CA2049077A1 - 2,3-dihydrobenzofurylmethyl esters, their preparation and pesticides containing them - Google Patents

Abstract

O.Z. 0050/41848 Abstract of the Disclosure: 2,3-Dihydrobenzofurylmethyl esters of the general formula I

I

where R1 is hydrogen, C1-C4-alkyl, C2-C4-alkenyl, C2-C4-alkynyl or cyano, R2 and R3 independently of one another are each hydrogen or C1-C4-alkyl and n is 0 or 1, processes for their preparation and pesticides containing them.

Description

O.Z~ 48 2~3-Dihydrobenzofurylmethyl esters. their pre~aration and pesticides containin~ them The present invention relates to 2,3-dihydro-benzofurylmethyl esters of the general formula I
Rl F 3C-C ( C I ) =CH--CH--CH--CO 2--CH~R 3 H3C CH3 (F)n where R1 is hydrogen, Cl-C4-alkylt C2-C4-alkenyl, C2-C4-alkynyl or cyano, R2 and R3 independently of one another are each hydrogen or Cl-C4-alkyl and n is 0 or 1.
The present invention furthermore relates to 10 proce~ses for the preparation of the compounds I, agents containing them and methods for their use for controlling pestsO
DE-A 21 08 932 describe3 2,2-dimethyl-2,3-dihydrobenzofur-6-ylmethyl chrysanthemumates having 15 insacticidal activity. Furthermore, ÉP-A 23 637 dis-closes 2,3-dihydrobenzofurylmethyl ester~ whose general formula embrace~ the 2,3-dihydrobenzofurylmethyl esters of the general formula I which were described at the outset.
It ij an ob~ect of the present invention to provide novel compounds having Lmproved insecticidal and acaricidal activity.
We have found that this object is achieved by the 2,3-dihydrobenzofurylmethyl esters I defined at the ~5 out~e~. We have also found pxocesses for the preparation of the~e 2,3-dihydrobenzofuryl~ethyl ester~, agents cont~ining them and methods for the use of these com-pounds aR in~ecticides and acaricides.
The 2,3-dihydrobenzofurylmethyl es~ers I are 30 obtainable by various method~. They are particularly advantageously obtained by ona of the processes A and B
described below.

- 2 - O.Z~ 48 Process A
The compounds I are ob~ained, for example, by e~terifying a 2,3-dihydrobanzofuxylmethyl derivative of the general formula II in a con~entional manner with a carboxylic acid of the general formula IIIa or with a derivative ~hereof.
Rl F3C-C(CI)=CH--CH--CH--C02H + H~CH~R3 / \ (F)n III II
Rl , F 3C-C ( C I ) =CH--C~ CO 2--CH_~R 3 / \(F)n The reaction can be carried out by the conven-tional esterification methods known from the literature.
1. If a carboxylic acid and an alcohol are u~ed as starting materials in this reaction, the reaction is usually carried out at from -10 to 120C, preferably from 10 to 40C, in an inert organic ~olvent in the presence of an acidic catalyst (cf. Houben-Weyl, Vol. VIIII page 516 et seq.).
Aprotic nonpolar solvents, such as aliphatic and aromatic hydrocarbons and chlorohydrocarbons, eg. petrol-eum ether, benzene 7 toluene, xylene, ga~oline, dichloro-methane, chlorofonm, tetrachloromethane, 1,2-dichloro-ethane or chlorobenzene, ethers, such as diethyl ether, di-n-butyl ether, methyl tert-butyl e her, tetrahydro furan or dioxane, ketones, eg. ace~onel methyl ethyl ketone or methyl isopropyl ketone, and nitriles, such as acetonitrile and propionitrile, and corresponding mix-tures are particularly ~uitable for thi~ esterification _ 3 ~ o~z. 0050/41848 method. Examples of acidic catalysts used are sulfuric acid, hydrogen halides, sulfonic acid and acidic ion exchanger~ or polymers.
The catalyst is generally used in amounts of from 0.001 to 10 mole equivalents, preferably from 0.01 to 0.1 mole equivalent, based on the carboxylic acid IIIa.
Furthermore, the equilibrium of the reaction can be shifted in the desired direction by removing from the reaction mixture the water formed in the reaction or the ester, for example by azeotropic distillation or by binding the water in sulfuric or a hydrohalic acid or binding the water to molecular sieves.
In general, the alcohol and the carboxylic acid are reacted with one another in equimolar amounts. It may be advantageous for the yield if the alcohol is used in an excess or in le~s than the stoichiometric amount based on the carboxylic acid.
2. If an activated carboxylic acid and an alcohol are used as starting materials in this reaction, the reaction is usually carried out at from 0 to 100C, preferably from 15 to 25C, in an inert organic solvent in the presence of a base (Houben--Weyl, Vol. E5, page 691 et seq.).
The activated carboxylic acid derivatives used are, for example, anhydrides, halide~, suGh as chlorides and bromide~, or imidazolide~.
The abovementioned aprotic nonpolar solvents are particularly suitable for this esterification method.
The bases used are in particular aliphatic, aromatic and he~erocyclic amineæ, such as dimethylamine, trie~hylamine, piperidine~ dLme~hylaniline, dimethylbenz-ylamine, pyridine and 2 picolineO
The base i~ generally u~ed in an excess of not more than 5.0, preferably not more than 2.0/ in par-ticular from 1.1 to 1.35, mole equivalent~, based on the carboxylic acid deri~ative.
The abovementioned bases can also be used - 4 - 0.~ 848 directly as solvents.
In general, the alcohol and the carboxylic acid deri~ati~e are reacted ~ith one another in equimolar amounts. It may be advantageous for the yield to use the alcohol in an exces~ or in less than the stoichiometric amoun~, based on the carboxylic acid derivative.

3. In addition to the possibilities described above, it is known that, instead of the alcohol, a corresponding activated derivative can also be used as a s~arting material for ~he esterification, said derivati~e being esterified with the salt of a carbo~ylic acid.
Suitable activated alcohol derivatives for this method of es~erification are, for example, the corres-ponding halides t in particular chlorides and bromides, and the sulfonic esters, such as ~oluenesulfonic esters and ben~enesulfonic esters.
Alkali metal, ~lkaline earth metal, silver and lead salts are used as the salts of the carboxylic acids.
This procedure is usually carried out at from -10 to 150C, preferably from 80 to 130C, in a polar inert solvent in the presence of one of the ~ases sta~ed in general and in particular for t.he procedure described under 2. (Houben-Weyl, Vol. VIII, page 541 et seq. and Vol. E5, page 6B4 e~ seq.).
Solvents such as water, alcohols, in particular methanol, ethanol and isopropanol, dimethylformamide and dimethyl sulfoxide are ~uitable for this reaction.
The salts of the carboxylic acids are prepared by reacting the carboxylic acids with the corresponding met~l hydroxide~, carbonates and bicarbonates in the abovemen~ioned ~olven~. With a 5uitable choice o~ the reaction parameters, the reaction ean al~o be carried out by the one-pok method, ie. without isolation of the salts of the carboxylic acids.

