AU596406B2

AU596406B2 - Halogenated heterocyclic ethers, the preparation thereof and their use as herbicides

Info

Publication number: AU596406B2
Application number: AU71445/87A
Authority: AU
Inventors: Kurt Hans Gerhard Pilgram
Original assignee: Shell Internationale Research Maatschappij BV
Current assignee: Shell Internationale Research Maatschappij BV
Priority date: 1986-04-14
Filing date: 1987-04-13
Publication date: 1990-05-03
Anticipated expiration: 2007-04-13
Also published as: AU7144587A; GB8708790D0; ES2005552A6; IL82206A0; GR870593B; BR8701754A; BE1002100A5; PL265141A1; DK189587A; HU201221B; IT8767301A0; GB2188931A; JPH0778051B2; KR880012607A; FR2597101A1; DK189587D0; KR950001023B1; ZW6887A1; ZA872625B; PH23777A

Description

Commonwealth of Australia JB2H04 i i I: .596406 SPRUSON FERGUSON FORM 10 COMMONWEALTH OF AUSTRALIA PATENTS ACT 1952 COMPLETE SPECIFICATION

(ORIGINAL)

FOR OFFICE USE: 7 i r i j jr

I

i r

IC

a 4 I i.

tr *l 10 I t I tr I 41

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Class Int. Class Complete Specification Lodged: Accepted: Published: Priority: Related Art: This document conta;ns th:w amendments made un. r Section 49 and is corrct i.rprinting.

Name of Applicant: Address of Applicant: Actual Inventor: S Address for Service: Complete Specification SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ B.V.

Carel van Bylandtlaan 30, 2596 HR The Hague, the Netherlands KURT HANS GERHARD PILGRAM Spruson Ferguson, Patent Attorneys, Level 33 St Martins Tower, 31 Market Street, Sydney, New South Wales, 2000, Australia for the invention entitled: "HALOGENATED HETEROCYCLIC ETHERS)11E Gssm t e a-r1o-b M rtre-o f Ol% a -I Qse- MS \-\e.YCvkrAqLs The following statement is a full description of this invention, including the best method of performing it known to us SLSR/na/124W 1-i'-.SNr K 3580 FF HALOENATED HE7CYCLIC ETPF ICIDES Compounds of the formun~laR whereini R is 3-halo--2-thienyl, 5-halo-3 ,4-dihydro-2H-pyran- 6-yl, 2-halo-1-cyclopenten-2.-yl or 2-halo-1--cyclohexen-l-yl in 44 044which halo is chioro or fluoro and RIis the hydrocarby. residue selected from certain known oxygen heterocyclic alcohols (R O0), are useful as herbicides and plant growth regulators.

1K3.0 -r 1A HALOGENATED HETEROCYCLIC ETHER HERBICIDES The present invention relates to rr, halogenated heterocyclic ethers, to their preparation, to their use as herbicides and plant growth regulators, and to formulated compositions containing them.

ThL present invention provides a compound of the formula I

R

1 0 CH 2 R I wherein R is 3-halo-2-thienyl, 5-halo-3,4-dihydro-2H-pyran-6-yl, 2- .halo-l-cyclo-1-penten-l-yl or 2-halo-l-cyclohexen-l-yl in which halo is chloro or fluoro and Rp is the residue of a non-aromatic oxygenheterocyclic alcohol (R OH), R 1 containing up to 16 carbon atoms and being a group selected from: 5 a) m W

I

44 25 I t I 4 It4 wherein N is a methyl or ethyl group; X is a single bond or -C(CH 3 2

Y

is a single bond or -CH 2 with the proviso that both X and Y are not a single bond; Z is H, or an optionally substituted alkyl group containing 1 to 4 carbon atoms; b) 4

I~

JLH/6521F 2 wherein each R 2 individually represents a hydrogen atom, a halogen atom, an optionally substituted alkyl, cycloalkyl or aryl group, each containing up to 6 (chain/ring) carbon atoms, or two R 2 together represent an 3 4 5 6 alkylene of up to 6 carbon atoms, R R R and R each individually represents a hydrogen atom, a halogen atom having an atomic number of from 9 to 35, inclusive, an optionally substituted alkyl, alkoxy, alkylthio or aryl group each containing up to 6 carbon atoms or one of R 3 and R and one of R and R together represent a carbon-carbon bond 7 8 or an epoxide moiety; R and R each represents a hydrogen atom or an optionally substituted alkyl group containing up to 6 carbon atoms; I ^or c) 1 4 SR .R 6 R. R ta z i CH R 7 Y

A

X -W CH2- X;

S

o wherein R 3

R

4 R R and R 7 each individually is a hydrogen atom or an alkyl group containing from 1 to 4 carbon atoms, W is an oxygen atom or -CH 2

X

1 is an oxygen atom or -CH 2 Y is a 9 carbon-carbon bond, or an oxygen atom, -CH 2

-C

2

H

4 or -CHR 9 in which R is an alkoxymethyl group containing from 1 to 4 carbon atoms In the alkoxy portion thereof; Z is a carbo6ncarbon bond, an oxygen atom,

-CH

2 or -C 2

H

4 with the proviso that no two adjacent of N 1

X

1 Y and Z1 are simultaneously either oxygen atoms or -C2H 4 and the J sum of the ring atoms in W 1 X, Y and Z 1 is an integer of from 3 4 to wherein said optional substituents in formulae and are selected from one or more atoms of chlorine, fluorine and bromine.

The compounds are useful as herbicides for controlling (combating) undesirable or unwanted plants.

'4 3 Si f-- 3 Optional substituents in formulae 1, and include 1 or more atoms of chlorine, fluorine and bromine.

Examples of compounds within the scope of the invention include 2-((3-fluoro-2-thienyl)methoxy)- ,4-diethyl-7-oxa-bicyclo[2.2.1]heptane, 2-((5-chloro-3,4-dihydro-2H-pyran-6-yl)methoxymethyl)-2-ethyloxaspiro[4.5]decane, 2-((2-fluoro-l-cyclo-hexen-l-yl)methoxymethyl)-2-ethy1tetrahydrofuran, 2-((2-fluoro-l-cyclopenten-l-yl)methoxymethyl)-2,5-dinethyltetrahydrofuran, and 2-((5-fluoro-3,4-dihydro-2H-pyran-6-yl)methoxy-l-methyl-4isopropenyl-7-oxabicyclo[22.2.1-heptane.

The compounds of formula I may exhibit geometrical and optical isomerism and can be prepared in geometrical and/or optically-active forms, and as racemates. The various individual optically and geometrical combinations of the materials of the invention usually h-ave some different herbicidal properties. The present invention contemplates all the herbicidally active forms resulting from synthesis and deliberately formed mixtures.

