IE912920A1

IE912920A1 - Process for the preparation of aminomethylphosphonic acid¹and aminomethylphosphinic acids

Info

Publication number: IE912920A1
Application number: IE292091A
Authority: IE
Original assignee: Hoechst Ag
Priority date: 1990-08-17
Filing date: 1991-08-16
Publication date: 1992-02-26
Also published as: CA2089650A1; BR9106767A; CN1059148A; AU8309591A; HUT64355A; ES2069901T3; ATE118008T1; IL99203A; KR100214903B1; AU653954B2; DE59104516D1; WO1992003449A1; EP0543845B1; DK0543845T3; CA2089650C; ZA916502B; CN1028996C; DE4026027A1; HU213457B; GR3015357T3

Abstract

Aminomethanephosphonic acid and aminomethylphosphinic acids are interesting biologically active compounds or intermediates for the production of biologically active compounds. Such compounds having the formula (I), in which R?1 is OH, C1?-C4?-alkyl or phenyl, can be produced in a technically easy manner, by reacting with water at 80 to 300 C compounds having the formula (II), in which R?2 is H, C1?-C6?-alkyl, benzyl, phenyl, if necessary substituted by C1?-C4?-alkoxy and/or halogen, and R?1 has the same meaning as above.

Description

Description Process for the preparation of aminomethylphosphonic acid and aminomethylphosphinic acids Herbicidal and plant-growth-regulating actions are known of aminomethylphosphonic acid; aminomethylphosphinic acids are also industrially valuable compounds having a biological activity or can be used as intermediates for the preparation of biologically active compounds (see the article by L. Maier Advances in the Chemistry of Aminophosphinic Acids in the periodical Phosphorus and Sulfur 1983, Vol. 14, p. 295-322, in particular 317-323 and literature cited therein). Aminomethylphosphonic acid is furthermore valuable as an intermediate for the preparation of N-phosphonomethylglycine (see EP-A-214,578) .

Aminomethylphosphonic acid can be prepared from acylaminomethylphosphonic acids by hydrolysis with hydrochloric acid (US-A-2,304,156; US-A-2,328,358; M. Soroka, Synthesis 1989, 547). It is a disadvantage of this process that the aminomethylphosphonic acid can only be obtained in high yields during working-up when special measures are applied. For example, M. Soroka describes working-up with the aid of pyridine or propylene oxide, which cause the separation of hydrogen chloride from the aminomethylphosphonic acid. Another disadvantage is that, without complicated ultrapurification, the acylaminomethylphosphonic acids contain traces of formaldehyde, due to the production process. The treatment with hydrochloric acid in the hydrolysis then results in the formation of bischloromethyl ether as undesirable by-product, which has been identified clearly as a carcinogenic working substance. There is therefore a demand for hydrolysis processes which can be carried out on an industrial scale and which exclude the formation of -2the by-product bischloromethyl ether.

The invention relates to a process for the preparation of compounds of the formula I h2nch2p in which R1 is hydroxyl, Cj-C^-alkyl, preferably Cx-C2alkyl, in particular methyl, or is phenyl, which comprises reacting acylaminomethylphosphonic or acylaminomethylphosphinic acids of the formula II O .R2 / rzconhch2p: II OH in which R2 is hydrogen, alkyl having 1 to 6 carbon atoms, preferably 1 to 3 carbon atoms, or is benzyl or phenyl, unsubstituted or substituted by one or more radicals from the group comprising Ci-C^-alkyl, C^-C^-alkoxy and halogen, and R1 is as defined above, with water, at 80 to 300’C, preferably 150 to 250’C.

Some of the starting substances of the formula II are known, or some are accessible analogously to known methods. For example, the acylaminomethylphosphonic acids of the formula II can be prepared from N-(hydroxymethyl)20 amides and PC13 (see US-A-2,328,358; US-A-2,304,156 or M. Soroka, Synthesis 1989, 547 and literature cited therein).

The acylaminomethylphosphonic acids as well as the acylaminomethylphosphinic acids of the formula II can also be prepared by the process in German Patent -3Application P 4,026,026.7.

Examples of preferred starting substances of the formula II are formylaminomethylphosphonic acid, acetylaminomethyl phosphonic acid, benzoylaminomethylphosphonic acid, (acetylaminomethyl)(methyl)phosphinic acid and (benzoylaminomethyl)(phenyl)phosphinic acid.

The starting substances of the formula II are treated with water, if appropriate with an excess of water, and the mixture is brought to reaction temperature, and it may be necessary to carry out this process under pressure, as a function of the temperature.

The extent of the excess of water is not particularly critical for the reaction; for example, for reasons of better handling, it may be advantageous to use a 2 to molar, preferably 10 to 25 molar, excess of water. The reaction temperatures are 80 to 300 °C, preferably 150 to 250eC. The reaction times depend on the substrate, reaction temperature and pressure and are generally in the range from 5 to 40 hours, preferably 10 to 35 hours.

