GB2037771A - ???-substituted benzyl phosphonic acid ester derivatives - Google Patents

Abstract

The invention relates to the use, as herbicides, of alpha -substituted or ???,???- disubstituted benzyl phosphonic acid esters, thiol esters and ester amides and compositions containing such compounds. The phenyl of the benzyl radical may optionally be mono-, di- or tri-substituted. The invention further provides novel compounds of the above-mentioned structure and processes for making such compounds.

Description

SPECIFICATION Phosphonic acid ester derivatives The invention relates to the use, as herbicides, of benzyl phosphonic acid ester derivatives of formula I,

wherein Y1 is hydrogen or halogen (preferably chlorine), either Y2 is hydrogen, halogen (preferably chlorine, bromine or fluorine, more preferably chlorine), C1-10alkyl, C1-10alkoxy; C3-7cycloalkyl or C3-7cycloalkoxy, and Y3 is hydrogen; halogen (preferably chlorine, bromine or fluorine, more preferably chlorine); nitro; cyano;C1-10alkyl, C1-10alkoxy, C2-10alkoxyalkoxy, C2-10alkenyl, C2-10alkenyloxy or C1-10alkylthio, each alkyl or alkenyl radical or moiety being unsubstituted or substituted by halogen (preferably chlorine and/or fluorine);benzyl, phenyl or phenoxy, each phenyl radical or moiety being unsubstituted or substituted by up to 2 substituents selected from halogen (preferably chlorine, bromine or fluorine, more preferably chlorine), nitro, cyano, C1-6alkyl, C16alkyl, C1~6alkoxy, C16alkylthio, each alkyl radical or moiety being unsubstituted or substituted by halogen (preferably chlorine and/or fluorine);-CONRxRy; CORp; -COORp;

-SO2Rp; -NRxRy; -CH=N-ORp;

or Y2 and Y3 are on adjacent carbon atoms and, together, form a methylenedioxy or ethylenedioxy group; either each Rx and Ry, independently, is C-10alkyl or C3-10alkenyl, or Rx and Ry, together with the nitrogen to which they are attached, form a pyrrolidine, piperidine, N-methyl-piperazine or morpholine group; Rp is phenyl; or C1-10 alkyl unsubstituted or substituted by chlorine and/or fluorine; Z1 and Z2, independently, are 0 ores, either R1 is C,~,0 alkyl unsubstituted or substituted by halogen (preferably C1, F); C37cycloalkyl, unsubstituted or substituted by halogen (preferably C1 ); C14alkyl mono-substituted by C13alkoxy, phenyl or phenoxy, the phenyl or phenoxy being unsubstituted or substituted by up to 2 substituents selected from halogen (preferably chlorine), C1 4alkyl, C,~4alkoxy and tri-fluoromethyl; C26alkenyl, unsubstituted or substituted by halogen (preferably chlorine); C24alkynyl;; or phenyl, unsubstituted or substituted by up to 2 substituents selected from halogen (preferably chlorine), C14alkyl, C1-4alkoxy or trifluoromethyl and R2 is hydrogen or has one of the significances of R, or R1 and R2 are joined to form, together with the a-carbon atom, a C37cycloalkylidene radical unsubstituted or substituted by halogen (preferably chlorine) or C1 4alkyl, X is, independently, 0, S or NR5, R3 is unsubstituted C18alkyl; C14alkyl substituted byC13alkylthio or halogen (preferably Cl, F); C6alkenyl; C36al kynyl; tetrahydrofur-2-ylmethyl; tetrahydro-2H-pyran-2-ylmethyl; C56cycloalkyl, either R4 and R5 have, independently, a R3 significance, or R4 and R5 are joined to form, together with the nitrogen atom to which they are attached, a piperidine, pyrrolidine, N-methyl-piperazine or morpholine radical.

Accordingly, the present invention provides a method of combating weeds in a locus which comprises applying to said locus a herbicidally effective amount of a compound of formula I, as defined above.

The compounds of formula I exhibit a broad spectrum of herbicidal activity, both against monocotyledonous weeds such as Apera spica venti, Alopecurus myosuroides, Echinochloa crus-gali, A vena fatua and Agrostis alba, and dicotyledonous weeds such asAmaranthus retro flexus, Capsella buras-pastoris, Chenopodium alba, Gallium aparine, Senecio vulgaris, and Stellaria media, as indicated after pre- and post-emergence greenhouse treatment with test dosages equivalent to 0.2, 1.0 and 5.0 kg of active agent/ha of treated surface. The determination of the herbicidal effect is made 28 days after treatment. During the test, the greenhouse is kept at a temperature of 20 to 24 C and exposed to 14 to 17 hours daylight per day.On the other hand, the compounds exhibit under simitar greenhouse test conditions no substantial damaging effect to crops such as cereals (e.g. wheat, barley, rye and maize), carrots, sunflower and soya bean with test dosages corresponding to 5.0 kg active agent/ha crop locus.

Accordingly, the compounds are also indicated for the selective control of weeds in crops such as cereals (e.g. wheat, barley, rye and maize), carrots, sunflower and soya bean.

The amount of compound of formula I to be applied to attain the desired effect will, as will be appreciated, depend on the plant involved, the locus to be treated, and other variabls such as the particular compound employed, the mode of application, conditions of treatment etc. However, in general, satisfactory total weed control may be obtained when the compound is applied at a rate in the range of from about 0.5 to 6 kg/hectare, preferably from 1 to 4 kg/hectare of treated area. The compounds are preferably applied post-emergence.

For selective herbicidal use, e.g. in the crops above mentioned, the rate should be chosen so as to secure maximum destruction of the weeds with minimum damage to the crop. In general, for selective weed control, satisfactory results are obtained when the compound is applied at a rate of 0.5 to 4 kg/hectare, preferably at from 1.0 to 3 kg/hectare. The compound is preferably applied post-emergence of the weeds, more preferably post-emergence both the weeds and crop.

In general a relatively rapid onset of activity is observed.

The compounds may be employed, and, indeed, are preferably employed, as herbicidal compositions in association with suitable carriers, diluents or adjuvants. Such compositions also form part of the present invention.

The herbicidal compositions may be in solid or liquid form. Solid forms, e.g. dusting and granulate forms, may be produced by mixing or impregnating solid herbicide carriers or diluents, such as diatomaceous earth, kaolin, chalk, talc, limestone or cellulose powder, with the compounds.

