Tetrahydrofurane derivatives, processes for their preparation and their use as herbicides.

The present invention relates to new tetrahydrofuran derivatives, several processes for their preparation and their use as herbicides, in particular as selective herbicides.

It has already become known that chloroacetanilides, such as, for example, 2-ethyl-6-methyl-N- (l'-methyl-2'-methoxyethyl) chloroacetanilide, can be used as herbicides, in particular for combating grassy weeds (cf. DT-OS 2 328 340). However, the selectivity of these compounds is not always satisfactory.

There were new tetrahydrofuran derivatives of the formula<chemistry id="chem0001" num="0001"><img file="EP0000002A1_D0001.tif" /></chemistry>in which<ul id="ul0001" list-style="none"><li>R¹ to R⁶ are identical or different and represent hydrogen, alkyl, haloalkyl, alkoxyalkyl, optionally substituted phenyl or optionally substituted benzyloxyalkyl,</li><li>R⁵and R⁶ also together represent a saturated carbocyclic ring,</li><li>R^? represents hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxyalkyl, optionally substituted phenyl or optionally substituted benzyloxyalkyl,</li><li>R⁸ and _R9 are identical or different and represent hydrogen, alkyl, alkenyl, alkynyl, cycloalkyl, alkoxy, optionally substituted phenyl or optionally substituted benzyl and benzyloxy,</li><li>R¹⁰ represents hydrogen, alkyl, alkenyl, alkynyl, haloalkyl or optionally substituted phenyl and</li><li>Y represents optionally substituted aryl, with the proviso that if Y represents phenyl, this must be substituted if R 'to R'⁰ Mean hydrogen, found.</li></ul>

These new tetrahydrofuran derivatives have strong herbicidal, in particular selective, herbicidal properties.

Furthermore, it was found that the tetrahydrofuran derivatives of the formula (I) are obtained if<ul id="ul0002" list-style="none"><li>(a) Alcoholates of 2-hydroxymethyl-tetrahydrofuran derivatives of the formula<chemistry id="chem0002" num="0002"><img file="EP0000002A1_D0002.tif" /></chemistry>in which<ul id="ul0003" list-style="none"><li>R¹ to R⁹ have the meaning given above and</li><li>M represents an alkali or alkaline earth metal,</li><li>with a compound of the formula<chemistry id="chem0003" num="0003"><img file="EP0000002A1_D0003.tif" /></chemistry></li><li>in which</li><li>R¹⁰ and Y have the meaning given above and</li><li>Z represents halogen, in particular chlorine or bromine, the mesylate or tosylate radical,</li><li>if appropriate in the presence of a diluent, or if one</li></ul></li><li>(b) Diols of the formula<chemistry id="chem0004" num="0004"><img file="EP0000002A1_D0004.tif" /></chemistry>in which<ul id="ul0004" list-style="none"><li>R¹ bi s R¹⁰</li><li>and Y have the meaning given above,</li><li>heated in the presence of an acidic catalyst and optionally heated in the presence of a diluent.</li><li>Compounds of formula (I) in which either R 'and R⁷ or R¹ and R⁴ or R⁴and R⁵ stand for hydrogen can also be obtained if one</li></ul></li><li>(c) Dihydrofuran derivatives of the formulas<chemistry id="chem0005" num="0005"><img file="EP0000002A1_D0005.tif" /></chemistry><chemistry id="chem0006" num="0006"><img file="EP0000002A1_D0006.tif" /></chemistry>and or<chemistry id="chem0007" num="0007"><img file="EP0000002A1_D0007.tif" /></chemistry> in which<ul id="ul0005" list-style="none"><li>R¹ to R¹⁰</li><li>and Y have the meaning given above,</li><li>hydrogenated with hydrogen in the presence of a catalyst and optionally in the presence of a diluent.</li><li>Compounds of formula (I) in which R¹, R⁴, R⁵ and R⁷ stand for hydrogen can also be obtained if one</li></ul></li><li>(d) Furan derivatives of the formula<chemistry id="chem0008" num="0008"><img file="EP0000002A1_D0008.tif" /></chemistry>in which<ul id="ul0006" list-style="none"><li>R², R³, R⁶, R⁸,</li><li>R⁹, R¹⁰ and Y have the meaning given above,</li><li>hydrogenated with hydrogen in the presence of a catalyst and optionally in the presence of a diluent.</li></ul></li></ul>

Surprisingly, the tetrahydrofuran derivatives according to the invention are superior to the known herbicides, such as, for example, 2-ethyl-6-methyl-N- (1'-methyl-2'-methoxyethyl) chloroacetanilide, and also have a significantly better action Selectivity in important crops. The active compounds according to the invention thus represent a significant enrichment of the herbicidal compositions, in particular the grass herbicides.

