CA1098529A - O-aryl n-phosphonomethylglycinonitriles and the herbicidal use thereof - Google Patents

Abstract

Abstract of The Disclosure O-aryl N-phosphonomethylglycinonitriles are described as well as a process for producing same. These phosphonomethyl substituted glycinonitriles are useful as herbicides.

Description

O-ARYL N-PHOSP~ONOMET~YLGLYCINONITRILES
AND THE HERBICIDAL USE THEREOF

This invention relates to novel O-aryl N-phosphono~
methylglycinonitriles which are useful as herbicides and to a method for their prepaxati~. This inven-tion further relates to herbicidal comPoSitions and to herbicidal methods employing said O-arvl ~ phosphonomethylglycinonitriles.
According to U.S. Patent 3,923,877, N-phosphono-methylglycine can be produced by reacting a dihydrocarbylphos-phite with 1,3,5-tricyanomethyl-hexahydro 1,3,5-triazine in the presence of a catalyst, such as hydrogen halide, a Lewis acid, a carboxylic acid halide or a carboxylic acid anhydride and then hydrolyzing the resultant product. Yields by this process are extremely low. The patent states that the reaction takes place between the phosphite and the triazine to produce an in-termediate ester of ~-phosphonomethylglycinonitrile. The con-venient esters according to the patent are aliphatic of 1 to 6 carbon atoms or phenyl-substituted aliphatic groups such as benzyl and preferable alkyl of 1 to 6 carbon atoms. These esters are hydrolyzed to yield N-phosphonomethylglycine, a post-emergent herbicide. It has been found that the O,O-di-etpyllN-phosphonomethylglycinonitrile produced in accordance with the process of the reference had no post-emergent herbici-dal activity at 4.48 kg/hectare and no pre-emergent herbicidal activity at 5.60 kg/hectare.
It has now been discovered that O,O-diaryl N-phos-phonomethylglycinonitriles can be produced by the reaction of a diaryl phosphite with l,3,5-tricyanomethyl-hexahydro-1,3,5-tri-azine without the need of any catalyst. It has further been discovered that these glycinonitriles so produced, as well as the corresponding mono-aryl esters produced by mild hydrolysis 3u of the diester compounds have pre- and post-emergent herbicidal ' -2-, AG-1065 35~
activity which is totally unexpected due to the inactivity o-f the diethyl N-phosphonomethylglycinonitrile.
The N-phosphonomethylglycinonitriles of this inven-tion are compounds having the formula z .. H
Y a )2-b p - CH2 - N - CH2 - CN R (I) (~)b wherein Aryl is selected from phenyl, naphthyl or biphenylyl, each X i5 a substituent on said Aryl selected from halogen, alkyl of 1 to 4 carbons, alkoxy and alkylthio of 1 to 3 carbons, alkoxycarbonyl of 2 to 3 carbon atoms, methylenedioxy, cyano, trifluoromethyl or nitro, Z is oxygen or sulfur, a is an integer from zero to 3, b is an integer from zero to 1. R is a strong acid capable of forming a salt with the amino group, and x is zero or 1, provided that x must be zero when b is 1 According to the above proviso, the strong acid salts are only formed with a diester. When a strong acid is added to a monoester (see formula IV below) the sinyle aryl ester group may b~ hydrolyzed from the molecule.
The N~phosphonomethylglycinonitriles of formula I
whereinlx ànd b are zero are produced by forming an admixture consisting essentially of a phosphorous acid ester of the formula z (Aryl ~a~)2 P - H (II~

wherein X, Z and a are as above defined and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (also named N-methyleneglycinonitrile trimer) of -the formula ,CH2CN
/ N \

C~2 lH2 (III) NC--CH2-N.~ ~ N-CH2CN

and heating said admixture to a temperature sufficiently ele-vated to initiate the reaction and maintaining a temperature sufficient to sustain the reaction of the phosphorous acid es-ter with the triazine to produce said N-phosphonomethylgly-cinonitrile I-Although a solvent is not necessary in the process of the instant invention, it is sometimes desirable to employ . .
a solvent for convenience and ease of reaction. A solvent is ~lso useful to control the temperature o the reaction. The sol-vent employed is one in which the txiazine is soluble and ~hich does not react with either of the reactants. Such inert ; solvents include acetonitrile, ethyl acetate, tetrahydrofuran and the like.
It has been found that the reaction temperature can be as low as about 25C to about 110C. Higher temperatur~ can belemp~oyed but no commensurate advantages are obtained thereby since the reactlonlis essentially complete by the time~the temperature reaches about 85C.
As can be seen from the above formulas II and III, the ratio of the phosphorous acid ~ester to triazine should be 3 to 1 for best results. Higher or lower ratiGs could be employed but no con~ensurate advantages are obtained thereby, since at higher ratios excess phosphorous acid ester would have to be separated and at lower ratios of ester to triazine by-product formation is possible.
The reaction is generally conducted at atmospheric A~-1065 pressure for economy. However, higher or lower pressures can be employed but no commensurate advantages are obtained thereby.
To produce compounds of formula I wherein b is 1 and x is 0, that is compounds of the formula . H
(Aryl X -O) - P - CH2 - N - CH2 - CN (IV) OH
wherein X, Z and a are as above defined, one merely forms a solution of a compound of the formula Z
, H
(Aryl Xa )2 P - CH2 - N - CH2 - CN (V) wherein X, Z and a are as above defined, in a solvent contain-ing, at least one mole equivalent of water and maintains the solution at ambient temperatures at which one of the (Aryl X~-O) groups is hydrolyzed. The s~lvent preferred for the hydrolysis is acetone. The desired material is isolated by standard pro-cedures such as fxactional ~rystallization or vacuum evaporation of the solvent and other volatile hydrolysis products wherein the desired material can be crystallized from a sultable solvent. ~ -To produce the compounds of formula I wherein b is zleroland x is 1, i.e., compounds of the formula " H
(Aryl X -)2 ~ P - CH2 N C~2 wherein X, Z and a have the above-defined meanings, one dissolves a compound of formula V in an anhydrous solvent such as chloro-form and adds to said solution a strong acid, either in a sol-vent or in some instances the acid is added per se, wi-th stirring at ambient temperature for a time sufficient to allow said com-pound of formula V and said acid to react to produce the com-pound of formula VI. In many instances the desired product precipitates in crystalline form from the reaction solution.
In other instances a 50-50 volume mixture of chloroform and di-ethyl ether is added to induce product crystallization or to separate it from the reaction solution as an oil.
The compounds of formula VI are salts of the diester of formula V and can also be repxesented by the formula Z, H2 ~.
(Aryl X -)2 ~ P - CH2 - N CH2 1 (VII) wherein X, Z and a are as above-defined and Rl is the anion of the strong acid.
Illustrative of the groups substituted on the phenyl, naphthyl or bi~he~ylyl and represented by X are, for example, halogen such as chlorine, fluorine and bromine; alkyl such as methyl, ethyl, ; propyl and butyl; alkoxy such as methoxy, ethoxy and propoxy;
alkylthio such as methylthio, ethylthio and propylthio; as well as methylenedioxy~ cyano, trifluoromethyl and nitro. It is apparent from the formula that the groups represented by X can be the same or different on the same aryl ringO
The strong acids which are useful in preparing the ; strong acid salts of formula I, VI and VII are those having a PXa i~ water of 2.5 or less and include, for example, p-; toluenesulfonic acid, p-chlorobenzenesulfonic acid, trichloro-acetic acid, oxalic acid, fluoboric acid, hydrogen chloride, hydrogen bromide, hydriodic acid, trifluoroacetic acid, penta-fluoropropionic acid, heptafluorobutyric acid, trifluoromethane-sulfonic acid, nitric acid, sulfuric acid, phosphoric acid, trichloromethanephosphonic acid, perchloric acid, methanesul-fonic acid and the like.
In preparing the strong acid salts of formulas I, VI and VII it is preferred to employ the diester of the phos-phonic acid and the strong acid in equal molar ratios for ease ' -6-of isolation o~ the strong acid salt. Higher or lower ratios of ester to acid can be employed although isolation of the product is made more difficult because of the presence of an excess of one of the reactants.
Hydrolysis of the N-phosphonomethylglycinonitriles represented by formula I to yield ~-phosphonomethylylycine can be conveniently and rapidly carried out by heating the glycino-nitrile to moderate temperatures (60-100C.) in admixture with at least a slight excess over one mole equivalent (for example 1.01 ,mole equivalent) of aqueous hydrochloric acid or aqueous hydrobromic acid which are conveniently 1.0 normal and prefer-ably at least 2~0 normal. Usin~ concentrated aqueous hydro-chloxic or hydrobromlc acid a satisfactory hydrolysis to N-phosphonomethylglycine occurs within 24 hours at room tempera-ture.
The compounds represented by formula I are useful as herbicides for both pre~emergent and post-emergent application.
The following general procedures show the preferred ' methods of produclng the various compounds of this invention.
The diaryl esters of formula V are preferably pro duced by one of the following two methods.
l l (A) An acetonitrile solution (50 ml.) of 1,3,5-tricyanomethyl-hexahydro-1,3,5-tria2ine (3.4 g., 0.0167 mole) and the diarylphosphite (.050 mole) are admixed in a reaction vessel and heated from 45C to ~5~C for from 1 to 90 hours un-til all of the phosphlte or triazine is consumed as determined ny n.m.r. analysis. If the n.mOr. spectral analysis indicates that no impurities are present, the product is isolated by vacuum concentration. If impurities are present, the product i5 lsolated and purified by crystallization or chromatographic-ally. In some instances, the diester product may be difficult to isolate in a highly pure form because hydrolysis occurs during the attempted isolation 8~

