Cyclohexane-1,3-dione derivatives,their manufacture and their use as herbicides

Cyclohexane-l,3-dione derivatives, their manufacture and their use as herbicides )BASF Aktiengesellschaft

C: 65837

- la The present invention relates to cyclohexane-1,3-dione derivatives, to their preparation and to herbicidal compositions which contain these compounds as active ingredients.

It is known that cyclohexane-1,3-dione derivatives can be used for controlling undesirable grasses in broad-leaved crops. Active ingredients possessing furyl or thienyl substituents have a relatively weak action (German Laid-Open Application DOS 2,439,104)'. Moreover, European Laid-Open Application 0,071,707 discloses heterocyclically substituted cyclohexane-1,3-dione derivatives which possess a good herbicidal, action against plants from the grass family. _______

In our Israel Patent 65805 (corresponding to DE 3,121,355) herein referred to as the main patent, there are described and claimed. herbicidally active cyclohexandione derivatives of the formula _z0R²' 0 HN . Y z

2 ו where R is alkyl of 1 to 4 carbon atoms, R is alkyl of 1 to 4 carbon atoms, alkenyl of 3 or 4 carbon atoms, alkynyl of 3 or 4 carbon atoms or haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen atoms, X is straight-chain or branched alkylene of 1 to 5 carbon atoms, which is optionally substituted by phenyl, n is 0 or 1, Y is dihydropyranyl, tetrahydrothiopyranyl, tetrahydropyranyl, dioxanyl, dioxolanyl, dithiolanyl or dihydrothiopyranyl, optionally substituted by lower alkyl,? and Z is hydrogen or methoxycarbonyl, or a salt thereof, The present invention is concerned with a further group of such cyclohexane-l,3־dione not specifically disclosed in the main patent which carry certain heterocyclic substituents in the

5-position, and salts thereof. These compounds have substantially greater herbicidal action than the prior art active ingredients against a number of grass species (wild and cultivated species). They are very well tolerated by both broad-leaved crop plants and monocotyledon crops which do not belong to the grass family. Moreover, in spite of having a good action against grasses, some of these compounds are also tolerated by the crop plant wheat when they are used in certain doses.

The novel cyclohexane־l,3־dione derivatives of the present invention are of the formula _xNH-0R³ ' C _ק (I) where A is tetrahydropyran-4-yl, 3-methyltetrahydropyran-4yl, 1,4-dioxanyl, 2-methyl-l,3-dithiolan-2-yl, or

2,6-dimethyltetrahydrothiopyran-3-yl, or is 1,3-dioxepan-5yl which is substituted by alkyl of to 8 carbon atoms, by alkylene.of 4 or 5 carbon atoms or by .unsubstituted or raethyl-substituted cycloalkyl or bicycloalkyl of 6 to 12 carbon atoms, is hydrogen or

3 raethoxycarbonyl, R is alkyl of 1 to 4 carbon atoms and R is alkyl of 1 to 4 carbon atoms, alkenyl of 3 or 4 carbon -גtoms, haloalkenyl of 3 or 4 carbon atoms and 1 to 3 halogen substituents, or propargyl, and salts thereof .

The compounds of the formula I can occur in a number of forms, all of which are within the scope of the invention claimed:

<img file="IL73400A_D0001.tif" />

The 1,3-dioxepan-5-yI radicals A in formula I ;are . substituted by straight-chain or branched alkyl of 1 to 8 carbon atoms, eg. methyl, ethyl, isopropyl, tert.butyl, 1,2-dimethylbut-4-yI or 1-ethyl-n-pentyI, or by cycloalkyl or bicycloalkyl of 6 to 12 carbon atoms, eg. cyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl or bicycloheptyl such as bi eye 10C3 .1 .1 Jhepty I. The cycloalkyl and bicycloalkyl radicals may furthermore carry one or more methyl substituents. Moreover, the 1,3-dioxepan-5yl radicals can be substituted by alkylene of 4 or 5 carbon atoms, ie. tetramethylene or pentamethylene, so. that, for example, spiro compounds are formed.

In formula I, R² is straight-chain or branched alkyl of 1 to 4 carbon atoms, ie. methyl, ethyl, n-ppopyl, isopropyl, π-butyl, sec.-butyl, isobutyl or tert.-butyl.

and R³ is propargyl, alkyl of 1 to 4 carbon atoms, alkenyl of 3 or 4 carbon atoms or haloalkenyl of 3 or 4 carbon atoms which can contain not more than three halogen substituents, eg. chlorine, bromine or fluorine, examples of radicals being methyl, ethyl, n-propyl, iso־ propyl, n-butyl, sec.-butyl, isobutyl, tert.-butyl, allyl, 1-chloroprop-1-en-3-y I, 2-chloroprop-1-en-3-y I, 1,3-dich loroprop-1-en-3-yI and 1,2,3-trich loroprop-1-en-3-y I.