As examples of adjuvants which may be comprised in the compositions may be given wetting and dispersing agents, e.g. condensation products of formaldehyde with naphthalene sulphonate and alkyl benzene sulphonates, adhesion imparting agents, e.g. dextrin, and emulsion stabilizers, e.g. ammonium caseinate.Such adjuvants are suitable for incorporation into, e.g., wettable powder composition forms, or for use together with suitable solvents, e.g. hydro-carbons such as benzene, toluene, xylene, tetrahydronaphthalene, alkylated naphthalenes, kerosene, aromatic petroleum hydrocarbon fractions (e.g. the commercial Shellsol AB having a b.pt. range of 187-213 C), ketones, such as isophorone, acetone, cyclohexanone, diisobutylketone and methylethylketone, alcohols, such as isopropanol, ethanol and methylcyclohexanol, chlorinated hydrocarbons such as tetrachloroethylene, ethylene chloride or trichloroethylene, to form emulsion concentrates.

The herbicidal compositions may contain, aside from the compound of formula I as active agent, other active agrochemical agents, such as other herbicides.

Concentrate forms of the compositions generally contain from 2 to 80%, preferably from 5 to 70% by weight of the compound of formula I, as active agent.

Application forms of the compositions generally contain from 0.01 to 10% by weight of the compound of formula I as active agent.

Specific examples of herbicidal compositions are given hereinafter.

In the compounds of formula I, ring A preferably bears at least one substituent.

The compounds of formula la

wherein Yia, Y2a, Y3a, R7a, R2a, R3a and XaR4a(including R5a) have the above significances of Y1,Y2,Y3, R1, R2, R3, and XR4(including R5) respectively, with the provisos that (i) if Y1a, Y2a and Y3a are hydrogen, both OR3a and XaR4a are C2H50 or i-C3H70 and Ria is CH3, C2H5, n-C3H7, n-C4Hg, AC5H11, allyl or benzyl, then R2a is not hydrogen or C25alkyI, (ii) if Y1a, Y2a, Y3a and R2a are hydrogen, and OR3a and XaR4a are both C2~5alkoxy, then Ria is different from phenyl, or (iii) if Y1a, Y2a and R2a are hydrogen, Y3a is methyl and OR3a and XaR4a are both C2H5O, then R1a is different from methyl, (iiii) if Y1a, Y2a and Y3a are hydrogen, R2ais methoxy-methyl and OR3a and XaR4a are both C2H50, then Ria is different from methyl are new and form part of the present invention. Where ring A is trisubstituted, such is preferably trichloro substituted. Ring A, however, is preferably mono- or di-substituted.

As examples of substituted alkyl radicals as Y3 may be given -CF3 and CH2CH2C1. As examples of substituted alkoxy radicals as Y3 may be given -OCF3, -OCHF2, -OCF2C1, O-CH2CH2CI and -OCF2CHF2. As an example of a substituted alkenyl radical as Y3 may be given -CH:CC12. As an example of a substituted alkylthio group as Y3 may be given -SCF3. Such are also suitable examples of the relevant groups as substituents on any phenyl or phenoxy group as Y3.

Of the unsubstituted alkyl groups as R1, those containing from 3 to 6 carbon atoms are preferred. Where R and R2 are identical and are unsubstituted alkyl they are preferably n-propyl, i-propyl or n-butyl.

Where R1 and R2 are different and R2 is hydrogen or primary ( ~4alkyl then R1 is preferably branched in the a-position and means especially i-propyl, sec.-butyl, 3-pentyl, 2-pentyl, 3-hexyl, cyclohexyl and cyclopentyl.

The preferred significance of X in the compounds of formula I, isO and NOR5. Any unsubstituted alkyl as R4 and Rg is preferably of 2 to 6 carbon atoms.

As a particularly preferred class of compounds of formula I may be given the compounds of formula Ib,

wherein Y'2 is hydrogen or chlorine, Y'3 is chlorine, bromine, C15 alkoxy, C35- alkenyloxy or C1-5alkyl, R'1 is unsubstituted C3-6alkyl or C36cyclo-alkyl, R2'is hydrogen or unsubsitued C1-4alkyl, X' is O or NR'5, and R'3', R'4 and R', independently, are unsubstituted C2-4alkyl.

Where Y'2 and Y'3 are both chlorine, said chlorines are preferably in the 2- and 4-positions.

The compounds of formula I may be obtained by (a) preparing compounds of formula Ic

wherein Y1, Y2, Y3,R1,R3,R4 and X are as defined above, and R"2 has the above significance of R2 with the proviso that R"2 is hydrogen where Xis O or NR5 (wherein R5 is as defined above), by reacting a compound of formula II

wherein Q, is chlorine or OR3, and Y1, Y2, Y3, R1, R"2 and R3 are as defined above, with a compound of formula Ill R4XM III wherein X and R4 are as defined above, and either M is hydrogen when Xis O or NR5, or M is an alkalimetal cation (preferably sodium), when Xis sulphur, or (b) preparing compounds of formula Id

wherein Y1, Y2, Y3, R3 and XR4 are as defined above and either R1III is unsubstituted C110aIkyl and R2111 hydrogen, or both R1111 and R1III are phenyl or substituted phenyl by reacting a compound of formula IV

wherein Y1, Y2, Y3, R1'11 and R"' are as defined above, and Q2 is halogen (e.g.CI, Br, preferably bromine), with a compound of formula V,

wherein X, R3 and R4 are as defined above, or (c) preparing compounds of formula le

wherein R1lv and R2IV have the above significances of R1 and R2 with the proviso that not both R1'V R2lv are phenyl or substituted phenyl, XII is O or NR5, and Y1,Y2,Y3,R3,R4 and R5 are as defined above, by mono- or disubstituting a compound of formula VI

wherein R6 is hydrogen, phenyl or substituted phenyl, and X", Y1,Y2,Y3,R3 and R4 are as defined above, with one or two compounds of formula VII R7O3 VII wherein R7 has the above significance of R1 with the proviso that it is not phenyl or substituted phenyl, and Q3 iS a leaving group, such as bromine, iodine, mesyloxy ortosyloxy, or with a compound of formula Vlla Q3-R8-Q3 Vllla wherein R8 is C2-6alkylene unsubstituted or substituted by halogen (preferably chlorine) or Cl~,alkyl, and Q3 is as defined above, or (d) preparing compounds of formula If

wherein X", Y1, Y2, Y3, R3 and R4 are as defined above, and R1v is methyl, phenyl or substituted phenyl by reacting a compound of formula VIII

wherein Q4 is a halogen (e.g. iodine, chlorine or bromine) and Y1, Y2, Y3 and R1V are as defined above, with a compound of formula IX

IA wherein R3, R4 and Xl are as defined above.