The preferred nQn-aromatic oxygen-heterocycles providing the group

R

1 include those of formula in which X is a single bond, Y is

-CH

2 W is methyl and Z is a hydrogen atom or a 1-methylethyl group or W and Z each is an ethyl or methyl group or X is -C(CH3)2-, Y is

-CH

2 and Z is a hydrogen atom. Preferably X is a single bond, Y is -CH2-, W is a methyl group and Z is a 1-methylethyl group or N and Z each is an ethyl or methyl group; 4 4 404 00 444 @4 000 o 4s 4444 0 4 444, 4444 4 4 P 44 I 444, JLH/4768W 7 CC tQ 0 I C *~0C p

IC.

C 1 I I

CCCI

00CC 4 those of formula in which each R independently is a hydrogen atom or a methyl group or the two R2's taken together form a pentamethylene group, R R R R 6 and R 8 are hydrogen atoms and R 7 is a hydrogen atom, a methyl or ethyl group; preferably each R 2 is a methyl group and R7 is a methyl or, especially, an ethyl group; and those of formula in which W1 is an oxygen atom or -CH2-, 1 1 X is an oxygen atom or Y is an oxygen atom, -CH2-, 3 9 1 -C2H 4 or -CHR in which R is methoxymethyl, Z is an oxygen c\ atom or -CH2-, and the sum of the ring atoms in W X Y and 1 is an integer of from 3 to 5; preferably, W and Z 1 are each -CH 2 and one of X and Y is -CH 2 and the other is an oxygen atom or W is -CH2-, and X 1 and Z 1 each is an oxygen 1.

atom and Y is -C 2

H

4 R is preferably a 3-chloro-2-thienyl or 3-fluoro-2-thienyl group.

A further aspect of the invention resides in the preparation of the compounds of formula I, wherein the compounds of formula I of the invention are prepared by treating the L2> appropriately substituted non-aromatic oxygen-heterocyclic alcohol (R OH) with a compound XCH 2 R in which R has the meaning in formula I and X is a leaving atom or group, for example a halogen atom, such as bramine, chlorine or icdine, or a sulphonate group, for example a mesyloxy, tosyloxy group or the like, preferably in the presence of a strong base and an inert diluent. The strong base is suitably an alkali metal hydride, hydroxide or carbonate, including, for example, sodium hydride, sodium hydroxide, potassium carbonate and the like. Inert diluents are suitably organic solvents, such as ethers, aromatic hydrocarbons and the like, including, for example, diethyl ether, dimethylformamide, tetrahydrofuran, dimethyl sulfoxide, toluene, methylene chloride and the like. The reaction is usually carried out under normal pressures and ambient temperatures. Suitable temperatures for the reaction are from about 0° to about 120 0 preferably from about 20 0 °C to about BK53.005 I ii,

I~I

*1 C 4U-t t i* 4 '4, 4 4 4I 4 4* '4' 100 0 C. The product ethers are recovered and isolated by conventional techniques. In some cases, the ethers may be formed prior to formation of the oxabicycloalkane system.

The reactants XCH2R are conventional kinds of etherification materials generally known in the art and are readily prepared by conventional methods known for preparing halides and sllfonates of alcohols.

For example, 1-(brommethyl)-2-chlorocyclohexene is prepared by treating the corresponding alcohol with PBr 3 in k benzene. The alcohol is readily prepared by treating cyclohexanone with POC1 3 in dimethylformamide Ziegenbein and W. Lang, Chem. Ber, 93 page 2743 (1960)) to give the corresponding aldehyde which is treated with Red-Al (sodium bis (2-methoxyethoxy) -aluminum hydride) in toluene to give the desired alcohol. In a similar manner a 2-(chloramethyl)-3halothiophene is prepared by treating a 3-halothiophene with formaldehyde and HC1. The 3-bromothiophene is obtained by bromination of thiophene followed by treatment with zinc dust; treating the resulting product with cuprous chloride in 2C. dimethylformamide gives the corresponding chloro compound. The (5-halo-3,4-dihydro-2H-pyran-6-yl) methylhalides are prepared from 5-halo-3,4-dihydro-2H-pyran-6-yl) methanols.

The oxabicycloalkanol reactants for preparing compounds wherein R^ is a group of formula are obtained generally by one or more of the following routes: directly by (a) epoxidation-cyclization of unsaturated cyclic alcohols, with or without isolation of epoxy alcohol intermediates; and indirectly by Diess-Alder reactions of furans with dienophiles or (c) Birch reduction.

c Detailed routes are described below for the different ring systems.

In the epoxidation-cyclization of unsaturated cyclic alcohols involves treatment in an inert solvent with an oxidizing agent followed by an acid. The alcohols are either cycloal-3-en-l-ols, or (ii) cycloalk-3-ene-l-methanols. The BK53.005 a+~ama~' -6 *i U a arr 9.9, 99D ~94.

a O cycloalk-3-en-l-olsi are prepared from 1-oxaspiro(2.5)oct-5-enes by hydrogenolysis; from cycloalk-3-en-l-ones by treatment with a Grignard reagent; by dealkylating or hydrolyzing, respectively, Diels-Alder adducts of vinyl ethers or esters prepared from dienes, such as isoprene, and vinyl ether or ester dienophiles in which the alpha-position of the vinyl group is substituted by alkyl, CO 2 R or CON(R The cycloalk-3-ene-l-methanols are alpha-terpineol; Diels-Alder adducts cr allylic alcohols; or products obtained from Diels-Alder adducts of CL alpha-beta unsaturated carbonyl conpounds, such as acrylates, crotonates, acrolein or alkyl vinyl ketones, by partial reduction or treatment with a Grignard reagent; or from 1-oxaspiro- oct-5-enes by rearrangeent and partial reduction of the resulting carbonyl compounds; from cycloalk-3-en-l-ones by partial reduction.

In the Diels-Alder type adducts of furan with dienophiles may require vigorous reaction conditions, including high pressure and low temperature, for example, as described, in Dauben, W.G. et al., J. Amer. Chem. Soc., 102, page 6894 (1980).

2-o When the dienophile is nitroethylene, the resulting product is partially hydrogenated, converted to the ketone, and reduced to the corresponding alcohol, e.g. by treatment with a hydride or metal. When this alcohol has the endo form, it can be epimerized with base or aluminum isopropoxide in the presence of a ketone to the corresponding exo alcohol.

