Ethyl 2[4-(7-chloroquinolin-3-yloxy)phenoxy]propionate, the N-oxide, and herbicidal compositions and methods employing them

Abstract

The invention concerns novel compounds of the formula I ##STR1## The compounds are herbicides and in further embodiments the invention provides herbicidal compositions containing as active ingredient a compound of formula I and a process for severely damaging or killing unwanted plants by applying to the plants or to the growth medium of the plants an effective amount of a compound of formula I.

Description

This invention relates to organic compounds having biological activity and in particular to organic compounds having herbicidal properties, to processes for the preparation of such compounds, to intermediates useful in the preparation of such compounds and to herbicidal compositions and processes utilizing such compounds.

We have now found a new class of quinolines which exhibit biological activity, and in particular herbicidal activity.

Accordingly the invention provides a compound of formula I: ##STR2## or a salt thereof wherein:

A, B, D, E, J, U and V are independently chosen from the group consisting of hydrogen, halogen, nitro, cyano, thiocyano, amino, C.sub.1 to C.sub.6 alkylamino, di(C.sub.1 to C.sub.6 alkyl)amino, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 haloalkyl, C.sub.2 to C.sub.6 alkenyl, C.sub.3 to C.sub.7 cycloalkyl, C.sub.1 to C.sub.6 alkoxy, C.sub.1 to C.sub.6 haloalkoxy, C.sub.1 to C.sub.6 alkylthio, C.sub.1 to C.sub.6 alkylsulfinyl, C.sub.1 to C.sub.6 alkylsulfonyl, C.sub.1 to C.sub.6 haloalkylsulfinyl, C.sub.1 to C.sub.6 haloalkylsulfonyl, sulfo, C.sub.1 to C.sub.6 alkoxysulfonyl, sulfamoyl, N-(C.sub.1 to C.sub.6 alkyl)-sulfamoyl, N,N-di(C.sub.1 to C.sub.6 alkyl)sulfamoyl, carboxy, (C.sub.1 to C.sub.6 alkoxy)carbonyl, carbamoyl, N-(C.sub.1 to C.sub.6 alkyl)carbamoyl, N,N-di(C.sub.1 to C.sub.6 alkyl)carbamoyl, phenyl, phenoxy, phenylthio, and the groups substituted phenyl, substituted phenoxy and substituted phenylthio wherein in each group the phenyl ring is substituted with from 1 to 3 substituents chosen from the group consisting of halogen, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 haloalkyl, C.sub.1 to C.sub.6 alkoxy, nitro and cyano;

R.sup.1 is chosen from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.2 to C.sub.6 alkenyl, C.sub.2 to C.sub.6 alkoxyalkyl, C.sub.1 to C.sub.6 haloalkyl, acetyl, propionyl and C.sub.2 to C.sub.6 alkoxycarbonyl, R.sup.2 is chosen from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.2 to C.sub.6 alkenyl, C.sub.2 to C.sub.6 alkoxyalkyl and C.sub.1 to C.sub.6 haloalkyl, or R.sup.1 and R.sup.2 together may form a methylene, ethylidene, propylidene or isopropylidene group;

W is chosen from the group consisting of cyano, thiocarbamoyl, ##STR3## and CH.sub.2 Z wherein: G is chosen from the group consisting of hydroxy, mercapto, C.sub.1 to C.sub.10 alkoxy, C.sub.1 to C.sub.10 haloalkoxy, C.sub.2 to C.sub.10 alkenyloxy, C.sub.2 to C.sub.10 alkynyloxy, C.sub.1 to C.sub.10 alkylthio, C.sub.2 to C.sub.10 alkenylthio, C.sub.2 to C.sub.10 alkynylthio, C.sub.3 to C.sub.7 cyclo-alkoxy, C.sub.3 to C.sub.7 cycloalkoxy substituted with 1 or 2 C.sub.1 to C.sub.4 alkyl groups, phenoxy, phenylthio, benzyloxy, benzylthio, the group C.sub.1 to C.sub.10 alkoxy substituted with a substituent chosen from the group consisting of C.sub.1 to C.sub.6 alkoxy, amino, ammonio, cyano, N-(C.sub.1 to C.sub.6 alkyl)-amino, N,N-di(C.sub.1 to C.sub.6 alkyl)amino and N,N,N-tri(C.sub.1 to C.sub.6 alkyl)ammonio, the groups phenoxy, phenylthio, benzyloxy and benzylthio wherein in each group the phenyl ring is substituted with from 1 to 3 substituents chosen from the group consisting of halogen, nitro, cyano, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 haloalkyl and C.sub.1 to C.sub.6 alkoxy, the group OM wherein M is the cation of an inorganic or organic base, the group --NHSO.sub.2 R.sup.3 wherein R.sup.3 is chosen from C.sub.1 to C.sub.10 alkyl and C.sub.1 to C.sub.6 halo alkyl, and the group --NR.sup.4 R.sup.5 wherein R.sup.4 and R.sup.5 are independently chosen from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, phenyl and benzyl or R.sup.4 and R.sup.5 together form a heterocyclic ring, and the group --O--N.dbd.R.sup.10 wherein R.sup.10 is a C.sub.1 to C.sub.10 alkylidene group; Z is chosen from the group consisting of halogen, hydroxy, mercapto, C.sub.1 to C.sub.10 alkoxy, C.sub.1 to C.sub.10 haloalkoxy, C.sub.1 to C.sub.10 alkylthio and the group --NR.sup.4 R.sup.5 wherein R.sup.4 and R.sup.5 are as hereinbefore defined;

X is chosen from oxygen and sulfur;

Y is chosen from oxygen, sulfur and the group NR.sup.6 wherein R.sup.6 is chosen from hydrogen, C.sub.1 to C.sub.10 alkyl, C.sub.2 to C.sub.10 alkenyl, C.sub.2 to C.sub.10 alkynyl, C.sub.2 to C.sub.10 alkoxyalkyl, cyanomethylene, C.sub.1 to C.sub.6 -(alkoxy)carbonylmethylene, C.sub.1 to C.sub.10 haloalkyl, formyl, C.sub.2 to C.sub.10 alkanoyl, phenyl, benzyl, benzoyl, and the groups phenyl, benzyl and benzoyl wherein in each group the phenyl ring is substituted with from 1 to 3 substituents chosen from the group consisting of halogen, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 halo-alkyl, C.sub.1 to C.sub.6 alkoxy, nitro and cyano;

k is chosen from 0 and 1; and

n is 0, 1 or 2.

The compounds of formula I wherein R.sup.1 and R.sup.2 are not the same, are optionally active and the present invention also includes the individual stereo isomers of such compounds, and mixtures of those stereo isomers in addition to the racemic mixture of stereo isomers.

Preferred A, B, D and E include hydrogen, halogen, nitro, cyano, amino, C.sub.1 to C.sub.6 alkylamino, di(C.sub.1 to C.sub.6 alkyl)amino, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 haloalkyl, C.sub.2 to C.sub.6 alkenyl, C.sub.1 to C.sub.6 alkoxy, C.sub.1 to C.sub.6 haloalkoxy, C.sub.1 to C.sub.6 alkylthio, carboxy and (C.sub.1 to C.sub.6 alkoxy)carbonyl.

Preferred J, U and V include hydrogen, halogen, nitro, cyano, C.sub.1 to C.sub.6 alkyl and C.sub.1 to C.sub.6 haloalkyl.

Preferred R.sup.1 include hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.2 to C.sub.6 alkoxyalkyl and (C.sub.1 to C.sub.6 alkoxy)carbonyl.

Preferred R.sup.2 include hydrogen and C.sub.1 to C.sub.6 alkyl.

Preferred W include the groups: (a) ##STR4## wherein G is chosen from the group consisting of hydroxy, C.sub.1 to C.sub.10 alkoxy, C.sub.1 to C.sub.10 haloalkoxy, C.sub.2 to C.sub.10 alkenyloxy, C.sub.2 to C.sub.10 alkynyloxy, C.sub.10 to C.sub.10 alkylthio, C.sub.2 to C.sub.10 alkenylthio, C.sub.2 to C.sub.10 alkynylthio, phenoxy, benzyloxy, cyclohexyloxy, the group C.sub.1 to C.sub.10 alkoxy substituted with a substituent chosen from the group consisting of C.sub.1 to C.sub.6 alkoxy, amino, N-(C.sub.1 to C.sub.6 alkyl)amino, N,N-di(C.sub.1 to C.sub.6 alkyl)amino and N,N,N-tri(C.sub.1 to C.sub.6 alkyl)ammonio, the group NR.sup.4 R.sup.5 wherein R.sup.4 and R.sup.5 are independently chosen from hydrogen, C.sub.1 to C.sub.6 alkyl, benzyl and phenyl, the group OM wherein M is an alkali metal ion, alkaline earth metal ion or an ammonium ion HN.sup..sym. R.sup.7 R.sup.8 R.sup.9 wherein R.sup.7, R.sup.8 and R.sup.9 are independently chosen from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.1 to C.sub.6 hydroxyalkyl, phenyl and benzyl, the group --NHSO.sub.2 R.sup.3 wherein R.sup.3 is C.sub.1 to C.sub.6 alkyl, and the group --O--N.dbd.R.sup.10 wherein R.sup.10 is a C.sub.1 to C.sub.10 alkylidene group; and (b) the group --CH.sub.2 Z wherein Z is chosen from the group consisting of halogen, hydroxy, mercapto, C.sub.1 to C.sub.10 alkoxy, and the group --NR.sup.4 R.sup.5 wherein R.sup.4 and R.sup.5 are independently chosen from the group consisting of hydrogen, C.sub.1 to C.sub.6 alkyl, benzyl and phenyl.