If the sodium alcoholate of tetrahydrofurfuryl alcohol and 2-fluorobenzyl bromide are used as starting materials, the course of the reaction can be represented by the following formula (process variant a):<chemistry id="chem0009" num="0009"><img file="EP0000002A1_D0009.tif" /></chemistry>

If 1- (2-fluorobenzyloxy) pentane-2,5-diol is used as the starting material and p-toluenesulfonic acid as the catalyst, the course of the reaction can be represented by the following formula (process variant b):<chemistry id="chem0010" num="0010"><img file="EP0000002A1_D0010.tif" /></chemistry>

If 2,3-dihydro-2- (2-fluorobenzyloxymethyl) furan and hydrogen are used as starting materials, the course of the reaction can be represented by the following formula (process variant c):<chemistry id="chem0011" num="0011"><img file="EP0000002A1_D0011.tif" /></chemistry>

If 2- [1- (2-chlorobenzyloxy) prop-1-yl] furan and hydrogen are used as starting materials, the course of the reaction can be represented by the following formula (process variant d):<chemistry id="chem0012" num="0012"><img file="EP0000002A1_D0012.tif" /></chemistry>

Formula (II) provides a general definition of the alcoholates of 2-hydroxymethyltetrahydrofuran derivatives to be used as starting materials for process variant (a). In this formula, R1 to R are⁶ the same or different and are preferably hydrogen, straight-chain or branched alkyl having 1 to 6 carbon atoms, haloalkyl having up to 2 carbon atoms and up to three identical or different halogen atoms, fluorine, chlorine and bromine in particular being halogens, alkoxyalkyl having 1 or 2 carbon atoms in each alkyl part, and for optionally substituted phenyl and benzyloxyalkyl with 1 to 2 carbon atoms in the alkyl part, the preferred substituents are: halogen, alkyl and alkoxy each having 1 or 2 carbon atoms and haloalkyl having up to 2 carbon and up to three identical or different halogen atoms, such as in particular fluorine and chlorine. R 'and R⁶ also preferably together represent a saturated carbocyclic ring with a total of 3 to 6 carbon atoms.

R⁷ preferably represents hydrogen, straight-chain or branched alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, alkenyl and alkynyl each having 2 to 4 carbon atoms, alkoxyalkyl having 1 or 2 carbon atoms in each alkyl part and optionally substituted phenyl and benzyloxyalkyl having 1 up to 2 carbon atoms in the alkyl part, the substituents which are preferably those in R 'to R⁶ already preferably mentioned.

R⁸ and R⁹ are identical or different and are preferably hydrogen, straight-chain or branched alkyl having 1 to 6 carbon atoms, cycloalkyl having 3 to 6 carbon atoms, alkenyl and alkynyl each having 2 to 4 carbon atoms, alkoxy having 1 to 4 carbon atoms and optionally substituted phenyl, benzyl or benzyloxy, the substituents which are preferably those in R1 to R⁶ already preferably mentioned.

M preferably stands for the alkali metals sodium and potassium and for 1 equivalent of the alkaline earth metals magnesium and calcium.

The alcoholates of the formula (II) are known or can be prepared by known methods. They are obtained, for example, by reacting the corresponding 2-hydroxymethyl-tetrahydrofuran derivatives with suitable strong bases, such as, for example, alkali metal or alkaline earth metal amides, hydrides or hydroxides, in an inert solvent. The 2-hydroxymethyl-tetrahydrofuran derivatives mentioned are likewise known or can be prepared by known methods (compare, inter alia H. Kröper, in Houben-Weyl, 'Methods of Organic Chemistry', Volume 6/3, p.519ff (1965) and the literature cited there).

Examples of the 2-hydroxymethyl-tetrahydrofuran derivatives on which the alcoholates of the formula (II) to be used according to the invention are based are:<ul id="ul0007" list-style="none"><li>2-hydroxymethyl tetrahydrofuran</li><li>2- (1-hydroxyprop-1-yl) tetrahydrofuran</li><li>2- (1-hydroxyethyl) tetrahydrofuran</li><li>2- (3-hydroxypent-3-yl) terahydrofuran</li><li>2- (hydroxyphenylmethyl) tetrahydrofuran</li><li>2- (2-hydroxyprop-2-yl) tetrahydrofuran</li></ul>

Formula (III) provides a general definition of the compounds to be used as starting materials for process variant (a). In this formula, R stands¹⁰ preferably for hydrogen, straight-chain or branched alkyl having 1 to 6 carbon atoms, alkenyl and alkynyl each having 2 to 4 carbon atoms, haloalkyl having up to 2 carbon atoms and up to three identical or different halogen atoms, fluorine, chlorine and bromine in particular being halogens , as well as for optionally substituted phenyl, the preferred substituents being those at R 'to R⁶ in the case of the starting materials of the formula (II) which are preferably already mentioned.

