CH642666A5 - METHOD FOR PRODUCING PHOSPHORUS-CARBON-NITROGEN BONDINGS. - Google Patents

Description

The object of the invention is to eliminate these disadvantages and to develop a simple process for the preparation of compounds of the formula I containing phosphorus-carbon-nitrogen bonds, mainly of N-phosphonomethylglycine and its derivatives, the can form the desired compound in purified form.

The process according to the invention for the preparation of compounds of the general formula I

The invention relates to a process for the preparation of compounds of the formula I containing phosphorus-carbon-nitrogen bonds, preferably of N-phosphonomethylglycine and their derivatives, which are known as compounds having a herbicidal action.

The compounds containing phosphorus-carbon-nitrogen bonds gained great importance in the field of crop protection because of their broad-spectrum herbicidal activity. The good herbicidal activity is paired with a low residual activity, which means that the active ingredient degrades relatively quickly in the soil.

Numerous synthetic methods have become known in the specialist literature for the preparation of the compounds of the formula I containing phosphorus-carbon-nitrogen bonds, primarily for the preparation of N-phosphonomethylglycine and their derivatives.

In US Pat. No. 2,635,112, a primary or secondary amine is allowed to react with aldehyde or ketone and phosphorous acid dialkyl ester to produce the compounds of the formula I containing phosphorus-carbon-nitrogen bonds. A disadvantage of the preparation is that in the case of dialkyl phosphorous acid, both the formation of the ester and its isolation, and the subsequent hydrolysis, is a lengthy process. The resulting active ingredient is resistant to acids and bases, so its isolation is complicated. Another disadvantage of the phosphoric acid ester is that its treatment requires special supervision, since it is extremely toxic.

0 II

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/ R3

HO - P - C - K

I I \

OH R,

R,

Where

Ri and R2 are the same or different, namely hydrogen atoms or organic radicals,

R3 and R4 are the same or different, namely hydrogen atoms, hydroxyl groups or organic radicals, 55 characterized in that in the presence of water a phosphorus halide with ammonia, or a water-soluble ammonium salt, with a primary or secondary amine, further with aldehyde or Ketone is reacted.

The process according to the invention is particularly advantageous when a secondary amine is used as the starting material, since the end product can be freely produced from by-products. In addition to the primary and secondary amine, ammonia can also be used as the reagent. Among the primary and secondary amines, the aminocarboxylic acids or 6-aminodicarhonic acids and monohydric amino alcohols are advantageous. The use of monoethylamine, dimethylamine and the N-alkyl derivatives of glycine, for example sarcosine, is also expedient. As a phosphorus halide

Phosphorus trichloride used. The system is saturated with hydrochloric acid under the given reaction conditions. The desired reaction product is obtained from the mixture either by reducing the reaction volume or by adding a water-miscible organic solvent.

When one of the substituents R 1 and R 2 is a hydrogen atom, the reagent to be used is an aldehyde such as formaldehyde, acetaldehyde, capronaldehyde, benzaldehyde, 2-bromoacetaldehyde and the like. But if R and R2 represent an organic radical, then the reagent is a ketone. The ketone used is, for example, acetone, methyl ethyl ketone, acetophenone, butyrone, 2-pentanone, 3-pentanone, 1-chloro-2-propanone. In general, an aldehyde containing at most 30 carbon atoms and a ketone containing at most 20 carbon atoms is used as the reagent. If an ammonium reagent is used instead of a primary or secondary amine, this can be aqueous ammonia or a readily soluble ammonium salt, such as ammonium chloride, ammonium acetate, ammonium bromide, ammonium carbonate, ammonium phosphate or a similar ammonium salt.

The product produced according to the invention crystallizes easily and is chemically uniform. Neither the NMR nor the IR spectrum show impurities. The yield is generally over 90%. The content of compounds containing PCN (phosphorus-carbon-nitrogen) bond in the resulting product is over 98%.

The process is suitable for the preparation of all compounds containing phosphorus-carbon-nitrogen bonds that have become known and can be used advantageously.