Preferred X is oxygen.

Preferred Y include oxygen and the group NR.sup.6 wherein R.sup.6 is chosen from hydrogen, C.sub.1 to C.sub.6 alkyl, C.sub.2 to C.sub.10 alkenyl and C.sub.2 to C.sub.10 alkynyl.

Preferred n is 0 or 2.

More preferably:

A, B, D, E and J are independently chosen from hydrogen, halogen, nitro, cyano, C.sub.1 to C.sub.6 alkyl and C.sub.1 to C.sub.6 haloalkyl;

U and V are hydrogen;

R.sup.1 and R.sup.2 are independently chosen from hydrogen and C.sub.1 to C.sub.6 alkyl;

W is the group ##STR5## wherein G is chosen from hydroxy, C.sub.1 to C.sub.10 alkoxy, C.sub.2 to C.sub.10 alkenyloxy, C.sub.2 to C.sub.10 alkynyloxy, C.sub.1 to C.sub.10 alkylthio and the group OM wherein M is an alkali metal ion or an alkaline earth metal ion;

X is oxygen;

Y is chosen from oxygen and the group NR.sup.6 wherein R.sup.6 is chosen from hydrogen and C.sub.1 to C.sub.6 alkyl;

k is chosen from 0 and 1; and

n is 0.

Examples of the compounds embraced by the invention include:

methyl 2-[4-(6-chloroquinolin-2-yloxy)phenoxy]propionate (1); methyl 2-[4-(6-trifluoromethyl-1-oxide-quinolin-2-yloxy)phenoxy]propionate (2); ethyl 2-[4-(7-chloroquinolin-3-yloxy)phenoxy]-propionate (3); methyl 2-[5-(6-bromoquinolin-4-yloxy)-2-nitrophenoxy]-propionate (4); methyl 2-[2-(6-chloroquinolin-2-yloxy)-5-chlorophenoxy]-propionate (5); ethyl 2-[4-(6,7-dichloroquinolin-2-yloxy)phenoxy]-propionate (6); ethyl 2-[4-(6,8-dichloroquinolin-2-ylthio)phenoxy]-propionate (7) 2-[4-(6-bromoquinolin-2-yloxy)phenoxy]propiononitrile (8); methyl 4-[4-(6-bromoquinolin-2-yloxy)phenoxy]valerate (9); N-methanesulfonyl 2-[4-(6-chloroquinolin-2-yloxy)-phenoxy]propionamide (10); 2-[4-(6-chloroquinolin-2-yloxy)phenoxy]propyl chloride (11); methyl 2-{4-[N-(6-chloroquinolin-2-yl)-N-methylamino]-phenoxy}propionate (12); methyl 2-{4-[N-(3-chloroquinolin-2-yl)-N-methylamino]-phenoxy}propionate (13); ethyl 2-{4-[N-(7-chloroquinolin-3-yl)-N-methylamino]-phenoxy}propionate (14); methyl 2-{5-[N-(6-bromoquinolin-2-yl)-N-methylamino]-2-nitrophenoxy}propionate (15); methyl 2-{2-[N-(6-trifluoromethylquinolin-2-yl)amino]-5-chlorophenoxy}propionate (16); methyl 2-{4-[N-(6,7-dichloro-1-oxide-quinolin-2-yl)-N-methylamino]phenoxy}propionate (17); ethyl 2-{4-[N-(6,8-dichloroquinolin-4-yl)-N-ethylamino]-phenoxy}propionate (18); 2-{4-[N-(6-bromoquinolin-2-yl)-N-methylamino]phenoxy}-propiononitrile (19); methyl 4-{4-[N-(6-bromoquinolin-2-yl)amino]phenoxy}-valerate (20); N-methanesulfonyl 2-{4-[4-(6-chloroquinolin-2-yl)-N-methylamino]phenoxy}propionamide (21); and 2-{4-[N-(6-chloroquinolin-2-yl)amino]phenoxy}propyl chloride (22).

Preferred compounds of the invention are those 2-quinolinyl compounds in which the phenyl ring is 1,4-substituted, that is, compounds of formula II: ##STR6##

Particular examples of the compounds of the invention are detailed in Tables 1, 2 and 3 below.

TABLE 1______________________________________ ##STR7## IIIa Com-pound SubstituentsNo A, B, D, E, J k Y R.sup.1 R.sup.2 G______________________________________ 1 6-Cl 0 O CH.sub.3 H CH.sub.3 O12 6-Cl 0 NCH.sub.3 CH.sub.3 H CH.sub.3 O23 all H 0 NCH.sub.3 CH.sub.3 H CH.sub.3 O24 all H 0 O CH.sub.3 H CH.sub.3 O25 6,8-Cl.sub.2 0 O CH.sub.3 H CH.sub.3 O26 6,8-Cl.sub.2 0 NCH.sub.3 CH.sub.3 H CH.sub.3 O27 3-Cl 0 O CH.sub.3 H C.sub.2 H.sub.5 O28 3-Cl 0 NCH.sub.3 CH.sub.3 H C.sub.2 H.sub.5 O29 6-Cl 0 NH CH.sub.3 H CH.sub.3 O30 3,6-Cl.sub.2 0 O CH.sub.3 H C.sub.2 H.sub.5 O31 6-Br 0 O CH.sub.3 H C.sub.2 H.sub.5 O32 4-CF.sub.3, 6-Cl 0 O CH.sub.3 H C.sub.2 H.sub.5 O33 all H 1 O CH.sub.3 H C.sub.2 H.sub.5 O34 6-F 0 O CH.sub.3 H C.sub.2 H.sub.5 O35 6-Cl 0 O H H C.sub.2 H.sub.5 O36 6-Cl 0 O CH.sub.3 CH.sub.3 C.sub.2 H.sub.5 O42 6-Cl 0 O CH.sub.3 H HO43 6-Cl 0 O CH.sub.3 H KO44 3-NO.sub.2 0 NH CH.sub.3 H C.sub.2 H.sub.5 O45 3-NO.sub.2, 6-Cl 0 O CH.sub.3 H C.sub.2 H.sub.5 O______________________________________ TABLE 2______________________________________ ##STR8## IIIb Com-pound SubstituentsNo A, B, D, E, J k Y R.sup.1 R.sup.2 G______________________________________37 all H 0 O CH.sub.3 H C.sub.2 H.sub.5 O38 all H 1 O CH.sub.3 H C.sub.2 H.sub.5 O______________________________________ TABLE 3______________________________________ ##STR9## IIIcCom-pound SubstituentsNo A, B, D, E, J k Y R.sup.1 R.sup.2 G______________________________________39 2-CF.sub.3, 6-Cl 0 O CH.sub.3 H C.sub.2 H.sub.5 O40 2-Br 0 O CH.sub.3 H C.sub.2 H.sub.5 O41 3-NO.sub.2 0 O CH.sub.3 H C.sub.2 H.sub.5 O______________________________________

The compounds of the invention may be prepared by a variety of methods and in a further aspect the invention provides methods for the preparation of the compounds of formula I.

Compounds of formula Ia ##STR10## wherein G is not hydroxy may be prepared from the acid of formula Ib (I; W.dbd.--CO.sub.2 H) by, for example, neutralisation of the acid with a base to give an acid salt, esterification of the acid with an alcohol, thiol, phenol or thiophenol to give an acid ester, or reaction of the acid (or acid halide derivative thereof) with an amine to give an amide (SCHEME A). Processes known in the art for the preparation of acid salts, acid esters, acid halides and acid amines may be adapted, without undue experimentation, to prepare compounds of the invention of formula Ia from compounds of the invention of formula Ib. ##STR11##

Nitriles of the invention of formula Ic (I; W.dbd.--C.tbd.N) may be prepared, for example, from the acid amide of formula Id (I; W.dbd.--CONH.sub.2) (SCHEME B). ##STR12##

Alcohols of the invention of formula Ie (I; W.dbd.--CH.sub.2 OH) may be prepared from the acid or acid esters of formula If ##STR13## wherein G.dbd.OH or O-alkyl) by reduction (SCHEME C). Processes known in the art for the reduction of acids or acid esters to alcohols, for example lithium aluminium hydride reduction, may be adapted, without undue experimentation, to prepare alcohols of the invention of formula Ie from esters of the invention of formula If. ##STR14##

Alkyl halides of the invention of formula Ig (I; W.dbd.--CH.sub.2 -halogen) may be prepared from alcohols of formula Ie (I; W.dbd.--CH.sub.2 OH) by halogenation. Processes known in the art for the conversion of alcohols to alkyl halides, for example halogenation with reagents such as thionyl chloride, may be adapted, without undue experimentation, to prepare alkyl halides of the invention of formula Ig from alcohols of the invention of formula Ie.

