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

The invention relates to 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- (1'-methyl-2'-methoxyethyl) chloroacetanilide, can be used as herbicides, in particular for controlling grass-like weeds (cf. DE-A-2 328 340). However, the selectivity of these compounds is not always satisfactory.

There were tetrahydrofuran derivatives of the formula I.<chemistry id="chem0001" num="0001"><img file="EP0000002B1_D0001.tif" /></chemistry>in which<ul id="ul0001" list-style="none"><li>R¹ to R⁶ are the same or different and represent hydrogen, straight-chain or branched C₁_₈‾- alkyl, C_1-2-Halogenalkyl with up to three identical or different halogen atoms (where in particular fluorine, chlorine and bromine are halogens), alkoxyalkyl with 1 or 2 carbon atoms in each alkyl part, and for each optionally by halogen, C._1-2-Alkyl, C_1-2-Alkoxy or C_1-2Haloalkyl with up to three identical or different halogen atoms (such as in particular fluorine and chlorine) substituted phenyl or benzyloxyalkyl with 1 or 2 carbon atoms in the alkyl part,</li><li>R⁵ and R⁶ also together represent a saturated carbocyclic ring with a total of 3 to 6 carbon atoms,</li><li>R⁷ for hydrogen, straight-chain or branched C_1-6-Alkyl, C_3-6Cycloalkyl, C_2-4Alkenyl, C_2-4- Alkynyl, alkoxyalkyl with 1 to 2 carbon atoms in each alkyl part, and for each by halogen, C_1-2-Alkyl, C_1-2-Alkoxy, or C_1-2Haloalkyl with up to three identical or different halogen atoms (in particular fluorine and chlorine) substituted phenyl or benzyloxyalkyl with 1 or 2 carbon atoms in the alkyl part,</li><li>R ^ and R⁹ are the same or different and represent hydrogen, straight-chain or branched C_1-6- alkyl, C_2-4Alkenyl, C_2-4Alkynyl, C_3-6Cycloalkyl, C_1-4-Alkoxy, and for each optionally by halogen, C_1-2-Alkyl, C_1-2-Alkoxy or C_1-2Haloalkyl with up to three identical or different halogen atoms (such as in particular fluorine and chlorine) substituted phenyl, benzyl or benzyloxy,</li><li>R¹⁰for hydrogen, straight-chain or branched C_1-6-Alkyl, C_2-4Alkenyl, C_2-4Alkynyl, C_1-2 Haloalkyl with up to three identical or different halogen atoms (whereby halogen, in particular fluorine, chlorine or bromine), and for optionally by halogen, C_1-2-Alkyl, C_1-2-Alkoxy or C_1-2-Halogenalkyl with up to three identical or different halogen atoms (such as in particular fluorine and chlorine) substituted phenyl and</li><li>Y represents optionally substituted aryl having 6 to 10 carbon atoms (in particular phenyl and naphthyl), which can carry one or more identical or different of the following substituents: the halogens fluorine, chlorine or bromine; Alkyl and alkoxy, each with 1 to 4 carbon atoms; Haloalkyl, haloalkoxy and haloalkylthio, each with up to 4 C atoms and up to 5 halogen atoms (in particular with up to 2 C atoms and up to 3 identical or different halogen atoms, the halogen being in particular fluorine, chlorine and bromine); optionally substituted by halogen, (in particular fluorine, chlorine or bromine), alkyl and alkoxy each having 1 to 2 carbon atoms and halogenoalkyl having up to 2 carbon atoms and up to 3 identical or different halogen atoms (such as in particular fluorine and chlorine) Phenyl, phenoxy or phenoxycarbonyl; Alkoxycarbonyl with 1 to 4 carbon atoms in the alkyl part; the methylenedioxy group and the tri, tetra or pentamethylene radical; with the proviso that if Y is phenyl, this must be substituted if R¹ to R¹⁰ Mean hydrogen</li></ul>found.

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

Furthermore, it was found that the tetrahydrofuran derivatives of the formula 1 are obtained when<ul id="ul0002" list-style="none"><li>(a) Alcoholates of 2-hydroxymethyl-tetrahydrofuran derivatives of the formula II<chemistry id="chem0002" num="0002"><img file="EP0000002B1_D0002.tif" /></chemistry>in which<ul id="ul0003" list-style="none"><li>R¹ to R⁹ have the meaning given above and</li><li>M stands for an alkali or alkaline earth metal (in particular for sodium and potassium and for 1 equivalent of magnesium and calcium),</li><li>with a compound of formula III<chemistry id="chem0003" num="0003"><img file="EP0000002B1_D0003.tif" /></chemistry>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></ul>in a manner known per se, if appropriate in the presence of a diluent, or if one</li><li>(b) Diols of formula IV<chemistry id="chem0004" num="0004"><img file="EP0000002B1_D0004.tif" /></chemistry>in which<ul id="ul0004" list-style="none"><li>R¹ to R¹⁰ and</li><li>Y have the meaning given above,</li></ul>heated in a conventional manner in the presence of an acidic catalyst and optionally in the presence of a diluent.</li></ul>