Erno- and exo-oxabicycloalkanol intermediates can be separated by conventional methods, such as crystallization, chromatography and the like, and the geometric forms can be resolved by classical resolution methods to give a substantially 3- pure single, optically-active isomer.

Non-limiting illustrations of the preparation of representative CcOpounds of the Invention follow.

In one embodiment, R1 0 is derived from an alcohol having the formula I BK53.005 7

CH

S3 O OH

Z

wherein Z has the above nmeaning. Compound I can be prepared froman cyclohex-3-en-1-ols by epoxidation-cyclization, or (2) Diels-Alder adducts of furans, such as 2,5-dimethylfuran, with dienophiles, such as nitroethylene, as described below.

The epoxidation of cyclohex-3-en-1-ols into the corresponding epoxy-alcohol is effected by action of an oxidizing agent, particularly a peroxide, such as m-chloroperbenzoic acid, peracetic acid, tert-butyl hydroperoxide (TBHP) or equivalent peroxide reagents. The oxidation to cis-alcohols with TBHP is conducted in the presence of an appropriate transition metal catalyst, e.g. vanadium.

Preferably, the complex is an organic couplex, for example, with beta-diketones, o-hydroxybenzaldehydes or o-hydroxybenzophenones and particularly with acetylacetone; for example, vanadiu (IV) bis(2,4-pentanedionate) oxide is preferred. The reaction is suitably conducted in the presence A of an inert solvent such as chlorinated hydrocarbons contain from I to 4 carbon atoms or a benzene ring, for example, carbon 6 94 -Ic4 tetrachloride, chloroform, dichlorcaethane, chlorobenzene and 1,2- or 1,3-dichlorabenzze and the like. Ethers are generally those containing from 4 to 6 carbon atoms, for example, diethyl ether, methyl tert-butyl ether and diisopropyl ether.

Tetrahydrofuran and dioxane are also useful. Suitable alkanes i1 containrl from 5 to 10 carbon atoms, for example, n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane and their isomers. Petroleum fractions rich in alkanes are also suitable.

Petroleum ether is also suitable. Cyclohexane and methylcyclohexane are examples of useful cycloalkane solvents S, containing fran 6 to 8 carbon atoms. Suitable artmatic BK53.005 i i 8 #91# 9 499 hydrocarbon solvents contain from 6 to 10 carbon atoms, for example, benzene, toluene, m- and p-xylene, the trimethylbenzenes, and the like. The reaction is conducted at temperatures conveniently in the range of from about -10 0 C to about 50 0 C or slightly above. Generally, the temperature is from about -5 0 C to about 40 0 C, preferably from about 10 0 C to about 30 0 C. The molar ratio of reactants can vary. Generally, a molar ratio of cyclohex-3-en-l-ol to oxidizing agent is from about 0.8 to about 1. The reaction is usually conducted by 'c forming a mixture of the alcohol and oxidizing agent, preferably while agitating the reaction mixture, e.g. by stirring, and maintaining the desired reaction temperature. The resulting cis-epoxy-alcohol may be purified or converted without isolation into the 2-exo-hydroxy-7-oxabicyclo- heptane by cyclization as described below.

The cyclization (ring closure) step surprisingly gave a high yield of product having the exo-hydroxy configuration in the resulting 7-o.aDicyclo[2.2.1]heptan-2-ol. Many acids will catalyze this reaction, but a relatively strong acid such as L-C sulfuric or p-toluenesulfonic acid is suitable. Preferably, the acid is methanesulfonic acid or an arylsulfonic acid, such as p-toluenesulfonic, benzenesulfonic acids, or the like. Of these, p-toluenesulfonic acid is preferred. The reaction is suitably conducted by adding the acid to the epoxy-alcohol contained in an inert solvent of the type previously described for use in the preparation of the epoxy-alcohol. The reaction is conducted at a temperature conveniently in the range of from about 0°C to about 50°C or slightly above. Generally, the temperature is from about 5°C to about 40 C, preferably rxTs about 10 0 C to about 30 0 C. The molar ratio of reactants can vary. Generally, the molar ratio of acid to epoxy-alcohol is from about 0.01 to about 0.10, and preferably from about 0.02 to about 0.04.

Thus, a 1,4-disubstituted-3-cyclohexen-l-ol is converted mainly to 2-exo-hydro~,--14-disubstituted-7-oxabicyclo [2.2.1 heptane by treating it with an oxidizing agent, such as BK53,005 .9 9 99 4999 4 #999 7( I t4 9tert-butyl hydroperoxide, or in-chloroperbenzoic acid, and then a strong acid, such as p-toluenesulfonic acid. Especially useful for obtaining a 2-exo-hydroxy-1 4-disubstituted-7-oxabicyclo- (2.2.1]heptane is treatme~nt of the corresponding 3-cyclohexen-l-ol with tert-butyl hydroperoxide and vanadium (IV) 1his 4-pentanedionate) oxide as catalyst in me~thylene chloride followed by treatme~nt of the in-terrrediate epoxide, preftrably in situ, with a sulfonic acid, particularly p-toluenesulfonic acid. Also, acid present during the epoxidation step produces the desired product.

The epaxidation-cyclization is disclosed and claimed in U.S. patent 4,487,945.

In situations where the endo form is desired, it can be obtained by oxidation of the 2-exo-hydroxy compound to the corresponding ketone followqed by reduction of the kzetonE. 1,dth sodium borohydride.

The 3-cyclohexen-l-ols useful for the preparation of non Ca~ipound I can also be synthesized as described below or obtained fromn natural sources (which offer the advantage of optically-active materials).

where Z is 1-mmthylethyj., the starting compound is terpinen-4-ol, which occurs naurl, Terpinen-4-ol is converted to 2-exo-hydroxy-l-methyl-4- (1-nethylethyl) -7-oxabicyclo heptane by treatmnent with an oxidizing agent, for example, a peroxide such as mr-chloroperbenzoic acid, peracetic acid or tert-butyl hydroperoxide, in an inert solvent in the presence of a strong acid. The spatial. configuration of -the terpinen-4-ol used is retained in the ,reaction product. Thus, ()2-exo-hvdroy-J.- 'emthyl-4- (I-irethylethyl) -7-oxabicyclo (2.2 .Iiiheptane can be obtained. 2-ondo--ydroxy-l-methyl-4- (1-m eth-,4!.

ethyl) -7-oxabicyclot2,2.llheptane is- k A',n Z.- Garsida et al,, Chem. Scpage 716-721 '9i 2-exo- and ent~Io-Uydroxy-!-nmthyl.-4- (t-m,9 BK53 .005 i i 10 oxabicyclo[2.2.1]heptanes are converted to the ethers of the invention as described above. Although terpinen-4-ol occurs in nature in optically active and racemic forms, it can also be prepared by epoxidation of terpinolene, e.g. with peracetic acid in methylene chloride, followed by reduction of the epoxide, e.g. with sodium diethylaluminum hydride in tetrahydrofuran.