(B) A mixture of a diaryl phosphite (0.05 mole) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (3.4 g.,0,0167 mole) is charged into a reaction vessel and heated to from 60 to 100C for from 20 minutes to one hour, until all of the phosphite or triazine has been consumed as determined by n.m.r.
spectral analysis. The products are purified by crystallization or chromatography.
The monoaryl esters of N-phosphonomethylglycinoni-trile are prepared by dissolving the diaryl ester in acetone containin~ a small amount of water (usually about 2~ by weight water) and stirring the reaction mixture for ~rom 18 to 72 hours. The mono esters are usually crystalline and are col-lected by filtration, washed with acetone and air dried.
The stro~ acid salts of the diaryl esters are preferably prepared by the following general procedure. A
solution of the strong acid (or the acid per se) (0.01 mole) is added dropwise to a chloroform solution of the diester at ambient temperature and allowed to stand. If cxystals form they are collected by filtration, washed with a 50 volume percent chloroform~ether mixture and air dried. Otherwise a 50 volume percent chloroform-ether mixture is added to cause tle salt to crystallize or to coms out of solution as an oil.
Hydrolysis of the N-phosphonomethylglycinonitriles represented by formula I to yield N-phosphonomethylglycine is readily accomplished by the following general procedure. The crude or purified reaction products of a diaryl phosphite with 1,3,5-tricyanomethyl hexahydro~l,3,5-triazine are hydrolyzed by addiny thereto at least a slight excess over one mole equivalent (for example at least 1.01 mole) aqueous hydrochloric acid or hydrobromic acid and heating the mixture to about 100C. for several hours under reflux conditions until it has been determined by n.m.r. spectral analysis that sub-_~

stantially all of the glycinonitrile has been hydrolyzed to N-phosphonomethylglycine. The reaction mixture is then twice extracted with chloroform to remove the phenol formed during the hydrolysis and the aqueous layers are filtered and evapor-ated to dryness. The solids residue is dissolved in water and the solution cooled to 0C. to cause crystallization of the N-phosphonomethylglycine.
The crude or purified reaction products of a diaryl-phosphite with 1,3,5-tricyanomethvl-hexahydro-1,3,5-triazine can be hydrolyzed by adding thereto a base selected from alkali metal hydroxides or a tetraalkylammonium hydroxide wherein the alkyl radicals contain from 1 to 4 carbon atoms, forming a mixture of said compound and base in water, heating the mixture to effect complete hydrolysis to a salt of N-phosphonomethyl-glycine and then converting the salt to N-phosphonomethyl-glycine by contacting an aqueous solution of the salt with a cationic exchange resin.
The following experiments serve to further illustrate the invention, all parts being parts by weight unless otherwise specifically set forth.
Example 1 Di(p-chlorophenyl)phosphite (23.32 g., 78% pure, 0.06 mole) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (4.08 g., 0.02 mole) were mixed in a reaction vessel at ambient temperature and the mixture heated to 100C for 20 minutes to give G,O-di (p-chlorophenyl) N-phosphonomethylglycinonitrile in 100% yield, 27 g., n21 = 1.5747.
Example 2 An acetonitrile solution (10 ml.) of di(3,4-dimethyl-phenyl) phosphite (8.7 g., .03 mole) was added to an acetonitrilesolution (S0 ml.) of 1,3,5-tricyanomethyl-hexahydro-1,3,5-tri-azine (2.04 g., 0.01 mole) and the mixture was heated at 55C

_g_ f3r 90 hr. Filtration of the solid present and evaporation of the solvent gave a burgundy colored oil which by n.m.r. analysis contained the desired product and the aminal of this product.
Chromatography of the oil (8.0 g.) over silica gel (450 g.) with 50% cyclohexane/50~ ethyl acetate (60 ml. fractions) gave O,O-di(3,4-dimethylphenyl) N-phosphonomethylglycinonitrile in fractioIls 30-41 which melted at 61-64C after removal of the solvent. The solid was recrystallized from carbon tetra-chloride-isooctane, m.p. 63-66C, 3.1 g. oktained (40% yield).
Example 3 A stirred mixture of 0.02 mole di(_-methylthiophenyl)-phosphite and 0.0067 mole of 1,3,5-tricyanomethyl-hexahyaro-1,3,5-triazine was heated to 80C for 1.0 hr. resulting in a dark red brown oil. Half of the sample was then placed in the refrigera-tor for 8 days giving a semi-solid mass. The sample was then recrystallized from 70 ml. carbon tetrachloride to give a pink solid. The solid was dissolved in 100 ml. hot carbon tetra-chloride and Eiltered through celite covered with 5.0 g. silica gel. The filtrate was concentrated to 50 ml. and put in the re~rigerator overnight. The suspension was filtered to give 1.8 g. (45%) of a white solid identified as O,O-di(_-methyl-thiophenyl) N-phosphonomethylglycinonitrile having a melting point of 64-65C and the following analysis.

Calc'd: C: 51.8; H: 4.9; N: 7.1 Found: C: 51.7; H: 4.9; N: 7.1 Example 4 A solution of di(_-methoxyphenyl)phosphite (8.05 g~, 91% pure, .025 mole) and 1,3,5-tricyanomethyl-hexahydro-1,3,5~

triazine (1.7 g., 0.0083 mole) was heated at 55C for 73 hours and then filtered. The filtrate was concentrated to a dark brown oil (9.6 g.). The oil (5.8 g.) was adhered on 8 grams silica gel and extracted with 80 ml. ethyl acetate. The ethyl acetate solution was concentrated and the resulting oil adhered on 4.0 g. silica gel. This silica gel was extracted with 70 ml.
of ethyl acetate and the solution concentrated under vacuum to yield a pale yellow oil, n = 1.5542. The yellow oil wa~
found to be O,O-di(o-methoxyphenyl) N-phosphonomethylglycino-nitrile containing a small amount of _-methoxyphenol.