4. The estsr~ of type I can al~o be obtained by transesterification. For this purpose, lower alkyl esters (preferably methyl and e~hyl esters) of the r~

- 5 - O. Z . 0050/41848 carboxylic acid IIIa are reacted in a conventional manner (Houben-Weylt Vol. E5, page 702 et seq.; GB-A 2 0Q5 269), in an inert, aprotic nonpolar solvent as stated in general and in particular for Process ~1., with the corresponding alcohol II (Z = OR) in the presence or absence of a catalyst. The catalysts used are inorganic acids, such as sulfuric acid and hydrohalic acids, and Lewis acids, such as boron trifluoride, aluminum tri-chloride, titanium tetrachloride and tetraalkoxy-titanates~
In general, the alcohol derivative and thecarbo~ylic acid are reacted with one another in equLmolar amounts. It may be advantageous for the yield to use the alcohol deriva~ive in an exces~ or in less than the stoichiometric amount, based on the carboxylic acid.

Process B
Compounds I in which Rl is cyano can be prepared not only by the processes described above but also by reacting a 2,3-dihydrobenzofurylaldehyde of the general formula IV with a halide of a carboxylic acid of the general formula IIIb in a conventional manner in the presence of an alkali metal cyanide or of an alkaline earth metal cyanide.

F 3C-C ( C 1 ) =CH--C\-/H-COHa 1 + O=CH~R 3 / \ (F)n IIIb IV
CN

1~ F 3C--C ( C I ) =CH--C~--~H--CO 2 CI~R 3 / \ (F)n I (Rl = CN) - 6 0.~ 48 In formula IIIb; Hal is halogen/ such as fluor-ine, chlorine, bromine or iodine, in particular chlorine or bromine.
This reaction is usually carried out at ~rom 0 to 100C, preferably from 15 to 25C, in an inert organic solvent or in a 2-phase system with the addition of water.
Aprotic nonpolar solvents, such as aliphatic and aromatic hydrocarbons and halohydrocarbons, are par-~icularly sul~able.
If the reaction is carried out in a two-phase system, it may be advantageous to add a phase transfer catalyst to the mixture (Dehmlow et al., Phase Transfer Catalysis, Verlag Chemie, Weinheim (1983)). Examples of suitable phase transfer catalysts are quaternary ammonium and phosphonium salts, in particular tetrabutyla~monium chloride. The amount of catalyst added i5 in general from 0.2 to 20, preferably from 1 to 5, mol ~, based on compound IV.
The alk~li metal and alkaline earth metal cyan--ides used are ~he cyanides o~ lithium, of sodium, of potassium, of cesium, of calcium and of barium.
The cyanide is used in general in amount~ of from 1.0 to S.0, preferably from 1.05 to 1.2, mole equiva-lents, based on the aldehyde IV.
In general~ the aldehyde and the acyl halide are reacted with one another in equLmolar amounts. It may be advantageou~ for the yield to use the aldehyde in less than the stoichiometric amount, based o~ the acyl halide.
The starting materials require~ for the prepara-tion~of the compounds I are known rom the literature (for carboxylic acids and derivatives thereof t cf. EP-A
3 336; for 2,3-dihydrobenzo~urylmethyl alcohol~, cf. EP-A 23 637) or can be prepared according to the literature ci~ed.
The alcohols of the general fonmula II are particularly advantageously obtained by metallizing a s~ 7 ~

- 7 - O.Z. 0050/41848 2,3~dihydrobenzofuryl halide of the general formula V in a conventional manner, then formylating the product and either reducing the resulting benzaldehyde of the general formula IV or reacting it with an organometallic compound MRl X~=R 3 OHC~R 3 (F)nv ~F)nlv R2 HO = R3 OHC~R3 ~1 11 (Rl = H) (F)nIV ~ HO~R3 (F)n 11 (Rl ~ H) In formula V, X is chlori.ne, bromine or iodine~
in particular bromine.
For the conversion of V into IV, magnesium in the form of turnings is usually used as the metallizing reagent (Grignard reagent). However, it is also possible to co~vert the compound V into a corresponding organo-mPtallic compound by reaction with an appropriate organo-alkali m~tal compound, such as tert-butyllithi~m or phenyllithium. The organometallic derivative of compound V prepared in this manner is then usually reacted in situ with a formylating ag~nt, preferably N-formylpiperidine or dime~hylformamide, to give the benzaldehyde IV
(Houben-Weyl, Vol. E3, page 116 et seq.).
The further conversion of IV into II is carried out in a conventional manner, either using a cu~tomary reducing agent, ~uch a~ hydrogen or an alkali metal or alkaline earth metal hydride, ~o give the primary alcohols (R1 - H) or by reaction with an organometallic compound MRl, where M is an alkali metal, an alkaline - 8 - O.Z. 0050/41848 earth metal or a transition metal and R1 is not hydrogen (Gattermann-Wieland, Walker de Gruyter Verlag, Berlin (1982)).
The compounds of the formula I can be obtained by the processe~ described both in the fo~n of pure isomers, enantiomers and diastereomers and in th~ form of mixtures of the structural i~omers and can be used in these forms as active ingredients. The mi~tures of the struct~ral isomers (enantiomers, diastereomers) can be separated into their sterically pure constituents in a conventional manner; in specific cases, their biological activity is dependent on their steric configuration. Preferably used isomers are tho~e in which the substituents of the cyclopropane ring are cis to one another.
In view of the intended use of the compound~ I in pesticides, suitable substituents are the following radicals~
R~ is hydrogen;
Cl-C4-alkyl, such as methyl, ethyl, propyl, l-methylethyl, butyl, l-methylpropyl, 2 methylpropyl or 1,1-dLmethyleth-yl, preferably methyl or l-methylethyl;
C2~C4-alkenyl t such as ethenyl, I-propenyl, 2-propenyl, l-methylethenyl, l-butenyl, 2-butenyl, 3-butenyl, l-methyl-l-propenyl, 2-methyl-1-propenyl, 1-methyl-2-propenyl or 2-methyl-2-propenyl, preferably e~henyl, C2-C4-alkynyl, such a3 ethynyl, l-propynyl, 2-propynyl, l-but~nyl, 2-butynyl, 3-butynyl or 1-methyl 2-propynyl, preferably eth~nyl;
or cyano;
R2 and R3 independently o one another are each hydrogen or Cl~C4-alkyl a~ stated above for Rl, preferably methyl, ethyl or propyl, and n is 0 or 1.
Particularly preferred 2,3 dihydrobenzofuryl~
methyl eqter~ ara those of the general formula I in which R1 is hydrogen, Cl-C4-alkyl as ~tated above in general and in partioular, - 9 - O.Z. 0050/~1848 C2-C4-alkynyl as stated above in general and in particular or cyano, R2 and R3 lndependently of one another are each hydrogen or Cl-C4-alkyl as stated above in general and in par ticular and n is 0.
Other preferred 2,3-dihydrobenzofurylmethyl esters of the general formula I are those in which R1 is hydrogen, Cl-C4-alkyl as stated above in general and in particular, C2 C4-alkenyl as stated above in general and in particular, C2-C4-alkynyl as stated above in general and in particular or cyano, R2 and R3 independen~ly of one another are each Cl-Cb-al~yl as stated above in general and in particular and n is 0.
Examples of the particularly preferred 2,3-dihydrobenzofurylmethyl esters of the general formula IA
and IB are listed in the Table below.