Preparation of 3-cyclohexen-l-ols can be effected from p-substituted phenols in which the substituent group corresponds to methyl in the formula I of the invention by procedures of the literature for the Birch-type reduction of derivatives of benzene, many of which are detailed in Rodd's Chemistry of Carbon Compounds, Second Edition, Vol. II, Part B, pages 1-4 (1968). In an example, paracrosol is fixat -ethylated to protect the hydroxy group yielding the corresponding p-methylanisole. This p-methylanisole is treated with a reducing agent such as lithium-ammonia or sodium anmonia and the resulting product S1. is hydrolyzed to yield the corresponding 4-methyl-3-cyclohexen-1-one. Treatment of this ketone with an appropriate organometallic (Grignard) reagent, ZMgBr or ZLi in which Z corresponds to that in the formula I of the invention and is alkyl, e.g. at 20-60 0 C in the presence of anhydrous ethers, yields the desired 1,4-disubstituted-3-cyclohexen-1 -l intermediate. The 4-methyl-3-cyclohexen-l-one can also be reduced, e.g. by hydrides, to the corresponding 3-cyclohexen-l-ol unsubstituted in position-,.

Lc The 2-hydroxy-7-oxabicyclo heptanes useful as precursors of compounds of the invention can also be prepared from Diels-Alder adducts of suitably-substituted furans, as dienes, and dienophiles. For example, 2,5-dimehylfuran adds readily to nitroethylene to give 1, 4 -diethyl-2-nitrobicyclo- [2.2.1]hept-5-ene. Similar adducts can be prepared from BK53,005 L

A

2, 5-dialkylfurans and dienophiles such as acrolein and acrylate esters.

R R NO 2NO2 2O 2 R R NOH H/ 1 1E2 0 2 0 CH2 Pd/ R R In another embodiment of the inventicoAi, R 0 is dJerived from an alcohol having the formula II 0 OH wherein Z has the above meains apod I wherenin y, has tha-pove ais. r a ond wihaueu cd ofr 4 (2ph-xabiycl,22eit-he tn6os an be pom ropeaedy fr (1 a rpeoies, such as alhdrtenpeoxid or Dils-lereaddu cido a suitabl susitu t buaikemyene n hdilopies ontinin anjo aougnt fnctio,as ilstradbelo.2.For ean-le (1 th a paroxid sruch ast tydooxgen-peoxtigbidee) mchrOxbzicdatido BX53. 005 12this alcohol, e.g. with N-brnmoacetzimide in aqueous acetone at gives 1,3,3-trimethyl-2-oxabicyclo[2.2.2]octan-6-one.

Subsequent reduction of this ketone, for example with sodium borohydride in tert-butanol, yields a mixture of alcohols predominant in the endo isomer (hydroxy group syn to oxygen-containing bridge). Conversion to the ether of formula I of the Invention follows the earlier described procedures with retention of configuration.

Diels-Alder adducts are formed from suitably, readily \o available dienophiles including an acrylate ester, acrolein, methacrolein, methyl vinyl ketone, allyl alcohol, a crotonate ester and the like. The diene component is isoprene, 2,3-dimethylbutadiene and the like. For example, the SDiels-Alder adducts IIa are prepared by treating the portion of the compound of formula IIa above the dotted line 3 c 2 3 with a dienophile (methyl acrylate) corresponding to the portion of the como.nd of formula IIa below the dotted line. Many such reactions are detailed in Rodd's Chemistry of Carbon Compounds, Second Edition, Vol II, Part B, pagrs 5-6 (1968). Treatment of IIa with the appropriate Grignard reagent methyl magnesium bromide, ethyl magnesium bromide or the like) gives an Salpha,alpha 4-trimethyl- (or triethyl)-cyclohex-3-ene-l-methanol of formula IIb below.

3

J

OH

CH

3

CH

3 BK53.005 T t i i 1 13 Alcohol IIb is oxidized, for example, with a peroxide, such as hydrogen peroxide or m-chloroperbenzoic acid, in a suitable solvent, such as methylene chloride, preferably in the presence of a strong acid, to yield a major amunt of 1,3,3-trimethyl-2oxabicyclo-[2.2.2]octan-6-exo-ol. This exo form can be converted, if desired, into an endo-rich or suL--..±aily pure endo form. First, oxidation to the corresponding ketone, 1,3,3-trimethyl-2-oxabicyclo[2.2.2]-octan-6-one, is effected with a suitable oxidizing agent. For example, the exo form is \o combined with oxalyl chloride and dimethyl sulfoxide in methylene chloride followed by addition of triethylamine. Then, the resulting ketone is converted into the endo-alcohol by reduction. For example, the ketone in a mixture of dimethoxyethane and tert-butanol is treated with sodium Sborohydride. Classical resolution can be applied to the 1,3,3-trialkyl-2-oxabicyclo[2.2.2]octan-6-ols to give e substantially pure individual optical forms. The 1,3,3-trialkyl-2"oxabicyclo [2.2.2]octan-6-ols are converted into the desired ethers of the Invention, with retention of QO configuration. This reaction is carried out, preferably in the presence of a base, such as sodium hydride, and, if desired, an inert solvent, such c\s NN-dimethylacetamide, o*o.0 N,N-dimethylformamide, benzene, toluene or the like. The compounds of the invention can be recovered and purified by conventional techniques, In another embodiment of the invention, R 0 is derived frcom an alcohol having the; fctula III I i

CH

0 OH BK53.005 _I qw- c 14 c t(

C

a zl S.'r III can be prepared by condensation of 1,4-dibroo-2-methyl-2butene with an alkyl acetoacetate, in the presence of base, followed by thermolysis of the 2-isopropenyl-l-acetylcyclopropanecarboxylate intermediate to a l-acetyl-3-methyl-3-cyclopentenecarboxylate, which is hydrolyzed and decarboxylated to the corresponding ketone. Treatment of the ketone with two equivalents of Grignard reagent, methyl magnesium bromide, yields the corresponding alcohol derivative. This alcohol is epoxidized and cyclized to 1,3,3-trimethyl-2-oxabicyclo 2.2.1] heptan-exo-6-ol (III). This exo-alcohol can be oxidized to the corresponding ketone followed by reduction to a corresponding endo-2-oxabicyclo[2.2.1]heptan-6-ol as described for the compounds of formula II above. An example of one alternative method is the condensation of a 1,4-dibromo-2-methyl-2-butene with a malonic acid dialkyl ester, again using base, followed by thermolysis. The resulting cyclopentene derivative is treated with, sodium chloride in dimethyl sulfoxide to eliminate one of the ester functional groups. Treatment of the resulting mono ester with the Grignard reagent, methyl magnesium bromide, yields the alcohol derivative described in the first methodology. See, also, Spurlock et al., Chemical Abstracts, 76:153024e (1972) for preparation of a 2-oxabicyclo[2.2.1]heptan-6-ol.