Example 5 A solution of 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (13.6 g~, 0.066 mole) and diphenyl phosphite (46.8 g., 0.2 mole) in acetonitrile (100 ml.) was heated at 55C for 48 hours. The n.m.r. of the crude reaction mixture indicated com-plete conversion to O,O-diphenyl N-phosphonomethylglycinonitrile.
The acetonitrile was removed ln vacuo to yield 57 g. (94.4%) of a viscous black oil. The oil was dissolved in chloroform, 114 g. of silica yel added and the mixture evaporated to dryness ln vacuo. The product-impregnated silica gel was then placed on a column containing a slurry of chloroform and silica gel (200 g.) and eluted until the product was no longer detected in the eluent by n.m.r. The chloroform eluents were concentrated, dissolved in methylene chloride and washed twice with cold 5%
KOH (100 ml.), then with water. The methylene chloride layer was dried over MgSO4, filtered and evaporated leaving 37.9 g.
of a light yellow oil which solidified on standing. The solid had a melting poin~ of 64-67.5C and was identified as O,O-diphenyl N-phosphonomethylglycinonitrile, obtained in 75% yield~

Example 6 . . .
An acetonitrile solution (100 ml.) of di(m-tolyl)-phosphite (10.7 g., .04 mole) and 1,3,5-tricyanomethyl-hexa-hydro~l,3,5-triazine (2.72 g., .0133 mole) was heated to 50C

', :

5~

for 3 days. The solution turned a wine red color, and the solvent was evaporated leaving 12.4 g. of a red oil (92.4%
recovery). The oil (9.0 g.) was chromatographed over silica gel eluted with 60% cyclohexane/40% ethyl acetate with 60 ml.
fractions taken. Fr. 45-63 were pure OyO~di(m-tolyl) N-phos-phonomethylglycinonitrile, n25 = 1.5467 (1.25 g., 14% yield) which had the following analysis.
Calc'd- C: 61.81; H: 5.80; N: 8.48 Found: C: 61.75; H: 5.81; N: 8.41 Example 7 A solution of di(_-nitrophenyl)phosphite (15.2 g., 83% pure, .0392 mole) and 1,3,5-tricyanomethyl-hexahyaro-1,3,5-triazine (2.66 g., .013 mole) in acetonitrile was heated to 50C for 20 hours. N.m.r. analysis indicated complete reaction.
The solution was filtered and the solvent removed in vacuo leaving 13 g. of an amber oil identified as O,O-di(m-nitrophenyl) N-phosphonomethylglycinonitrile which gave the following analysis.
Calc'd: C: 45.93; H: 3.34; N: 14.28 Found: C: 45.80~ H: 3.39; N: 14.27 Example 8 ~ methoxyphenyl)phosphite (0.05 mole, 15.63 g., 94% pure) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (3.4 g., .0167 mole)were dissolved in acetonitrile and the -solution heated to reflux for 1 hour. The solvent was evaporated off in vacuo yielding a dark pink oil (19.0 g.).
This oil (5 g.) was subjected to high pressure liquid ~ 9 AG-1065 chromatography using a mixture of cyclohexane and ethyl acetate (40/60 vol. %) to recover 4.1 g. of O,O-di(~-methoxyphenyl) N-phosphonomethylglycinonitrile as an Oilr n25 = 1.5541, 82% yield~

A mixture of 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (2.04 g., .01 mole) and di(p-fluorophenyl~phosphite (8.8 g., 91.6~ pure, 0.03 mole) in acetonitrile (50 ml.) was heated to 55C for 70 hours. The reaction mixture was then iltered and the solven-t removed ln vacuo to yield a brown oil, n25 = 1.5270, which was 92% pure O,O-di(p-fluorophenyl N-phos-phonomethylglycinonitrile.
; Example 10 Di(m-chlorophenyl)phosphite (9.93 g., 91.5% pure, .03 mole) dissolved in acetonitrile (20 ml.) was added to 1,3,5-tri-cyanomethyl-hexahydro-1,3,5-triazine (2.04 g. t .01 mole) dissolved in acetonitrile (50 ml.), and the mixture was heated to 55~C for 70 hours. The acetonitrile was removed ln vacuo leaving a light pink oil, n25 = 1.5656, which was 92~ pure o,o-di(m-chlorophenyl) N-phosphonomethylglycinonitrile.
The following compounds can also be prepared by the above procedures:
''' .

O,O-di(p-cyanophenyl) N-phosphonomethylglycino-nitrile- - ~
OjO-di(_~biphenylyl) N-phosphonomethylglycino- ~
nitrile Example 11 The diester (4.0 g., .099 mole) prepared in Example 10 was dissolved in 100 ml of 2~ aqueous acetone and the solu-tion stirred at ambient temperature for 6 days during which time a solid formed. The solids were collected, washed with acetone and dried to yield 1.55 g. (60~) O-m-chlorophenyl N--13~

~ 5 ~9 AG-1065 phosphonomethylglycinonitrile as a solid having a me~ting poin~ of 181-182C and having the following analysis.
Calc'd: C: 41.5; H: 3.9; N: 1008 Found: C: 41.5; H: 3.9; N: 10.8 Exarnple 12 The diester prepared in Example 9 (2.38 g., .069 mole) was dissolved in 2% aqueous acetone (100 ml.) and stirred at ambient temperature for 3 days. The resulting slurry was fil-tered and the solids washed with acetone giving 0.87 g. of a tan solid having a melting point of 258-262C. The mother liquor was allowed to stand for six weeks and the resulting solids were collected and washed with acetone to give an addi-tional 0.8 grams of material having the same melting point which was identified as O-~-fluorophenyl N-phosphonomethylglycino-nitrile in a 98~ yield and having the following analysis.
Calc'd: C: 44.3; H: 4.1; N: ll.5 Found: C: 44.3; H- 4.2; N: :Ll.5 xample 13 O,O-Diphenyl N-phosphonomethylglycinonitrile (1.51 g., O.G05 mole) was stirred in 50 ml. of 2N hydrochloric acid with heating until all of the material dissolved (2 hours). An amber oil was noted in the bottom of the flask and found to be phenol. The flask was cooled to room temperature and the hydro-chloric acid solution washed twice with methylene chloride (25 ml.) to remove any starting material and the phenol forrned in the reaction. The hydrochloric acid solution was then cooled in an ice bath during which time crystals began to form. The crystals were collected, washed with cold water and air dried.
The crystals were identified as O-phenyl N-phosphonomethyl-glycinonitrile and had no distinct melting point. The crystals gave the following analysis.

85 ~ AG-1065 Calc'd: C: 47.79; H: 4.90; N: 12.39 Found: C: 47.52 H: 4.93; N: 12.12 Example 14 0,O-di(m-tolyl) N-phosphonomethylglycinonitrile (4.0 g., 0.012 mole) was dissolved in acetone (50 ml.) containing water (1 ml.) and stirred for 60 days at ambient temperature.
Three crops of crystals were obtained. The first two crops of ; crystals had a melting point of 161-166C and were determined to be impure. The third crop had a melting point of 179-179.5C and were found to be analytically pure O-m-tolyl N- -phosphonomethylglycinonitrile, which was obtained in 53% yield and had the following analysis.
Calc'd: C: 50.0; H: 5.5; N: 11.7 Found: C: 50.0; H: 5.5; N: 11.7 Example 15 O,O-di(m-nitrophenyl) N-phosphonomethylglycinonitrile t3~15 g., .008 mole) was dissolved in acetone (50 ml.) and water (1 ml.) and stirred at room temperature for 16 hours.
Solids formed which were collected and washed with acetone yielding 1~1 grams (51%) yield of a material identified as O-m-nitroph nyl N-phosphonomethylglycinonitrile having a melting point of 174-176C with decomposition and having the following analysis.
Calc'd: C: 40.0; H: 3.4; N: 15.6 Found: C: 40.0; ~: 3.4; N. 15.5 Example 16 An acetonitrile solution (100 ml.) of di(m-tri~luoro- -tolyl)phosphite (11.64 g., 0.0314 mole) and 1,3,5-tricyano-methyl-hexahydro-1,3,5-triazine (2.15 grams, O.OlOS mole) was heated at 50C overnight. The acetonitrile was evaporated off under vacuum and solids began formlng. The residue material ; AG-1065 S~

was dissolved in acetone (50 ml.) and water (1 ml.~ and stirred overnight at ambient temperature during which time solids formed.
The solids were collected and washed with acetone yielding 3.5 grams (39.5%) of a white solid having a melting point of 195-196C and identified as O-m-trifluorotolyl N-phosphonomethyl--glycinonitrile and having the following analysis.
Calc'd: C: 40.8; H~ 3.4; N: 9.5 Found: C: 41.0; H: 3.5; N: 9.7 Example 17 O,O-di(p-chlorophenyl) N-phosphonomethylglycino-nitrile (9.0 g., 0.024 mole) was dissolved in acetone (50 ml.~
and water (1 ml.) and stirred at room temperature for two days.
A solid formed which was collected and weighed 2.35 grams. The solid had a melting point of 170C with decomposition and was identified as O-~-chlorophenyl ~ phosphonomethylglycinonitrile.
The mother liquor was allowed to stand for several weeks and an additional 0~85 grams was collected. The total yield of the product was 3.2 grams (51% yield).