Y preferably represents optionally substituted aryl having 6 to 10 carbon atoms, in particular phenyl and naphthyl, which can carry one or more identical or different substituents. Preferred substituents are the halogens fluorine, chlorine or bromine; Alkyl and alkexy of 1 to 4 carbon atoms; Haloalkyl, haloalkoxy and haloalkylthio with up to 4 carbon atoms and up to 5 halogen atoms, in particular with up to 2 carbon atoms and up to 3 identical or different halogen atoms, the halogens being in particular fluorine, chlorine and bromine; phenyl, phenoxy or phenoxycarbonyl optionally substituted by halogen, in particular fluorine, chlorine or bromine, alkyl and alkoxy each having 1 to 2 carbon atoms and haloalkyl having up to 2 carbon and up to 3 identical or different halogen atoms, such as in particular fluorine and chlorine; Alkoxycarbonyl having 1 to 4 carbon atoms in the alkyl part; the methylenedioxo group and the tri, tetra or pentamethylene radical. In the event that Y is phenyl, this must be substituted if R'bis R '⁰ Mean hydrogen.

The starting materials of the formula (III) are generally known compounds of organic chemistry. Examples include:<ul id="ul0008" list-style="none"><li>Benzyl chloride, benzyl bromide, benzyl mesylate, benzyl tosylate, 2-fluorobenzyl bromide, 3-fluorobenzyl bromide, 4-fluorobenzyl bromide, 2-chlorobenzyl chloride, 3-chlorobenzyl chloride, 4-chlorobenzyl chloride, 2-bromobenzyl chloride, 3-bromobenzyl chloride, 4-bromobenzyl chloride, 4-bromobenzyl chloride, 4-bromobenzyl chloride, 4-bromobenzyl chloride Methylbenzyl chloride, 4-methylbenzylchloride, 2-methoxybenzylchloride, 3-methoxybenzylchloride, 4-methoxybenzylchloride, 2-trifluoruethylbenzylchloride, 3-trifluoromethylbenzylchloride, 4-trifluoromethylbenzylchloride, 4-phenylbenzyl chloride, 2,6-difluorobenzyl chloride, 2,6-dichlorobenzyl chloride, 2,4-dichlorobenzyl chloride, 3,4-dichlorobenzyl chloride, 2,5-dichlorobenzyl chloride, 2,6-dimethylbenzyl chloride, 2,4-dimethylbenzyl bromide, 3,4- Dimethylbenzyl chloride, 2,3-dimethylbenzylchloride, 3,4-dioxomethylenebenzylchloride, 2,6-chlorofluorobenzylchloride, 2-fluoro-5-chlorobenzylbromide, 2-fluoro-4-chlorobenzylbromide, 3-chloro-4-fluorobenzylbromide, 3,4-tetramethylenebenzylchloride, 2-methyl-6-chlorobenzyl chloride, 2-methyl-6-fluorobenzyl chloride, 2-fluoro-3-methylbenzyl chloride, 2-fluoro-4-methylbenzyl chloride, 2-fluoro-5-methylbenzyl chloride, 2-methyl-3-chlorobenzyl chloride, 2-methyl-4-chlorobenzyl chloride, 2- Methyl 5-chlorobenzyl chloride, 2,4,5-trichlorobenzyl bromide, 2,4,6-trichlorobenzyl bromide, diphenylmethyl bromide, 1-bromo-1-phenyl-ethane, 1-bromo-1- (2-fluorophenyl) -ethane, 1- Bromine 1- (2-methylphenyl) ethane.</li></ul>

Formula (IV) provides a general definition of the diols to be used as starting materials for process variant (b). In this formula, R 'to R ​​are⁹ preferably for the radicals which have already been mentioned as preferred for the alcoholates of the formula (II). R¹⁰ and Y preferably represent the radicals which have already been mentioned as preferred for the compounds of the formula (III).