Illustrative Embodiments The invention is illustrated by the following embodiments which describe the preparation of typical species of the invention. The embodiments are presented for the purpose of illustration only and should not be regarded as limiting the invention in any way. The identity of the products, including intermediates, was confirmed by elemental, infrared and nuclear magnetic resonance (NMR) and mass spectral analyses as necessary.

Embodiment 1 -2-exo-Hydroxy-l-methyl-4- (1-methylethyl) -7oxabicyclo[2.2.11] heptane To a solution of 22.3g of 85% m-chloroperbenzoic acid in

I

BK53.005

CC-

i i

I

a ,o I a OII

,I

o *0 o a0 0 00 Ig oo 0 0 0 0 .00 i roa I ftt

P

S- e 15 150 ml of methylene chloride was added over 40 minutes a solution of 15.4g of (+)-terpinen-4-ol in 30 ml methylene chloride at a temperature of about 0°C. The reaction mixture was stirred for 20 hours at room temperature, then cooled to 5°C. A solid was filtered and rinsed with cold methylene chloride. The combined filtrates were washed successively with one-eighth saturated potassium carbonate, saturated sodium sulfite, and then water, dried and Claisen distilled to yield 8.9gof product, b.p. 109-113 0 C at 8 rm Hg (1060 Pa).

Recrystallization of the solidified distillate from pentane gave g of the desired product, m.p. 42-58 0

C.

Embodiment 2 -2-exo-Hydroxy-l-methyl-4-(l1-methylethyl)-7oxabicyclo[2.2.1]heptane To a solution of 30.8 g of (+)-terpinen-4-ol and 0.8 g of vanadium (IV) bis(2,4-pentanedionate) oxide in 300 ml of methylene chloride was added 22.0 g of 90% tert-butyl hydroperoxide. The resulting reaction, initially mildly exothermic, was held at reflux for 2 hours, to obtain the epoxide, then 0.8 g of p-toluenesulfonic acid in 10 ml of glyme was added. The resulting reaction mixture was refluxed for hours, and cooled, and 0,8 g of anhydrous sodium acetate was added with stirring. After filtration, the filtrate was concentrated and Claisen distilled to give 2P.4 g of the desired product, b.p. 80-95C (2 mm Hg; 270 Pa).

Embodiment 3 -2-exo (2-Chloro-l-cyclohexen-l-yl) methoxy-lmethyl-4-(1-methylethyl)-7-oxabicyclo[2.2.1]heptane A suspension jf 0.6 g of sodium hydride from hexane-washed oil-dispersion in 20 ml of anhydrous dimethylformamide under

N

2 was stirred at ambient temperature while adding 1.6 g of the alcohol of Embodiment 2. The mixture was heated gradually to about 80° C, stirred until hydrogen evolution had ceased hours), cooled to ambient temperature, and treated dropwise with g of l-(bromomethyl)-2- chlorocyclohexene with stirring for 2 days. Excess sodium hydride was deccposed by addition of

I

BK53.005 ibmw -16ml of water. The mixture was then diluted with ether, washed with water several time~s to remove dimethylfornamide, shaken Witt- brine, dried over Na SO 4 and stripped of solvent to yield 3.2g of dark brown oil. This crud~e product was chroaacographed on a silica gel flash column (CH 2 Cl 2 /Et 2 O0, by volume 95/5) to yield 0. 95 g of the desired ether as a yellowish oil.

~1 Embodiment 4 H+ -2-exo-2-Chlorocyclopenten-1-ylhmthoxyT-lmethyl-4- (1-methylethyl) -7-oxabicyclo 1 2.2. 1] heptane Following procedures similar to those described in Embodime~nt 3 above, the desired product was prepared by tcreating the alcohol of Emibodiment 2 with 1- (bronunethyl) -2--chlorocyclopentene to yield the desired ether as a yellow liquid.

Embodiments 5-8 Following procedures similar to those described in Embodiment, 3 above, the desired product was prepared by treating the alcohols, R 1 OH, of Embodiments 5-8 with the desired halide, HaICH 2 R, to yield the ethers set out below: R 1 OH HalCH R R 1QCH R a, nbodiment R OH R R OCH R 2- 2-ethyl-2- (hydroxy- 2-chiorocyclo- light amrber 04 methy,) -1-oxaspiro- hexenyl syrup 1[4.5] decane 6 2-ethyl-2- (hydroxy- 2-chlorocyclo- light amber metyl oxaspiro- pentenyl oi 14. 7 2-ethyl-2- (hydroxy- 2-rhlorocyclo- light amber methyl) 7-dioxasp- hexenyl syrup iro 308 2-ethyl-2- (hydroxy- 2-chlorocyclo- light amber methyl) -l,7-dioxasp- pentenyl syrup iro 14.5] decane BK53.005 7 1- 1;- I: S t I I 4i 41 *44' 17 Embodiment 9 (+)-2-exo-(3-Chloro-2-thienyl)methoxy-l-methyl- 4-(1-methylethyl)-7-oxabicyclo[2.2.1]heptane To a stirred suspension of 1.2 equivalents of sodium hydride (from hexane-washed 50% oil-dispersion) in dry dimethylformamide under nitrogen was added 1 equivalent of the alcohol of Embodiment 2. The mixture was gradually heated to about 70-80°C. When hydrogen no longer evolved after about 1 hour at elevated temperature, the mixture was cooled in an ice bath to 5-10 0 C for the dropwise addition of 1 equivalent of c 2-(bromomethyl)-3-chlorothiophene. Stirring was continued at room temperature. The reaction mixture was recovered as described in Embodiment 3 above, and the desired product was purified by flash chromatography on silica gel to give the desired ether as an amber oil.