Preferred eye lohexane-1,3-dione derivatives of the formula I are those in which is hydrogen and those in which is alkyl of 2 or 3 carbon atoms. Preferred radicals A are tetrahydropyran-4-yI, 2,6-dimethyltetrahydrothiopyran-3-yI, and 1,3-dioxepan-5-yl which is .־.* substituted by alkyl of 1 to 8, in particular 1 to 4, carbon atoms, by alkylene of 4 or 5 carbon atoms or by unsubstituted or methyl-substituted cycloalkyl or bicycloalkyl of 7 to 12 carbon atoms, in particular 1,3dioxepan-5-y I which is unsubstituted or substituted by straight-chain or branched alkyl of 1 to 4 carbon atoms.

Examples of suitable salts of the compounds of the formula 1 are the alkali metal salts, in particular the potassium and sodium salts, the alkaline earth metal salts, in particular calcium, magnesium and barium salts, manganese, copper, zinc and iron salts, ammonium and phosphonium salts, eg. aIkylammoniurn, dia Ikylammoniurn, trialkylammonium, tetraalkylammonium, benzy 11ria I ky lammonium and tri phenylphosphonium salts, and trialkylsulfonium and trו a IkyIsu Ifoxonium salts.

The compounds of the formula I can be obtained by reacting a compound of the formula

<img file="IL73400A_D0002.tif" />

2 where A, R¹ and R have the above meanings, with a hydroxylamine derivative R³0-NHjY, in which R³ has the

- O.Z. 0050/36792 above meanings and Y is an anion. The reaction is advantageously carried out in the heterogeneous phase in an inert diluent at from 0 to 80°C or from 0°C to the boiling point of the reaction mixture, 5 in the presence of a base. Examples of suitable bases are carbonates, bi carbonates,-acetates, alcoholates, hydroxides and oxides of alkali and alkaline earth metals, in particular of sodium, potassium, magnesium and calcium. It is also possible to use an organic base, eg. pyridine 10 or a tertiary amine.

Examples of suitable solvents are dimethyl sulf״ oxide, alcohols, such as methanol, ethanol or isopropanol, benzene, hydrocarbons and ch lorohydrocarbons, such as chloroform, di ch loroethane, hexane or cyclohexane, esters, 15 such as ethyl acetate, and ethers, such as dioxane or tetrahydrofuran .

The reaction is complete after a few hours, and the product can then be isolated by evaporating down the mixture, adding water, extracting with a nonpolar sol״ 20 vent, such as methylene chloride, and distilling off the solvent under reduced pressure.

The compound's of the formula I can furthermore be obtained by reacting a compound of the formula II with a hydroxylamine of the formula R^O-NHg, in which has the 25 above meanings, in an inert diluent at from 0°C to the boiling point of the reaction mixture, in particular from 15 to 70°C. If necessary, the hydroxylamine can be used in the form of an aqueous solution.

Examples of suitable solvents for this reaction 30 are alcohols, such as methanol, ethanol, isopropanol or cyclohexanol, hydrocarbons and chlorohydrocarbons, such as hexane, cyclohexane, methylene chloride, toluene or di ch loroethane, esters, such as ethyl acetate, nitriles, such as acetonitrile, and cyclic ethers, such as tetra35 hydrofuran.

The alkali metal salts of the compounds of the formula I can be obtained by treating these compounds

- O.Z. 0050/36792 with sodium hydroxide or potassium hydroxide in aqueous solution or in an organic solvent, such as methanol, ethanol or acetone. It is also possible to use a sodium alcoholate or potassium alcoholate as the base.

The other metal salts, eg. the manganese, copper, zinc, iron, calcium, magnesium and barium salts, can be prepared from the sodium salts by reaction with the corresponding metal chlorides in aqueous solution. Ammonium, sulfonium, sulfoxonium and phosphonium salts can be prepared by reacting a compound of the formula I with an ammonium, phosphonium, sulfonium or sulfoxonium hydroxide, if necessary in aqueous solution.

The compounds of the formula II can be prepared, ujing a conventional method (Tetrahedron Lett. 29 (1975), 2491), from a eye lohexane-1,3-dione of the formula III, which may also occur in the tautomeric forms of the formulae Illa and 11lb :

<img file="IL73400A_D0003.tif" />

(III) (Illa) (Illb)

It is also possible to prepare compounds of the formu la II via the intermediate stage of the enol esters, which are obtained, possibly as isomer mixtures, in the conversion of compounds of the formula III, and undergo rearrangement in the presence of an imidazole or pyridine derivative (Japanese Preliminary Published Application 79/063,052) .

Compounds of the formula III are obtained by processes known from the Literature, as can be seen from the equations below:

- O.Z. 0050/36792

<img file="IL73400A_D0004.tif" />

<img file="IL73400A_D0005.tif" />

<img file="IL73400A_D0006.tif" />

Aldehydes of the general formula A-CHO are obtained by processes known from the literature, for example by oxidation of the corresponding alcohols, reduction of car5 boxylic acid derivatives or hydroformylation of olefins. The Examples which follow illustrate the preparation of the eyeLohexane-1,3-dione derivatives of the formula I. Parts by weight bear the same relation to parts by volume as that of the kilogram to the Liter.

The H-NMR spectra were recorded using

- O.Z. 0050/36792 deuterochLoroform as a solvent and tetramethylsilane as an internal standard. The chemical shifts are stated as fi CppmJ in each case. The following abbreviations have been used to indicate the signal structure:

s = singlet, d = doublet, t = triplet, q = quartet, m= multiplet, strongest signal.