DD299432A5 - PROCESS FOR PREPARING N-PHOSPHONOMETHYL GLYANE - Google Patents

Abstract

The invention relates to a process for the preparation of N-phosphonomethylglycine. In a single integrated process, glycine is reacted with formaldehyde and cyclopentadiene in the presence of an acid at about 25C to 40C; Added phosphorus trichloride and filtered the filtered reaction mixture after addition of water and hydrolyzed to obtain the N-phosphonomethylglycine. {Process; manufacture; N-phosphonomethylglycine; glycine; Formaldehyde; Cyclopentadiene; phosphorus trichloride}

Description

Flowchart I

H ₂ NCH ₂ -Y + HCHO +

II

solvent

N-CH ₂ -Y

The presence of an acid is required when Y is CON (R ₁ )], COOR or CN. No additional acid is necessary if Y

COOHist.

In the course of the reaction, which is illustrated in the flow diagram I, and dienes, except cyclopentadiene, such as. B.

substituted cyclopentadienes can be used to provide the corresponding azanorbornenes.

The thus obtained N-substituted azabicycloalkene intermediates, such as. B. N-substituted azanorbornene Intermediates of formula I, wherein Y is preferably COOH, may be reacted with a phosphoric acid equivalent, e.g. B. Dialkyl phosphite, or a phosphorus trihalide, preferably phosphorus trichloride, in the presence of a solvent,

preferably a C, -C ₄ alkylcarboxylic acid, preferably acetic acid, are reacted, optionally

Hydrolysis in the presence of aqueous acid or base, preferably acid, followed by N-phosphonomethylglycine according to Representation in the flow diagram II to produce, wherein Y corresponds to the above given description, R _{2 is} H or C, -C ₄ alkyl

and X is Cl or Br.

Flowchart Il

"N-CH _n -Y

HP (OR ₂ ) ₂ or PX ₃ IV

III

1. solvent

2. (optional) aqueous ^HH aqueous 0H ~

or

(HO) ₂ P-CH ₂ -Nh-CH ₂ -COOH

According to the invention, N-phosphonomethylglycine is produced by the particularly advantageous integrated one-pot process. In this process, the N-substituted azabicyclo-1-olene intermediate becomes an azanorbornene compound of the formula I wherein Y is preferably COOH and in situ by reaction of glycine with about 1.0 to 1.5 molar equivalents of formaldehyde and about 1.0 to 2 , 5 molar equivalents of cyclopentadiene in the presence of glacial acetic acid at a temperature range of about 20 ° C-40 ° C, preferably 25 ° C-35 ° C, generated in about 1 to 24 hours and then this reaction mixture is about 1.0 to 3, 0 molar equivalents of a phosphorus trihalide, preferably 1.0 to 1.5 molar equivalents of phosphorus trichloride, treated and heated for 5 to 16 hours at a temperature range of about 35 ⁰ C to 60 ° C. This is followed by dilution of the cooled reaction mixture with about 1.0 to 5.0 parts by volume of water, filtering, heating at reflux to hydrolyze the N-acetyl compound of formula VII, distilling the filtrate, volume to volume reducing the reaction mixture with water, cooling, re-filtering and treating the filtrate with sufficient aqueous base to adjust the pH to about 1.3 to 1.5, and isolating (recovering) the product N Phosphonylmethylglycine by filtration.

Hydrolysis and isolation of the product N-phosphonomethylglycine may alternatively be achieved by the addition of 5 to 30 molar equivalents of water (0.1 to 1.0 part by volume) to the cooled reaction mixture following heating with phosphorus trichloride.

Ausfuhrungsbelsplel

To further understand the invention, the following example illustrates primarily specific details. With the exception of the provisions in the claims, the invention is not limited thereby. Unless otherwise stated, Alta Tei are parts by mass. The term HPLC refers to high pressure liquid chromatography.

Preparation of N-phosphonomethylglycine via 2-Azablcyclo (2.2.1) -hept-5-ene-Esslgs8ure in a single integrated process

A stirred mixture of glycine (16.0 g, 0,20MoI) and Methylformcel (55% formaldehyde, 10% water and 35% methanol) (12.2 g 0,22MoI formaldehyde) in 60 ml of glacial acetic acid at 2O ⁰ C (with cyclopentadiene 16 , 5g, 0.25 mol). The temperature is maintained at 25 ° C-30 ° C with ice bath cooling to control the exotherm. The reaction mixture is stirred for 3 hours at 25 ⁰ C, followed by 3 hours at 25 ⁰ C under 25 inches of mercury vacuum followed. (HPLC assay shows about 91% yield of 2-azabicyclo (2.2.1) hept-5-ene-2-acetic acid.)

The stirred reaction mixture is treated at 25 ⁰ C and phosphorus trichloride (34,3g, 0.25 mol), heated at 40 "C for 4 hours to 45 ⁰ C, cooled to 2O ⁰ C, then 350 ml of water are added with stirring. The reaction mixture is filtered and the filter cake washed with 50 ml of water. the combined filtrates are concentrated by distillation at 100 ⁰ C to 105 ⁰ C, to about 350 ml of distillate are collected. the reaction mixture is cooled to 20-25 ⁰ C, filtered and the filtrate 50% NaCH solution to pH 1.4 The resulting precursor is filtered to give N-phosphonomethylglycine as a gray solid, mass = 28.7 g, HPLC assay indicating a purity of 63%.

Claims (3)

1. A process for the preparation of N-Posphonmethylglycin, characterized by the reaction of glycine with formaldehyde and cyclopentadiene in the presence of an acid at a temperature of about 25 ° C to 4O ⁰ C, to obtain a reaction mixture; the addition of phosphorus trichloride to said reaction mixture at a temperature of about 15 ⁰ C to 25 ° C; heating the resulting cooled reaction mixture to a temperature of about 3O ⁰ C to 8O ⁰ C, to obtain a heated reaction mixture; mixing the heated reaction mixture with water; filtering and hydrolyzing to obtain the N-phosphonomethylglycine. 2. The method according to claim 1, characterized in that the glycine is reacted with about 0.9 to 10.0 molar equivalents of formaldehyde and about 1.0 to 10.0 molar equivalents of cyclopentadiene in the presence of acetic acid. 3. The method according to claim 1, characterized in that said reaction mixture 1.0 to 5.0 molar equivalents of phosphorus trichloride are added and the formaldehyde consists of paraformaldehyde. Field of application of the invention The invention relates to a process for the preparation of N-phosphonomethylglycine which is used as a herbicide and growth regulator. Characteristic of the known state of the art For technical development, it should be emphasized that there is a constant search for better methods of producing this agronomically important compound. Object of the invention The aim of the invention is to provide N-phosphonomethylglycine in a more effective manner. Explanation of the essence of the invention The invention has for its object to develop a rational process for the preparation of N-phosphonomethylglycine without the use of esters. The achievement of this object is based on the surprisingly found finding that N-substituted azanorbornenes of the formula I where Y is COOR, CON (R ₁ )] or CN and R and R _{1 are} each independently hydrogen or alkyl Intermediates for the preparation of N-phosphonomethylglycine. N-CH ₂ -Y The compounds of formula I described above can be formed by reacting aminomethyl (methylamine) compounds of formula II, or their protonated salts H ₂ NCH ₂ -Y II wherein Y is as previously described for formula I, is reacted with about 0.90 to 10.0 molar equivalents of formaldehyde and about 1.0 to 10.0 equivalents of cyclopentadiene in the presence of a solvent, as shown in flow diagram I.