Embodiment 10 -2-exo- (3-Chloro-2-thienyl)methoxy-1, 4-diethyl-7-oxabicyclo[2.2.1)heptane A 100 ml round bottom, 3-neck reaction flask equipped with a stirrer, an internal thermnmeter, a reflux condenser and a dropping funnel was charged with 0.96 g of 50% sodium hydride in "2 cl mineral oil followed by 40 ml of dimethyl sulfoxide. The mixture was stirred while 3.4 g of 2-exo-hydroxy-1,4 -diethyl-7oxabicyclo[2.2.1]heptane was added dropwise and stirring was continued with heating to 80°C for 1 hour. The resulting dark mixture was stirred at room teiperature while 3.3 g of 2- (-chloromthyl)-3-chlorothiophene was added dropwise accompanied by an exotherm to 450C. The stirred reaction mixture was heated to 80°C for 1 hour, poured over ice water, acidified (HC1) and extracted thrice with methylene chloride.

The combined extracts were washed twice with water, dried (MgSO 4 filtered, concentrated, and flash column chromatographed using silica gel and mthylene chloride eluent to give two separate 1.0 g amounts of the desired product as a dark syrup.

Embodiment 11 (3-Chloro-2-thienyl)methyl ether of 2-ethyl-2- (hydroxymethyl) 7-dioxaspiro decane BK53.005 j v-- 1 \o 4 4 Ia t 4 4 4 a 4 4a4 44 4 18 Following procedures similar to those descriled in Embodiment 9 above, the desired product was prepared by treating 2-ethyl-2- (hydroxymethyl) -1,7-dioxaspiro[4.5]decane with 2-(l-bromanethyl)-3-chlorothiophene to obtain the ether as an amber syrup.

Embodiment 12 3-Chloro-2-thienylmethyl ether of 2-ethyl-2- (hydroxymethyl) -1-oxaspiro decane Following procedures similar to those described in Embodiment 9 above, the desired product was prepared by treating 2-ethyl-2- (hydroxymethyl) -1-oxaspiro decane with 2-(1-bromomethyl)-3-chlorothiophene to obtain the ether as a light amber oil.

For application, a compound of Formula I ordinarily is applied most effectively by formulating it with a suitable inert carrier or surface-active agent, or both. The invention, therefore, also includes compositions suitable for combatting unwanted plants, such compositions comprising an inert carrier or surface-active agent, or both, and as active ingredient at least one compound of Formula I; and the preparation of such compositions. Some of the compounds of Formula I are useful as selective herbicides, e.g. in soybeans, cotton, sugar beets and the like.

The term "carrier" as used herein means an inert solid or liquid material, which may be inorganic or organic and of synthetic or natural origin, with which the active compound is mixed or fomiulated to facilitate its application to the plant, seed, soil or other object to be .reated, or its storage, transport and/or handling. Any of the materials customarily employed in formulating pesticides, herbicides, or fungicides horticulturally acceptable carriers are suitable.

Suitable solid carriers are natural and synthetic clays and silicates, for example, natural silicas such as diatomaceous earths; magnesium silicates, for example, talcs; magnesium aluminum silicates, for example, attapulgites and vermiculites; aluminum silicates, for example, kaolinites, montmorillonites BK53.005 1- 2 1~ 19 and micas; calcium carbonate; calcium sulfate; synthetic hydrated silicon oxides and synthetic calcium or aluminum silicates; elements such as, for example, carbon and sulfur; natural and synthetic resins such as, for example, coumarone resins, polyvinyl chloride and styrene polymers and copolymers; bitumen; waxes such as, for example, beeswax, paraffin wax, and chlorinated mineral waxes; solid fertilizers, for example, superphosphates; and ground, naturally-occurring, fibrous materials, such as ground corncobs.

Examples of suitable liquid carriers are water, alcohols such as isopropyl alcohol and glycols; ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone; ethers such as cellosolves; aromatic hydrocarbons such as benzene, toluena and xylene; petroleum fractions such as kerosene, light mineral oils; chlorinated hydrocarbons such as carbon tetrachloride, perchloroethylene and trichloromethane.

PTso suitable are liquefied, normally vaporous and gaseous compounds. Mixtures of different liquids are often suitable.

The surface-active agent may be an emulsifying agent or a 2- dispersing agent or a wetting agent/ it may be nonionic or ionic. Any of the surface-active agents usually applied in formulating herbicides or insecticides may be used. Examples of suitable surface-active agents are the sodium and calcium salts of polyacrylic acids and lignin sulfonic acids; the condensation products of fatty acids or aliphatic amines or amides containing at least 12 carbo atoms in the molecule with ethylene oxide and/or propylene oxide; fatty acid esters of glycerol, sorbitan, sucrose or pentaerythritol; condensates of these with ethylene oxide and/or propylene oxide; condensation products of fatty alcohols alkyl phenols, for example, p-octylphenol or p-octylcresol, with ethylene oxide and/or propylene oxide; sulfates or sulfonats of these condensation procucts, alkali or ilkaline earth metal salts, preferably sodium salts, of sulfuric or sulfonic acid esters containing at least 10 carbcn atoms in the molecule, for example, sAlum lauryl sulfate, sodium B" -r' BK53.005 20 secondary alkyl sulfates, sodium salts of the sulfonated castor oil, and sodium alkylaryl sulfonates such as sodium dodecylbenzene sulfonate; and polymers of ethylene oxide and copolymers of ethylene oxide and propylene oxides.

The compositions of the invention may be prepared as wettable powders, dusts, gramiI.es, solutions, emulsifiable concentrates, emulsions suspension concentrates and aerosols.

Wettable powders are usuallyj eapea to contain 25 to 75% by weight of active compound and usually contain, in addition to \o the solid carrier, 3-10% by weight of a dispersing agent, 2-15% of a surface-active agent and, where necessary, 0-10% by weight of stabilizer(s) and/or other additives such as penetrants or stickers. Dusts are usually formulated as a dust concentrate having a similar composition to that of a wettable powder but without a dispefrsnt or surface-active agent, and are diluted in the field with further solid carrier to give a composition usually containig 0.5-10% by weight of the active compound.

Granules are usually prepared to have a size between 10 and 100 BS mesh (1.676-0.152 urm), and may be manufactured by 2 c agglomeration or impregnation techniques. Generally, granules will contain 0.5-25% by weight of the active compound, 0-1% by weight of additives such as stabilizers, slew release modifiers and binding agents. Emulsifiable concentrates usually contain, in addition to the solvent and, when necessary, cosolvent, 10-50% weight per volume of the active compound, 2-20% weight per volume emulsifiers and 0-20% weight per volume of appropriate additives such as stabilizers, penetrants and corrosion inhibitors, Suspension concentrates are compounded so as to obtain a stable, non-sedimenting, flowable product and usually contain 10-75% weight of the active compound, 0.5-5% weight of dispersing agents, 1-5% of surface-active agent, 0.1-10% weight of suspending agents, such as defoamers, corrosion inhibitors, stabilizers, penetrants and stickers, and as carrier, wartr or an organic liquid in which the active compound is substantially insoluble; certain organic solids or N BK53.005 la 7--CC

C-CIY

I

o 4 S 044 I0 S 4as '4,4 4,, 0404 440404 0 2c, 0#o 40 21 inorganic salts may be dissolved in the car-:ier to assist in preventing sedimentation or as antifreeze agents for water.