The diols of the formula (IV) are known or they can be prepared by known methods. Examples include:<ul id="ul0009" list-style="none"><li>1-benzyloxy-pentane-2,5-diol</li><li>1- (2-fluorobenzyloxy) pentane-2,5-diol</li><li>1- (2-chlorobenzyloxy) pentane-2,5-diol</li><li>1- (2-methylbenzyloxy) pentane-2,5-diol</li><li>1- (2-bromobenzyloxy) pentane-2,5-diol</li><li>1- (4-fluorobenzyloxy) pentane-2,5-diol</li><li>1- (2,6-dichlorobenzyloxy) pentane-2,5-diol</li><li>1-benzyloxy-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2-fluorobenzyloxy) -5,5-dimethylpentane -2,5-diol</li><li>1- (2-chlorobenzyloxy) -5,5-dimethyl-penran-2,5-diol</li><li>1- (2-methylbenzyloxy) -5,5-dimethylpentan-2,5-diol</li><li>1- (2-bromobenzyloxy) -5,5-dimethyl-penatan-2,5-diol</li><li>1- (4-fluorobenzyloxy) -5,5-dimethylpentan-2,5-diol</li><li>1- (2,6-dichlorobenzyloxy) -5,5-dimethylpentan-2,5-diol</li><li>1-benzyloxy-2,5,5-trimethyl-pentane-2,5-diol</li><li>1- (2-fluorobenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1- (2-chlorobenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1- (2-methylbenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1- (2-bromobenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1- (4-fluorobenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1- (2,6-dichlorobenzyloxy) -2,5,5-trimethylpentan-2,5-diol</li><li>1-benzyloxy-2-ethyl-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2-fluorobenzyloxy) -2-ethyl-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2-chlorobenzyloxy) -2-ethyl-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2-methylbenzyloxy) -2-ethyl-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2-bromobenzyloxy) -2-ethyl-5,5-dimethyl-pentam-2,5-diol</li><li>1- (4-fluorobenzyloxy) -2-ethyl-5,5-dimethyl-pentane-2,5-diol</li><li>1- (2,6-dichlorobenzyloxy) -2-ethyl-5,5-dimethyl-pentane-2,5-diol</li></ul>

The formulas (Va), (Vb) and (Vc) generally define the dihydrofuran derivatives to be used as starting materials for process variant (c). In these formulas, R 'to R' preferably represent the radicals which have already been mentioned as preferred for the alcoholates of the formula (II). R¹⁰ and Y preferably represent the radicals which have already been mentioned as preferred for the compounds of the formula (III).

The dihydrofuran derivatives of the formulas (Va), (Vb) and (Vc) are not yet known. However, they can be obtained in a simple manner if, according to process variant (a), alcoholates of 2-hydroxymethyl-dihydrofuran derivatives of the formulas<chemistry id="chem0013" num="0013"><img file="EP0000002A1_D0013.tif" /></chemistry><chemistry id="chem0014" num="0014"><img file="EP0000002A1_D0014.tif" /></chemistry><chemistry id="chem0015" num="0015"><img file="EP0000002A1_D0015.tif" /></chemistry>in which<ul id="ul0010" list-style="none"><li>R 'to R9</li><li>and M have the meaning given above,</li><li>with a compound of formula (III) if appropriate in the presence of a diluent.</li></ul>

Formula (VI) provides a general definition of the furan derivatives to be used as starting materials for process variant (d). In this formula, R², R³, R ', R⁵ and R⁹ preferably for the radicals which have already been mentioned as preferred for the alcoholates of the formula (II). R¹⁰ and Y preferably represent the radicals which have already been mentioned as preferred for the halides of the formula (III).

The furan derivatives of the formula (VI) are not yet known. However, they are obtained in a simple manner if, according to process variant (a), alcoholates of 2-hydroxymethyl-furan derivatives of the formula<chemistry id="chem0016" num="0016"><img file="EP0000002A1_D0016.tif" /></chemistry>in which<ul id="ul0011" list-style="none"><li>R2, R³, R⁶, R8,</li><li>R⁹ and M have the meaning given above,</li><li>with a compound of formula (III) if appropriate in the presence of a diluent.</li></ul>

Examples of starting materials of the formula (VI) are:<ul id="ul0012" list-style="none"><li>2- (2-fluorobenzyloxymethyl) furan</li><li>2- [1- (2-fluorobenzyloxy) eth-1-yl] furan</li><li>2- [1- (2-chlorobenzyloxy) prop-1-yl] furan</li><li>2- [1- (2-fluorobenzyloxy) prop-1-yl] furan</li><li>2- [1- (2-fluorobenzyloxy) eth-1-yl] furan</li><li>2- [1- (2-methylbenzyloxy) eth-1-yl] furan</li><li>2- [1- (benzyloxy) eth-1-yl] furan</li><li>2- [3- (2-fluorobenzyloxy-pent-3-yl] furan</li><li>2- [3- (2-methylbenzyloxy) pent-3-yl] furan</li><li>2- [3- (2-chlorobenzyloxy) pent-3-yl] furan</li><li>2- (1- (2-chlorobenzyloxy) eth-1-yl] furan</li><li>2- [α- (2-fluorobenzyloxy) benzyl] furan</li><li>2-Ea- (2-chlorobenzyloxy) benzyl] furan</li><li>2- [2- (2-fluorobenzyloxy) prop-2-yl] furan</li><li>2- (α-phenylbenzyloxy-methyl) furan</li></ul>