Example 18 21 g~ of a solution containing 83.8% by weight of ; di(3-methyl-4-nitrophenyl)phosphite (0.05 mole) and 1,3,5-tri-cyanomethyl-hexahydro-1,3r5-triazine (3~4 g., 0.0167 mole) were dissolved in 100 ml. of acetonitrile and heated to 70C for one hour. The acetonitrile solvent was then removed under vacuum and the residue dissolved in 50 ml. of acetone containing 1 ml.
of water and stirred at ambient temperature. The crystals (4.3 g., 30% yield) were identified as O-(3-methyl-4~nitrophenyl) N-phosphonomethylglycinonitrile, having a melting point of 181-182C. The material had the followlng analysis.
Calc'd: C: ~2.1; H: 4.2; N: 14.7 Found: C: 42.2; H 4.3; N: 14.7 Example 19 O,O-di(p-methoxyphenyl) N-phosphonomethylglycino~
nitrile (3.0 g., .0082 mole) was dissolved in acetone (50 ml.) and water (1 ml.) and stirred at ambient temperature for three months. During this period solids formed. The solids were removed by filtration, washed with ace~one and dried. Solid material was identified as O-~-methoxyphenyl N~phosphonomethyl-glycinonitrile and had a melting point of 185-195C with de~
composition. The material gave the following analysis.
Calc'd: C: 46.9; H: 5.1; N: 11.0 Found: C: 47.1; H: 5.2; N: 10.8 Example 20 Di(o-chlorophenyl)phosphite (19.5 g., 80% by weight, 0.05 mole) was added to an acetonitrile solution (50 ml.) of 1-3,5-tricyanomethyl-hexahydro-1,3,5-triazine (3.4 g., 0~01640 ; mole~ and heated to 70C for 2 hours. A 15 ml. portion of the reactant solution was concentrated and dissolved in acetone (S0 ml.~ and water (1 ml.) and stirred overnight during which time solids formed. The solids were collected, washed with acetone and dried, yielding 3.2 grams (82~ yield) of a material identified as O-o-chlorophenyl N-phosphonomethylglycinonitrîle having a melting point of 170-171C and the following analysis.
Calc'd: C: 41.5; H: 3.9; N: 10.8 Found: C: ~1.4; H: 3.9; N: 10.7 :
Example 21 O,O-di(p-fluorophenyl) N-phosphonomethylglycinonitrile (2.38 g., .06'~ mole) was stirred in a 50 volume percent mixture of carbon tetrachloride and methylene chloride, filtered and methanesulfonic acid (0.67 grams, .069 mole) was added. The solution was allowed to stand ovexnight, the crystals formed were collected by filtration and washed with carbon tetra-~85Z9 AG-1065 chloride to give 2.68 grams of a white crystalline material identified as the methanesulfonic acid salt of O,O-di(~-fluoro-phenyl) N-phosphonomethylglycinonitrile. This salt had a melting point of 132-132.5C and gave the following analysis.
Calc'd: C: 44.2; H: 4.0; N: 6.5; S: 7.4 Found: C: 44.0; H: 4.0; N: 6.6; S: 7.5 Exam ~e 22 p-Toluenesulfonic acid ~1.9 gram, 0.01 mole~ was re-fluxed in benzene (100 ml.) and the water present removed by azeotroping with benzene. This benzene solution was added to a benzene-methylene chloride solution (50/50 volume percent, ; 100 ml.) of O,O-diphenyl N-phosphonomethylglycinonitrile (3.02 grams, 0.1 mole). The mixture was stirred for one minute at room temperature, during which crystallization occurred. The resulting slurry was stirred at room temperature overnight and then filtered to yield a white sol:Ld, identified as the _-toluenesulfonic acid salt of'O,O--diphenyl N-phos'phbnomethylgly-cinonitrile'(4.38 grams, 92.4% yiel'd),'having a meIting psint of 152-153C. The compound gave'the'following analysis.

Calc'd: C: 55.7; H: 4.9; N: 5.9 Found: C: 55.4; H: 4.9; N: 5.7 Example 23 A chloroorm solution of p-chlorobenzenesulfonic acid (1O92 grams, 0.01 mole) was added to a chloroform solution of O,0-diphenyl N-phosphonomethylglycinonitrile (3.0 grams, 0.01 mole). The mixture was stirred and ater 10 minutes crystalliza-tion commenced. The slurry was then stirred overnight, filtered and the solids washed with chloroform leaving 4.0 grams of a white solid (81%), melting point 14g-151C; identified as the ~0 ~-chlorobenzenesulfonic acid salt of O,O-diphenyl N-phosphono-methylglycinonitrile, having the following analysis.
Calc'd: C: 51.0; H: 4.1; N: 5.7 Found- C: 50.7; H: 4.1; N: 5.7 A chloroform solution (20 ml.) of krichloroacetic acid tl.63 grams, .01 mole) was added to a chloroform solution ~100 ml.) of O,O-diphenyl N-phosphonomethylglycinonitrile (3.0 grams, .01 mole) and stirred overnight at room temperature.
Crystallization c~uld not be induced and the solvents were removed ln vacuo leaving a light yellow oil, 3.75 grams (80%) n25 = 1.5410, identified as the trichloroacetic arid salt of O,O-diphenyl N-phosphonomethylglycinonitrile, having the following analysis.
Calc'd: C: 43.9; H: 3.5; N: 6.0 Found: C: 43.9; H: 3 5; ~: 5 9 Example 25 ;

An acetone solution (25 rnl.) of oxalic acid dihy-drate (1.26 grams, 10 mole) was added to an acetone solution of O,O-diphenyl N~phosphonomethylglycinonitrile (3.02 grams, 10 mole). After I0 minutes, the salt started crystallizing from the solution. The solution was stirred overnight, cooled and the solids (l.9 grams) were collected and washed with acetone. A second crop was obtained by concentrating the mother liquor, 0.8 gram. The yield was 2.7 grams, 69%, melting point 165C dec. The crystals were identified as the oxalic acid salt of 0,O-diphenyl N-phosphonomethylglycinonitrile, and had the following analysis.
Calc'd: C: 52.1; H: 4.4; N: 7.1 Found: C: 52.1; H: 4.4; N: 7.1 Example 26 .
An ether solution of perchloric acid was added to , 8 52~ AG-1065 a chloroform-ether solution of 0,0-diphenyl N-phosphonomethyl-glycinonitrile (3.0 grams, 10 mole3. The perchlorate salt slowly crystallized as white prisms. The solids, identified as the perchloric acid salt of 0,0-diphenyl N-phosphonomethyl-glycinonitrile, were collected and washed with ether-chloroform to give 0.73 gram, 18~ yield, melting point 166-168C. The salt had the following analysis.
Calc'd: C: 44.7; H: 4.0; N: 7.0 Found: C: 44.8; H: 4.0; N: 7.0 Example 27 A chloroform-methanol solution of trichloromethane phosphonic acid (1.99 grams, 0.01 mole) was added to a chloro-form solution of 0,0-diphenyl N-phosphonomethylglycinonitrile (300 grams, 10 mole). After 10 minutes, ether was added, and no crystals formed. Petroleum ether was then added until just before the cloud point. After 10 minutes, crystals began to form, and it was allowed tostand an additional 10 minutes. The crystals were collected in two crops, 2.9 grams, 58~ yield, meltiny point 145-146C. The crystals were identified as the trichloromethane phosphonic acid salt of 0,0-diphenyl N-phos-phonomethylglycinonitrile, and had the following analysis.
Calc'd: C: 38.3; ~: 3.4; N: 5.6 Found: C: 38.3; H: 3.5; N: 5.6 Example 28 An ether solution of fluoboric acid was added to a chloroform-ether solution of 0,0-diphenyl N-phosphonomethylgly-cinonitrile (3.0 grams, 10 mole). The solution was stirred overnight, the solids were filtered, washed with ether-chloro-form (50/50) leaving white crystals, 1.1 grams, 28~ yield, melting point 156-158C, identified as the fluoboric acid salt of 0,0-diphenyl N-phosphonome'chylglycinonitrile, having the -20~