Of particular interest in current practice are waterdispersible granular formulations. These are in the form of dry, hard granules that are essentially dust-free, and are resistant to attrition on handling, thus minimizing the formation of dust. On contact with water, the granules readily disintegrate to form stable suspensions of the particles of active material. Such formulations contain 90% or (up to more by weight of finely divided active material, 3-7% by weight of a blent of surfactants, which act as wetting, dispersing, suspending and binding agents, and may contain up to 3% by weight of a finely divided carrier, which acts as a resuspending agent.

Aqueous dispersions and emulsions, for example, compositions obtained by diluting a wettable powder or a concentrate according to the invention with water, also lie within the scope of the present invention. The said emulsions may be of the water-in-oil or of the oil-in-water type, and may have thick, mayonnaise-like consistency.

It is evident from the foregoing that this invention contemplates compositions containing as little as about 0.5% by weight to as much as about 95% by weight of a compound of Formula I as the active ingredient.

The compositions of the invention may also contain other ingredients, for example, other compounds possessing pesticidal, especially insecticidal, acaricidal, herbicidal or fungicidal properties, as are appropriate to the intended purpose.

The invention also resides in the protection of a locus or area from undesirable plants, by applying a ccmpound of Formula I, ordinarily in a ccmposiition of one of the aforementioned types, to soil in which the seeds of the unwanted plants are present, or to the foliage of the unwanted plants. The active compound, of course, is applied in an amount sufficient to exert the desired action, BK53,005 44 054 0e 0 yl r 9

U

-22 The amount of the compound of the invention to be used in combatting undesired plants will naturally depend on the condition of the plants, the degree of activity desired, the formulation used, the mode of application, the climate, the season of the year, and other variables. Reccamendations as to precise amounts are, therefore, not possible. In general, however, application to the locus to be protected of from 0.1 to 10.0 kg per hectare of the compound of Formula I will be satisfactory.

C Examples of Activity with Respect to Plants In the following examples, the species of plants that were tested were: Barnyardgrass (watergrass) Echinochloa crus-galli Large crabgrass Digitaria sanguinalis Downy broe Bracus tectorm Yellow foxtail Setaria lutescens Redroot pigweed Amaranthus retroflexus Sicklepod Cassia obtusifolia Velvetleaf Abutilon theoplrasti 2 Garden cress Lepidium sativun Johnson grass Sorg halpense Morningglory -Ipooea sp.

Test Procedures The preememgence (soil) herbicidal activity of compounds of Formula I was evaluated by planting seeds of banyardgrass, garden cress, iy barom, velvetleaf, yellow foxtail, and sicklepod o morningglory in test tubes, nominally measuring x 200 millimeters, filled about three-quarters full of untreated soil, in each case covered on top with about 2.5 cubic centimeters of soil treated with a certain amount of ts compound. The treated soil applied to the tubes containing the barnyardgrass and cres seeds contained one milligram of the test compound per tube, and containe 0.1 milligram of the test compound per each tube containing the seeds of the other plants.

BR53.Q05 -I 7 o, 23 The dosages were approximately 20 and 2.0 pounds of test compound per acre, respectively (that is, approximately 22 and 2.2 kg per hect re respectively). The seeds were planted on top of the treated al and covered with about 1.5 cubic centimeters of untreated soil. The planted soil was held under controlled conditions of temperature, moisture, and light for 9 to 10 days.

The nmounts of germination and growth in each tube were evaluated on a 0 to 9 scale, the numeric ratings having the following meanings: Rating Meaning 9 No living tissue 8 Plant severely damaged and expected to die 7 Plant badly damaged, but expected to live 6 Moderate damage, but complete recovery expected Intermediate damage (probably unacceptable for crop plants) 3-4 Observable damage 1-2 Plant slightly affected, possibly by the chemical, possibly due to biological variability 0 No visible effect The postemergence (foliar) herbicidal activity of compounds of Formula I was evaluated by spraying 10-day-old large crabgrass plants, 13-day-old pigweed plants, 6-day-old johnsongrass plants, 9-day-velvetleaf plants, 9-day-old yellow foxtail plants and either 9-day-old sicklepod plants or morningglory plants to runoff with a liquid formulation of the test compound. The crabgrass and pigweed plants were sprayed with 2.4 ndllilit.s of a 0.25% solution (about ten pounds of the test compound per acre, that is, about 11 kg/ha), and other plants were sprayed with 2.4 milliliters of a 0.025% solution (about one pound of the test compound per acre, that is, about 1.1 kg/ha). The sprayed plants were held under controlled conditions of temperature, moisture and light for 7 to 8 days, when the effect of the test compound was evaluated visually, the results being rated on the 0 to 9 scale described above.

BK53.005 -24- Results of the preemergence and postenergence herbicidal activity tests are set forth in Table I.

BK53.005 t#a 4** 4 25 TABLE I HEPBICITDPL ACTIVITY Preemergence Postemergence Banyard- Garden Downy Velvet- Yellow Sickle- Crab- Pig- Johnson- Velvet Yellow Sickle- Ccupound grass Cress Brane leaf Foxtail pod grass weed grass leaf Foxtail pod 12 9 4 6 0 7 0 7 6 2 4 4 2 11 9 6 6 4 5 4 7 4 3 5 5 2 9 9 6 9 4 9 0 9 5 5 4 7 2 9 7 9 5 8 0 7 3 7 6 7 2 3 9 7 9 5 8 2 5 3 0 0 0 0 4 9 7 S 8 2 4 9 0 3 0 0 6 0 5 0 5 u 5 6 3 4 2 3 6 9 5 9 0 6 0 4 4 2 2 2 2 7 9 7 9 0 5 0 6 5 2 4 2 2 !39 4 7 5 8 0 4 2 0 4 5 2 BK53.005 _j 1 26 Selectivity Test Procedures The preemergence activity of the compounds of Embodiments 9 and 10 was further determined with rjspect to certain ccamon species of weeds, by spraying a formulation of the test compound on soil in small pots in which seeds of the plants had been sown. The postemergence herbicidal activity of compounds of Embodiments 9 and 10 was evaluated with respect to the weeds, by spraying a formulation of the test compound on the foliage of the young growing plants. In each series of tests, the plants \o were grown in pots placed in narrow trays and sprayed with the formulation. The results of the tests at 1.0 and 0.25 lb/acre, that is, about 1.1 and 0.28 kg/ha, were evaluated on the basis of the 0-9 scale described with respect to the earlier tests.