- lQ - O.Z... ~o~ ~4Q8~ 7 TABLE
Rl F3C-C(CI)=CH-CH-CH-C02-CH ~ R3 IA

Rl F3C-C(CI)=CH-C~ C02-CH ~ R3 IB

Rl R2 R3 CH(CH3)2 CH3 CH3 C_CH CH3 CH3 CH(CH3)2 CH3 CH2CH3 CH(CH3)2 CH2CH3 CH2CH3 H C~3 CH2CH2CH3 CH(CH3)2 CH3 CH2CH2CH3 C-CH CH3 . CH2CH2CH3 H CH3 CH(CH3)2 C--CH ccH33 CH(CH3)2 CN - CH3 CH(CH3)2 - CH3 (cH2)3cH3 CH(CH3)2 CH3 (CH2)3C~3 C-.CH C~3 (cH2)3cH3 CN CH3 (CH2)3CH3 H CH3 CH(CH3)CH2CH3 C-CH ccH33 CH(CH3)CH2CH3 CN CH3 CH(CH3)CH2c~3 H CH3 C(CH3)3 CH(CH3)2 C~3 C(CH3)3 O~ 48 TABLE (continued) Rl R2 R3 C-CH CH3 C(CH3) 3 CN CH3 C(CH3) 3 H H H
CH(CH3) 2 H H
C----Cil H H
CN H H