Compounds of the formula I in which either R¹ and R⁷ or R¹ and R⁴ or R⁴ and R⁵ stand for hydrogen can also be obtained if one<ul id="ul0005" list-style="none"><li>(c) Dihydrofuran derivatives of the formulas Va, Vb and Vc<chemistry id="chem0005" num="0005"><img file="EP0000002B1_D0005.tif" /></chemistry><chemistry id="chem0006" num="0006"><img file="EP0000002B1_D0006.tif" /></chemistry>and or<chemistry id="chem0007" num="0007"><img file="EP0000002B1_D0007.tif" /></chemistry>in which<ul id="ul0006" list-style="none"><li>R¹ to R¹⁰and</li><li>Y have the meaning given above,</li></ul>hydrogenated in a conventional manner in the presence of a catalyst and optionally in the presence of a diluent with hydrogen.</li></ul>

Compounds of the formula I in which R¹, R⁴, R⁵ and R⁷ stand for hydrogen can also be obtained if one<ul id="ul0007" list-style="none"><li>(d) Furan derivatives of the formula VI<chemistry id="chem0008" num="0008"><img file="EP0000002B1_D0008.tif" /></chemistry>in which<ul id="ul0008" list-style="none"><li>R², R³, R⁶, R⁸, R⁹, R¹⁰ and Y have the meaning given above,</li></ul>hydrogenated in a conventional manner in the presence of a catalyst and optionally in the presence of a diluent with hydrogen.</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, in their herbicidal action and, moreover, show a markedly better selectivity compared to important kulfur plants. 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="EP0000002B1_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="EP0000002B1_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="EP0000002B1_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="EP0000002B1_D0012.tif" /></chemistry>

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 (cf., 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="ul0009" list-style="none"><li>2-hydroxymethyl tetrahydrofuran</li><li>2- (-hydroxyprop-1-yi) tetrahydrofuran</li><li>2- (1-hydroxyethyl) tetrahydrofuran</li><li>2- (3-hydroxypent-3-yl) tetrahydrofuran</li><li>2- (hydroxyphenylmethyl) tetrahydrofuran</li><li>2- (2-hydroxyprop-2-yl) tetrahydrofuran</li></ul>

The compounds to be used as starting materials for process variant (a) are generally defined by formula III.

The starting materials of formula III are generally known compounds of organic chemistry. Examples include:<ul id="ul0010" 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, 4-bromobenzyl chloride Methylbenzyl chloride, 4-methylbenzylchloride, 2-methoxybenzylchloride, 3-methoxybenzylchloride, 4-methoxybenzylchloride, 2-trifluoromethylbenzylchloride, 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-dioxymethylenebenzylchloride, 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-phenylethane, 1-bromo-1- (2-fluorophenyl) -ethane, 1- Bromine 1- (2-methylphenyl) ethane.</li></ul>

Formula IV generally defines the diols to be used as starting materials for process variant (b).

The diols of the formula IV are known or they can be prepared by known methods. Examples include:<ul id="ul0011" 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-dimethylpentan-2,5-diol</li><li>1- (2-chlorobenzyloxy) -5,5-dimethylpentan-2,5-diol</li><li>1- (2-methylbenzyloxy) -5,5-dimethylpentan-2,5-diol</li><li>1- (2-bromobenzyloxy) -5,5-dimethylpentan-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-pentane-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).

The dihydrofuran derivatives of the formulas Va, Vb and Vc are not yet known, but they can be obtained in a simple manner if, according to process variant (a), alcoholates of 2-hydroxymethyl-dihydrofuran derivatives of the formulas VIIa, Vllb and Vllc<chemistry id="chem0013" num="0013"><img file="EP0000002B1_D0013.tif" /></chemistry><chemistry id="chem0014" num="0014"><img file="EP0000002B1_D0014.tif" /></chemistry><chemistry id="chem0015" num="0015"><img file="EP0000002B1_D0015.tif" /></chemistry>in which<ul id="ul0012" list-style="none"><li>R 'to R⁹ and</li><li>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 generally defines the furan derivatives to be used as starting materials for process variant (d).

The furan derivatives of the formula VI are not yet known. However, they can be obtained in a simple manner if, according to process variant (a), alcoholates of 2-hydroxymethyl-furan derivatives of the formula VIII<chemistry id="chem0016" num="0016"><img file="EP0000002B1_D0016.tif" /></chemistry>in which<ul id="ul0013" list-style="none"><li>_R², R³, R °, R ", R⁹ and M have the meaning given above,</li></ul>with a compound of the formula III, if appropriate in the presence of a diluent.