The above processes may be carried out in conventional manner.

Where in process (a) Q1 is chlorine, the process is preferably carried out so as to react 2 mols of the compound of formula III with 1 mol of the compound of formula II.

Where, in process (a), the compound of formula li is reacted with an amine or alcohol, the process is suitably carried out in the presence of a teriary amine, such as pyridine or triethylamine and optionally in the presence of catalytic amounts of an acylation accelerator such as p-dimethylamino pyridine. Conveniently, the compound of formula II, optionally dissolved in a solvent such as CH2C12, 1,2-dichloroethane, benzene, toluene, xylene, glyme(1 ,2-dimethoxyethane), dig lyme[CH3(OCH2CH2)20CH3] or an excess of R4XH, is added, at O-30C, to a mixture of the amine or alcohol reagent with the tertiary amine and any acylation accelerator and the reaction brought to completion by stirring for 1 to 18 hours at 20-1400C, preferably at room temperature.Where the reagent is an amine the preferred reaction media are ethers and hydrocarbons.

Where, in process (a), the compound of formula II is reacted with an alkali-metal thiolate the reaction is suitably carried out at 0-300C in an ether or hydrocarbon solvent, such as in glyme, diglyme, benzene, toluene, xylene or in CH2C12, optionally in the presence of a phase transfer catalyst such as benzyltrimethyl ammonium bromide or in a dipolar solvent such as dimethyl formamide. Process (a) is especially useful for the preparation of compounds of formula I wherein either Xis S or XR4 is part of a primary alcohol R40H or of an amine HNR4R5 wherein the a-carbon atoms of both R4 and R5 are unbranched.

Process (b) is suitably carried out in a solvent such as glyme ortoluene, conveniently by reaction at reflux temperature or in dimethyl formamide or HMPT (hexamethyl phosphoric triamide) or a solvent mixture, e.g.

toluene/HMPT at room temperature. Alternatively, the reaction may be carried out in the absence of a solvent at 20-1 20 C. A suitable reaction time, with or without solvent, is from 0.5 to 18 hours. Process (b) is preferably used for the production of compounds of formula I wherein both R1 and R2 are phenyl or substituted phenyl or wherein R, is unsubstituted C, ~Oalkyl and R2 is hydrogen. Q2 is then preferably bromine.

In process (c), where it is desired to obtain a compound of formula lewherein R2lv is hydrogen or R1lv and R2iv are joined, the reaction is, of course, carried out so as to react the compounds of formula VI and formulae VII or Vlla in a mol ratio of 1:1. Where it is desired to obtain a compound of formula le wherein R21V is other than hydrogen and is different from RXlv, the reaction is suitably carried out in two stages, in the first stage the compound of formula VI being reacted with one compound of formula VII (in a 1:1 mol ratio) and, in the second stage, the reaction product so obtained being reacted with another compound of formula VII.

Where, in process (c), it is desired to react the compound of formula VI with one mol of the compound of formula VII or Vlla, the reaction is suitably carried out in the presence of a base such as sodium hydride and in a solvent such as glyme, dimethylformamide, dimethyl-sulphoxide (DMSO), HMPT or toluene or in a solvent mixture, e.g. toluene/HMPT. A suitable reaction temperature is from 0"-80"C and a suitable reaction time is from 9 to 18 hours. Separation of the resulting reaction product from any remaining unreacted compound of formula VI is suitably carried out chromatographically or by selective hydrolysis of the latter, e.g. by treatment with 5% potassium hydroxide in a ethanol/water (9:1) mixture at 20-80"C for 2-18 hours. If desired, in place of the sodium hydride, a stronger base, such as sodium amide, can be employed with a lowering of the reaction temperature and/or shortening of the reaction time.

Where, in process (c) it is desired to dialkylate the compound of formula VI (as described above), the reaction is suitably carried out in the presence of at least two equivalents of a strong base such as sodium methylsulphinyl carbanion in DMSO or DMSO/toluene or of sodium amide in an organic solvent, as described above or in liquid ammonia. Where the reaction is carried out in an organic solvent, a suitable reaction temperature is from -10 to 45"C for 5-60 minutes, followed if necessary by stirring for 30 mins. to 24 hours at 25-700C. Any mixture of the disubstituted product with the mono.substituted product can be separated chromatographically.

When sodium methylsulphinyl carbanion is used as a base this carbanion is freshly prepared by reaction of sodium hydride with excess dry dimethyl sulphoxide at 70"C bath temperature under nitrogen with stirring for 45-60 minutes. When sodium amide is used as a base, the reaction is suitably carried out in the presence of an equivalent amount of hexamethyldisilazane. The latter variante is advantageously used when steric hindrance occurs.

Process (d) is conveniently carried out by heating a mixture of the reagents, in general preferably in the presence of potassium iodide, at from 60 to 2000C. The reaction is then suitably brought to completion by stirring the reaction mixture for 5 mins to 8 hours at 60 to 21 0'C preferably for al hour at about 160"C. Where, however, the compound of formula VIII is a di-phenylchloro-methane, or a p-nitrobenzylhalide, the reaction is preferably carried out in the absence of the potassium iodine but employing a compound of formula VIII wherein Q4 is chlorine or bromine. Where R1 is methyl, Q4 is preferably iodine. Where R1 is phenyl or substituted phenyl, Q4 is preferably chlorine.

The resulting compounds of formula I may be isolated and purified in conventional manner.

The processes (a), (b), (c) and )d), insofar as they relate to the production of compounds of formula la are also part of the present invention.

In order to indicate, in the process claims, that the processes (a), (b), (c), and (d) relate to the preparation of novel compounds of formula la, the substituents in the formulae involved will be marked by "a" e.g. Ria, Za etc.