The compounds of the formula I are suitable for effectively controlling pests from the class consisting of the insects, arachnids and nematodes. They can be S used as pesticides in crop protec~ion, in the hygiene and veterinary sectors and for the protection of stored materials.
The insect pe~ts include, from thP order of the butterflies (Lepidoptera), for example Agrotis ypsilon, Agrotis segetum, Alabama argillacea, Anticarsia gemmatalis, Argyresthia conjugel.la, Autographa gamma, Bupalus piniarius, Cacoecia murin~ana, Capua reticulana, Cheimatobia brumata, Choristoneura fumiferana, Chori toneura occidentalis, Cirphis unipuncta, Cydia pomonella, Dendrolimu pini, Diaphania nitidalis, Diatraea grandiosella, Earias insulana, Elasmopalpus lignosellus, Eupoecilia ambiguella, Evetria bouliana, F~ltia subterxanea, Galleria mellonslla, Grapholita funebrana, Grapholita mole~ta, Heliothis armigera, ~eliothi~ virescen~, Heliothis zea, Hellula undalis, Hibernia .defoliaria, Hyphantria cunea, Hyponomeuta malinellu~, Reifferia lycopersicella/ Lambdina fiscel-laria, Laphygma exigua, Leucoptera coffeella, Leucoptera scitella, Lithocolletis blancardella, Lobesia bo~rana, Loxo~tege ~ticticalis, ~yman~ria dispar, Lymantria monacha, Lyonetia clPrkella, Malacosoma neustria, Mamestra bra~sicae, Orgyia pseudot~ugata, Os~rinia ~J ~
- 12 - O.Z. 00~0/41848 nubilalis, Panolis flamea, Pectinophora gossypi~lla, Peridroma saucia, Phalera bucephala, PhthorLmaea operculella, Phyllocnistis citrella, Pieris brassicae, Plathypena scarbra, Plutella ~rylostella, Pseudoplusia includens, Phyacionia frustrana, Scrobipalpula absoluta, Sitotroga cerelella, Sparganothis pilleriana, Spodoptera fr~giperda, Spodoptera littoralis, Spodoptera litura, Thaumatopoea pityocampa, Tortrix ~iridana, Trichoplusia ni and Zeiraphera canadensis;
from the order of the beetles (Coleoptera), for example Agrilus sinua~us, Agxiotes lineatus, Agriotes obscurus, Amphimallus solstitialis, Anisandrus dispar, Anthonomus grandis, Anthonomu~ pomorum, Atomaria linearis, Blastophagus piniperda, Blitophaga undata, Bruchus rufimanus, Bruchus pisorum, Bruchu~ lentis, Byc~iscus be~ulae, Cassida nebuloæa, Cerotoma trifurcata, Ceuthorrhynchus assLmilis, Ceuthorrhynchus napi, Chaetocnema tibialis, Conoderus ve~pertinus, Crioceris asparagi, Diabro~ica longicornis, Diabro ica 12-punctata, Diabrotica virgifera, Epilachna varivestis, Epitrix hirtipennis, Eutinobothrus b:rasiliensis, Hylobius abietis, Hypera brunneipennis, Hypera postica, Ips typographus, Lema bilineata, Lema melanopus, Leptino~arsa decemlineata, Limonius californicu~/ Lissorhoptrus oryzophilu~, Melanotus communis, Meligethes aeneus, ~elolontha hippocastani, Melolontha melolontha, Onlema oryzae, Ortiorrhynchu~ sulcatus, Otiorrhynchu o~atus, Phaedon cochleariae, Phyllotrcta chrysocephala, Phyllophaga sp., Phyllop2rtha horticola, Phyllotreta nemorum; Phyllotreta striolata, Popillia japonica, Sitona lineatus and Sitophilus granariay from the order of the Diptera, for example Aedes aegypti, Aedes vexans, Anastrepha ludens, Anopheles maculipennis, Ceratitis capitata, Chrysomya bezziana, Chrysomya hominivorax, Chrysomya macellaria, Contarinia sorghicola, Cordylobia anthropophaga, Culex pipiens, Dacus cucurbi~ae, Dacus oleae, Dasineura brassicae, Fannia 7P~
- 13 - O.Z. 0050/4184~
canicularis t Gasterophilus intestinalis, Glossia morsitan~, Haematobia irritans, Haplodiplosis equestris, Hylemyia platura, Hypoderma lineata, Liriomyza sativae, Liriomyza trifolii, Lucilia caprina, Lucilia cuprina, Lucilia sericata, Lycoria pectoxalis, Mayetiola destructor, Musca domestica, Muscina stabulans, Oestrus ovis, Oscinella frit, Pegomya hysocyami, Phorbia antiqua, Phorbia brassicae, Phorbia coarctata, Rhagoletis cerasi, Rhagoletis pomonella, Tabanus bovinus, Tipula oleracea and Tipula paludosa;
from the order of the Thysanoptera, for example Erankliniella fusca, Frankliniella occidentalis, Frankliniella tritici, Scirtothrips citri, Thrips oryzae, Thrips palmi and Thrips tabaci;
from the order of the H~menoptera, for example Athalia rosae, Atta cephalo~esl Atta sexden~, Atta texana, Hoplocampa minuta, Hoplocampa testudinea, Monomorium pharaonis, Solenopsis geminata and Sole~opsis invic~a;
from the order of the Heteroptera, for example Acrosternum hilare, Blissus leucopterus, Cyrtopeltis no~.atus, Dysdercus cingulatus, Dysdercu~ intermedius, Eurygaster integriceps, Euchistus Lmpictiventris, Leptoglossus phyllopus, Lygus lineolaris, Lygus pratensis, Nezara viridula, Pie!sma quadrata, Solubea insularis and Thyanta perditor;
from the order of the Homoptera, for example Acyr~hosiphan onobrychis, Ad~lges laricis, Aphidula na~turtii, Aphis fahae, Aphis pomi, Aphis sambuci, Brachycaudus cardui, Brevicoryne bra~sicae, Cerosipha go~ypii, Drayfusia nordmannianae, Dreyfu~ia piceae, Dyasphis ~adicola~ DysaulacGrthum pseudosolani, Empoasca fabae, ~acrosiphum avenae, Macrosiphum euphorbiae, Macrosiphon rosae, Megoura viciae, Metopolophium dirhodum, Myzodes persicae, Myzus cera~i, Nilaparvata lugen~, Pemphigus bursarius, Perkinsiella saccharicidaj Phorodon humuli, Psylla mali, Psylla piri, Rhopalomyzus ascalonicu~, Rhopalosiphum maidi~, Sappaphi~ mala, - 14 ~ O.~ 848 Sappaphis mali, Schizaphis graminuml Schizoneura lanuginosa, Trialeurodes vaporariorum and Viteus vitifolii~
from the order of the Isoptera, for example Calotermes flavicollis, Leucotermes flavipes, Reticulitermes lucifugus and Termes natalensis;
from the order o~ the Orthoptera, for example Acheta domestica, Blatta orientalis, Blatella germanica, Forficula auricularia, Gryllotalpa gryllotalpa, Locusta migratoria, Melanoplus birittatus, Melanoplus femur-rubrum, Melanoplus mexicanus, Melanoplus sanguinipes, Melanoplus spretus, Nomadacris septemfasciata, Periplaneta americana, Schistocerca amsricana, Schistocerca peregrina, Stauronotus maroccanus and Tachycine~ asynamorus;