, ~ 5,~9 AG-1065 following analysis.
Calc'd: C: 46.2; H: 4.1; N: 7.2 Found: C: 46.0; H: 4.2; N: 7.2 Example 29 Gaseous hydrogen bromide was bubbled into a chloro-form solution of O,O-diphenyl N-phosphonomethylglycinonitrile (3.0 grams, 10 mole). The solution was allowed to stand over-night as the hydrobromide crystallized. The crystals were collected and washed with ether, leaving 3.0 grams, 78% yield~
identified as the hydrogen bromide salt-of O,O-diphenyl N-phos- -phonomethylglycinonitrile, having the following analysis~
Calc'd: C: 47.0; H: 4.2; N: 7.3 Found: C: 47~1î H: 4.3; N: 7.4 Example 30 A 57% solution of hydriodic acid (2 ml.) was added to a chloroform solution of O,O-diphenyl N-phosphonomethylgly-cinonitrile (3~0 grams, 10 mole). The solution became cloudy and turned golden color. After two hours no solids formed, so ether was added to the cloud point and crystallization commenced. The solution was stirred an additional hour and the solids, identified as the hydriodic acid salt of O,O-diphenyl N-phosphonomethylglycinonitrile, were collected as light yellow plates, melting point 163-164C, 2.4 grams, 56~ yield. The salt had the following analysis.
Calc'd- C: 41.9; H: 3.8; I: 29.5 Founa: C 41.8; H: 3.8; I: 29.3 Example 31 Trifluoroacetic acid (1.14 grams, 10 mole) was added to a chloroform solution of O,O-diphenyl N-phosphonomethylgly-cinonitrile (3.0 grams, 10 mole). The solution was stirredovernight and the solvent evaporated ln vacuo leaving a ligh-t ~ A&-1065 .v yellow oil, 4.0 grams, 96% yield, nD5 ~ 1.5172; identified as the trifluoroacetic acid salt of 0,0-diphenyl N-phosphono-methylglycinonitrile.
Example 32 Trifluoromethanesulfonic acid (1.50 grams, 10 mole, fumes) was added to a chloroform solution of 0,0-diphenyl N-phosphonomethylglycinonitrile (3.0 grams, 10 mole). The re action was stirred at room temperature for two hours, and ether was added to the cloud point. The product crystallized. After standing for one hour, the solids were collected and washed with chloroform-ether (50~) to yield 3.8 grams, 84% yield, melting point 119-120C, identified as the trifluoromethanesul-fonic acid salt of 0,0-diphenyl N phosphonomethylglycinonitrile, having the following analysis.
Calc'~: C: 42.5; H: 3.6; N: 6.2 Found: C: 42.7; H: 3.6; N: 6.2 Example 33 To a chloroform solution of 0,0-diphenyl N-phosphono-methylglycinoni~rile (15.1 grams, .05 mole) was added methane-sulfonic acid (5.0 grams, .051 mole) and the solution stirred for two hours at ambient temperatures. A solid precipitated and was collected, washed with ether and dried. The solid weighed 15.90 grams and was identified as the methanesulfonic acid salt of 0,0-diphenyl N-phosphonomethylglycinonitrile, having a melting point of 147-150C. The yield of the salt was 82.1%. The salt had the following analysis.
Calc'd: C: 44.2; H: 4.0, N: 6.5; S: 7.4 Found: C: 44.0; H: 4.0; N: 6.6; S: 7.5 Example 34 An ether solution (10 ml.) of nitric acid (70% by weight, 0.9 g., .01 mole) was added to a chloroform solution

-2~-(100 ml.) containing O,O-diphenyl N-phosphonomethylglycinonitrile l3.0 g., .01 mole). No clouding occurred. Additional diethyl ether was added, and then isooctane (20 milliliters) at which time solids began crystallizing out of the solution. The mix-ture was stirred for one hour at ambient temperatures, the cry-stals collected, washed with chloroform and air-dried~ The crystals weighed 2.66 grams and were identified as the nitric acid salt of ,-diphenyl N-phosphonomethylglycinonitrile, having a melting point of 116-116.5C. The yield was 72% of theory. The salt had the following analysis.
Calc'd: C: 49.32; H: 4.42; N: 11.5 Found: C: 49.2; H: 4.42; N: 11.6 ..
Exampl~ 35 To a solution of O,O diphenyl N-phosphonomethylgly-cinonitrile (3.0 g., 0.01 mole~ in chloroform- (100 ml.) was added an ether solution of 98% sulfuric acid (1.01 g., 0~01 mole). Additional chloroform was added and the mixture stirred for two hours. The solids were removed by filtration and washed with chloroform, then ether, and dried to give 3.9 grams of a material identified as the sulfuric acid salt of o,O-diphenyl N-phosphonomethylglycinonitrile, having a melting point of 151-151.5C. The salt was obtained in 100% yield and had the following analysis. -Calc'd: C: 45.0; H: 4.28; S: 8.01 Found- C: 44.90; H: 4.27; S: 8.05 Example 36 An ether solution of phosphorus acid (.01 mole) was added to a chloroform solution of O,O-diphenyl N~phosphono-methylglycinonitrile (3.0 g., .01 mole) at ambient tempera-ture with stirring~ The solution clouded immediately. Anoil was present in the bottom of the flask. After cooliny, -23~

~ 5 29 AG-1065 the solvent was decanted off, evaporated to dryness and dried over anhydrous magnesium sulfate. The solid material was iden~ified as the phosphoric acid salt of O,O-diphenyl N-phosphonomethylglycinonitrile, having a melting point of 74.5-78.5C. The salt was obtained in 2S% yield and had the following analysis.
Calc'd: C: 45.0; H: 4.5; N: 7.0 Found: C: 44.8; H: 4.6; N: 7.1 Example 37 A heterogeneous solution of O,O-diphenyl N phosphono-methylglycinonitrile (60.4 g., 0.2 mole) in ethanol (500 ml.) was cooled in an ice bath, and dry HCl was bubbled through.
The solution was allowed to stand, ethyl ether was added, and a white solid was collected by suction iltration. More white solid formed on bubbling dry HCl through the ethanol-ether mother liquor at about 0C., and it was collected and washed with ether. The yield wa~ 62.7 g. (93%) of the hydrochloride salt of O,O-diphenyl N-phosphonome~hylglycinonitrile, m.p.
112-123C. The salt had the following analysis.
Calc'd: C: 53.19; H: 4.79; N: 8.27 Found: C: 53.51; H: 4.78; N: 8.30 Di(2,4,6-trimethylphenyl)phosphite (17.8 g., 0.05 mole) was added to an acetonitrile solution (50 ml.) of 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (3.4 g., 0.0164 mole), and the mixture was heated at 80C. for 18 hours. The black solution which formed was filtered and concentrated to an oil.
A portion (7 g.) was chromatoyraphed over silica gel (450 g.) with 70% cyclohexane/30% ethyl acetate t60 ml. fractions) to give 1.0 g. (14%) of O,O-di(2,4,6-trimethylphenyl) N-phosphono-methylglycinonitrile, m.p. 118-120C., in fractions 28-40 which , AG-1065 8~2~