The starting materials employed in the above processes are either known or may be obtained in conventional manner from available starting materials. For example, the compounds of formula VI are conveniently obtained by process (b) or (d).

As will be appreciated, interconversion of one compound of formula I to another may be carried out in conventional manner.

As will also be appreciated the compounds of formula I possess asymmetric centres when R1 and R2 differ and/or when XR4 and OR3 are different, and may therefore exist in optically active, diasteromeric or racemic forms. It is to be understood that the present invention is not intended to be limited to any particular form.

The following Examples, in which all parts and percentages are by weight and temperatures are in C, further illustrate the invention.

EXAMPLE 1 (process a) Production of a-/soprop yl-4-ch/orobenzylphosphon/c acid di-n-hexylester 4.049 (0.015 ml) a-isopropyl-4-chlorobenzylphosphonic acid dichloride in 12 ml chloroform were added, dropwise, over 10 minutes at 10-25 and with stirring, to a mixture of 3.069 (0.03 mol) 1-hexanol, 3.5 g pyridine and 0.77 g (0.0063 mol) 4-dimethylaminopyridine and the whole was stirred for 18 hours at room temperature. The reaction mixture was then poured onto ice, ether extracted and the extract washed successively with water, in NaOH(2x), water, 6N H2SO4, water and a saturated aqueous solution of NaCI (hereinafter designated as brine), followed by drying over magnesium sulphate and evaporation.The residue was purified chromatographically to yield the title product nD = 1.4898.

EXAMPLE 2 (process a) N,N-Diethyl-a-(2-butyl)-4-chlorobenzylphosphonic acid amide ethyl ester 6.18 g (0.02 Mol) a-(2-butyl)-4-chlorobenzylphosphonic acid monoethylester monochloride in 5 ml 1 2-dimethoxy-ethane were added under cooling to a mixture of 4.7 g (0.064 mol) diethylamine, 2.45 g (0.02 mol) 4-dimethylamino-pyridine and 5 ml 1,2-dimethoxyethane and the reaction mixture was then taken up in ether, washed with water and brine, dried over magnesium sulphate and evaporated. The residue was purified chromatographically to yield the title product as a colourless oil, nD = 1.5065.

The product is a diestereomeric mixture.

EXAMPLE 3: (process b) a-83-Pentyl)-4-phenoxybenzylphosphonic acid diethyl ester To 0.38 g (7.81 mMol) of a 50% sodium hydride dispersion in oil were added slowly, under nitrogen atmosphere, 1.07 g (7.81 mMol) of diethylphosphite. Under slight cooling one obtains, under hydrogen development, a grey, thick paste which is reacted with 2.0 g (6.0 mMol) of a-(3-pentyl)-4- phenoxybenzylbromide. The reaction mixture is stirred for 16 hours at 80 . After cooling, a little water was added and the reaction mixture extracted with ether. The extract was washed with water and brine, dried over magnesium sulphate and evaporated.The residue was purified chromatographically (50 g silica-gel with hexane/ethyl acetate 1:1) to yield the title product as a colourless oil, nD = 1.5293.

EXAMPLE 4: (process c), monalkylation) Production of a-isoprop yl-4chlorobenzyl phosphonic acid diethyl ester

To 4.32g of 80% sodium hydride (0.144 mol) in 270 ml dimethyl formamide were added dropwise, over a period of 45 minutes and under a nitrogen atmosphere, a mixture of 34.59 (0.131 mol) 4chlorobenzylphosphonic acid diethyl ester and 33.49 (0.196 mol) 2-iodopropane, and the resulting suspension stirred for 20 hours at room temperature. The reaction mixture was then cooled slightly, 20 ml of water added and ether extracted. The ether extract was washed successively with water, twice with 1 N sodium hydroxide, again with water and then with brine, followed by drying over magnesium sulphate and evaporation.The residue contained a mixture of the title product together with the diethyl ester starting material in a ratio of 60:40 and was subjected to treatment for 24 hours, with stirring, in 200 ml of a 5% KOH solution in a 9:1 mixture of ethanol/water, the title product being isolated by ether extraction, as described above, as a chromatographically pure colourless oil nD = 1.5010.

EXAMPLE 5: (process c), monoalkylation) Production of a-n-hexyl-2,4-dichlorobenzyl-phosphonic acid diethyl ester

31.5 ml of a 50% (0.355 mol) sodium amide suspension in toluene were added to 350 ml toluene and, with gentle cooling, to this was then added, over a period of 20 minutes under a nitrogen atmosphere and with stirring, 105g (0.355 mol) of 2,4-dichlorobenzylphosphonic acid diethyl ester. The resulting orange coloured suspension was further stirred for 20 minutes at 35 , followed by cooling to 5 , after which, over a period of 25 minutes, at 5- 15 ,58.69 (0.355 mol) of 1 -bromohexane were added. After removal of the cooling bath, the mixture was stirred for a further 1- hours, then water added and an ether extraction carried out.The extract was then washed with water and then brine, followed by drying over magnesium sulphate and evaporation.

The resulting yellow oil was purified by chromatography (1 kg silica gel with hexane/ethyl acetate 7:3) to give the title product in pure form nD20= 1.5040.

EXAMPLE 6 : (process c), mono- and di-alkylation) Production of a-isoprop yl-4-chlornbenzylphosphonic acid di-n-butylesterand a,a,-diisopropyl-4-chlorobenzylphos- phonic acid di-n-butylester Under a nitrogen atmosphere and at room temperature 6.4g (0.02 mol) of 4-chlorobenzylphosphonic acid di-n-butyl ester were added dropwise to 1.8 ml of 50% (0.2 mol) sodium amide suspension in 24 ml benzene)HMPT (1 :1) and the slightly warm mixture cooled to 10 . Over a period of 25 minutes was then added, at 10-15 , a solution of 5.lg (0.03 mol) 2-iodopropane in 5 ml benzene and, after removal of the cooling bath, the resulting reaction mixture stirred for a further 30 minutes.The mixture was then re-cooled, 20 ml water added and the product ether extracted, the ether extract being washed with water and brine, dried over magnesium sulphate and evaporated down. After chromatographic separation (200g silica gel with hexane/ethyl acetate 7:3) the title products were obtained in pure form, the former having nod20 = 1.4942, the latter nD = 1.5075.