The alcoholates of the formulas (VIIa), (VIIb), (VIIc) and (VIII) are known or can be prepared by known methods. They are obtained, for example, by reacting the corresponding 2-hydroxymethyl-dihydrofuran derivatives or 2-hydroxymethyl-furan derivatives with suitable strong bases, such as, for example, alkali metal or alkaline earth metal amides, hydrides or hydroxides, in an inert solvent. The 2-hydroxymethyl derivatives mentioned are also known or can be prepared by known methods (see, inter alia, H. Kröper in Houben-Weyl, 'Methods of Organic Chemistry', Volume 6/3, pp. 519ff (1965) and the one cited therein Literature).

Inert organic solvents are preferably used as diluents for the implementation according to process variant (a) according to the invention. These preferably include ethers such as diethyl ether, tetrahydrofuran or dioxane, aromatic hydrocarbons such as benzene or toluene, and in individual cases also chlorinated hydrocarbons such as chloroform, methylene chloride or carbon tetrachloride.

In process variant (a), the reaction temperatures can be varied within a substantial range. In general, one works between 0 and 120 ° C, preferably at 20 to 100 ° C. The process variant (a) according to the invention is preferably carried out in molar amounts. However, it is also possible to use the alcoholates of the formula (II) or the compounds of the formula (III) in excess of up to 1 mol. To isolate the end products, water is added to the reaction mixture, the organic phase is separated off and worked up and purified in the customary manner. In individual cases, the end product can also be distilled off from the reaction product directly after the solvent.

According to a preferred embodiment, the procedure is advantageously carried out in such a way that a 2-hydroxymethyltetrahydrofuran derivative is used, the latter converted into the alkali metal alcoholate of the formula (II) in a suitable inert solvent by means of alkali metal hydride or amide, and the latter without Isolation immediately reacted with a compound of formula (III) and thus the compounds of formula (I) according to the invention obtained in one operation. The compound of formula (III) can also be added to the reaction mixture before the alcoholate is prepared.

According to a further preferred embodiment, the preparation of the alcoholate of the formula (II) and the reaction according to process (a) according to the invention are advantageously carried out in a two-phase system, such as, for example, aqueous sodium hydroxide solution or potassium hydroxide solution / toluene or methylene chloride, with the addition of a phase transfer catalyst, such as ammonium or phosphonium compounds.

The reaction according to process variant (b) according to the invention is preferably carried out without a solvent.

The reaction according to the invention in process variant (b) is carried out in the presence of an acid catalyst. All commonly used inorganic and organic acid catalysts can be used. These preferably include organic acids, such as p-toluenesulfonic acid, inorganic acids, such as hydrochloric acid and sulfuric acid, and metal halides, such as aluminum chloride.

The reaction temperatures in process variant (b) can be varied within a substantial range. Generally one works between 80 and 250 ° C, preferably between about 100 and 220 ° C.

To isolate the end products in process variant: b) the reaction mixture is distilled in vacuo and the water is then separated off in the customary manner.

For the reactions according to the invention according to process variants (c) and (d), inert organic solvents are preferably suitable when using a diluent. These preferably include alcohols, such as methanol and ethanol, and ethers, such as diethyl ether and tetrahydrofuran.

The reactions according to the invention according to process variants (c) and (d) are carried out in the presence of a catalyst. You can use all commonly used hydrogenation catalysts. These preferably include noble metal, noble metal oxide (or noble metal hydroxide) catalysts or so-called 'Raney catalysts', such as in particular platinum, platinum oxide, nickel, rhodium, rhodium oxide, ruthenium, palladium and osmium.

The reaction temperatures can be varied over a wide range in process variants (c) and (d). I: n generally between 20 and 200 ° C, preferably at 80 to 150 ° C.

The reactions according to process variants (c) and (d) can be carried out under normal pressure, but also under elevated pressure, preferably at 1 to 200 atm.

When carrying out process variants (c) and (d) according to the invention, 1 mol of the compounds of the formulas (Va), (Vb), (Vc) or (VI) is preferably employed in 2 mol of hydrogen and 0.01-01 mol of catalyst a. To isolate the end products, the catalyst is filtered off, if appropriate freed from the solvent in vacuo and the products of the formula (I) obtained are purified by distillation or recrystallization.

The compounds of the formula (I) according to the invention can optionally be present in different geometric isomers which can be obtained in different proportions. They are also available as optical isomers. The case may arise that certain isomers have a greater activity than others, so that it may be expedient to prepare or isolate the more active components. All isomers are claimed according to the invention.