crystallized on standing. The product had the following analysis.
Calc'd: C: 65.27; H: 7.04; N: 7.25 Found: C: 65.38; H: 7.07; N: 7.18 Example 39 A solution of the diester product of Example 3 (0.025 mole) in wet acetone (50 ml.) was heated at reflux temperature for 2 hours and then allowed to stand at ambient temperature for 5 days. The suspension was filtered to give an impure pinkish solid (0.9 g.). The filtrate was placed in a stoppered flask and allowed to stand at ambient temperature for 30 additional days. The resulting suspension was filtered, and the solid was washed with acetone (50 ml.~. There was obtained 4.5 g. (65%) of O-_-methylthio N-phosphonomethylgly-cinonitrile as a white solid, m.p. 2S0-253C. (dec.~. The product had the following analysis.
Calc'd: C: 44.12; H: 4.81i N: 10.29 Found: C: 4~26; H: 4.86; N: 10.22 Example 40 Diphenyl thiophosphite (8.2 g., 0O0246 mole) and 1,3, 5-tricyanomethyl-hexahydro-1,3,5-triazine (1.68 g., 0.00823 mole) were dissolved in acetonitrile (50 ml.) and heated to 60-65C. for 2~hours~. The resulting oil was chromatographed over silica gel (450 g.) eluted with 60% cyclohexane/40% ethyl acetate (60 ml. fractions) to give 1.6 g. (20~) of O,O-diphenyl N-thiophosphonomethylglycinonitrile, nD = 1.5847, in fraction 30. The product had the following analysis.
Calc'd: C: 56.60; H: 4.75; N: 8.80; S: 10.07 Found: C: 56.40; H: 4.80; N: 8.73; S: 10.26 Example 41 An acetonitrile solution (100 ml.) of di(~-naphthyl) phosphite (33.5 g., 0.1 mole) and 1,3,5~tricyanomethyl-hexa-hydro-1,3,5~triazine (20.4 g., 0.1 mole) was heated to reflux for one hour and then concentrated to a red-brown oil. A 10 g. sample was purified by high pressure liquid chromatography over silica gel, eluting with 60% cyclohexane/40% ethyl acetate (20 ml. fractions). Fractions 45-64 were combined and concentrated, and the resulting oil was crystallize-l from carbon tetrachloride to give 1.1 g. of O,O-di(~-naphthyl) N-phosphonomethylglycinonitrile as a buff colored solid, m.p.
104-105C. The product gave the following analysis.
Calc'd: C: 68.65; H: 4.76; N: 6.96 Found: C: 68.58; H: 4.79; ~: 6.92 Example 42 A stirred solution of di(3 r 4-methylenedioxyphenyl) ; phosphite (0.05 mole) a~d 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (0.0167 mole) in acetonitrile (75 ml.~ was heated to 75C. for 3 hours and then allowed to stand at ambient temperature overnight. The resulting solution was concentrated to an amber oil. To a chloroform solution (100 ml.) of said oil (7.6 g., 0.02 mole), methanesulfonic acid (1.92 g., 0.02 mole) was added dropwise. After stirring for 15 minutes, ether (200 ml.) was added, and a white solid precipitated. The solid was recrystallized twice from acetone to give 4.6 g. (47~) of the methanesulfonic acid salt of O,O-di(3,4~methylenedioxy-phenyl) N-phosphonomethylglycinonitrile, m.p. 135-136.5C. The product had the following analysis~
Calc'd: C: 44.45; H: 3.94; N~ 5.76 Found: C: 44.26; H: 3.94; N: 5.71 Example 43 A solution of 0.01 mole of the amber oil of Example 42 in wet acetone (70 ml.) was refluxed for 4 days. The amber 1~ Q ~ AG-1065 solution was then allowed to stand for one day at ambient temperature. The resulting susp~nsion was filtered to give 1.7 g. of 0-(3,4-methylenedioxyphenyl) N-phosphonomethylglycino-nitrile as a white solid, m.p. 160-161C.
Example 44 A stirred solution of di(3,4-dichlorophenyl)phosphite (0.04 mole) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (0.013 mole) in acetonitrile (40 ml.) was heated to 80C.
and maintained for 18 hours~ The resulting solution was con-centrated to an oil, wet acetone (80 ml.) was added, and themixture was refluxed for 80 hours. Tha resul~ing suspension was filtered to give a white solid which was washecl with acetone (50 ml.) to give 6.3 g. t53%) of 0-(3,4-dichlorophenyl) N-phosphonomethylglycinonitrile, m~p~ 169-170C.
~xample 45 Diphenyl phosphite (234 g., 1.0 mole) was added to an acetonitrile solution (300 ml.) of 1,3,5-tricyano~ethyl-hexa- -hydro-1,3,5-triazine (68 g.; 0.333 mole) and heated at 75-82C.
for 3 hours. The solution was cooled and concentrated in vacuo to give a black oil which was mainly the product of ~x-ample 5. A sample of this oil (101 g.) was adhered onto siIic~ gel (which was dissolved in chloroform, more silica gel added and solvent evaporated), and this material was chromatographed over silica gel (1.1 kg.) eluted with chloro-form (1 liter fractions). Fractions 13-14 were combined, con-centrated and recrystallized from dichloromethane-cyclohexane to give 51 g. of 0,0-diphenyl N-phosphonomethylglycinonitrile.
Example 46 Diphenyl phosphite (33.43 g., 0.1 mole (70% pure) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (6.73 g., 0.033 mole) were stirred in a flask and heated to 100C. (by an oil bath). After 40 minutes the reaction was complete (n.m~r.

analysis). The crude reaction mixture was hydrolyzed by adding 150 ml. of 2N HCl and refluxing for 16 hr. The resulting material was extracted with chloroform (to remove the phenol) twice and the aqueous layers were filtered and evaporated to dryness to give a burned orange solid which was dissolved in 60 ml. of water and cooled to 0. The resulting crystals were collected and air dried to give 10.7 g. of N-phosphonomethyl-glycine. Analysis-95~% pure. Additional crops were isolated by evaporating and adding ethanol, all these materials contained varying amounts of ammonium chloride and aminomethyl phosphonic acid. Mother li~uors from the above crystallizations contained mainly phosphorous acid (4.4 g.).
Example 47 _ Di(p-methoxyphenyl) phosphite (30.82 g., 0.1 mole 95.5~ pure) and 1,3,5-tricyanomethyl~hexahydro-1,3,5-triazine (6.81 g., 0.0333 mole) were mixed, stirred and heated to 100C.
After 15 minutes all of the hexahydrotriazine had dissolved in the phosphit~; an aliquot indicated the reaction to be about S0~ complete. The mixture was heated for an additional 15 minutes and then hydrolyzed and worked up as described in Example 46.
The first crop 10.1 g. (dry) n.m.r. indicates pure N-phosphono-methylglycine. No other crops could be obtained in pure form.
N.m.r. of mother liquor indicates a complex mixture.
Example 48 Di~_-chlorophenyl phosphite (19.6 g., 0.05 mole, 78 pure) and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine (3.41 g., 0.0167 mole) were mixed at room temperature (no exotherm).
The slurry was heated to 100C. for 20 minutes (n.m.r. aliquot indicated reaction was complete). Following the workup and hydrolysis procedures described in Example 46, 4.8 g. of N-phosphonomethylglycine were isolated (lst crop 56~). The 2nd crop 0.44 g. was NH4Cl. N.m.r. analysis of the mother liquors were very complex indicating that the hydrolysls conditions - v~ere too harsh for optimum yields.
Example 49 The tetramethylammonium hydroxide salt of ~-phosphono-methylglycîne was prepared by dissolving 6 g. (0.02 mole) of O~O-diphenyl-N-phosphonomethylglycinonitrile in 30 ml. of water containing 14.5 g. (0.08 mole) of tetramethylammonium hydroxide and then heating the mi~ture for 16 hours at 100C.
until by n.m.r. spectrum analysis it was determined that all of the glycinonitrile had been con~erted to the tetramethyl-: , .
ammonium hydroxide salt of N-Phos~honomethylglycine. The solution was cooled and extracted with methylene chloride to ;
remove the phenol and then vacuum concentrated, yielding a mixture of the tetramethylarnmonium salts. The recovered salt product was dissolved in 20 ml. water and placed in an ion exchange column packed with a commercial cation exchange resin ('IDowex 50"*)and then eluted with water at room temperature.
The eluate was concentrated yieldin~ 2.4 g. of a beige colored crystalline solid (71% yield). The crystalline solid was ~ound by n.m.r. spectrum analysis to ~e essentially pure N-phosphonomethylgl~cine.
Example 50 The disodium salt of N-phosphonomethylglycine was prepared by mixing 6.04 g. (0.02 mole) of O,O-diphenyl-N-phosphonomethylglycinonitrile with 50 ml. of water containing

3.2 g. (0.08 mole) of sodium hydroxide and then heating the mixture with continuous stirring for one hour at 70C. at which time the n.m.r. spectrum analysis of the reaction mixture lndicated approximately one third of the reaction mixture had been converted to the disodium salt. Continuing the reaction for 4 more hours at 70C. indicated by n.m.r. spectrum analysis a 40% conversion to the disodium salt. Further heating for 15 aZditional hours at 70C. resulted in an 80 to 90%

.