from the class of the Arachnoidea, for example Acarina, such as Amblyo~ma americanum, Amglyomma variegatum~ Argas persicus, Boophilus annula~us, Boophilus decoloratu~, Boophilus microplus, Brevipalpus phoenicis, Bryobia praetiosa, Dermacentor silvarum, Eotetranychus carpini, Eriophyes sheldoni, Hyalomma truncatum, I~odes ricinus, Ixodes rubicundus, Ornithodorus moubata, Otobins megnini, Paratetranychus pilosus, Permanys-~us gallinae, Phyllocaptrata oleivora, Polyp:hago~ar~onemus latus, Psoropte~ ovis, Rhipicephalus appendiculatus, Rhipicephalus ever~si, Saccopte~ scabiei, Tetranychus cinnabarinus, Tetranychus kanzawai, Tetranychus pacificu~, Tetranychus telaxiu3 and Tetranychus urticae;
from the class of the nematodes, for example root gall nematode~, eg. Meloidogyne hapla, Meloidogyne incognita and Meloidogyne ja~anica, cyst-forming nematodes, eg.
Globodera rostochiensis, Heterodera avenae, Heterodera glycinae, Heterodera schatii, Hetrodera triflolii, and stem and leaf eelworms/ eg. Belonolaimus longicaudatus, Ditylenchus deRtructor, Ditylenchus dipsaci, Heliocotylenchus multicinctus, Longidorus elongatus, Radopholus SLmili5, Rotylenchus robustus, Trichodorus - 15 - 0.~ 848 primitivus, Tylenchoxhynchus claytoni, Tylenchorhynchus dubius, Pratylenchus ne~lectus~ Pratyl~nchus penetrans, Pratylenchus curvitatus and Pratylenchus goodeyi.
The active ingredients can be used a~ such, in the form of their formulations or in the application forms prepared therefrom, for example in the form of directly sprayable solutions, powders~ suspensions or dispersions, emulsions, oil disp~rsions or pastes, dusting agents, broadcasting agents or granules by spraying, atomizing, dusting, broadcasting or pouring.
The application fo~m depend entirely on the intended uses; they should in any case ensure a very fine dis-tribution of the novel active ingredients.
Mineral oil fractions ha~ing a medium to high boiling point such as kerosene or diesel oil, and coal ~ar oils and oil of vegetable or animal origin, aliphat-ic, cyclic and aromatic hydrocarbons, eg. benzene, toluene, ~ylene, paraffin, tetrahydronaphthalene, alkyla~ed naphthalenes or derivatives thereof, methanol, ethanol, propanol, butanol, chloroform, carbon tetra-chloride, cyclohexanol, cyclohexanone, chlorobenzene, isophorone and strongly polar solvents, eg. dimethylform-amide, d.umethyl sulfoxide, N-methy~lpyrrolidone and water, are suitable for the preparation of directly sprayable solution~, emulsion3, past~s or oil dispersions.
Aqueou~ application $orm~ can be prepared from emulsion concentrate~, paste~ or wet~able powders (spray powders, oil dispexsions) by adding water. For th~
preparation o~ emulsions, paste~ or oil dispex~ions, the substances, as such or dissolved in an oil or 501vent, can be homogenized in water using wetting agen~s, ad-herents, dispersants or emulsifiers. ~owever, con centrates which con~ist of active ~ub tance, wetting agents, adherents, dispersant~ or emul~ifiers and pos-sibly solvents or oil and which are suitable for dilutionwith water can also be prepared.
Suitable surfactant~ are alkali metal, alkaline - 16 - O.Z.~ ~Ql~8 earth metal and ammonium salts of ligninsulfonic acid, naphthalenesulfonic acid, phenolsulfonic acid, dibutyl-naphthalenesulfonic acid, alkylarylsulfonates, alkyl sulfates, alkylsulfonates, fatty alcohol sulfates and S fatty acids and alkali metal and alkaline earth metal salts thereof, salts of sl~lfated fatty alcohol glycol e~hers, condensates of sulfonated naphthalene and naph-thalene derivatives with formaldehyde, condensa~es of naphthalene or of naphthalenesulfonic acid with phenol and formald~hyde, polyoxyethylene octylphenol ether, e~hoxylated isooctylphenol, octylphenol, nonylphenol, alkylphenol polyglycol ethers, tributylphenyl polyglycol ethers~ alkylarylpolyether alcohols, isotridecyl alcohol, fat~y alcohol/ethylene oxide conden~ates, ethox~lated ca~tor oil, polyoxyethylene alkyl ethers, etho~ylated polyoxypropylene, lauryl alcohol polyglycol ether acetal, sorbitol esters, ligninsulfite waste liquors and methyl-cellulose.
Powders, broadcasting agents and dusting agents can be prepared by mixing or milling the active sub-stances together with a solid carrier.
The formul2tions contain in general from 0.01 to 95, preferably from 0.1 to 90, % ~y weight of the active ingredient. The active ingredients are used in a purity of from 90 to 100%, preferably from 95 to 100% (according to NMR spectrum).
Examples of formulation~ are:
I. 5 parts by weight of compound No. 1.001 are thoroughly mixed with 95 parts by weight of finely divided kaolin. A dus~ing agent which - contain~ 5~ by weight of the active ingredient is ob~ained in ~his manner.
II. 30 part~ by weight of compound No. 1.002 are thoroughly mixed with a mix~ure of 92 parts by weight of silica gel powder and 8 parts by weight of liquid paraffin, which were sprayed onto the ~urface of this silica gel. A formulation of the - 17 ~ O.Z.~ 8 active ingredient having good adhesion is ob-tained in this manner (active ingredient content 23~ by weight~.
III. 10 parts by weight of compound No. 1.001 are dissolved in a mixture which consists of ~0 parts by weight of xylene, 6 parts by weight of the adduct from 8 to 10 moles of ethylene oxide with 1 mole of oleic acid N-monoethanolamide, 2 parts by weight of the calcium salt of dodecylbenzene-sulfonic acid and 2 parts by weight of the adduct of 40 moles of ethylene oxide with 1 mole of ca~tor oil (active ingredient content 9~ by weight).
IV. 20 parts by weight of compound No. 1.010 are dissolved in a mixture of 60 parts by weight of cyclohexanone, 30 parts by weight of isobu~anol, 5 parts by weight of the adduct of 7 moles of ethylene oxide with 1 mole of isooctylphenol and 5 parts by weight of the adduct of 40 moles of ethylene oxide with l mole of castor oil (activ~
ingredient content 16% by weight).
V. 80 parts by weight of compound No. 1.002 are thoroughly mixed with 3 parts by weight of the sodium salt o diisobutylnaphthalene-alpha-~ulfonic acid, lO parts by weight of the sodiu~
alt of a llgnin~ulfonic acid obtained from a sulfite waste liquor and 7 parts by weight of silica gel powder, and the mixture is milled in a hammer mill (active ingredient content 80% by weight).
YI. - 90 par~s by weight of compound No. 1.~10 are mixed with 10 parts by weight of N-methyl-~-pyrrolidone, and a solution which i~ Ruitable for u8e in the form of very ~mall drops is ob~ained (active ingredient cont~nt 90% by weight~.