EXAMPLE 7 : (process c), monoalkylation) a- (3- Pentyl)-4- (3-pentyloxy)b enzylphosphonic acid diethyl ester Within 20 minutes 105.8 g (0.337 Mol) 4- (3-pentyloxy)-benzylphosphonic acid diethyl ester are added at 3" and under nitrogen atmosphere to 18.4 g solid sodium amide (precipitate of a 50% sodium amide suspension in toluene) in 250ml dry toluene. Then 56 g(0.33mol) 3-pentyl methanesulphonate is added. After removal of the cooling bath the temperature of the reaction rises up to 45" (when 40 is reached the mixture is slightly cooled additionally with an ice bath) and drops then slowly under stirring until room temperature is reached. After a reaction duration of 4 hours the mixture is cooled, 50 ml water added and an ether extraction carried out. The extract is then washed with water and then brine, followed by drying over magnesium sulphate and evaporation. After fractionated distillation of the residue one obtains the pure title product, B.pt. 170'/0.08 mm Hg.

EXAMPLE 8 : (process c), di-alkylation) a,a-Di-n-propyl-4-r2-butyloxyJbenzylphosphonic acid diethyl ester To a solution of sodium methylsulphinyl carbanion in dimethyl sulphoxide (freshly prepared by reaction of 1.50 g (0.031 mol) of a 50% sodium hydride dispersion in oil with 15 ml dry dimethyl sulphoxide at 70 bath temperature under nitrogen with stirring for 45 minutes) were added dropwise at 15 C 3.009 (0.01 mol) 4-(2-butyloxy)benzylphosphonic acid diethyl ester. Five minutes later, after cooling to 5", 3.80g (0.031 mol) 1-bromopropane were added dropwise whereupon a white precipitate was formed. The cooling bath was removed and the mixture stirred for a further 15 minutes, then water was added and an ether extraction carried out.The extract was washed with water and brine, dried over magnesium sulphate and evaporated.

The residue was purified chromatographically (50 g silica gel with hexane/ethyl acetate 75:25) to yield the title product as an oil, n20= 1.4949.

EXAMPLE 9 : (process c), di-alkylation) α,α-Di-n-butyl-4-chlorobenzyl-phosphonic acid diethyl ester Under nitrogen atmosphere, at 3", 8.14 g (0.031 mol) 4-chlorobenzylphosphonic acid diethyl ester are added dropwise to 3.4 g solid sodium amide (precipitated portion of a 50% sodium amide suspension in toluene) in 24 ml benzene/HMPT (1:1). Within 35 minutes are then added, at 3", 11.4 g (0.062 mol) n-butyliodide. After removal of the cooling bath, the reaction mixture is stirred over night at room temperature. Then water is added, the reaction mixture extracted with ether, the extract washed with water and brine, dried over magnesium sulphate and evaporated.The obtained yellow oil is purified chromatographically (100 g silica gel with hexane/ethyl acetate 8:2) and distillated to yield the title product, B.pt. 138'/0.06 mm Hg.

EXAMPLE 10: (process d) α-(4-Chlorophenyl)-4-chlorobenzylphosphonic acid diethyl ester 13.6 g (0.05 Mol) di-(4-chloro-phenyl)chloromethane were stirred with 12.5 g (0.075 mol) triethylphosphite under a nitrogen atmosphere at 160" (oil bath temperature 200") for 3 hours, followed by 6 hours at 160-172" (oil bath temperature 200-210 ). The reaction mixture was purified chromatographically (250 g silica gel with hexane/ethyl acetate 7:3) to give the title product, n20= 1.5508.

Following the procedure of the appropriate Example 1 to 10, above, employing appropriate starting materials, the following compounds of formula I are obtained.

T 1. B L '

I,7i'""Sil-.lon. i Pr 1.2.9"1 "' P.pr. .Tlgrl ae5s jll -C CH A 1.5018 a,b.c,d CH3 1.5072 c 12 13 C2Hg - 8 1.5029 a,h,e 1.sOss n-CjH7 n-Cjn7 1.5055 1 C, (1) in case only 1 substitl:ent is listed, the others are H (2) in case XR4-OR3 only 1 sabstituent (OR3) is listed

Ex. ,, (11 -- - Procea] 12 B () 20 r Procens rx . 12 3 2 he XR42 "0 a fl.pt. or n.pt l 7 4-cl i-C3I17 CN3 C25 1.5055 e 1 8 1-C31I7 103117 . 1.4956 c 19 .. n-C1?9 11 1.4998 a,b,c 20 n 2-C4119 11 1.5035 a,b,c, 21 n t-C 1119 H 1.4982 a,b,c 22 . n-C51111 H 1.4970 a.b.c 23 e 2-CSItll H w 1.5005 a.b.c 24 3-C51111 H 1.5018 a.b,c 75 " t-C5H11 H 1.4925 a.b.e 2G p-C61113 n . 1.5160 a.b,c 27 - 2-C61113 H . 1.4981 a.b.c 28 E -C)12c11-CII2 H l.S105 a,c 29 | -CII2C-OI I - 1.5160 a.C 3,7 -Cll II N 1.5415 a,c 31 H .@ N . 1.5178 a.e I 32 1 II H - . 35C(m.pt.) a,d II 11 . i-C3N7 . 1.5490 c II I I (2, Ir.s. I :xly (1) R R1 DRJ/IR I n .ph. or Hpt.

io.j 12.3 ( r I OC2Hg L.5198 a,e 36 ≈ - n-C19H21 H - 1.4882 a.b,c 37 . .. H N . 1.5502 a.d 3L " 3-C6 1113 H 1.5010 a,b.e 39 g0 (cI1;;0Cl E . 1.5440 a,b,c 40 4-C1 | -CH2C;CH2 N -OC2115 a,c Cl 2 -CH2C CN2 2 . a 2 .. a ,, I Q i-CIA I C 46 .. -C112CC12- - a 13 - -CH2CH2CH2CH2-- 216 a,c 48 - -C112C112CN2C112C12 . a,c 49 " -CII3CII2CH2CH2CIl2CH2- . a c