Examples of particularly effective representatives of the active compounds according to the invention include the preparation examples and the examples in Table 1:<ul id="ul0013" list-style="none"><li>2-benzyloxymethyl-5-methyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -5-methyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -5-methyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -5-methyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -5-methyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-methyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -5-methylterahydrofuran</li><li>2-benzyloxymethyl-2-methyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-methyl-tetrahydrofuran</li><li>2-benzyloxymethyl-2-ethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-ethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-ethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-ethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-ethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-ethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-ethyl-tertahydrofuran</li><li>2-benzyloxymethyl-2-propyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-propyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-propyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-propyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-propyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-propyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-propyl-tertahydrofuran</li><li>2-benzyloxymethyl-2,5,5-trimethyltertahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2,5,5-trimethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2,5,5-trimethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2,5,5-trimethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2,5,5-trimethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2,5,5-trimethyl-tetrahydrofuran</li><li>2-benzyloxymethyl-2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-ethyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-ethyl-5,5-dimethyl-tertahydrofuran</li><li>2-benzyloxymethyl-2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -5-chloromethyl-tetrahydrofaran</li><li>2- (2-bromobenzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-propyl-5,5-dimethyl-tetrahydrofuran</li><li>2-benzyloxymethyl-2-phenyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-phenyl-tetrahydrofuran</li><li>2-lenzyloxymethyl-2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-ethyl-5-phenyl-tetrahydrofuran</li><li>2-benzyloxymethyl-2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2,5-diethyl-5-methyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li><li>2-benzyloxymethyl-2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2-methyl-5-phenyl-tetrahydrofuran</li><li>2-benzyloxymethyl-5-ethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (benzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2,5-dimethyl-5-vinyl-tetrahydrofuran</li><li>2- (benzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -2,5-dimethyl-5-ethyl-tetrahydrofuran</li><li>2- (benzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2-fluorobenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2-chlorobenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2-methylbenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-methoxymethyl-tetrah:₇drofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -5-methcxymethyl-tetrahydrofuran</li><li>2- (benzyloxymethyl) -5-chloromethyl-tetrahydrofuran</li></ul>

The active compounds according to the invention influence plant growth and can therefore be used as defoliants, desiccants, haulm killers, germ inhibitors and in particular as weed killers. Weeds in the broadest sense are understood to mean all plants that grow up in places where they are undesirable. Whether the substances according to the invention act as total or selective herbicides depends essentially on the amount used.

The active compounds according to the invention can be used, for example, in the following plants:<ul id="ul0014" list-style="none"><li>Dicot weeds of the genera: Mustard (Sinapis), cress (Lepidium), bedstraw (Galium), starwort (Stellaria), chamomile (Matricaria), dog chamomile (Anthemis), button herb (Galinsoga), goose foot (Chenopodium), nettle (Urtica), ragwort (Senecio), Foxtail (Amaranthus), purslane (Portulaca), Norway burdock (Xanthium), morning glory (Convolvulus), morning glory (Ipomoea), knotweed (Polygonum), sesbania (Sesbania), ambrosia (Ambrosia), thistle (Cirsium), thistle (Carduus) Goose thistle (Sonchus), nightshade (Solanum), Swamp cress (Rorippa), rotala, celandine (Lindernia), dead nettle (Lamium), honorary award (Veronica), common mallow (Abutilon), emex, thorn apple (Datura), violet (viola), hemp nettle, hollow tooth (Galeopsis), poppy (Papaver) , Knapweed (Centaurea).</li></ul>

Dicotyle cultures of the genera: Cotton (Gossypium), soybean (Glycine), turnip (Beta), carrot (Daucus), haricot bean (Phaseolus), pea (Pisum), potato (Solanum), flax (Linum), morning glory (Ipomoea), Bean (Vicia), tobacco (Nicot: .ana), tomato (Lycopersicon), peanut (Arachis), cabbage (Brassica), cos (Lactuca), cucumber (Cucumis), pumpkin (Cuburbita).

Monocot weeds of the genera: Chicken Millet (Echinochloa), Bristle Millet (Setaria), Millet (Panicum), Finger Millet (Digitaria), Lieschgras (Phleum), Panicle Grass (Poa), Fescue (Festuca), Eleusine, Brachiaria, Lolch (Lolium), Trespe (Bromus) (Avena), yellow grass (Cyperus), black millet (Sorghum), grasshopper (Agropyron), canine grass (Cynodon), monocharia, fimbristylis, arrow herb (Sagittaria), swamp (Eleocharis), cornice (Scirpus), Paspalum, Ischaemium, Sphenum , Ostrich grass (Agrostis), Foxtail grass (Alopecurus), wind straw (Apera).