VII. 2Q part~ by weight of compound No. 1.001 are dis~olved in a mixture which consiQt~ of 40 parts ~ 0.~ 48 by weight of c~clohexanone, 30 parts by weight of isobutanol, 20 par~ by weight of the ad~uct of 7 moles of ethylene oxide with 1 mole of isooct~
ylphenol and 10 parts by weight of ~he adduct of 40 moles of ethylene oxide with 1 mole of ca~tor oil. By pouring the solution into 100,000 parts by weight of water and finely distributing i~
therein, an aqueous dispersion which contains 0.02% by weight of the activ~ ingredient is obtained.
VIII. 20 parts by weigh of active ingredient No. 1~002 are thoroughly mixed with 3 par~s by weight of the sodium salt of diisobutylnaphthalene-~-sulfonic acid, 17 parts by weight of the sodium salt of a ligninsulfonic acid o~tained from a sulfite waste liquox and 60 parts by weight of silica gel powder, and the mixture is milled in a hammer mill. By finely distributing the mixture in 20,000 paxts by weight of water, a ~pray liquor which contains 0.1% by weight of the active inyredient is obtained.
Granules, for example coated, Lmpregnated and homogeneous granules, can be p.re~ared by binding the active ingredients to solid carriLers. Examples of solid carriers are mineral ear~hs, such as silica gel, silicas, silicates, talc, kaolin, attac:lay~ limestone, lime, chalk, bole, loess, clay, dolomite, kieselguhr, calcium sulfate, magnesium sulfate, magne~ium oxide, milled plastic~, fertilizers, eg. ammonium sulfate, ammonium phosphate, ammonium nitrate and ureas, and vege~able products, such as grain flour~, bark meal, wood meal and nutshell meal, cellulo~e powd~rs and other solid carriers.
Tha active ingredien~ concentration3 in the 3~ ready-to-use formulations can be varied within wide ranges.
In general, they are from 0.0001 to 10~, - 19 - o.z. ~5~4~4~8 preferably from 0o01 to 1~.
The acti~e ingredients can also be successfully used by the ultralow volume (ULV~ method, with which it is possible to apply formulations containing more than 95~ by weight of acti~e ingredient or even the active ingredient without additives.
The application rate of active ingredient under open air conditions is from 0.01 to 10, preferably from 0.05 to 5, in particular from 0.1 to 1, kg/ha of a.s.
(active subs~ancej.
Oils of various types, herbicides, fungicides, other pesticides and bactericides may be added to the active ingredients, if necessary directly before use (tank mix). These agents can be mixed with the novel agen~s in a weight ratio of from 1 : 10 to 10 : 1.
By adding other in~ecticides or acaricides, it is possible to Lmprove the action of the novel compounds I
and to adapt it to the particular requirements. Examples of additives which are suitable in this respect are phosphorus compound3, carbamates, ureas, halohydrocarbon~
and pyrethrum and other pyrethroids. Combinations of the compounds I with synergistic compounds, such as alpha-(2-(2-butoxy)-etho~y) 4,5-me~thylenedioxy-2-propyl-toluene, propynyl ethers, propynyl oxime~, propynyl carbamates, propynyl pho~phonates, 2-(3,4-methylenedio~yphenoxy)-3,6,g-trioxaundecane, N-~2-ethylhe~yl)-bicyclo~2.2.1~hept-5-ene-2,3-dicarbox-imide, S,S,S tributyl phosphorstrithioa~e, octachlorodiisopropyl ether and 1,2-methy].enedioxy-4~(2-octyl~ulfinyl)-propylbenzena, are also advantageou~.
Furthermore, the u~e of stabilizers from the group con~isting of antioxidants and of ~he W ab~orbers - 20 - O.Z~0~0~/11848 may also be advantageous.
Examples of Syntheses The methods described in the following Examples o Syntheses were used with appropriate modification of the starting compounds in order to obtain further com-pounds I. The compounds thus obtained are shown in the Tables below, together with physical data.
Preparation of starting materials 1. 2-Ethyl-6-formyl 2-methyl-2,3-dihydrobenzofuran 0.081 mole o magnesium turnings in 10 ml of absolute tetrahydrofuran (THF) is initially taken and is activated with one drop of dibromoethane. After the reaction begins, 0.081 mole of 6-bromo-2-ethyl-2-methyl-2,3-dihydrobenzofuran, dissolved in 70 ml of absolute THF, is added dropwise. ~he refluxing mixture is stirred for 2 hour~, after which 0.089 mole of N-formylpiperidine in 20 ml of absolute THF is added dropwi~e at 0-5C.
Stirring is continued for 16 hour~ at room temperature, after which 80 ml of NH4Cl solution (semiconcentrated in H2O) and 50 ml of 10% str~ngth HCl are added. After the addition of diethyl ether, the phas0s are separated. The organic phase is dried and filtered, the solvent is removed and 0.043 mole of product i~ obtained by column chromatography.
lH-NMR (300 MHz; CDCl3) 0.9`1.0 (3H); 1.4 (3H); 1.7-1.8 (2H), 2.9-3-~ (2H); 7-1-7.4 (3H~; 9.9 ~lH) Example IV-2 in Table 1 ~$~7~
- 21 - O.Z.- 0050/41848 6 Formyl 2,3-dihydrobenzofurans IV
Exa~ple R2 R3 lH-NMR ~300 ~Xz; CDCl No.
S IY-l CH~ CH3 *l.S (6H); 3O05 (2H);
7.1-7.4 (3H); 9.9 (lH) IV 2 CH3 CHzCH3 0.9~1.0 (3H); l.4 (3H);
1.7-1.8 (2H); 2.9-3.2 (2H);
7.1-7.4 (3H); 9.9 (lH) IV-3 CH2~3 CH~CH3 0.8 1.05 (6H); 1.6-1.8 (4H) 3.05 (2H); 7.1 7.4 (3H) 9.85 (lH) *~00 ~z 2. 6-(2~2-Diethyl-2,3-dihydrobenzofuranyl~-methanol 0.0495 mole of NaBH~ in 80 ml of absolute ethanol is initiallv taken at 20C. While stirring and with constant cooling , 0.0985 mole of 2,2-diethyl-6 fom~yl-2,3-dihydrobenzofuran i-q added dropwi~e at a rate such that the ~emperature does not exceed 25C. After complete addition, stirring i~ continued for 16 hours at 20C.
The solvent is removed under reduced pressure from a water jet, and the remaining residue is introduced into 200 ml of 5% strength HCl. The sol.ution in hydrochloric acid is extracted with ether. '~he organic phase is 2S washed with dis~illed H2O, dried, f:iltered and freed from the solvent. The yield of the desired product is 0.094 mole.
~_NMR ~200 ~Hz; CDCl3) 0~8-1.0 (6H); 1.6-1.0 (4H); 2.4 (lH); 2-9 (2H);
4.5 (2H); 6.7-7.2 (3H) Examp1e II 3 in Table 2 3. 1-(2',2'-Dimethyl-2',3'-dihydrobenzofuran-6'-yl)-2-methylpropan-l-ol 0.18 mole of Mg is coverPd with a layer of 10 ml of absolute diethyl ether. The solvent is brough~ to the boil, and 0.18 mole of 2-bromopxopane, dissolved in 100 ml of absolute diethyl ether, is added dropwise.