Cx Y 1,2.3(1) 11 P OR /~ Charaetorination o. 1,2,3 1 R2 /R4'7 nl3 , B.pt. or H.pt Process ~ no . D.pt. or M.pt 50 4-Cl 2-msthyl- ll -OC 11 1.4562 a,b,e .butyl 51 - 2-ethyl- II N . 1.4963 a,b,e, butyl 52 - clchexyl N - 1.5225 a,c 53 . 3-heptyl II - a,b,e 54 . 4-wethyl I? H 1.4975 a.b.c 2-pentyl ~ S5 . 3-CsHll CllZ -oc2115 1.5042 c st " , C2ns | " 1. 5160 c 57 - -c3 5 1.506 4 c 58 . S-C5H11 N -O-Cllg-n a,b,c 54 " 2-C5H11 N - ,b.c Ço . 3-c5111l N - ,b,c 61 . 4D H 2~0CHg M.pt.60-62' 82 - 2-C4!89 II -DC3H7-l 1.4917 - - H -O- C311f~ c.b.e 84 2,4-cl2 !2 C41 9 11 -oC2ll5 ' s,c 85 ' !i-C5lill . ,c G6 ' I2-CI11 1? N C G7 . 3-c5111l H . 1.5116 C 88 - tiD II - C v. s (I,T oR t2) Characterisation no.l 1,2 31 111 R2 3/X4 nO , B.pt. 20 H.p PrOcess .~ ~ -C1 4-cl l l-c3lX7 D OCH3 1.5185 a,b,c Gg " N l-OC3117 57-59?i.pt.) c 70 N n-OC3117 a.b.c il N * I n"OC51111 a.b.e 172 " : " N n-OC81117 .,bye 11 " : H H -OJs 1.4920 a,b.e , 4 N * e 175 N " c 76 * -Ol a.b.c 177 - H r a.b.e 78 . " H -O & 1.4921 a.b,e 79 1 * " H -ow c oo N II - a, b, c SI . H -OJ ~ a,c 8 2 11 N ~oJ~~ C SI 3 . I? - C 84 - - H - 74-76' (m.pt.) c 85 . . H .-CH2CH-CH2 | . bc 9Ç " " I H 11 -O-CIIZCLCH

IEx-IY -t.,,,,I I.e. YX "" i R1 R2 3/X4 nDO,B.pt.er 20 no U ,fl.pt.crn.ptProcaa 88 - lC:?I7 0-Cil2CH2OCH3 a.b.c 87 . 4-Cl H OC??2C1120C2?15 a.b.c 89 " N oC??2C??25C2115 a.b.c 90 . ., N o-C112CH20-iC3M7 a.b.c 91 . , - Q124;) a.b,e 92 " . N SOCH20 a.b,c 93 - N OC2N5/-Sc2115 a 94 " ll oc2lls/n-sc4ll9 a 95 " - N oc2115/~llXcil3)2 a,b,c 96 | " II -OC2115/-N(C2115}2 a.b.c, 97 n w N -OC2115/-N(nC117)1 a,b,e 9 8 n w -OC2li51-H 4iC3H7? 2 c 99 " N oC2115/ 1 a,b,r 103 n -OC1)15/-13 a.b.e 01 n w D -OC2H5/-N(n-CH9)2 a,b,c 102 N . II -OC2115 1.4911 a.b,e 103 3-Cl II 1.5013 a.b.e 104 2-C1 - II 1.5023 a.c 105 2r4~CI . N . 1.5133 a.c loG 2, G-cl . H . . 1.5159 a,e 10) g 3 3.4-Cl3 4-C12 N 1.5152 a,b,e 109 3,5-C12 - II - 1.5125 a.b.c 109 3 N . 107-/0.04 mm a,b,c 110 j 4-cC113 . N . 1.4998 a,b,c 11 t 3.1 O) - N . 1.5082 a.b,e 12 4l03 " H 0-1 40-42-tm.Pt.l s.c 113 .-c,-Cl , N , ' 1.5372 a,b,c 114 4-br -c5111l II .pt.16370.06rn. a,b,e It 4-I N . . 1.4828 a,b.c 131 4-C 1 . H . 1.5088 a.b.c I rx. 111 or 2} Process No. 1,2.1 (1) R2 S 112 B pt. 2) Characterisation x144 n0 , B.pt.orN.pt 117 4-COOC2115 3-CSI3L1 ll C2ll5 a 116 4-CONtC113)2 . N . I? " a,e 219 4-coCII3 - H I a 120 4 -Co " II - S.C 121 3-CF3 - N " 1.4618 a,b,c 122 4-ocll=Ccl2 II N a,e 123 4-OCr3 - N - a,b,c 124 4-sCE3 - II - a,b.e 325 4-OCr3CH2 - 1? a,b,c 126 4-OCllF2 - 1? 1.4761 a,b.c 127 4-OCF2C1 I? " 128 4-SO2C3 " II - a,b.c 129 4-5o2CN3 . I? a 130 4-CN=CC12 - II - * a 131 4-C??-N-0CH3 . H - a 132 4-Ci H N . b,c 133 2-N02 N a S-OtCF3 134 3-Cl. 4oCH3 - II - a,b,e 135 40Cl - N . . 1.5364 136 3-oXcl II - .b.c 437 4-0ç) N 2 - H . 1.5482 428 4-o;tCl I? - x,b,c 39 4-0CF3 - It 1 .soy4 a.b.e 40 4-oecil II - a,b.e 141 4-o-al . II a.b.c 142 3-Cl.4-0C11 - I? a,b,e 143 3-Cl. 4-O1C. - N . rl,b,e -C1

rx, Y (1) ~ or (2) ) Sheracterisatlon, ( I, 2, I ,/3xn4 > 2R4 n20,D pt, or ?1.put.

144 H 1-Sj14 H C2ll5 1.4930 a,b,e 149 4-t-C4Hg N 1.4905 a,b,e 146 3-lJ 2 - H * 1.5122 .,byre 147 4-OCH 3 If - 1.4992 a,b,o 148 4-0 > ~ . N . 1.4902 a.b.c 149 4-0(cil2)9cil3 II " 1.4833 a,b,c 150 44 - ll - a,b 152 4 < ) . H . a,b 152 4-Il (C2))9) 2 D II 1.5118 a,b,e 153 4-0 < . H . 1.4918 a,b,e 154 4-SC2H5 . N - 1.pt.157'/0.03rnmI)g a,b,e 155 4-S-C2115 II N a,b 156 4-OC 63 H - 1.5010 .,blue 197 * -C4ll9 -C4ll9 - 1.4907 158 n-c3117 I? i-OC3li7 1.4808 b.c 159 4-CII3 n~C3H7 -oC2H5 c 160 4-n-C5JIll " - c 161 4-CII26 * ' C 162 4-Cl)20C)l3 . . C 163 4-OCR3 " . 1.5035 c 164 4-OC - . - 1.4939 c 165 Y . -oX/ 1.4875 c 166 " . . ' i-OC3117 1.48G4 C 167 4-os ,Cl . - C21iS H.pt. 61-62- o 168 4 ~ ' " 1.5058 c rx, y (1) | R1 R2 oR3 (2) ci,nracteris3tion, IJo 1, 2, 3 /X4 nj7j ,D.pt . or )4.put Precoss ~ . no .5.pt.