Ethers of the invention of formula Ih (I; W.dbd.--CH.sub.2 OR) may be prepared from alcohols of formula Ie (I; W.dbd.--CH.sub.2 OH) by alkylation. Processes known in the art for the conversion of alcohols to ethers, for example by reaction with alkyl halides using the Williamson ether synthesis, may be adapted, without undue experimentation, to prepare ethers of the invention of formula Ih from alcohols of the invention of formula Ie.

Ethers (thioethers) of the invention of formula Ih (Ii) [I; W.dbd.--CH.sub.2 OR(--CH.sub.2 SR)] may be prepared from alkyl halides of formula Ig (I; W.dbd.CH.sub.2 -halogen) by alkoxylation (thioalkoxylation). Processes known in the art for the conversion of alkyl halides to ethers (thioethers), for example by reaction with alcohols (thiols) using the Williamson ether synthesis, may be adapted, without undue experimentation, to prepare ethers (thioethers) of the invention of formula Ih (Ii) from alkyl halides of the invention of formula Ig.

Amines of the invention of formula Ij (I; W.dbd.--CH.sub.2 NR.sup.4 R.sup.5) may be prepared from the alkyl halides of formula Ig (I; W.dbd.--CH.sub.2 -halogen) by amination or from the amides of formula Ik ##STR15## by reduction. Processes known in the art for the conversion of alkyl halides to amines, for example by reaction with amines, and for the conversion of amides to amines, for example by reduction with agents as lithium aluminium hydride, may be adapted without undue experimentation, to prepare amines of the invention of formula Ij from alkyl halides of the invention of formula Ig and from amides of the invention of formula Ik respectively.

N-oxides of the invention of formula I wherein k is 1 may be prepared from compounds of the invention of formula I wherein k is 0 by oxidation. Processes known in the art for the conversion of quinolines to quinoline N-oxides, for example oxidations using persulfates, peroxides, peracids or peresters, may be adapted, without undue experimentation, to prepare N-oxides of the invention.

Compounds of the invention of formula I in which Y is the group NR.sup.6 wherein R.sup.6 is not hydrogen may be prepared from compounds of the invention of formula I in which Y is the group NR.sup.6 wherein R.sup.6 is hydrogen by, for example, alkylation or acylation. Processes known in the art for the preparation of derivatives of secondary amines, for example alkylations with alkyl halides and acylations with acyl halides, may be adapted, without undue experimentation, to prepare the novel compounds of the invention wherein R.sup.1 is not hydrogen.

Compounds of formula I wherein A, B, D, E, U, V, Y, X, R.sup.1, R.sup.2, J, W, k and n are as hereinbefore defined may be prepared by the condensation of a phenol or thiophenol of formula IX with a compound of formula X wherein hal is chlorine, bromine or iodine, preferably in the presence of an alkaline material; according to SCHEME D. ##STR16##

Compounds of formula I may also be prepared by:

(a) the condensation the appropriate quinoline derivative of formula V, wherein L is a leaving group (for example, alkylsulfonyl, chlorine, bromine or iodine) with the appropriate compound of formula VI according to SCHEME E. ##STR17##

(b) the following steps in sequence:

(i) the condensation of the appropriate quinoline derivative of formula V, wherein L is a leaving group (for example, alkylsulfonyl, chlorine, bromine or iodine) with the appropriate compound of formula VII, wherein Q is hydroxy, mercapto, C.sub.1 to C.sub.6 alkoxy or C.sub.1 to C.sub.6 alkylthio to give a compound of formula VIII wherein Q is hydroxy, mercapto, C.sub.1 to C.sub.6 alkoxy or C.sub.1 to C.sub.6 alkylthio; (ii) the dealkylation of the compound of formula VIII prepared in step (i) above wherein Q is C.sub.1 to C.sub.6 alkoxy or C.sub.1 to C.sub.6 alkylthio to give a compound of formula IX; and (iii) the condensation of the product of formula IX obtained in step (i) or step (ii) above with a compound of formula X according to the process described for SCHEME D above (Steps (i) and (ii) are shown in SCHEME F); or ##STR18##

(c) the following steps in sequence:

(i) the condensation of the appropriate quinoline derivative of formula XI with the appropriate benzene derivative of formula XII wherein L is a leaving group (for example, alkylsulfonyl, chlorine, bromine or iodine) and Q is hydroxy, mercapto, C.sub.1 to C.sub.6 alkoxy or C.sub.1 to C.sub.6 alkylthio, to give a compound of formula VIII wherein Q is as hereinbefore defined; (ii) the dealkylation of the compound of formula VIII prepared in step (i) above wherein Q is C.sub.1 to C.sub.6 alkoxy or C.sub.1 to C.sub.6 alkylthio, to give a compound of formula IX according to the process described for SCHEME F step (ii) above; and (iii) the condensation of the product of formula IX obtained in step (i) or step (ii) above with a compound of formula X according to the process described for SCHEME D above (step (i) is shown in SCHEME G). ##STR19##

The condensation reaction illustrated in SCHEMES D, and E to G wherein Y is oxygen or sulfur, and outlined above are preferably carried out in the presence of an alkaline material. Suitable alkaline materials include alkali metal and alkaline earth metal hydroxides and carbonates such as, for example, sodium hydroxide, potassium hydroxide, sodium carbonate and potassium carbonate.

The condensation reactions illustrated in Schemes D to G and outlined above are also preferably carried out in the presence of a solvent. Suitable solvents include ketones such as, for example, acetone, methyl ethyl ketone and methyl isobutyl ketone, and dipolar aprotic solvents such as, for example, dimethylformamide, dimethylacetamide, dimethylsulfoxide, N-methylpyrrolidone, hexamethylphosphoramide and sulfolan.

The reaction conditions required to effect the condensation reactions illustrated in SCHEMES D, E, F, and G and outlined above vary according to the nature of the reactants and the solvent used. In general the reaction is facilitated by the application of heat and usually a reaction temperature in the range of 40.degree. to 150.degree. C. and reaction time of between 0.5 and 20 hours is satisfactory. However, higher or lower reaction temperatures and/or shorter or longer reaction times may be used if desired.

The dealkylation reactions illustrated in SCHEMES F and G and outlined in paragraphs (b) (ii) and (c) (ii) above may be effected using a variety of reagents known in the art. For example, aryl-alkyl ethers may be cleaved using reagents such as pyridine hydrochloride, hydriodic acid, hydrobromic acid, sodium thioethoxide in dimethylformamide, acetyl p-toluenesulphonate, sodium or potassium iodide in formic or acetic acid, lithium iodide in 2,4,6-collidine and boron tribromide. Reaction times and reaction conditions vary widely depending on the dealkylation agent used and the ether to be cleaved.

The reaction conditions generally employed when using the above "ether-cleavage" reagents are known to those skilled in the art and may be adapted without undue experimentation to effect the "ether-cleavage" reactions illustrated in SCHEMES F and G and outlined in paragraph (b) (ii) and (c) (ii) above.

The quinoline derivatives of formula V and XI which may be used to prepare the compounds of the invention of formula I may be prepared by the use of one or more of the processes known in the art for the synthesis of quinoline derivatives. For example, quinoline syntheses described by:

(i) Perkin and Robinson (Skraup Synthesis), J. Chem. Soc., 103, 1977, (1913); (ii) Johnston et al, J C S Perkin I, 1648, (1972); (iii) Meth-Cohn et al, Tetrahedron Letters, 4885, (1979); and (iv) Pettit and Kalnins, J. Org. Chem., 25, 1365, (1960).

The compounds of formula VIII ##STR20## which are useful intermediate in the preparation of compounds of formula I, are novel compounds. Therefore, in a further embodiment the invention provides compounds of formula VIII wherein A, B, D, E, J, k, Y, U, V and Q are as hereinbefore defined.

The compounds of formula I are active as herbicides and therefore, in a further aspect the invention provides a process for severely damaging or killing unwanted plants which process comprises applying to the plants, or to the growth medium of the plants, an effective amount of a compound of formula I as hereinbefore defined.

Generally speaking the compounds of formula I are herbicidially effective against a variety of plants. However, certain of the compounds of the invention are selectively active against monocotyledonous plants, dicotyledonous plants being relatively unaffected by rates of application to the compounds of the invention which are severely damaging or lethal to other plant species.

Moreover, certain of the compounds of formula I are selectively active within the group of monocotyledonous plants and may be used at a rate sufficient to kill or severly damage monocotyledonous weeds in a monocotyledonous cereal crop.

Therefore, in yet a further aspect the invention provides a process for selectively controlling the growth of weeds in crops which process comprises applying to the crop, or to the growth medium of the crop, a compound of formula I, as hereinbefore defined, in an amount sufficient to severely damage or kill the weeds but insufficient to damage the crop substantially.