- 22 - O.Z~ 9~1~48 Refluxing i~ carried out for 1 hour, after which the mix-ture is cooled to -20C. At this temperature, 0.12 mole of6-formyl~2,2-dimethyl-2,3-dihydrobenzo~uran,dis~olved in 130 ml o~ absolute diethyl ether, is added dropwise.
Stirring is carried out for 16 hours at 20C, after which the mixture is poured into 400 ml of ice water, acidified with 10% strength HCl and then extracted with diethyl etherO The organic phase is wa~hed with water. After drying and filtration, the solvent is removed under reduced pressure. 0.1 mole of product is obtained.
H-NMR (200 MHæ; CDCl3) 0.75 (3H3; 0.95 (3H); 1.4 (6X); 1.9 (lH); 2-0 (lH);
2-95 (2H); 4-2 (lH); 6.7-7.1 (3H
Example II-4 in Table 2 4 . 1- ( 2'-Ethyl-2'-methyl-2',3'-dihydrobenzofuran-6'-yl)-prop-2-yn-1-ol Acetylene i.s passed into 50 ml of absolute THF
at 0C for 25 minutes. 32 ml of a 1.5 N solution of methylmagnesium chloride in THF are then added dropwise at from -20 to 25C in the course of 25 minutes. Acetyl-ene is passed in at the ~ame temperature for one hour.
A solution of 0.032 mole of 2-ethyl-6-formyl-2-methyl-2,3-dihydrobenzofuran in 20 ml of absolute THF is then added dropwise. Stirring i~ cont:inued for 2 hours at -20C and for 16 hours at 20C. rrhe reac~ion solution is poured into 200 ml of iC2 water, acidified with 10 strength HCl and then extracted with diethyl ether.
After d~ying and filtration, the solvent is removed under reduced pressure.
Finally~ purification by chromatography over a silica gel column is carried out. 0.023 mole of product is obtained.
H-N~R (300 MH~; CDCl33 0.9 (3H3; 1.4 (3H); 1.7 (2H); 2.6 (2H); 2-95 (lH); 3.05 (lH) 5.35 (lH); 6-9-7-2 (3H) Example II-7 in rTable 2 - ~3 ~ O~ 17848 6-(2',3'-Dihydrobenzofuranyl)-methanols Il Example Wo. Rl R2 R3 I~ NMR (CDCl 3) _ I l _ I H CH 3 CH 3 300 MHZ
1.45 (6H); 2~6 (lH); 2.95 (2H);
4,55 (2H); 6,7-7.1 (3H) 0-9 13H); 1~35 (3H); 1,7 (2H);
2.4 (lH); 2,9 (lH); 3~0 ~lH);
4,55 (2H); 6,85-7~1 (3H3 0.8-loO (6H); 1.6-1,9 (4H);
2~4 (lH); 2.9 ~2H); 4.5 (2H);
6,7-7~Z (3H) 11-4 CH(CH3)2 CH3 CH3 200 MHZ
0~75 (3H); 0~95 13H); 1.4 (6H);
1,9 ~lH); 2.0 (lH); 2~95 (2H);
4~2 (lH); 6.7-7.1 (3H) 11-5 CH(CH3)2 Cff3 CH2CH3 300 MH2 0.75 (3H); 0~9-1,0 (6H); 1~4 (3H)~
1.6-2.0 (4H); 2.85 (lH); 3~05 (lH);
4~2 (1~4); 6~6-7~1 (3H) 11-6 C_CH CH3 CH3 250 MHZ
1.45 (6H); 2,55 (lH~; 2.60 (IH);
3.0 ~2H); 5.35 (lH); 6,9-7,2 (3H) ll-7 C_CH CH3 CH2CH3 300 MHZ
0,9 (3H); 1,4 (3H); 1,7 (2H);
2.6 (2H); 2095 (lH); 3,05 (lH);
5,35 (IH); 6.8-7,2 (3H) - ~4 - o.z. ~ 8 5. [(2'-E~hyl-2'-methyl 2',3'-dihydrobenzofuran-6'-yl)-~-cyano]-methyl 3-(2'-chloro-3',3~,3'-trifluoroprop-2'-enyl)-2,2-dimethylcyclopropane-1-carboxylate O.016 mole of 2-ethyl-6-formyl-2-methyl-2,3-dihydroben~ofuran is dissolved in 75 ml of diethyl ether, and a solution of 0.018 mole of KCN in 10 ml of H2O is added. After the addition of 0.3 ml of a phase transfer catalyst (Lutensit ), 0.3 ml of NaHSO3 solution and 0.017 ml of 3-~2~-chloro-3~3~3~-trifluoroprop-2~-enyl)-2r2 dimethylcyclopropane~l-carbonyl chloride, stirring is carried out for 4 days at 20C. ~he phases are separated and the organic phase is washed twice with H2O. After drying, filtra~ion, removal of the solvent and chromatog-raphy over silica gel, 0.003 mole of product i~ isolated.
lH-NMR (200 MHz; CDCl3) 1.2-1.4 (6H~; 1.65 (6H); 1.8-2.5 (2H); 3.0 ~2H); 6.05 6.4 (1-5H); ~-8-7.3 (3.5H) Example 1.008 6. (2',2'-Diethyl-2',3'-dih~drobenzofuran-6'-yl)-methyl 3-(2'-chloro 3',3',3'-trifluoroprop-2'-enyl~-2,2-dimethylcyclopropane-1-carbo~ylate 0.015 mole of 6~(2,2-diethyl-2,3-dihydrobenzo-furanyl)-methanol i~ dis~olved in 20 ml of toluene, and 0.016 mole of picoline is added. 0.016 mole of 3-(2'-chloro-3',3',3'-trifluoroprop-2-enyl)-2,2-dLmethylcyclo-propane-l-carbonyl chloride i~ added to this mixture.
After 16 hour~, the mixtllre i9 filtered through a silica gel ~uction filter. The eluate is freed from the solvent and dried at 60C under reduced pres~ure from an oil pump.
0.012 mole of product is obtained.
H-NNR (200 MHz; CDCl3) 0.9 (6H); 1.05-1.4 (6H); 1.7 (4H); 1.8 2.5 (2~ .95 (2H); 5.05 (2H); 6.15 (0.5H); 6.7-7.2 (3.5H);
Example 1.003 - 25 - O.Z~ 0050/41848 Example No. Rl ~2 R3 MHz IH-NMR (CDC13) [~] ppm 1.001* H CH3CH3 300 1,3 (6H); 1,5 (6H);
2,0-2,2 (2H); 3,0 (2H);
5.1 (2H); 6.7-7,2 (4H) 1.002 H CH3CH2CH3 300 0,95 (3H); 1,2 (3H);
1.25-1,45 (6H); 1,7 (2H);
1,~-2.05 (lH); 2.15-2.45 (lH);
2.9 (lH); 3.1 (lH~; 5.1 (2H);
6,1 (0, SH); 6.6-7.2 (3 .5H) 1.003 H CH2CH3 CH2CH3 200 0.9 (6H); 1.05-1.4 (6H);
1.7 (4H); 1.8-2,5 (2H);
2.95 (2H); 5.05 (2H);
6,15 (0,5H); 6.7-7.Z (3.5H) 1.004 CH~CH3)2 CH3 CH3 200 0.8 (3H); 0.9 (3H);
1.1-1.3 (6H); 1,6 (6H);
1,8-2.4 ~3H); 2.95 (2H);
5,35 ~IH); 6~1 (0,5H);
1.005 CH(CH3)2 CH3 CH2CH3 300 0,7-1 Q (9H); 1.05-1.35 (6H);
1.~ 13~); 1.65-2.45 (5~);
2.~5 (lH); 3.05 (lH);
5.4 ~lH); 6.15 ~0,5H);
6.5-7,2 (3,5H) 1.006 C--CH CH3 CH3 300 1,0-1.4 ~6H); 1.45 (6H);
1,7-2.5 (2H); 2.65 (IH);
- 3,0 (2~); 6.15 (0,5~);
6,35 (IH); 6,8-7,2 (3,5H) 1.007** C---CH CH3 CH2CH3 300 0,95 (3H); 1~2-1.4 (6H);
1,~5 (3H); 1 75 ~2H);
1,9-2,2 (2H); 2 65 (lH);
2,9 (IH); 3.1 (Itl); 6,35 (IH);
6.8-7,2 (4H) - 26 - O.Z. o?PO~lQ787 ACTIVE INGREDIENT TA~LE 3 Example No. R1 R2 R3 MHZ tH-NMR (CDCI3) [~] ppm .