When the reaction is complete, working-up can be carried out in a simple manner, for example by removing the carboxylic acid as a solid (for example benzoic acid) or by distillation (for example acetic acid). The resulting aminomethylphosphonic acid, or aminomethylphosphinic acids, generally already have high purity. If appropriate, they can be obtained in ultrapure form by customary methods, preferably by crystallization.

Example 1 g (0.093 mol) of benzoylaminomethylphosphonic acid and g of water were placed in a sealed tube and maintained at 200°C for 20 hours. After cooling, the reaction material was digested with 100 ml of water. The benzoic -4acid was subsequently filtered off with suction. The filtrate was concentrated in vacuo by distillation until it had reached an internal temperature of 75°C. There remained 10.3 g (100 % of theory) of aminomethylphos5 phonic acid which, according to 31P-NMR spectrum analysis, had a purity of 95 %.

Example 2 g (0.093 mol) of benzoylaminomethylphosphonic acid and 20 g of water were placed in a sealed tube and maintained at 150eC for 20 hours. After cooling, the reaction material was then digested with methanol and filtered off with suction. 8.2 g (80 % of theory) of aminomethylphosphonic acid of a decomposition point of 310°C were obtained.

Example 3 g (0.093 mol) of benzoylaminomethylphosphonic acid and 20 g of water were refluxed for 30 hours. After cooling, the reaction material was digested with 100 ml of methanol and filtered off with suction. 5.3 g (52 % of theory) of aminomethylphosphonic acid of a decomposition point of 275’C were obtained. Unreacted benzoylaminomethylphosphonic acid could be isolated from the filtrate.

Example 4 21.3 g (0.1 mol) of benzoylaminomethylmethylphosphinic acid and 42 g of water were placed in a sealed tube and maintained at 200"C for 20 hours. After cooling, the mixture was digested with water, and benzoic acid was removed by filtration with suction. The filtrate was evaporated to dryness in vacuo. The crystalline residue was digested with methanol and filtered off with suction. g (73 % of theory) of aminomethylmethylphosphinic acid -5of a melting point of 255-261’C were obtained.

Example 5 g (0.073 mol) of benzoylaminomethylphenylphosphinic acid and 40 ml of water were placed in a sealed tube and maintained at 225°C for 23 hours. The benzoic acid was then removed by filtration with suction, followed by rinsing with water. The filtrate was concentrated to dryness in vacuo. There remained 12.5 g (100 % of theory) of crude amlnomethylphenylphosphlnic acid. After diges10 tion with methanol, the substance obtained had a melting point of 276-278eC.

Example 6 14.4 g (0.094 mol) of acetylaminomethylphosphonic acid and 28 g of water were fed into a sealed tube and maintained at 200°C for 20 hours. The mixture was then cooled, and the resulting reaction solution was freed in vacuo from water and acetic acid. The residue was digested with a mixture of 30 ml of methanol and 1 ml of water. 9.6 g (92 % of theory) of aminomethylphosphonic acid of a decomposition point of 270-278eC were obtained. -6HOE 90/F 249

Claims

1. Patent claims:

1. A process for the preparation of compounds of the formula I 2. 5 in which R 1 is hydroxyl, C 1 -C 4 -alkyl or phenyl, which comprises reacting acylaminomethylphosphonic or acylaminomethylphosphinic acids of the formula II 0 R' R z CONHCH 2 P. II OH in which R 2 is hydrogen, alkyl having 1 to 6 carbon atoms, 10 benzyl or phenyl, unsubstituted or substituted by one or more radicals from the group comprising Cj-C 4 -alkyl, C^-C^alkoxy and halogen, and R 1 is as defined above, with water, at 80 to 300 e C.

2. The process as claimed in claim 1, in which R 1 is 15 hydroxyl. 3. The process as claimed in claim 1, in which R 1 is methyl, ethyl or phenyl. 4. The process as claimed in claim 1, 2 or 3, in which R 2 is H, Ci-Ca-alkyl, benzyl or phenyl. 20 5. The process as claimed in claim 1, 2 or 3, in which R 2 is phenyl.

3. 6. The process as claimed in one or more of claims 1 -7to 5, in which the reaction temperature is 150 to 250*C.

4. 7. The process as claimed in one or more of claims 1 to 6, in which a 2 to 30 molar excess of water, based on 1 mol of compound of the formula II, is employed. 5

5. 8. The process as claimed in one or more of claims 1 to 7, in which the reaction time is in the range from 5 to 40 hours.

6. 9. A process according to claim 1 for the preparation of a compound of the formula (I) given and defined therein, substantially as hereinbefore described and exemplified.

7. 10. A compound of the formula (I) given and defined in claim 1, whenever prepared by a process claimed in a preceding claim.