The compounds of formula I may be applied directly to the plant (post-emergence application) or to the soil before the emergence of the plant (pre-emergence application). However, the compounds are, in general, more effective when applied to the plant post-emergence.

The compounds of formula I may be used on their own to inhibit the growth of, severely damage, or kill plants but are preferably used in the form of a composition comprising a compound of the invention in admixture with a carrier comprising a solid or liquid diluent. Therefore, in yet a further aspect the invention provides plant growth inhibiting, plant damaging, or plant killing compositions comprising a compound of formula I as hereinbefore defined and an inert carrier therefor.

Compositions according to the invention include both dilute compositions, which are ready for immediate use, and concentrated compositions, which require to be diluted before use, usually with water. Preferably the compositions contain from 0.01% to 90% by weight of the active ingredient. Dilute compositions ready for use preferably contain from 0.01 to 2% of active ingredient, while concentrated compositions may contain from 20 to 90% of active ingredient, although from 20 to 70% is usually preferred.

The solid compositions may be in the form of granules, or dusting powders wherein the active ingredient is mixed with a finely divided solid diluent, eg kaolin, bentonite, kieselguhr, dolomite, calcium carbonate, talc, powdered magnesia, Fuller's earth and gypsum. They may also be in the form of dispersible powders or grains, comprising a wetting agent to facilitate the dispersion of the powder or grains in liquid. Solid compositions in the form of a powder may be applied as foliar dusts.

Liquid compositions may comprise a solution or dispersion of an active ingredient in water optionally containing a surface-active agent, or may comprise a solution or dispersion of an active ingredient in a water-immiscible organic solvent which is dispersed as droplets in water.

Surface-active agents may be of the cationic, anionic, or non-ionic type. The cationic agents are, for example, quaternary ammonium compounds (eg cetyltrimethylammonium bromide). Suitable anionic agents are soaps; salts of aliphatic mono esters of sulphuric acid, for example sodium lauryl sulphate; and salts of sulphonated aromatic compounds, for example sodium dodecylbenzenesulphonate, sodium, calcium, and ammonium lignosulphonate, butylnaphthalene sulphonate, and a mixture of the sodium salts of diisopropyl- and triisopropylnaphthalenesulphonic acid. Suitable non-ionic agents are the condensation products of ethylene oxide with fatty alcohols such as oleyl alcohol and cetyl alcohol, or with alkylphenols such as octyl- or nonyl-phenol or octyl-cresol. Other non-ionic agents are the partial esters derived from long chain fatty acids and hexitol anhydrides, for example sorbitan monolaurate; the condensation products of the partial ester with ethylene oxide; and the lecithins.

The aqueous solutions or dispersions may be prepared by dissolving the active ingredient in water or an organic solvent optionally containing wetting or dispersing agent(s) and then, when organic solvents are used, adding the mixture so obtained to water optionally containing wetting or dispersing agent(s). Suitable organic solvents include, for example, ethylene dichloride, isopropyl alcohol, propylene glycol, diacetone alcohol, toluene, kerosene, methylnaphthalene, the xylenes and trichloroethylene.

The compositions for use in the form of aqueous solutions or dispersions are generally supplied in the form of a concentrate containing a high proportion of the active ingredient, and the concentrate is then diluted with water before use. The concentrates are usually required to withstand storage for prolonged periods and after such storage, to be capable of dilution with water to form aqueous preparations which remain homogeneous for a sufficient time to enable them to be applied by conventional spray equipment. Concentrates conveniently contain 20-90%, preferably 20-70%, by weight of the active ingredient(s). Dilute preparations ready for use may contain varying amounts of the active ingredient(s) depending upon the intended purpose; amounts of 0.01% to 10.0% and preferably 0.1% to 2%, by weight of active ingredient(s) are normally used.

A preferred form of concentrated composition comprising the active ingredient which has been finely divided and which has been dispersed in water in the presence of a surface-active agent and a suspending agent. Suitable suspending agents are hydrophilic colloids and include, for example, polyvinylpyrrolidone and sodium carboxymethylcellulose, and the vegetable gums, for example gum acacia and gum tragacanth. Preferred suspending agents are those which impact thixotropic properties to, and increase the viscosity of the concentrate. Examples of preferred suspending agents include hydrated colloidal mineral silicates, such as montmorillonite, beidellite, nontronite, hectorite, saponite, and saucorite. Bentonite is especially preferred. Other suspending agents include cellulose derivatives and polyvinyl alcohol.

The rate of application of the compounds of the invention will depend on a number of factors including, for example, the compound chosen for use, the identity of the plants whose growth is to be inhibited the formulations selected for use and whether the compound is to be applied for foliage or root uptake. As a general guide, however, an application rate of from 0.005 to 20 kilograms per hectare is suitable while from 0.1 to 10 kilograms per hectare may be preferred.

The compositions of the invention may comprise, in addition to one or more compounds of the invention, one or more compounds not of the invention but which possess biological activity. For example, as hereinbefore indicated the compounds of the invention are in general substantially more effective against monocotyledonous plants or grass species than against dicotyledonous plants or broad-leaved species. As a result, in certain applications the herbicidal use of the compounds of the invention alone may be sufficient to protect a crop. Accordingly in yet a still further embodiment the invention provides a herbicidal composition comprising a mixture of at least one herbicidal compound of formula I as hereinbefore defined with at least one other herbicide.

The other herbicide may be any herbicide not having the formula I. It will generally be a herbicide having a complementary action. For example, one preferred class is of mixtures comprising a herbicide active against broad-leaved weeds. A second preferred class is of mixtures comprising a contact herbicide.

Examples of useful complementary herbicides include:

A. benzo-2,1,3-thiadiazin-4-one-2,2-dioxides such as 3-isopropylbenzo-2,1,3-thiadiazin-4-one-2,2-dioxide (common name bentazon); B. hormone herbicides and in particular the phenoxyalkanoic acids such as 4-chloro-2-methylphenoxy acetic acid (common name MCPA), 2-(2,4-dichlorophenoxy)propionic acid (common name dichlorprop), 2,4,5-trichlorophenoxyacetic acid (common name 2,4,5-T), 4-(4-chloro-2-methylphenoxy)butyric acid (common name MCPB), 2,4-dichlorophenoxyacetic acid (common name 2,4-D), 4-(2,4-dichlorophenoxy)butyric acid (common name 2,4-DB), 2-(4-chloro-2-methylphenoxy)propionic acid (common name mecoprop), and their derivatives (eg salts, esters, amides and the like); C. 3-[4-(4-halophenoxy)phenyl]-1,1-dialkylureas such as 3-[4-(4-chlorophenoxy)phenyl]-1,1-dimethylurea (common name chloroxuron); D. dinitrophenols and their derivatives (eg acetates) such as 2-methyl-4,6-dinitrophenol (common name DNOC), 2-tertiarybutyl-4,6-dinitrophenol (common name dinoterb), 2-secondarybutyl-4,6-dinitrophenol (common name dinoseb) and its ester dinoseb acetate; E. dinitroaniline herbicides such as N',N'-diethyl-2,6-dinitro-4-trifluoromethyl-m-phenylenediamine (common name dinitramine), 2,6-dinitro-N,N-dipropyl-4-trifluoromethylaniline (common name trifluralin) and 4-methylsulfonyl-2,6-dinitro-N,N-dipropylaniline (common name nitralin); F. phenylurea herbicides such as N'-(3,4-dichlorophenyl)-N,N-dimethylurea (common name diuron) and N,N-dimethyl-N'-[3-(trifluoromethyl)phenyl]urea (common name fluometuron); G. phenylcarbamoyloxyphenylcarbamates such as 3-[(methoxycarbonyl)amino]phenyl (3-methylphenyl)-carbamate (common name phenmedipham) and 3-[(ethoxycarbonyl)amino]phenyl phenylcarbamate (common name desmedipham); H. 2-phenylpyridazin-3-ones such as 5-amino-4-chloro-2-phenylpyridazin-3-one (common name pyrazon);

I. uracil herbicides such as 3-cyclohexyl-5,6-trimethyleneuracil (common name lenacil), 5-bromo-3-sec-butyl-6-methyluracil (common name bromacil) and 3-tert-butyl-5-chloro-6-methyluracil (common name terbacil);

