined above, and ammonia gas is introduced into the solution at temperatures below 30 ° C; then a solution of cyanuric chloride in the ketone of formula R3-CO-R4, in which R3 and R4 have the same meaning as above, is added to the reaction mixture, and the reaction mixture is discarded utralizu the addition of a base at temperatures below ⁴⁵ C and the resultant mixture without separation of the reaction product was added an amine of formula R1R2NH, wherein R and R2 are as defined above, or with an excess of a ketone of formula R 3 -CO-R 4 is removed and the reaction product is separated . 2. A process according to claim 1, wherein the ammonium cyanide prepared optionally in situ in aqueous solution is reacted with a ketone of the formula R5-CO-R4, wherein R3 and R4 are as defined in item 1, and the reaction mixture is reacted. then, without separation of the reaction product, it is reacted with a solution of cyanuric chloride in a ketone of the formula R 3 -CO-R 4, wherein R 3 and R 4 are as defined in point 1. 3. A process according to claim 1, wherein the ketone of the formula R3-CO-R4, wherein R3 and R4 are as defined in item 1, is used in excess as a solvent. 4. A process according to claim 1 for the preparation of 2-chloro-4-ethylamino-6- (1-cyano-1-methylethylamino) -1,3,5-triazine, characterized in that R3-CO-R4 is used as the ketone. using acetone and an amine of the formula R1R2NH ethylamine and an aqueous sodium hydroxide solution as neutralizing agent. 5. A process according to claim 1 for the preparation of 2-chloro-4-ethylamino-6- (1-cyano-1-methylethylamino) -1,3,5-triazine, characterized in that acetone cyanohydrin is used as ketone cyanohydrin and amine of the formula R 1 R 2 NH ethylamine.