The following may be mentioned as starting materials of the formula VI:<ul id="ul0014" 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-Methylbenzyfoxy) 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- [α- (2-chlorobenzyloxy) benzyl] furan</li><li>2- [2- (2-fluorobenzyloxy) prop-2-yl] furan</li><li>2- (a-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-hydroxymethyldihydrofuran 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 likewise known or can be prepared by known methods (cf., inter alia, H. Kröper in Houben-Weyl, 'Methods of Organic Chemistry', Volume 6/3, pp. 519ff [1965] and those therein literature cited).

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. Generally 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-hydroxymethyl-tetrahydrofuran derivative is used, the latter converted into the alkali metal alcoholate of the formula 11 in a suitable inert solvent using alkali metal hydride or amide, and the latter immediately without isolation reacted with a compound of the formula III and thus obtained the compounds of the formula according to the invention in one operation. The compound of the 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, for example Ammonium or phosphonium compounds performed.

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). Generally one works 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, 2 mol of hydrogen and 0.01-0.1 mol of catalyst are preferably employed per mol of the compounds of the formulas Va, Vb, Vc or VI. 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 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="ul0015" list-style="none"><li>2-Benzyloxymethyl-5-methyl-tetrahydrofur.an</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-methyl-tetrahydrofuran</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-tetrahydrofuran</li><li>2-benzyloxymethyl-2-propyl-tetrahydrofuran n</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-tetrahydrofuran</li><li>2-benzyloxymethyl-2,5,5-trimethyl-tetrahydrofuran</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-tetrahydrofuran</li><li>2-benzyloxymethyl-2-propyl-5,5-dimethyl-tetrahydrofuran n</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-tetrahydrofuran</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-tetrahydrofura</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-benzyloxymethyl-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-tetrahydrofura</li><li>2- (2-methylbenzyloxymethyl) -5-ethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-ethyl-tetrahydrofura</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 n</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 n</li><li>2- (2-chlorobenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2-bromobenzyloxymethyl) -5-methoxymethyl-tetrahydrofura</li><li>2- (2-methylbenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (4-fluorobenzyloxymethyl) -5-methoxymethyl-tetrahydrofuran</li><li>2- (2,6-dichlorobenzyloxymethyl) -5-methoxymethyl-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, for example used in the following plants: dicot weeds of the genera: Mustard (Sinapsis), 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), winch (Convolvulus), morning glory (Ipomoea), knotweed (Polygonum), sesbanie (Sesbania), ambrosia (Ambrosia), scratch 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). Dicotyle cultures of the genera: Cotton (Gossypium), soybean (Glycine), turnip (Beta), Mohre (Daucus), haricot bean (Phaseolus), pea (Pisum), potato (Solanum), flax (Linum), morning glory (Ipomoea), Bean (Vicia), Tobacco (Nicotiana), 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), Hafer (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 (Orzya), 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 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 produced in a known manner, for example 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. If water is used as an extender, organic solvents can, for example, 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, for example 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 liquids which are gaseous at normal temperature and under normal pressure, for example 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 meals, such as highly disperse silica, aluminum oxide and silicates; as an emulsifier; non-ionic and anionic emulsifiers, such as polyoxyethylene fatty acid ester, polyoxyethylene fatty alcohol ether, for example Alkylaryl polyglycol ether, alkyl sulfonates, alkyl sulfates, aryl sulfonates and protein hydrolyzates; as dispersing agents: eg lignin sulfite liquor 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, finished formulation or tank mix being possible.

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 the plants emerge. 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

<ul id="ul0016" list-style="none"><li>Solvent: 5 parts by weight of acetone</li><li>Emulsifier: 1 part by weight of alkylaryl polyglycol ether</li></ul>

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="ul0017" list-style="none"><li>0% = no effect (like untreated control)</li><li>100% = total annihilation</li></ul>

Active ingredients, application rates and results are shown in the table below:<tables id="tabl0001" num="0001"><img file="EP0000002B1_D0017.tif" /></tables>

Production Examples Example 1

example 1

<chemistry id="chem0017" num="0017"><img file="EP0000002B1_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="EP0000002B1_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="EP0000002B1_D0020.tif" /></tables><tables id="tabl0003" num="0003"><img file="EP0000002B1_D0021.tif" /></tables><tables id="tabl0004" num="0004"><img file="EP0000002B1_D0022.tif" /></tables><tables id="tabl0005" num="0005"><img file="EP0000002B1_D0023.tif" /></tables><tables id="tabl0006" num="0006"><img file="EP0000002B1_D0024.tif" /></tables><tables id="tabl0007" num="0007"><img file="EP0000002B1_D0025.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:

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- Hydroxypropyl) furan added dropwise.

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 refluxed 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.

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. Ed.