The results of the tests showed observable damage by both materials against grass weeds such as Barnyard Grass, Downy Brale, Johnson-grass, Wild Oats, and Yellow Foxtail in pre-emergence tests. The material of Embodiment 10 also showed observable damage to broadleaf weeds, such as Morning Glory, Mustard, Pigweed, Sicklepod, and Velvetleaf in pre-emergence S' tests. The compounds of Embodiment 9 and 10 also showed *post-emergence tests. The compounds of Embodiment 9 and 10 also showed post-emergence activity against one or more of the above grass and broadleaf weeds.

i BK53.005

Claims

1. A compound of the formula I R 1 0 CH 2 R wherein R is 3-halo-2-thienyl, 5-halo-3,4-dihydro-2H-pyran-6-yl, 2- halo-l-cyclo-l-penten-l-yl or 2-halo-l-cyclohexen-l-yl in which halo is chloro or fluoro and R 1 is the residue of a non-aromatic oxygen- heterocyclic alcohol (R 1 OH), R 1 containing up to 16 carbon atoms and being a group selected from: ao 4 4 .444c 9~r 4444 44*4r 4 4I wherein W is a methyl or ethyl group; X is a single bond or -C(CH 3 2 Y is a single bond or -CH 2 with the proviso that both X and Y are not a single bond; Z is H, or an optionally substituted alkyl group containing 1 to 4 carbon atoms; b) I. 4 44 S4L 0 4) 4 4 4, 4 t 7 wherein each R 2 individually represents a hydrogen atom, a halogen atom, an optionally substituted alkyl, cycloalkyl or aryl group, each containing up to 6 carbon atoms, or two R 2 together represent an alkylene of up to 6 carbon atoms, R 3 R 4 R 5 and R each individually represents a hydrogen atom, a halogen atom having an atomic number of from 9 to inclusive, an optionally substituted alkyl, alkoxy, alkylthio or aryl group each containing up to 6 carbon atoms or one of R 3 and R 4 and one of l1F -r 28 R 5 and R 6 together represent a carbon-carbon bond or an epoxide moiety; R 7 and R 8 each represents a hydrogen atom or an optionally substituted alkyl group containing up to 6 carbon atoms; or c) 4 R 1 7 Z CH2 R S-WX 1 CH2- \0 wherein R 3 R R 5 R 6 and R 7 each individually is a hydrogen S atom or an alkyl group containing from 1 to 4 carbon atoms, WN is an oxygen atom or -CH 2 X 1 is an oxygen atom or -CH 2 yl is a carbon-carbon bond, or an oxygen atom, -CH 2 -C 2 H 4 or -CHR in S which R 9 is an alkoxymethyl group containing from 1 to 4 carbon atoms in 1 the alkoxy portion thereof; Z is a carbon-carbon bond, an oxygen atom, '1 1 -CH 2 or -C2 H 4 with the proviso that no two adjacent of W X 1 1 Y and Z are simultaneously either oxygen atoms or -C 2 H 4 and the 1 1 1 1 sum of the ring atoms in W X Y and Z is an integer of from 3 to wherein said optional substituents in formulae and are S selected from one or more atoms of chlorine, fluorine and bromine.

2. A compound according to claim 1 wherein R 1 is a group of formula in which X is a single bond, Y is -CH 2 W is methyl and Z is a hydrogen atom or a 1-methylethyl group or W and Z each is an ethyl or methyl group X is -C(CH 3 2 Y is -CH 2 and Z is a hydrogen atom; formula in which each R 2 independently is a hydrogen atom or a 2 methyl group or the two R 's taken together form a pentamethylene group, R 3 R 4 R 5 R and R are hydrogen atoms and R is a hydrogen atom, a methyl or ethyl group; or formula in which WN is an o;.;gen atom or -CH 2 X is an oxygen atom or -CH 2 Y is an oxygen atom, -CH 2 -C 2 H 4 or CHR 9 in which R 9 is methoxymethyl, Z 1 is an /k"j xygen atom or -CH 2 and the sum of the ring atoms in W 1 X Y 1 S22 )l 521 F i- M««8a' 29 and is an integer of from 3 to

3. A compound according to claim 2 wherein R is a group of formula wherein X is a single bond; W is methyl and Z is 1-methylethyl or W and Z each is ethyl; formula wherein each R 2 is a methyl group or taken together form a pentamethylene group; or formula wherein (1) W and Z are each -CH 2 X 1 and Z each is an oxygen atom and 1 is -C 2 H 4

4. A compound according to claim 3 wherein R is a group of formula wherein X is a single bond W is methyl and Z is 1-methylethyl.

A compound according to claim 3 wherein R is a group of formula wherein X is a single bond and W and Z each is ethyl.

6. A compound according to claim 3 wherein R 1 s a group of formula wherein the R s taken together form a pentamethylene group and R is an ethyl group.

7. A compound according to claim 3 wherein R 1 is a group of formula wherein W Y and Z 1 are -CH 2 and X 1 is oxygen atom.

8. A compound according to any one of the preceding claims, wherein R is 3-chlorothien-2-yl,

9. A process for the preparation of a compound of formula I, as claimed in any of claims 1 to 8, wherein a compound of the formula R -OH Is reacted with a compound of the formula X-CH 2 R where R and R are as defined in any preceding claim and X represents a leaving moiety.

A compound of the general formula I, whenever prepared by a process according to claim 9.

11, A berbicidal composition comprising as active ingredient a herbicidally effective amount of a compound according to any of claims 1 to S 8 or 10, and at least one inert carrier and/or surface-active ingredient.

12, A method of controlling undesirable plant growth in a plant, comprising contacting the plant or the locus of the plant with a herbicidally effective amount of a compound according to any one of claims I to 8 or 10 or a composition as defined in claim 11.

13. A compound of the general formula I as defined in claim 1 and substantially as hereinbefore described with reference to any one of Embodiments 3 to 12.

14. A process for the preparation of a compound of formula I as defined in claim 1 and substantially as hereinbefore described with reference to any one of Embodiments 3 to 12, 30 DATED this SIXTEENTH day of JANUARY 1990 Shell Internationale Research Maatschappij B.V. PdtLent Attorneys for the Applicant SPRUSON FERGUSON I, I. I *4 I ~*q 4*0k I 4 I I I 4* 1*1* I JLH/4768W