169 4-0-n-C4119 -C3117 fl-C3))7 DC2HS 1.4954 c 170 4-ogl . 1. " 1.5089 c 171 A-01'02 - El.pt. 100-102- c 272 4-oc2ll5 * . 1.4982 c 1?3 4-0Cl -04119 I? " a,b,e 174 H N 1.5468 a,b,c 179 4-C1 . N -0-CI)2 1.5176 a.b.c 176 2-OC H N -0C2ll5 1.4894 .,bye 177 4-OC . N II " 1.4891 a,b,e 178 - ' H i-0CH3))7 b,e 17'J H li -Dv( a.b.c 180 N 0-a-C3))7 a.b.c 161 * ll -OC2l)5/-)4)C2H5) a,b,c 182 * N H -0C2))5/-ll)a-C3))7) 2 a,b,c 183 4-o ' N -0C2ll5 a,b,e 184 4-o-~-C3ll7 , I? N a.b,c 185 4-0 < H N a.b.c 186 4-ow - H . a,b,c 187 4-61 - H . a.b.c 188 4-04 43 H . 1.5031 a,b,c EXAMPLE 189 4-Chlorobenzylphosphonic acid diethyl ester (compound of formula VI) To 0.95g (0.032 mol) of an 80% sodium hydride dispersion in 25 ml 1,2-dimethoxyethane were added, under a nitrogen atmosphere and at reflux temperature, over a period of 25 minutes, 4.37 g (0.032 mol) of diethylphosphite and stirring continued for a further 12 hours. To the cooled mixture, at room temperature, was added, dropwise, 4.64g (0.029 mol) of 4-chlorobenzylchloride in toluene and the whole stirred for 3 hours under reflux.After a further addition of 0.309 of the sodium hydride dispersion (at 45 ) and of 2.09 diethylphosphite (at reflux temperature) the reaction was brought to completion by stirring for 18 hours at a temperature of 80 . After cooling, a little water was added and the reaction mixture extracted with ether. The extract was washed with water and brine, dried over magnesium sulphate and evaporated. The residue was purrified chromatographically (100 g silica gel with hexane/ethyl acetate 1:1) to yield the title product as a colourless oil, B.pt. 140-149'/0.1 mmHg.

HERBICIDAL PREPARATION EXAMPLES Example A Wettable powder 25 Parts by weight of a compound of formula 1, 5 parts of a condensation product of formaldehyde and naphthalene sulphonate, 2 parts of alkyl benzene sulphonate, 5 parts of dextrin, 1 part of ammonium caseinate and 62 parts of diatomaceous earth are mixed homogeneously and then ground to an average particle size of less than 45 microns.

Example B Emulsion concentrate 25 Parts by weight of a compound of formula 1,65 parts of xylene and 10 parts of the mixed reaction product of an alkylphenol with ethylene oxide and calcium dodecylbenzene sulphonate are thoroughly mixed until homogeneous. The resulting emulsion concentrate is diluted before use.

Example C: Granulate 5 Kg of a compound of formula I are dissolved in 25l of methylene chloride. The solution is then added to 95 kg of granulated attapulgite (mesh size 24/28/inch). The solvent is then evaporated off under reduced pressure.

Claims (16)

1. A method of combating weeds in a locus which comprises applying to said locus a herbicidaliy effective amount of a compound of formula I

wherein Y1 is hydrogen or halogen, either Y2 is hydrogen, halogen, C1 10alkyl, C1-1O- alkoxy; C3~7cycloalkyl or C3-7cycloalkoxy, and Y3 is hydrogen; halogen; nitro; cyano; C110- alkyl, C~10-alkoxy, C2-10alkoxyalkyloxy, C2~10alkenyl, C2~10alkenyloxy or C1~1O- alkylthio, each alkyl or alkenyl radical or moiety being unsubstituted or substituted by halogen; benzyl, phenyl or phenoxy, each phenyl radical or moiety being unsubstituted or substituted by up to 2 substituents selected from halogen, nitro, cyano, C16aIkyl, C1-6alkoxy, C1-6alkylthio, each alkyl radical or moiety being unsubstituted or substituted by halogen; -CONRxRy;CORp; -COORp;

-SO2Rp; -NRxRy; -CH=N-ORp;

or Y2 and Y3 are on adjacent carbon atoms and, together, form a methylenedioxy or ethylene-dioxy group; either each Rx and Ry, independently, is C110alkyl of C3-,0alkenyl, or Rx and Ry, together with the nitrogen to which they are attached, form a pyrrolidine, piperidine, N-methyl-piperazine or morpholine group; Rp is phenyl. or C1-10alkyl unsubstitued by chlorine and/or fluorine; Z1 and Z2, independently, are 0 or S, either R1 is C1-10alkyl unsubstituted or substituted by halogen; C3~7cycloalky, unsubstituted or substituted by halogen;C1-4alkyl mono-substituted by C13alkoxy, phenyl or phenoxy, the phenyl or phenoxy being unsubstituted or substituted by up to 2 substituents selected from halogen, C1-4alkyl, C1 4alkoxy and trifluoromethyl; C2ealkenyl, unsubstituted or substituted by halogen; C24alkynyl; or phenyl, unsubstituted or substituted by up to 2 substituents selected from halogen, C14alkyl, C14alkoxy or trifluoromethyl; and R2 is hydrogen or has one of the significances of R1, or R1 and R2 are joined to form, together with the a-carbon atom, a C3-7cycloalkylidene radical unsubstituted or substituted by halogen or C1-4alkyl, X is, independently, 0, S or NR5, R3 is unsubstitued C1-8alkyl;C1-4alkyl substitued by C1-3alkoxy, C1-3alkylthio or halogen; C3-6alkenyl; C3-6alkynyl; tetrahydrofur-2-ylmethyl; tetrahydro-2H-pyran-2-ylmethyl; C5-6cycloalkyl, and Either R4 and R5 have, independently, a R3 significance, or R4 and R5 are joined to form, together with the nitrogen atom to which they are attached, a piperidine, pyrrolidine, N-methyl-piperazine or morpholine radical.