The advantages of the method according to the invention are summarized below:

1. The undesirable side reactions resulting from the decomposition of orthophosphorus acid or from the formation of heteropolyacid are excluded.

2. A separate addition of acid is unnecessary during the reaction, since the acid concentration of the reaction mixture can be regulated by adding water.

3. With the reaction temperature, the reaction can be influenced in the same proportion. This allows the reaction product to be regulated, which improves both the yield and the quality of the product obtained.

4. The production of a chemically uniform, pure product is made possible. Contamination with the related compounds formed as a by-product in the preparation of the compounds with PCN binding is overcome. The importance of this uniformity is easy to see, since the plant physiological effects of the related compound show extremely large deviations. By producing a pure product, a selective effect can be achieved with a broad spectrum instead of the total herbicidal effect.

The method according to the invention is described in more detail in the exemplary embodiments below.

example 1

In a flask equipped with a stirrer, 137 g of phosphorus trichloride are added to 300 ml of water with stirring, and 75 g of 50% strength aqueous glycine solution are added to the warmed-up solution. The reaction mixture is heated to the boiling point with constant stirring, and 200 g of 37% aqueous formaldehyde are slowly added in the course of 30 minutes. After the reaction has ended, the water is evaporated. The syrup consistency liquid obtained is dissolved in hot ethanol. After the ethanolic solution has cooled, a crystal-like product is separated out, which contains the N-diphosphonomethylglycine in a purity of 97%. Decomposition 642 666

point: 210 ° C. The yield is 93%.

Example 2

In a flask equipped with a thermometer, stirrer and reflux condenser, 51.7 g of phosphorus trichloride are added to 125 ml of water with stirring and cooling, and the temperature is kept below 40.degree. When the addition of phosphorus trichloride has ended, 50 g of imino-diacetic acid are added to the mixture and the mixture is heated to the boil. Using a reflux condenser, the mixture is allowed to boil and 119 g of 38% aqueous formaldehyde are added over 45 minutes. After the addition of formaldehyde is complete, the mixture is boiled for 3 hours. Then% of the water present is distilled, the solution is diluted with ethanol and left to cool. The crystals which have separated out are filtered off, washed with ethanol and water and dried. The product obtained is a high purity H-phosphonomethyl-imino-di-acetic acid. Decomposition point: 208 ° C. The yield is 95%.

114 g of the N-phosphonomethylimino-di-acetic acid prepared in the previous manner are mixed with 150 ml of water in a flask equipped with a stirrer. After the mixing, 50 g of concentrated sulfuric acid are added and the mixture is heated to 90 ° C. with stirring. At this temperature, 260 g of 30% aqueous hydrogen peroxide solution are added over the course of 3 hours, the temperature being kept constantly at 60.degree. After adding the hydrogen peroxide, it is kept at 90 ° C. for a further 3 hours.

After the reaction has ended, part of the water is evaporated, then the rest is diluted with ethanol and cooled. During cooling, the N-phosphonomethylglycine separates out like crystals and is dried after washing with water. The purity of the product: 98%, decomposition point: 230 ° C, yield: 95%.

Example 3

69 g of phosphorus trichloride and 44.5 g of N-methylglycine are added to 175 ml of water with stirring in a flask provided with a stirrer and reflux condenser. Accordingly, 188.4 g of 38% strength aqueous formaldehyde solution are added, the reaction mixture being kept at the boil. After the addition has ended, it is boiled for a further 2 hours and then evaporated to half the volume. After adding ethyl alcohol and cooling the mixture, the precipitated, crystalline product is washed with water and then dried. The product obtained is 97% pure N-phosphonomethylglycine. The yield is 90%.

Example 4

206 g of phosphorus trichloride are added to 525 ml of water with stirring in a flask provided with a stirrer and reflux condenser, the temperature of the mixture being at most 40 ° C. Then 27 g of ammonium chloride are added, heated to the boil, 565 g of 38% strength aqueous formaldehyde solution are added with boiling and the mixture is boiled for a further 1 hour. After the reaction, the mixture is cooled to room temperature and the precipitated crystal-like product is filtered out of the solution. The product obtained is an N-trimethylphosphonic acid of 98% purity. Decomposition point: 215 ° C. The yield is 97%.