Monocot crops of the genera: Rice (Oryza), Maize (Zea), Wheat (Triticum), Barley (Hordeum), Oats (Avena), Rye (Secale), Millet (Sorghum), Millet (Panicum), Sugar Cane (Saccharum), Pineapple (pineapple), asparagus (asparagus), leek (allium).

However, the use of the active compounds according to the invention is by no means restricted to these genera, but extends in the same way to other plants.

Depending on the concentration, the compounds are suitable for total weed control, for example on industrial and rail tracks and on paths and squares with and without tree cover. Likewise, the compounds for weed control in permanent crops, for example forest, ornamental wood, fruit, wine, citrus, nut, banana, coffee, tea, rubber, oil palm, cocoa, berry fruit and hop plants and for selective weed control. fighting in annual crops.

The active compounds according to the invention have, in particular, strong herbicidal effects against grasses, without damaging various crop plants. They can therefore preferably be used for selective weed control. The following crops are particularly suitable: beets, soybeans, beans, cotton, rapeseed, peanuts, vegetables, corn and rice.

The active compounds according to the invention can be converted into the customary formulations, such as solutions, emulsions, suspensions, powders, pastes and granules. These are made in a known manner, e.g. B. by mixing the active ingredients with extenders, that is to say liquid solvents, pressurized liquefied gases and / or solid carriers, if appropriate using surface-active agents, that is to say emulsifiers and / or dispersants and / or foam-generating agents. In the case of the use of water as an extender, z. B. organic solvents can also be used as auxiliary solvents. The following are essentially suitable as liquid solvents: aromatics, such as xylene, toluene, benzene or alkylnaphthalenes, chlorinated aromatics or chlorinated aliphatic hydrocarbons, such as chlorobenzenes, chloroethylene or methylene chloride, aliphatic hydrocarbons, such as cyclohexane or paraffins, e.g. B. Petroleum fractions, alcohols, such as butanol or glycol, and their ethers and esters, ketones, such as acetone, methyl ethyl ketone, methyl isobutyl ketone or cyclohexanone, strongly polar solvents, such as dimethylformamide and dimethyl sulfoxide, and water; Liquefied gaseous extenders or carriers mean those liquids which are gaseous at normal temperature and pressure, e.g. B. Aerosol propellants, such as dichlorodifluoromethane or trichlorofluoromethane; as solid carriers: natural rock powder, such as kaolins, clays, talc, chalk, quartz, attapulgite, montmorillonite or diatomaceous earth and synthetic rock powder, such as highly disperse silica, aluminum oxide and silicates; as an emulsifier; nonionic and anionic emulsifiers, such as polyoxyethylene fatty acid esters, polyoxyethylene fatty alcohol ether, for example Alkylaryl polyglycol ether, alkyl sulfonates, alkyl sulfates, aryl sulfonates and protein hydrolyzates; as a dispersant: e.g. B. Lignin sulfite waste liquor: a and methyl cellulose.

The active compounds according to the invention, as such or in their formulations for strengthening and supplementing their spectrum of action, can be combined with other herbicidal active compounds, depending on the intended use, ready formulation or tank mixture being possible.

Of particular note are the combinations of the active compounds according to the invention with 4-amino-3-methyl-6-phenyl-1,2,4-triazin-5 (4H) -one (metamitron) for beet crops, 4-amino-6-tert. -butyl-3-methylthio-1,2,4-triazine-5 (4H) -one (metribuzin) for soybeans, tomatoes and potatoes and 2-chloro-4-ethylamino-6-isopropylamino-1,3,5-triazine (Atrazine) for corn and soybeans, with 3- (3,4-dichlorophenyl) -1,1-dimethylurea (diuron) and 3- (3-trifluoromethylphenyl) -1,1-dimethylurea (fluomethuron) for cotton.

The formulations generally contain between 0.1 and 95 percent by weight of active compound, preferably between 0.5 and 90 percent by weight.

The active compounds can be used as such, in the form of their formulations or the use forms prepared therefrom, such as ready-to-use solutions, emulsions, suspensions, powders, pastes and granules. They are used in the customary manner, for example by spraying, spraying, dusting, scattering and pouring.

The active compounds according to the invention can be applied both after and in particular before emergence of the plants. They can also be worked into the soil before sowing. The amount of active ingredient used can fluctuate in larger areas. It essentially depends on the type of effect you want. In general, the application rates are between 0.1 and 10 kg of active ingredient per ha, preferably between 0.2 and 6 kg / ha.

The active compounds according to the invention not only have herbicidal properties, but also a fungicidal and insecticidal activity.

The good herbicidal effects of the active compounds according to the invention and their selective uses are evident from the examples below.