~ * Trademark conversion to the disodium salt. The reaction product was then concentrated yielding a dark amber colored glassy solid.
N-phosphonomethylglycine was produced by dissolving the solid in water and charging the solution into an ion exchange column packed with a commercial cation exchange resin ("Dowex 50").
The column was eluted with water at room temperature. The eluate was concentrated yielding 2.7 g. (80~ yield) of a light colored solid which according to nOm.r. spectrum analysis was essentially pure N-phosphonomethylglycine.
lO ~ The discovery that O-aryl N-phosphonomethylglycino-nitriles could be prepared in hi~h yields from the reaction of a diaryl phosphite with 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine in the absence of catalyst was most unexpected in view of the disclosures made in U.S. 3,923,877. This reference discloses use of acidic catalyst such as a hydrogen halide, a Lewis acid, a carboxylic acid anhydride or acid halide.
According to the sole example of this reference, a calculated yield of only 6.12% of the diethyl ester of N-phosphonomethyl-glycinonitrile was obtained in the reaction of a solution of diethyl phosphite and 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine saturated with hydrogen chloride. In contrast to such low yields, the presently disclosed process is characterized by yields of the diaryl esters of N-phosphonomethylglycinonitrile ranging between 45% and 100%. Surprisingly, when the example of U.S. 3,~23,877 was run with stoichiometric amounts of reactants and with the omission of the hydrogen chloride catalvst, no reactio could be detected when run at 40C. or even after 24 hours of reaction at 100C. The same negative result was obtained when the example was run as above (no acid catalyst) using acetonitrile as a solvent for the reactants and the reaction was conducted for 24 hours at 100C. In another experiment, running as above the example of the reference but using chloroEorm as a solvent for the reactants, no reaction at 40C. or at 100C. was observed.
When an acidic catalyst of the type disclosed in U.S.
3,923,877 was used in the reaction of a diaryl phosphite, i.e.
diphenyl phosphite, with 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine in the presence of hydrogen chloride according to the procedure described in the example of the reference, a yield of only 15% of the desired diester was obtained as compared to the 75% yield reported in Example 5. These results demon~
strate there are significant differences presently unexplainable between the reaction of dialkyl phosphites and diaryl phosphites with 1,3,5-tricyanomethyl-hexahydro-1,3,5-triazine.
xample 51 The post-emergence herbicidal activity of various compounds of this invention is demonstrated as follows. The active ingredients are applied in spray form to 14-21 day-old specimens of various plant species. The spray, a water or organic solvent-water solution containing active ingredient and a surfactant (35 parts butylamine salt of dodecylbenzenesul-fonic acid and 65 parts tall oil condensed with ethylene oxidein the ratio o~ 11 moles ethylene oxide to l mole tall oil), is applied to the plants in different sets of pans at several rates (kg per hectare) of active ingredient. The treated plants are plaed in a greenhouse and the effects are observed and recorded after approximately 2 weeks or approximately 4 weeks. The data is given in Tables I and II.

~ 5~.9 AG-1065 The post-emergence herbicidal activity index used in Tables I and II is as follows:
Plant Response Index 0-24~ Injury 0 25-4g% Injury 50-74~ Injury 2 75-99~ Injury 3 All Killed 4 Species not present at time of treatment *
In said Tables, WAT indicates weeks after treatment, : and the plant species treated are each represented by a code letter as follows: `
A - Canada Thistle K - Barnyard Grass ; : B - Cocklebur L - Soybean C - Velvet Leaf M - Sugar Beet : D - Morning Glory rJ - Wheat ~ E - Lambsquarters O - Rice :~ F - Smartweek P - Sorghum 2G ~ G - Nutsedge Q - Wild Buckwheat H - Quackgrass R~-- Hemp Sesbania : I - Johnson Grass S - Panicum Spp : J -- Downy Brome :T - Crabgrass ~ ~ :

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~0 ~ ~ ~ ~9 AG-1065 Example 52 The pre-emergent herbicidal activity of various com-pounds of this invention is demonstrated as follows. A good grade of top soil is placed in aluminum pans and compacted to a depth of three eighth to one-half inch from the top of each pan. A predetermined number of seeds or vegetative propagules of each of several plant species are placed on top of the soil in each pan and then pressed down. Herbicidal compositions (as described in Example 51) employing the active ingredients of this invention are applied by admixture with or incorporation in the top layer of soil.
In this method, the soil required to cover the seeds and propagules is weighed and admixed with a herbicidal compo-sition containing a known amount of activ~ ingredient. The pans are then filled with the admixture and leveled, Watering is carried out by permitting the soil in the pans to absorb molsture through apertures in the pan bottoms. The seed and propagule containing pans are placed on a wet sand bench and ~ maintained fox approximately two weeks under ordinary con-ditions of sunlight and watering. At the end of this periodthe number of emerged plants of each species is noted and com-pared to an untreated control. The data is given in Table III.
; The pre-emergent herbicidal acti~ity index used below is based upon the average percent control of each species as ~ollows:
Percent Control Index 0 - 25% 0 26 - 50%
51 - 75% 2 76 - 100~ 3 Plant species are identified in Tab].e III by the same code letters used in Example 51.

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C) _a~g-; , From the test results presented in Tables I and II, it can be seen that the post-emergent herbicidal activity of the compounds of this invention is, for the most part, general in nature. In certain specific instances, however, some selectivity is demonstrated. On the other hand, the test results showing pre-emergent herbicidal activity clearly show the selectivity of action on Canada Thistle and a few other species. In this regard it should be recognized that each individual species selected for the above tests is a representative member of a recognized family of plant species.
The herbicidal compositions, including concentrates which re~uire dilution prior to application to the plants, of this invention contain from 5 to 95 parts by weight of at least one active ingredient and from 5 to 95 parts by weight of an adjuvant in liquid or solid form, for example, from about 0.25 to 25 parts by weight of wetting agent, from about 0.25 to 25 parts by weight of a dispersant and from 4.5 to about 94.5 parts by weight of inert liquid extender, e.g , water, all parts being by weight of the total composition. Where required, from about 0.1 to 2.0 parts by weight of the inert liquid extender can be replaced by a corrosion inhibitor or anti-foaming agent, or both. The compositions are prepared by admixing the actlve ingredient with an adjuvant including diluents, extenders, carriers and conditioning agents to pro-vide compositions in the form of finely-divided particulate solids, pellets, solutions, dispersions or emulsions. Thus, the active ingredient can be used with an adjuvant such as a finely-divided solid, a liquid of organic origin, water, a wetting agent, a dispersing agent, an emulsifying agent or any suitable combination of these. From the viewpoint of economy and convenience, water is the preferred diluent.