J. triazine herbicides such as 2-chloro-4-ethylamino-6-(iso-propylamino)-1,3,5-triazine (common name atrazine), 2-chloro-4,6-di(ethylamino)-1,3,5-triazine (common name simazine) and 2-azido-4-(iso-propylamino)-6-methylthio-1,3,5-triazine (common name aziprotryne); K. 1-alkoxy-1-alkyl-3-phenylurea herbicides such as 3-(3,4-dichlorophenyl)-1-methoxy-1-methylurea (common name linuron), 3-(4-chlorophenyl)-1-methoxy-1-methylurea (common name monolinuron) and 3-(4-bromo-4-chlorophenyl)-1-methoxy-1-methylurea (common name chlorobromuron); L. thiolcarbamate herbicides such as S-propyl dipropylthiocarbamate (common name verolate); M. 1,2,4-triazine-5-one herbicides such as 4-amino-4,5-dihydro-3-methyl-6-phenyl-1,2,4-triazine-5-one (common name metamitron) and 4-amino-6-tert-butyl-4,5-dihydro-3-methylthio-1,3,4-triazin-5-one (common name metribuzin); N. benzoic acid herbicides such as 2,3,6-trichlorobenzoic acid (common name 2,3,6-TBA), 3,6-dichloro-2-methoxybenzoic acid (common name dicamba) and 3-amino-2,5-dichlorobenzoic acid (common name chloramben). O. anilide herbicides such as N-butoxymethyl-.alpha.-chloro-2',6'-diethylacetanilide (common name butachlor), the corresponding N-methoxy compound (common name alachlor), the corresponding N-iso-propyl compound (common name propachlor) and 3',4'-dichloropropionanilide (common name propanil); P. dihalobenzonitrile herbicides such as 2,6-dichlorobenzonitrile (common name dichlobenil), 3,5-dibromo-4-hydroxybenzonitrile (common name bromoxynil) and 3,5-diiodo-4-hydroxybenzonitrile (common name ioxynil). Q. haloalkanoic herbicides such as 2,2-dichloropropionic acid (common name dalapon), trichloroacetic acid (common name TCA) and salts thereof; R. diphenylether herbicides such as 4-nitrophenyl 2-nitro-4-trifluoromethylphenyl ether (common name fluorodifen), methyl 5-(2,4-dichlorophenoxy-2-nitrobenzoate (common name bifenox), 2-nitro-5-(2-chloro-4-trifluoromethylphenoxy)benzoic acid and 2-chloro-4-trifluoromethylphenyl 3-ethoxy-4-nitrophenyl ether; and S. miscellaneous herbicides including N,N-dimethyldiphenylacetamide (common name diphenamid), N-(1-naphthyl)phthalamic acid (common name naptalam) and 3-amino-1,2,4-triazole.

Examples of useful contact herbicides include:

T. bipyridylium herbicides such as those in which the active entity is the 1,1'-dimethyl-4,4'-dipyridylium ion (common name paraquat) and those in which the active entity is the 1,1'-ethylene-2,2'-dipyridylium ion (common name diquat), U. organoarsenical herbicides such as monosodium methanearsonate (common name MSMA); and V. amino acid herbicides such as N-(phosphonomethyl)-glycine (common name glyphosate) and its salts and esters.

The invention is now illustrated by, but in no way limited to, the following Examples.

EXAMPLE 1

Methyl 2-[4-(6-chloro-2-quinolinyloxy)phenoxy]-propionate (1)

A mixture of 2,6-dichloroquinoline (1.25 g, 0.6 mmole; prepared according to the method of O Fischer, Chem. Ber. 35, 3683 (1902)), methyl 2-(4-hydroxyphenoxy)-priopionate (1.3 g, 0.65 mmole) anhydrous potassium carbonate (1.0 g, 0.7 mmole) and dimethylformamide (20 ml) was heated under reflux for a period of 12 hours. The solvent was removed by evaporation under reduced pressure and the residue was partitioned between chloroform and water. The chloroform layer was dried (anhydrous magnesium sulfate) and the solvent was evaporated. The residue, a brown oil, was chromatographed over silica gel (40 g) with chloroform elution to give methyl-2-[4-(6-chloro-2-quinolinyloxy)phenoxy]propionate as a crystalline solid (0.75 g), mp 75.degree. C.

EXAMPLE 2

Methyl-2-[4-(2-quinolinyloxy)phenoxy]propionate (24) was prepared from 2-chloroquinoline and methyl 2-(4-hydroxyphenoxy)propionate following essentially the same procedure as that described in Example 1. The compound had a melting point of 95.degree.-100.degree. C.

EXAMPLE 3

Methyl 2-[4-(6,8-dichloro-2-quinolinyloxy)phenoxy]-propionate (25)

was prepared from 2,6,8-trichloroquinoline and methyl 2-(4-hydroxyphenoxy) propionate following essentially the same procedure as that described in Example 1. The compound had a melting point of 70.degree. C.

EXAMPLE 4

Ethyl 2-[4-(3-chloroquinolin-2-yloxy)phenoxy]propionate (27)

A mixture of 2,3-dichloroquinoline (2.0 g) (prepared by the method of Meth-Cohn, Tetrahedron Letters, 1979, 4885), methyl 2-(4-hydroxyphenoxy) propionate (2.1 g), anhydrous potassium carbonate (1.4 g) and dimethylformamide (60 ml) was heated under reflux for a period of 6 hours. The solvent was removed under reduced pressure and the residue was partitioned between water and chloroform. The chloroform layer was dried (anhydrous magnesium sulphate) and the solvent was evaporated. The residue was chromatographed over silica gel (40 g) with chloroform: petroleum ether (4:1) elution to give ethyl 2-[4-(3-chloro-2-quinolinyloxy)phenoxy]propionate as a pale yellow solid, mp 86.degree. C.

EXAMPLE 5

Ethyl 2-[4-(3,6-dichloroquinolin-2-yloxy)phenoxy]-propionate (30)

was prepared from 2,3,6-trichloroquinoline and ethyl (2-(4-hydroxyphenoxy)propionate following the same procedure as that described in Example 4. The compound had a melting point of 70.degree. C.

EXAMPLE 6

Ethyl 2-[4-(6-bromoquinolin-2-yloxy)phenoxy]-propionate (31)

was prepared from 6-bromo-2-chloroquinoline and ethyl 2-(4-hydroxyphenoxy)propionate following essentially the same procedure as that described in Example 1. The compound had a melting point of 85.degree. C.

EXAMPLE 7

Ethyl 2-[4-(6-fluoroquinolin-2-yloxy)phenoxy]-propionate (34)

was prepared from 2-chloro-6-fluoroquinoline and ethyl 2-(4-hydroxyphenoxy)propionate following essentially the same procedure as that described in Example 1. The compound was isolated as a pale yellow oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.1-6.8 (9H, m, quinoline and phenyl protons); 4.8 (1H, q, CH-CH.sub.3); 4.3 (2H, q, OCH.sub.2 -CH.sub.3); 1.6 (3H, d, CH-CH.sub.3); 1.2 (3H, t, OCH.sub.2 -CH.sub.3).

EXAMPLE 8

Ethyl 2-[4-(6-chloro-4-trifluoromethylquinolin-2-yloxy)phenoxy]propionate (32) and ethyl 2-[4-(6-chloro-2-trifluoromethylquinolin-4-yloxy)phenoxy]propionate (39)

(a) A mixture of 2,6-dichloro-4-trifluoromethylquinoline and 4,6-dichloro-2-trifluoromethylquinoline was prepared following the general method of Belli et al. Ric. Sci., Rend. Sez., A 3 (4), 530, (1963) (Chemical Abstracts 59:87436).

(b) The above mixture (1.5 g) together with ethyl 2-(4-hydroxyphenoxy)propionate (1.1 g), anhydrous potassium carbonate (0.8 g) and ethyl methyl ketone (80 ml) was stirred and heated under reflux for 24 hours. The solvent was evaporated under reduced pressure and the residue partitioned between water and dichloromethane. The dichloromethane layer was dried and the solvent was evaporated to give an orange oil. Chromatography over silica gel (50 g) with dichloromethane: n-hexane (1:1) elution gave ethyl 2-[4-(6-chloro-4-trifluoromethyl-2-quinolinyloxy)phenoxy]propionate as a colourless solid (0.15 g), mp 86.degree. C. from the first fraction and ethyl 2-[4-(6-chloro-2-trifluoromethyl-4-quinolinyloxy)phenoxy]propionate as a colourless solid (0.31 g), mp 72.degree. C. from the second fraction.

EXAMPLE 9

Ethyl 2-methyl-2-[4-(6-chloroquinolin-2-yloxy)phenoxy]-propionate (36) was prepared from 2,6-dichloroquinoline and ethyl 2-methyl-2-(4-hydroxyphenoxy)propionate following essentially the same procedure as that described in Example 1. The product was isolated after chromatography as a low melting point solid. Mass spectrum (m/e): 385 (parent ion; 30%); 312 (35%); 271 (100%); 270 (100).

EXAMPLE 10

Ethyl 2-[4-(quinolin-3-yloxy)phenoxy]propionate (37)

(a) 4-Methoxyphenol (7 g) was stirred with potassium hydroxide (2.6 g) at 150.degree. C. for 3 hours. Water formed during the reaction was removed under reduced pressure. 3-Bromoquinoline (5 g) and copper powder (0.1 g) were then added and the mixture was stirred and heated at 200.degree. C. for 2 hours. After cooling the mixture was partitioned between diethyl ether and water. The ether layer was separated and dried and the solvent was removed under reduced pressure to give 3-(4-methoxyphenoxy)quinoline as a dark solid which was recrystallized from petroleum ether to give pale yellow crystals (2.6 g), mp 104.degree. C.