Example A

Pre-emergence test

Solvent: 5 parts by weight of acetone

Emulsifier: 1 part by weight of alkylaryl polyglycol ether

To produce a suitable preparation of active compound, 1 part by weight of active compound is mixed with the stated amount of solvent, the stated amount of emulsifier is added and the concentrate is diluted with water to the desired concentration.

Seeds of the test plants are sown in normal soil and watered with the preparation of active compound after 24 hours. The amount of water per unit area is expediently kept constant. The concentration of active substance in the preparation is irrelevant, the only decisive factor is the amount of active substance applied per unit area. After three weeks, the degree of damage to the plants is rated in% damage compared to the development of the untreated control. It means:<ul id="ul0015" list-style="none"><li>0 % = no effect (like untreated control) 100% = total destruction</li></ul>

Active ingredients, application rates and results are shown in the table below:<tables id="tabl0001" num="0001"><img file="EP0000002A1_D0017.tif" /></tables> Manufacturing examples

example 1

<chemistry id="chem0017" num="0017"><img file="EP0000002A1_D0018.tif" /></chemistry>

(Process variant a)

20.4 g (0.2 mol) of tetrahydrofurfuryl alcohol are added dropwise at room temperature to a mixture of 4.8 g (0.2 mol) of sodium hydride (6.0 g of 80% sodium hydride in paraffin oil) in 200 ml of absolute dioxane. The mixture is then refluxed for a further 30 minutes, cooled to 50 ° C. and 38 g (0.2 mol) of 2-fluorobenzyl bromide are then added dropwise to the sodium salt thus obtained. The mixture is then heated under reflux for 3 hours, allowed to cool to room temperature, mixed with 20 ml of methanol to destroy excess sodium hydride and concentrated by distilling off the solvent in vacuo. The residue is taken up in 200 ml of water and extracted with methylene chloride. The organic phase is dried over sodium sulfate, filtered, the solvent is stripped off and the residue is fractionated in vacuo. 37.8 g (90% of theory) of 2- (2-fluorobenzyloxymethyl) tetrahydrofuran with a boiling point of 79 ° C./0.1 mm are obtained.

Example 2

<chemistry id="chem0018" num="0018"><img file="EP0000002A1_D0019.tif" /></chemistry>

(Process variant d)

25th g (0.1 mol) of 2- [1- (2-chlorobenzyloxy) propyl] furan are dissolved in 200 ml of methanol and after addition of 5 g of rhodium catalyst (5% rhodium on aluminum oxide) for 4 hours at 5 atm and Room temperature hydrogenated. The catalyst is then filtered off, the filtrate is concentrated by distilling off the solvent in vacuo and the residue is fractionally distilled in vacuo. 15.7 g (62% of theory) of 2- [1- (2-chlorobenzyloxy) propyl] tetrahydrofuran with a boiling point of 101-105 ° C./0.1 mm are obtained.

The compounds listed in Table 1 below can be prepared in an analogous manner.<tables id="tabl0002" num="0002"><img file="EP0000002A1_D0020.tif" /></tables><tables id="tabl0003" num="0003"><img file="EP0000002A1_D0021.tif" /></tables><tables id="tabl0004" num="0004"><img file="EP0000002A1_D0022.tif" /></tables><tables id="tabl0005" num="0005"><img file="EP0000002A1_D0023.tif" /></tables><tables id="tabl0006" num="0006"><img file="EP0000002A1_D0024.tif" /></tables>

Manufacture of raw materials

(a) The 2- [1- (2-chlorobenzyloxy) propyl] furan used as the starting product according to Example 2 can be prepared as follows:<ul id="ul0016" list-style="none"><li>To a mixture of 4.8 g (0.2 mol) of sodium hydride (6.0 g of 80% sodium hydride in paraffin oil) and 200 ml of absolute dioxane, 27.2 g (0.2 mol) of 2- (1- Hyroxypropyl) furan added dropwise.</li><li>The mixture is then heated under reflux for 30 minutes, cooled to 50 ° C. and 32 g (0.2 mol) of 2-chlorobenzyl chloride are then added dropwise to the sodium salt thus obtained. The mixture is then heated under reflux for a further 3 hours, 20 ml of methanol are added to destroy excess sodium hydride and the mixture is concentrated by distilling off the solvent in vacuo.</li><li>The residue is taken up in 200 ml of water and extracted with methylene chloride. The organic phase is dried over sodium sulfate, filtered, the solvent is stripped off and the residue is fractionated in vacuo. 36.0 g (72% of theory) of 2- [1- (2-chlorobenzyloxy) propyl] furan with a boiling point of 95-97 ° C./0.1 mm are obtained.</li></ul>