~ 9 AG-1065 The herbicidal compositions of this invention, particularly liquids and soluble powders, preferakly contain as a conditioning agent one or more surface-active agents in amounts sufficient to render a given composition readily dis-persible in water or in oil. The incorporation of a surface-active agent into the compositions greatly enhances their effi-cacy. By the term "surface-active agent" it is understood that wetting agents, dispersing agents, suspending agents and emulsifying agents are included therein. Anionic, cationic and non-ionic agents can be used with equal facility.
Preferred wetting agents are alkyl benzene and alkyl naphthalene sulfonates, sulfated fatty alcohols, amines or acid amides, long chain acid esters of sodium isothionate, esters of sodium sulfosuccinate, sul~ated or sulfonated fatty acid esters petroleum sulfonates, sulfonated vegetable oils, polyoxyethylene derivatives of phenols and alkylphenols -(particularly isooctylphenol and nonylphenol) and polyoxy-ethylene derivatives of the mono-higher fatty acid esters of hexitol anhydrides (e.g., sorbitan). Preferred dispersants are methyl cellulose, polyvinyl alcohol, sodium lignin, sul-fonates, polymeric alkyl naphthalene sulfonates, sodium naph-thalene sulfonate, polymethylene bisnaphthalenesulfonate and sodium ~-methyl-N-(long chain acid) taurates.
Water dispersible powder compositions can be made containing one or more active ingredients, an inert solid ex-tender and one or more wetting and dispersing agents. The inert solid extenders are usually of mineral origin such as the natural clays, diatomaceous earth and synthetic minerals derived from silica and the like. Examples of such extenders include kaolinites, attapulgite clay and synthetic magnesium silicate. The water~dispersible powder of this invention usu-ally contain from about 5 to about 95 parts by weight of active ingredient, from about 0.25 to 25 parts by weight of wetting agent, from about 0.25 to 25 parts by weight of dis~
persant and from 4.5 to about 94.5 parts by weight of inert solid extender, all parts being by weight of the total composition. Where required, from about 0.1 to 2.0 parts by weight o~ the solid inert extender can be replaced by a corrosion inhibi~or or anti-foaming agent or both.
Aqueous suspensions can be prepared by mixing to-gether and grinding an aqueous slurry of water-insoluble active ingredient in the presence of dispersing agents to obtain a concentrated slurry of very finely-divided particles~
The resulting concentrated aqueous suspension is characterized by its extremely small particle size, so that when diluted and sprayed, coverage is very uniform and usually contains from 5 ~o about 95 parts by weight active ingredient, from about .25 to 25 parts by weight dispersant, and from about 4.5 to 94.5 parts by weigh~ of water.
Emulsifiable oils are usually solutions of active 20 ingredient in water-immiscible or partially water-immiscible solvents together with a surface active agent. Suitable solvents for the active ingredient of this invention include hydrocarbons and water-immiscible ethers, esters or ketones.
The emulsifiable oil compositions generally contain from about 5 to 95 parts active ingredient, about 1 to 50 parts surface active agent and about 4 to 94 parts ~olvent, all parts being by weight based on the total weight o~ emulsifiable oil.

Although compositions o this invention can also contain other additaments, for example, fertilizers, phyto-toxicants and plant growth regulatns, pesticides and the likeused as adjuvants or in combination with any of the above-described adjuvants, it is preferred to employ the compo-sitions of this invention alone with sequential treatments with the other phytotoxicants, fertilizers and the like for maximum effect. For example, th~ field could be sprayed with a composition of this invention either before or after being treated with fertiliz~rs, other phytotoxicants and the like. The compositions of this invention can also be ad-mixed with the other materials, e.g., fertilizers, other phytotoxicants, etc., and applied in a single application.
Chemicals useful in combination with the active ingredients of this invention either simultaneously or sequentially in-clude, for example, triazines, ureas, carbamates, acetamides, acetanilides, uracils, acetic acids, phenols, thiolcarbamates, triazoles, benzoic acids, nitriles and the like.
Fertilizers useful in con~ination with the active ingredients include, for example, an~onium nitrate, urea, potash, and superphosphate.
When operating in accordance with the present in-vention, effective amounts of the glycinonitriles are applied to the plants, or to soil containing the plants, or are incorpora-ted into aquatic media in any convenient fashion. The applica-tion of liquid and particulate solid compositions to plants or soil can be carried out hy con~entional methods, e.g., power dusters, boom and hand sprayers and spray dusters. The compo sitions can also be applied from airplanes as a dust or a spray because of their effectiveness at low dosages. The applica~ion of herbicidal compositions to aquatic plants is usually carried out by adding the compositions to the aquatic media in the area where control of the aquatic plants is desired.
The application of an effective amount of the com-pounds of this invention to the plant is essen-tial and criti-~ AG-1065 cal for the practice of the present invention. The exact amount of active ingredient to be employed i5 dependent upon the response desired in the plant as well as such other factors as the plant species and stage of development thereof, and the amount of rainfall as well as the specific glycine employed~ In foliar treatment for the control of vegetative growth, the active ingredients are applied in amounts from about 0.112 to about 22.4 or more kilograms per hectare.
In pre-emergent treatments, the rate of application can be from about 0.56 to about 22.4 or more kilograms per hectare. In applications for the control of aquatic plants, the active ingredlents are applied in amounts of from about 0.01 parts per million to about 1000 parts per million, based on the aquatic medium. An effective amount for phytotoxic or herbicidal control is that amount necessary for overall or selective control, i~e., a phytotoxic or herbicidal amount.
It is believed that one skilled in the art can readily de-termine from the teachings of this specification, including examples, the approximate application rate~
Although the invention is described with respect to specific modifications, the details thereof are not to be construed as limitations except to the extent indicated in the following claims.

.

Claims (26)

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows:

1. A compound of the formula (I) wherein Aryl is selected from phenyl, naphthyl or biphenylyl, each X is a substituent on said Aryl selected from halogen, alkyl of 1 to 4 carbons, alkoxy and alkylthio of 1 to 3 carbons, al-koxycarbonyl of 2 to 3 carbon atoms, methylenedioxy, cyano, tri-fluoromethyl or nitro, Z is oxygen or sulfur, a is an integer from zero to 3, b is an integer from zero to 1, R is a strong acid capable of forming a salt with the amino group, and x is zero or 1, provided that x must be zero when b is 1.

2. A compound as defined in Claim 1 wherein a is zero.

3. A compound as defined in Claim 1 wherein x is one and b is zero.

4. A compound as defined in Claim 1 wherein x is zero and b is one.

5. A compound as defined in Claim 1 wherein both b and x are zero.

6. A compound as defined in Claim 1 wherein the strong acid has a pKa in water of 2.5 or less.

7. A compound as defined in Claim 1 wherein Aryl is phenyl and Z is oxygen.

8. A compound as defined in Claim 7 wherein x is one and b is zero.

9. A compound as defined in Claim ? wherein x is zero and b is one.

10. A compound as defined in Claim 7 wherein both b and x are zero.

11. A compound as defined in Claim 1 which is O,O-diphenyl N-phosphonomethylglycinonitrile, O,O-di(p-methoxyphenyl) N-phosphonomethylglycinonitrile, O,O-di(p-fluorophenyl) N-phosphonomethylglycinonitrile,O-phenyl N-phosphonomethyl-glycinonitrile, O-m-nitrophenyl N-phosphonomethylglycinonitrile, O-o-chlorophenyl N phosphonomethylglycinonitrile, the hydrogen bromide salt of O,O-diphenyl N-phosphonomethylglycinonltrile, trifluoroacetic acid salt of O,O-diphenyl N-phosphonomethylgly-cinonitrile or the methanesulfonic acid salt of O,O-diphenyl N-phosphonomethylglycinonitrile.

12. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 1.

13. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 2.

14. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 3.

15. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 4.

16. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 5.

17. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 6.

18. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 7.

19. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 8.

20. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 9.

21. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 10.

22. A herbicidal method which comprises contacting a plant or the plant growth medium with a herbicidally effec-tive amount of a compound of Claim 11.

23. A method for preparing a diester having the formula wherein aryl is selected from phenyl, naphthyl or biphenylyl, each X is a substituent on said aryl selected from halogen, alkyl of 1 to 4 carbon atoms, alkoxy and alkylthio of 1 to 3 carbons, alkoxycarbonyl of 2 to 3 carbon atoms, methylenedioxy, cyano, trifluoromethyl or nitro, Z is oxygen or sulfur and a is an integer from zero to 3, which comprises reacting together a diaryl phosphite of the formula wherein X, Z and a are as above defined and 1,3,5-tricyano-methylhexahydro-1,3,5-triazine in the absence of an acidic catalyst.

24. The method according to Claim 23 wherein the reaction is conducted at a temperature between 25° and 110°C.

25. The method according to Claim 24 wherein the diaryl phosphite and the triazine are reacted together in the presence of an inert solvent.

26. The method according to Claim 23 wherein the diaryl phosphite is diphenyl phosphite, di-(m-chlorophenyl) phosphite, di-(p-methoxyphenyl)phosphite, di-(3,4-dimethyl-phenyl)phosphite or di-(p-fluorophenyl) phosphite.