(b) A mixture of 3-(4-methoxyphenoxy)quinoline (2.6 g), acetic acid (20 ml) and hydrobromic acid (20 ml of 48%) was boiled under reflux for 5 hours. The solution was concentrated under reduced pressure, poured onto ice and the resultant precipitate was collected by filtration to give 3-(4-hydroxyphenoxy)quinoline as a dark brown solid (2.4 g), mp 250.degree. C.

(c) A mixture of 3-(4-hydroxyphenoxy)quinoline (2.4 g), ethyl 2-bromopropionate (2.1 g), anhydrous potassium carbonate (3.3 g) and dimethylformamide (50 ml) was stirred and heated at 80.degree. C. for 4 hours. The mixture was poured into water (500 ml) and extracted with diethyl ether (2.times.100 ml). The ether extracts were dried, evaporated to dryness and then chromatographed on silica gel (100 g) with dichloromethane elution. Ethyl 2-[4-(3-quinolinyloxy)phenoxy]-propionate was obtained as a pale yellow oil (1.9 g). Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.75 (1H, d); 8.1 (1H, bd); 7.7-7.3 (4H, m); 7.0 (4H, s, phenoxy protons); 4.75 (1H, q, CH--CH.sub.3); 4.25 (2H, q, OCH.sub.2 --CH.sub.3); 1.65 (3H, d, CH--CH.sub.3); 1.25 (3H, t, OCH.sub.2 --CH.sub.3).

EXAMPLE 11

Ethyl 2-[4-(3-nitroquinolin-4-yloxy)phenoxy]propionate (41) was prepared from 4-chloro-3-nitroquinoline and ethyl 2-(4-hydroxyphenoxy)propionate following essentially the same procedure as that described in Example 1. The compound was isolated as a yellow oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 9.3 (1H, s); 8.3-7.4 (4H, m, quinoline protons); 6.8 (4H, s, phenoxy protons); 4.7 (1H, q, CH--CH.sub.3); 4.2 (2H, q, OCH.sub.2 --CH.sub.3); 1.6 (3H, d, CH--CH.sub.3); 1.2 (3H, t, OCH.sub.2 --CH.sub.3).

EXAMPLE 12

Ethyl 2-[4-(1-oxide-quinolin-2-yloxy)phenoxy]propionate (33)

A solution of ethyl 2-[4-(2-quinolinyloxy)-phenoxy]propionate (1.15 g) and 3-chloroperoxybenzoic acid (0.81 g) in dichloromethane (50 ml) was kept at 20.degree. C. for 6 days. The solution was washed with aqueous 5% sodium metabisulphite solution and then with aqueous 5% sodium bicarbonate and then it was dried and evaporated to give an orange oil. Chromatography over silica gel (40 g) with dichloromethane elution gave first the starting material (0.6 g) and then ethyl 2-[4-(1-oxide-2-quinolinyloxy)phenoxy]propionate (0.49 g) as a brown oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.8 (1H, d); 8.0-6.8 (9H, m, quinoline and phenoxy protons); 4.8 (1H, q, CH--CH.sub.3); 4.2 (2H, q, OCH.sub.2 --CH.sub.3); 1.6 (3H, d, CH--CH.sub.3); 1.2 (3H, t, --CH.sub.2 CH.sub.3).

EXAMPLE 13

Ethyl 2-[4-(1-oxide-quinolin-3-yloxy)phenoxy]propionate (38) was prepared from ethyl 2-[4-(quinolin-3-yloxy)-phenoxy]propionate following essentially the same procedure as that described in Example 12. The compound was isolated as a pale brown viscous oil. Mass spectrum (m/e): 353 (parent ion; 100%); 337 (40%); 280 (60%); 236 (55%).

EXAMPLE 14

Ethyl 2-[4-(2-bromoquinolin-4-yloxy)phenoxy]propionate (40) was prepared from 2-bromo-4-nitroquinoline (Chem Abstracts 51: 6639) and ethyl 2-(4-hydroxyphenoxy)-propionate following essentially the same procedure as that described in Example 1. The compound was isolated as a colourless oil which solidified slowly on standing. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.5-7.4 (4H, m, quinoline protons); 7.1 (4H, d of d, phenyl protons); 6.6 (1H, s, C3 quinoline proton); 4.8 (1H, q, CHCH.sub.3); 4.3 (2H, q, OCH.sub.2 CH.sub.3); 1.65 (3H, d, CHCH.sub.3); 1.3 (3H t, OCH.sub.2 CH.sub.3).

EXAMPLE 15

Ethyl 2-[4-(6-chloroquinolin-2-yloxy)phenoxy]acetate (35) was prepared from 2,6-dichloroquinoline and ethyl 2-(4-hydroxyphenoxy) acetate following essentially the same procedure as that described in Example 1. The compound was isolated as a colourless solid, mp 95.degree. C.

EXAMPLE 16

2-[4-(6-Chloroquinolin-2-yloxy)phenoxy]propionic acid (42)

A solution of ethyl 2-[4-(6-chloro-2-quinolinyloxy)phenoxy]propionate (2.0 g) and potassium hydroxide (1.0 g) in methanol (20 ml) was warmed and stirred for 24 hours. The solution was poured into dilute hydrochloric acid (100 ml, 0.5 m) and extracted with ethyl acetate (2.times.50 ml). The ethyl acetate extracts were dried (MgSO.sub.4) and evaporated to give 2-[4-(6-chloro-2-quinolinyloxy)phenoxy]propionic acid as a brown solid, mp 130.degree. C. Mass spectrum (m/e): 343 (patent ion, 80%); 270 (80%); 164 (70%); 162 (100%).

EXAMPLE 17

Potassium 2-[4-(6-chloroquinolin-2-yloxy)phenoxy]-propionate (43) was prepared by the neutralization of the corresponding acid (Example 16) with methanolic potassium hydroxide and removal of the solvent under reduced pressure. The compound was obtained as a brown powder mp>150.degree. C. (dec).

EXAMPLE 18

Ethyl 2-[4-(6-chloro-3-nitroquinolin-2-yloxy)phenoxy]-propionate (43)

(a) 6-Chloro-3-nitroquinoline-1-oxide was prepared by the nitration of 6-chloroquinoline-1-oxide following the procedure described by Ochiai and Kaneko [Chem. Pharm. Bull. (Tokyo), 7, 267 (1959)]. The product was obtained as a pale yellow solid mp 238.degree. C. Mass spectrum (m/e): 224 (parent ion; 100%).

(b) 2,6-Dichloro-3-nitroquinoline was prepared by heating a mixture of 6-chloro-3-nitroquinoline-1-oxide and phosphorous oxychloride under reflux. The product was isolated as a nearly colourless crystalline solid, mp 190.degree. C. Mass spectrum (m/e): 242 (parent ion; 90%); 196 (100%).

(c) Ethyl 2-[4-(6-chloro-3-nitroquinolin-2-yloxy)phenoxy]propionate was prepared from 2,6-dichloro-3-nitroquinoline and ethyl 2-(4-hydroxyphenoxy)-propionate following essentially the same procedure as that described in Example 1. Proton magnetic resonance spectrum (CDCl.sub.3, .delta. in ppm): 8.6 (1H, s, C4 quinoline proton); 7.8-7.6 (3H, m, quinoline protons); 7.0 (4H, d of d, phenyl protons); 4.6 (1H, q, CHCH.sub.3); 4.2 (2H, q, OCH.sub.2 CH.sub.3); 1.6 (3H, d, CHCH.sub.3); 1.2 (3H, t, OCH.sub.2 CH.sub.3).

EXAMPLE 19

Methyl 2-{4-[N-(6-chloro-2-quinolinyl)-N-methylamino]-phenoxy}propionate (12)

(a) A mixture of 2,6-dichloroquinoline (1.1 g; prepared according to the method of O Fischer, Chem. Ber., 35, 3683 (1902), 4-(N-methylamino)phenol sulfate (1.5 g), ethanol (5 ml) and water (20 ml) was heated under reflux for a period of 24 hours. Water (50 ml) was added to the mixture and the aqueous mixture was extracted with chloroform (2.times.100 ml). The chloroform extracts were dried (anhydrous MgSO.sub.4) and the solvent was evaporated to give 4-[N-(6-chloro-2-quinolinyl)-N-methylamino]phenol (1.1 g) as a dark oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.0-6.6 and 7.2 (10H, m and d of d, quinoline, hydroxy and phenyl protons); 3.6 (3H, s, N--CH.sub.3).

(b) A mixture of 4-[N-(6-chloro-2-quinolinyl)-N-methylamino]phenol (1.1 g), methyl 2-bromopropionate (1.3 ml), anhydrous potassium carbonate (0.7 g) and acetone (20 ml) was heated under reflux with stirring for a period of 16 hours. The acetone was removed by distillation under reduced pressure and the residue was partitioned between water and chloroform. The chloroform extracts were dried (anhydrous MgSO.sub.4) and the solvent was evaporated. The residue was chromatographed over silica gel (40 g) with chloroform elution to give methyl 2-{4-[N-(6-chloro-2-quinolinyl)-N-methylamino]-phenoxy}propionate (1.05 g) as a colourless oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. ppm); 8.0-6.6 (9H, m, quinoline and phenoxy protons); 4.9 (1H, q, CH--CH.sub.3); 3.9 (3H, s, OCH.sub.3); 3.6 (3H, s, N--CH.sub.3); 1.6 (3H, d, CHCH.sub.3).