Example 5

In a flask equipped with a stirrer and reflux condenser, 138 g of phosphorus trichloride are added to 350 ml of water while stirring, the temperature being kept at about 40.degree. Then 62 g of cyclohexylamine hydrochloride are added, the mixture is heated to the boil and after half an hour

3rd

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25th

30th

35

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60

6S

642 666 4

Boil fed 108 g of benzaldehyde. The mixture is left to boil for a further 2 hours and is finally cooled to room temperature. The product obtained is cyclohexylamino di (benzylidene) phosphonic acid, the purity of which is 97%. Yield: 92%. 5

Example 6

138 g of phosphorus trichloride are added to 350 ml of water in a flask provided with a stirrer and reflux condenser,

the temperature should be about 40 ° C. 15 g of ethylenediamine are then added and the reaction mixture is heated to the boil. After boiling for half an hour, 170 g 38% aqueous formaldehyde solution are added and the mixture is cooled to room temperature. The white-colored, crystal-like material obtained is the ethylenediamine-tetramethylene-phosphonic acid. The product is formed with a 98% yield and a purity of 98%. The decomposition point is 241 ° C.

M

Claims (4)

642 666 PATENT CLAIMS 1 1 R4 OH R2 ^ Where R 1 and R 2 are identical or different, namely hydrogen atoms or organic radicals, R3 and R4 are the same or different, namely hydrogen atoms, hydroxyl groups or organic radicals, characterized in that in the presence of water a phosphorus halide is reacted with ammonia, or water-soluble ammonium salts, or primary or secondary amine, with aldehyde or ketone, whereupon the desired product is obtained from the reaction mixture by reducing the reaction volume or by using a water-miscible organic solvent. 1. A process for the preparation of a compound of the general formula I containing phosphorus-carbon-nitrogen bonds OR, il I1 y R-j HO - -P - .C - H v 2. The method according to claim 1, characterized in that the amine, amino carboxylic acid, aminodicarboxylic acid, monohydric amino alcohol, N-alkyl derivatives of glycine, advantageously monoethylamine, dimethylamine, N-methylglycine is used. 3. The method according to claim 1, characterized in that phosphorus trichloride is used as the phosphorus halide and the reaction mixture is saturated with hydrochloric acid. 4. The method according to claim 1, characterized in that as aldehyde formaldehyde, acetaldehyde, capronaldehyde, benzaldehyde, or 2-bromo-acetaldehyde, but as ketone but acetone, methyl ethyl ketone, acetophenone, butyrone, 2-pentanone, or l-chloro-2 -Propanon is used. In Belgian patent 774349, to produce a compound containing phosphorus-carbon-nitrogen bonds, the N-phosphonomethyl-glycine, chloromethylphosphonic acid is allowed to react with an amine, namely with glycine. The reactivity of the chloromethylphosphonic acid is weak, however, so the reaction requires strict reaction conditions during which by-products inevitably form. According to German patent specification 2355 351, a cyclic amine, such as tricyano-methyl-hexahydro-triazine, is reacted with phosphoric acid diester in the presence of a catalyst and an ester of N-phosphonomethyl-glycino in one step to produce the N-phosphonmethyl-glycine -Nitrile produced, which is hydrolyzed in the second stage. The night part of this process again consists in the difficulty of the preparation, or in the treatment of the phosphoric acid diester and the starting material, that is to say the tricyano-triazone derivative. The listed and other known methods generally use phosphoric acid or its derivatives as a reaction component. A common disadvantage of these processes is the possibility of the formation of by-products because of the hydrolysis of the phosphorous acid, which on the one hand worsens the quality of the desired products and on the other hand reduces the yield. The preparation of the compounds of the formula I containing phosphorus-carbon-nitrogen bonds is generally carried out in a concentrated medium containing a mineral acid. The risk of corrosion is therefore significant, the strict observance of the reaction parameters is absolutely necessary for the production of end products of reproducible quality and the course of the reaction is relatively slow.