2. A method according to Claim 1, wherein the compound is of formula Ib,

wherein Y'2 IS hydrogen or cnlonne, Y'3 is chlorine, bromine, C1-5alkoxy, C3-5- alkenyloxy or C1 9alkyl, R'1 is unsubstituted C3,alkyl or C3-6cyclo-alkyl, R'2 is hydrogen or unsubstituted C1-4alkyl, X' is O or NR'5, and R'3, R'4 and R'5, independently, are unsubstituted C2~4alkyl.

3. A method according to either of the preceding claims, wherein the locus is a crop locus selected from cereals.

4. A method according to any one of the preceding claims, substantially as described herein.

5. Acompound offormula la,

wherein Y1a Y2a, Y35, R1a. R2a. R3a and X,R4, (including R5a) are as defined in Claim 1 for Y1, Y2, Y3. R1. R2, R3 and XR4 including R5) respectively, with the provisos that (i) if Y1,, Y2a and Y3a are hydrogen, both OR3a and XaR4a are C2H50 or i-C3H70 and R15 is CH3.C2H5, n-C3H7, n-C4Hg, i-C,H11 1, allyl or benzyl, then R29 is not hydrogen or C2-5alkyl, (ii) if Y1a, Y2a, Ya, Y3a and R25 are hydrogen, and or3a different from phenyl, or (iii) if Y1a, Y2 and R25 are hydrogen, Y3ais methyl or OR3, and XaR4a are both C2H5O, then R15 is different from methyl, (iiii) if Y1a, Y, and Y3a are hydrogen, R2 is methoxymethyl and OR3a and X,R, are both C2H50, then R1, is different from methyl.

6. A compound according to Claim 5 wherein ring A is substituted and wherein R1a, where it is unsubstituted alkyl, is C3-6alkyl.

7. A compound of formula lb as defined in Claim 2.

8. A compound according to Claim 7 wherein Y'3 is 4-Cl, R1' is 2-butyl, R'3 is C2H5, X'R'4 is N(C2H5)2 and Y'2 and R'2 are hydrogen.

9. A compound according to Claim 7 wherein Y'3 is 4-(3-pentyloxy), R'1 is 3-pentyl, R'3 is C2H5, X'R'4 is OC2H5 and Y2' and R'2 are hydrogen.

10. A compound according to Claim 7, wherein Y'3 is 4-(2-butyloxy), R'1 and R'2 are n -C3H7, OR'3 and X14 are OC2H5 and Y'2 is hydrogen.

11. A compound according to claim 7 wherein Y'3 is 4-CI, R1' and R'2 are n-C4Hg, OR'3 and X'R'4 are OC2H5 and Y'2 is hydrogen.

12. A compound according to Claim 7, wherein Y'3 is 4-(2-butyloxy), R'1 is 2-butyl, OR'3 and X'R'4 are OC2HD1/45/8ANDY2' and R2'are hydrogen.

13. A compound according to Claim 7, wherein Y'3 is 4-(2butyloxy), R'1 is cyclopentyl, OR'3 and X'R'4 are OC2H5 and Y2' and R'2 are hydrogen.

14. A herbicidal composition comprising a compound according to any one of Claims 1 and 5 to 13, in association with a herbicide carrier of diluent.

15. A herbicidal composition according to Claim 14, substantially as described herein.

16. A process of producing a compound as defined in Claim 5, which comprises (a) preparing compounds of formula Ica

wherein Y1a, Y2a, Y3,, R3a, R45 and X, are as defined in claim 5, and R2a" has the significance of R2a in Claim 5 with the proviso that R"2a is H where X, is O or NR5,. by reacting a compound of formula Ila

wherein Q1 is chlorine or OR3a and Yaa, Y2a Y3a, Ria, R"2a and R35 are as defined above, with a compound of formula Illa R4aXaM Illa wherein Xa and R4a are as defined in Claim 5, and either M is hydrogen when Xa is O or NR5a,wherein R5a is as defined in Claim 5, or M is an alkalimetal cation when Xa is sulphur, (b) preparing compounds of formula Ida

wherein Y1a, Y2a, Y3a, R3a and XaR4a are as defined in Claim 5, and either R1aIII is unsubsituted C110alkyl and R2aIII is hydrogen, or both R1aIII and R2aIII are phenyl or substituted phenyl, by reacting a compound of formula IVa

wherein Y1a, Y2a, Y2a, Y35, R1aIII and R2aIII are as defined above, and Q2 is halogen, with a compound of formula Va

wherein Xe, R3a and R4a are as defind above, or (c) preparing compunds of formula lea

wherein R1aIV and R2aIV have the above significances of R1a and R2a with the provisio that not both R1aIV and R2aIV are phenyl or substituted phenyl, XaII is O or NR5a and Y1a, Y2a, Y35, R4a and R5a are as defined above, by mono- or di-substituting a compound of formula Vla

wherein R65 is hydrogen, phenyl or substituted phenyl, and Xa, Yie, Y2a, Y3ar R39 and R4a are as defined above, with one or two compounds of formula VIIa R7aO3 VIIa wherein R7a has the above significance of R1a with the proviso that it is not phenyl or subsituted phenyl and Q3 is a leaving group or with a compound of formula Vllaa Q3 Ria - Q3 Vllaa wherein R,5is C-6alkylene unsubstituted or substituted by halogen or C1-4alkyl, and Q3 is aa defined above, or (d) preparing compounds of formula Ifa

wherein XaII, Y1,' Y2a Y3a R3a and R4a are as defined above, and RVia is a methyl, phenyl or substituted phenyl by reacting a compound ofVllla

wherein Q4 is a halogen and Y1a, Y2a, Y3a and RYa are as defined above, with a compound of formula IXa

wherein R3a, R 4a and XII are as defined above.