EXAMPLE 20

Methyl 2-{4-[N-(2-quinolinyl)-N-methylamino]phenoxy}-propionate (23)

4-[N-(2-quinolinyl)-N-methylamino]phenol (mp 178.degree. C.) prepared from 2-chloroquinoline and 4-(N-methylamino)phenol sulfate following essentially the same procedure as that described in Example 19, Part a).

(b) Methyl 2-{4-[N-(2-quinolinyl)-N-methylamino]-phenoxy}propionate, a colourless oil, was prepared from 4-[N-(2-quinolinyl)-N-methylamino]phenol and methyl 2-bromopropionate following essentially the the same procedure as that described in Example 19, part b). Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 7.9-6.6 (10H, m, quinoline and phenyl protons); 4.8 (1H, q, CH--CH.sub.3); 3.8 (3H, s, OCH.sub.3); 3.6 (3H, s, N--CH.sub.3); 1.6 (3H, d, CH--CH.sub.3).

EXAMPLE 21

Methyl 2-{4-[N-(6,8-dichloro-2-quinolinyl)-N-methylamino]phenoxy}propionate (26)

(a) 4-[N-(6,8-dichloro-2-quinolinyl)-N-methylamino]-phenol was prepared from 2,6,8-trichloroquinoline and 4-(N-methylamino)phenol sulfate following essentially the same procedure as that described in Example 19, Part a). Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.0-6.6 and 7.1 (9H, m, and d of d, quinoline, OH and phenyl protons; 3.6 (3H, s, N--CH.sub.3).

(b) Methyl 2-{4-[N-(6,8-dichloro-2-quinolinyl)-N-methylamino]phenoxy}propionate, a solid mp 112.degree. C., was prepared from 4-[N-(6,8-dichloro-2-quinolinyl)-N-methylamino]phenol and methyl 2-bromopropionate following essentially the same procedure as that described in Example 19, Part b).

EXAMPLE 22

Ethyl 2-{4-[N-(3-chloroquinolin-2-yl)-N-methylamino]-phenoxy}propionate (28) was prepared from 2,3-dichloroquinoline following essentially the same procedure as that described in Example 19. It was isolated as a pale yellow oil. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 8.0 (1H, s); 7.8-6.8 (8H, m, quinoline and phenoxy protons); 4.7 (1H, q, CH--CH.sub.3); 4.2 (2H, q, OCH.sub.2 --CH.sub.3); 1.6 (3H, d, CH--CH.sub.3).

EXAMPLE 23

Methyl 2-{4-[N-(6-chloroquinolin-2-yl)amino]phenoxy}-propionate (29)

(a) A mixture of 2,6-dichloroquinoline (6.0 g), 4-aminophenol (3.3 g), hydrochloric acid (3 g) and ethanol (100 ml) was stirred and refluxed for 10 hours. The solvent was removed under reduced pressure and the residue partitioned between ethyl acetate and water. The ethyl acetate extracts on evaporation gave 4-[N-(6-chloro-2-quinolinyl)-amino]phenol (2.7 g) as a brown solid.

(b) Methyl 2-{4-[N-(6-chloro-2-quinolinyl)amino]-phenoxy}propionate was prepared from 4-[N-(6-chloro-2-quinolinyl)amino]phenol and methyl 2-bromopropionate essentially as described in Example 19, Part b). It was isolated as a sticky brown syrup. Proton magnetic resonance spectrum (CDCl.sub.3 ; .delta. in ppm): 7.9-6.7 (10H, m, NH, quinoline and phenoxy protons); 4.8 (1H, q, --CHCH.sub.3); 3.8 (3H, s, OCH.sub.3); 1.6 (3H, t, CH--CH.sub.3).

EXAMPLE 24

Ethyl 2-{4-[N-(3-nitroquinolin-2-yl)amino]phenoxy}-propionate (44)

(a) A mixture of 2-chloro-3-nitroquinoline [0.35 g, prepared by the method of Kaneko, Chem. Pharm. Bull. (Tokyo) 7, 273 (1959)], 4-aminophenol (0.6 g), acetonitrile (20 ml) and dilute hydrochloric acid (30 ml, 1 M) was heated under reflux for 16 hours. The resulting deep orange solution was concentrated under reduced pressure (to 20 ml) and extracted with ethyl acetate (50 ml). The ethyl acetate extract was dried and evaporated to give 4-[N-(3-nitro-2-quinolinyl)amino]phenol as an organge solid, mp 190.degree. C.

(b) A mixture of ethyl 2-bromopropionate (0.5 g), 4-[N-(3-nitro-2-quinolinyl)amino]phenol (0.5 g), anhydrous potassium carbonate (0.3 g) and ethyl methyl ketone (20 ml) was refluxed for 4 hours. The solvent was removed under reduced pressure and the residue was partitioned between methylene chloride and water. The organic layer was dried and evaporated to give ethyl 2-{4-[N-(3-nitro-2-quinolinyl)amino]phenoxy}propionate as an orange oil which was purified by chromatography over silica gel. Proton magnetic resonance spectrum: (CDCl.sub.3, .delta. in ppm): 9.6 (1H, s, NH); 8.9 (1H, s, C4 quinoline proton); 7.8-7.6 (4H, m, quinoline protons); 6.8 (4H, s, phenyl protons); 4.6 (1H, q, CHCH.sub.3); 4.2 (2H, q, OCH.sub.2 CH.sub.3); 1.6 (3H, d, CHCH.sub.3); 1.2 (3H, t, OCH.sub.2 CH.sub.3).

EXAMPLE 25

Concentrated formulations of the compounds of the invention were prepared by:

(a) in the case of oils and waxy solids, dissolving the compound in toluene containing 7% v/v "Teric" N13 ("Teric" is a Trade Mark and "Teric" N13, a product of ethoxylation of nonylphenol, is available from ICI Australia Limited) and 3% v/v "Kemmat" SC15B ("Kemmat" is a Trade Mark and "Kemmat" SC15B is a formulation of calcium dodecylbenzene sulfonate); or

(b) in the case of crystalline solids, adding 5 parts by weight of the compound and 1 part by weight of "Dyapol" PT ("Dyapol" is a Trade Mark and "Dyapol" PT is an anionic suspending agent) to 94 parts by weight of an aqueous solution containing 0.25% v/v of "Teric" N8 (a product of ethoxylation of nonylphenol) and ball-milling the mixture to produce a stable suspension. The emulsifiable concentrates and suspensions were then diluted with water to give an aqueous composition of the required concentration suitable for use in the evaluation of the pre-emergence and post-emergence herbicidal activity of the compounds of the invention.

EXAMPLE 26

The pre-emergent herbicidal activity of the compounds of the invention formulated as described in Example 25 was assessed by the following procedure.

The seeds of the test species were sown in rows 2 cm deep in soil contained in seed boxes. The monocotyledonous plants and the dicotyledonous plants were sown in separate boxes and after showing the two boxes were sprayed with the required quantity of a composition of the invention. Two duplicate seed boxes were prepared in the same manner but were not sprayed with a composition of the invention and were used for comparison purposes. All the boxes were placed in a glasshouse, lightly watered with an overhead spray to initiate germination and then sub-irrigated as required for optimum plant growth. After three weeks the boxes were removed from the glasshouse and the effect of the treatment was visually assessed. The results are presented in Table 4 where the damage to plants is rated on a scale of from 0 to 3 where 0 represents from 0 to 25% damage, 3 represents 75 to 99% kill and 3+ represents 100% kill. A dash (-) means that no experiment was carried out.

The names of the test plants are as follows:

______________________________________ Wh Wheat Ot Wild Oats Rg Ryegrass Jm Japanese millet P Peas Ip Ipomea Ms Mustard Sf Sunflower______________________________________ TABLE 4______________________________________PRE-EMERGENCE HERBICIDAL ACTIVITY Appli-Com- cationpound Rate Test PlantNo kg/ha Wh Ot Rg Jm P Ip Ms Sf______________________________________ 1 5 2 3 3 3+ 0 0 0 0 1 1 0 0 1 1 0 0 0 0 1 0.5 0 0 0 0 0 0 0 024 5 0 0 3+ 3+ 0 0 0 024 1 0 0 0 0 0 0 0 012 5 0 0 0 0 0 0 0 012 1 0 0 0 0 0 0 0 027 10 0 0 3 3+ 0 0 0 027 5 0 0 3 3 0 0 0 030 10 0 0 2 3+ 0 0 0 030 5 0 0 0 0 0 0 0 031 5 0 2 3 3+ 0 0 0 031 1 0 0 1 3+ 0 0 0 033 5 0 0 3 0 0 0 0 034 5 3 3 3+ 3+ 0 0 0 034 1 0 0 3+ 3+ 0 0 0 034 0.5 0 0 3 3 0 0 0 0______________________________________

EXAMPLE 27

The post-emergent herbicidal activity of the compounds of the invention formulated as described in Example 25 was assessed by the following procedure.

The seeds of the test species were sown in rows 2 cm deep in soil contained in seed boxes. The monocotyledonous plants and the dicotyledonous plants were sown in separate seed boxes in duplicate. The four seed boxes were placed in a glasshouse, lightly watered with an overhead spray to initiate germination and then sub-irrigated as required for optimum plant growth. After the plants had grown to a height of about 10 to 12.5 cm one box of each of the monocotyledonous plants and the dicotyledonous plants was removed from the glasshouse and sprayed with the required quantity of a composition of the invention. After spraying the boxes were returned to the glasshouse for a further 3 weeks and the effect of treatment was visually assessed by comparison with the untreated controls. The results are presented in Table 5 where the damage to plants is rated on a scale of from 0 to 3 where 0 represents 0 to 25% damage, 3 represents 75 to 99% kill and 3+ represents 100% kill. A dash (-) means that no experiment was carried out.

The names of the test plants are as follows:

______________________________________ Wh Wheat Ot Wild Oats Rg Ryegrass Jm Japanese millet P Peas Ip Ipomea Ms Mustard Sf Sunflower______________________________________ TABLE 5______________________________________POST-EMERGENCE HERBICIDAL ACTIVITY Appli-Com- cationpound Rate Test PlantNo kg/ha Wh Ot Rg Jm P Ip Ms Sf______________________________________1 5 3+ 3+ 3+ 3+ 0 0 0 11 1 3+ 3+ 3+ 3+ 0 0 0 01 0.5 3+ 3 3+ 3+ 0 0 0 01 0.25 3+ 3 3+ 3+ 0 0 0 024 5 0 0 3+ 3+ 0 0 0 024 1 0 0 3 3+ 0 0 0 012 5 3 3 3+ 3+ 0 0 0 012 1 0 0 1 3+ 0 0 0 027 10 2 3+ 3+ 3+ 0 0 0 027 5 1 0 3 3+ 0 0 0 030 10 3+ 3 3+ 3+ 0 0 0 030 5 3 3 3 3+ 0 0 0 031 5 2 3+ 3+ 3+ 0 0 0 031 1 2 2 3+ 3+ 0 0 0 033 5 0 0 3 3+ 0 0 0 034 5 3+ -- 3+ 3+ 1 3+ 1 234 1 3 -- 3+ 3+ 0 0 0 034 0.5 3+ 3+ 3+ 3+ 0 0 0 0______________________________________

EXAMPLE 28

The compounds were formulated for test by mixing an appropriate amount with 5 ml of an emulsion prepared by diluting 160 ml of a solution containing 21.8 g per liter of "Span" 80 and 78.2 g per liter of "Tween" 20 in methylcyclohexanone to 500 ml with water. "Span" 80 is a Trade Mark for a surface-active agent comprising sorbitan monolaurate. "Tween" 20 is a Trade Mark for a surface-active agent comprising a condensate of sorbitan monolaurate with 20 molar proportions of ethylene oxide. Each 5 ml emulsion containing a test compound was then diluted to 40 ml with water and sprayed on to young pot plants (post-emergence test) of the species named in Table 6 below. Damage to test plants were assessed after 14 days on a scale of 0 to 5 where 0 is 0 to 20% damage and 5 is complete kill. In a test for pre-emergence herbicidal activity, seeds of the test plants were sown in a shallow slit formed in the surface of soil in fibre trays. The surface was then levelled and sprayed, and fresh soil then spread thinly over the sprayed surface. Assessment of herbicidal damage was carried out after 21 days using the same scale of 0 to 5 as the post-emergence test. In both cases the degree of herbicidal damage was assessed by comparison with untreated control plants. The results are given in Table 6 below. A dash (-) means that no experiment was carried out.

TABLE 6__________________________________________________________________________PART ACom- APPLICATIONpound Method Rate TEST PLANTNo (kg/ha) Sb Rp Ct Sy Mz Ww Rc Sn Ip Am Pi Ca__________________________________________________________________________1 PRE 2 -- -- 0 0 4 5 5 0 3 0 0 01 PRE 0.5 -- -- 0 0 2 4 4 0 0 0 0 --1 PRE 0.2 1 1 0 0 3 4 3 1 0 0 1 --1 POST 2 0 0 0 2 5 4 4 1 0 0 0 01 POST 0.5 0 1 0 0 5 4 4 0 0 0 0 21 POST 0.2 0 0 0 0 5 4 4 1 0 0 0 012 PRE 2.0 0 0 0 0 1 0 0 0 0 0 0 012 POST 2.0 0 0 1 1 4 0 0 2 0 1 0 024 PRE 2.0 0 0 0 0 5 4 5 0 0 0 0 024 POST 2.0 0 0 0 0 5 1 3 1 0 0 0 126 PRE 5.0 0 0 0 0 1 0 0 2 0 -- 0 126 POST 5.0 0 1 2 0 0 0 0 2 0 3 1 327 PRE 2.0 0 0 0 0 2 0 2 0 0 0 -- 027 POST 2.0 0 1 0 0 4 3 0 0 3 5 0 028 PRE 2.0 0 0 0 0 0 2 0 2 0 0 0 028 POST 2.0 2 3 2 2 0 0 0 4 1 4 0 429 PRE 2.0 0 0 0 1 0 0 0 0 0 -- 0 029 POST 2.0 1 1 0 0 2 1 0 2 2 3 0 231 PRE 0.2 -- -- -- -- 2 2 2 -- -- -- -- --31 POST 0.2 -- -- -- -- 4 4 1 -- -- -- -- --__________________________________________________________________________PART BCom- APPLICATIONpound Method Rate TEST PLANTNo (kg/ha) Po Xa Ab Cv Ot Dg Pu St Ec Sh Ag Cn__________________________________________________________________________1 PRE 2 0 0 2 -- -- 5 4 5 -- 5 4 11 PRE 0.5 0 0 0 -- -- 5 1 5 -- 3 0 01 PRE 0.2 0 0 0 -- 1 4 0 4 2 -- 2 --1 POST 2 1 0 0 0 5 5 4 5 5 5 4 01 POST 0.5 0 0 0 0 4 5 2 5 5 5 4 01 POST 0.2 -- 0 0 0 4 4 1 5 5 5 5 012 PRE 2.0 0 0 0 -- 0 4 0 3 0 1 0 012 POST 2.0 1 0 0 0 0 0 0 2 1 3 1 024 PRE 2.0 0 0 0 -- 0 4 4 3 5 2 3 024 POST 2.0 0 0 0 0 0 0 0 2 5 4 3 026 PRE 5.0 1 0 0 -- 1 0 0 0 1 0 0 026 POST 5.0 0 2 1 -- 1 3 0 5 3 2 0 027 PRE 2.0 0 0 0 -- 0 0 0 0 5 1 0 027 POST 2.0 1 0 2 0 1 1 0 4 4 4 1 028 PRE 2.0 0 0 0 -- 0 0 0 0 0 0 3 --28 POST 2.0 4 2 2 -- 0 2 1 1 2 1 0 029 PRE 2.0 0 0 0 -- 0 0 0 0 1 0 0 029 POST 2.0 2 0 1 -- 1 2 0 2 1 1 0 031 PRE 0.2 -- -- -- -- 0 4 -- 0 -- 2 5 --31 POST 0.2 -- -- -- -- 4 4 -- 4 4 4 0 --__________________________________________________________________________

The names of the test plants were as follows:

______________________________________Sb Sugar beetRp RapeCt CottonSy Soy beanMz MaizeMw Winter wheatRc RiceSn Senecio vulgarisIp Ipomea purpureaAm Amaranthus retroflexusPi Polygonum aviculareCa Chenopodium albumPo Portulaca oleraceaXa Xanthium pensylvanicumAb Abutilon theophrastiCv Convolvulus arvensisOt Cultivated oats and wild oats (Avena fatua) Wild oats are used in the post- emergence test and cultivated oats in the pre-emergence testDg Digitaria sanguinalisPu Poa annuaSt Setaria viridisEc Echinochloa crus-galliSh Sorghum halepenseAg Agropyron repensCn Cyperus rotundus______________________________________

Claims

1. A compound of formula ##STR21## wherein: B is chloro;

R.sup.1 is methyl;

R.sup.2 is hyrogen;

G is ethoxy; and

k is chosen from 0 to 1.

2. A herbicidal composition comprising an active ingredient a compound as defined according to claim 1 and an agriculturally acceptable carrier therefor.

3. A process for severely damaging or killing unwanted plants which process comprises applying to said plants, or to the growth medium of said plants, an effective amount of a compound as defined according to claim 1.

4. A process for selectively controlling the growth of monocotyledonous weeds in dicotyledonous crops which process comprises applying to said crop, or to the growth medium of said crop, a compound as defined according to claim 1 in an amount sufficient to severely damage or kill the weeds but insufficient to substantially damage the crop.

5. A process according to claim 3 or claim 4 wherein the compound is applied at a rate in the range from 0.005 to 20 kilograms per hectare.