1.008 C_N C~3CH3 200 1.2 - 1.4 (6H); 1,65 (6H);
1.8-2,5 (2H); 3.0 (2H);
6,05-5,4 (1.SH);
6, 8- 7,3 ( 3 , 5H ) I.009C---N CH3CH2CH3 300 0,95 ( 3H); I,1-1,4 (6H);
I,45 (3H); 1,75 (2H);
1 . 8- ~ . 5 (2H); 2.95 (IH);
3.1 (lH); 6,1-6,4 (I,5H);
6,8-7.3 (3,5H) I .010*** H CH3 CH3 300 1,25 (3H); 1,35 (3H);
1.~7 (6H); 1.8 ( IH);
2,42 (IH); 3,0 (2H); 5~1 (2H);
6.15 (IH); 6.75-7.15 (3H) Isomer ratio with respect to the substituents on the cyclopropane ring 95 : 5 (ci~ s tran~) ~ cis Isomer with re~pect to the substituents on the cyclopropane ring tran~-Isomer with re~pect to the substituents on the cyclopropane ring Use Example~:
The insecticidal or acaricidal action of the compound~ of the general formula I can be demonstrated by the following experiments:
The active ingredient~ were prepared a) a~ a 0.1~ ~reng~h solution in acetone or b) a~ a 10% s~rength emulsion in a mixture of 70% by weight of cycloh~xanol, 20% by weight of Nekanil~ LN
(Lutensol3 AP6, wetting agent having an emulsifying and di~per~ing ac~ion and based on ~thoxylated alkylphenols) and 10% by weight of Emulphor~ EL
(Emulan3 EL, emulsifier ba~ed on ethoxylated fatty - 27 - O.Z. ~5~4 21cohols) and diluted to the desired concentration with acetone in the case of a) and with water in the case of b~.
After the end of the experiments, the lowest concentration at which the compounds resulted in in hibition or a kill rate of 80~100~ compared with the untreated control experiments was determined in each case (activity threshold or minimum concentration (mg)).
A) Aphis fabae (bean aphid); contact action, spray test Young bean plan~s (~icia faba) with an extensive colony of green aphids are treated wi~h the aqueous formulation of the test agent. For this purpose, the plant is placed on a turntable in the spray booth and is sprayed all round with a total of 50 ml of the formulation.
After 24 hours, the test is evaluated by deter-mining the kill rate.
The activity thresholds o~ compounds 1~001, 1.002 and 1.010 were 400 ppm and 1,000 ppm, respectively.
B) ~eliothis vire~cens, o~olarvicidal action Punched pieces (diameter 22 mm) of bushbean leaf are immersed in the aqueous active ingredient formula tion. The piece of leaf is placed with the upper side on a moist filter in a pla~tic Petri dish of 60 mm diameter and infested with about 15 Heliothis eggs. The eggs are no older than 24 hours. The Pet:ri diYh is closed, and hatching and kill rate of the young caterpillar~ are evaluated after 4 days.
The acti~ity thresholds of compounds l.OQ1 and 1~010 w~re 100 ppm.
C) -Plutella maculipenni~ (diamondback moth), ingestion-preventing action Young kohlrabi leaves are immersed for 3 second~
in the aqueous fonmulation of the test substance and placed on a circular filter (diameter g cm) moistened wi~h O.5 ml of water in a Pe~ri dish (diameter 10 cm).
The leaf is then infested with 10 ca~erpillar~ in the - 28 - O.Z. 0050/41848 fourth larval st~ge and the Petri dish is closed. After 48 hours, the prevention of ingestion is evaluated in percent.
The activity thresholds of compounds 1.001, 1.002 S and 1.010 were 10 ppm and 20 ppm, respactively.
D) Plutella maculipennis (diamondback moth), contact action Leaves of young cabbage plants are immersed for 3 seconds in the aqueous active ingredient emulsion, allowed to drip for a short time and then placed on a moistened filter in a Petri dish. The leaf is then infested with 10 caterpillars in the fourth stage.
After 48 hours, the kill rate in percent is e~aluated.
The acti~ity thresholds of compounds 1.001, 1.002 and 1.010 were from 4 to 20 ppm.
E) Tetxanychus telarius (common spider mite), contact action Potted bushbeans which have the second pair of secondary leaves and are strongly infested with mites are sprayed to run-off with the aqueous active ingredient formulation in the spray booth. For this purpose, the plants are placed on the turntable and are sprayed fxom all sides wikh a total of 50 ml of ~pray liquor.
The action is determined after 5 day~ by mean~ of a binocular microscope. The plant~ are kept under normal greenhouse conditions during thi~ time.
Th~ activity thresholds of compounds 1.001 and 1.002 were 1,000 ppm and 200 ppm, re~pectively.

Claims (10)

1. A 2,3-dihydrobenzofurylmethyl ester of the formula I

I

where Rl is hydrogen, Cl-C4-alkyl, C2-C4-alkenyl, C2-C4-alkynyl or cyano, R2 and R3 independently of one another are each hydrogen or C1-C4-alkyl and n is 0 or 1.

2. A 2,3-dihydrobenzofurylmethyl ester of the formula I as claimed in claim 1, where Rl is hydrogen, Cl-C4-alkyl, C2-C4-alkynyl or cyano, R2 and R3 independently of one another are each hydrogen or Cl-C4-alkyl and n is 0.

3. A 2,3 dihydrobenzofurylmethyl ester of the formula I as claimed in claim 1, where Rl is hydrogen, Cl-C4-alkyl, C2-C4-alkenyl C2-C4-alkynyl or cyano, R2 and R3 independently of one another are each Cl-C4-alkyl and n is 0.

4. A process for the preparation of a compound I as claimed in claim 1, wherein a 2,3-dihydrobenzofurylmethyl derivative of the formula II

II

where Z is hydroxyl or halogen, is esterified in a conventional manner with a carboxylic acid of the formula IIIa IIIa - 30 - O.Z. 0050/41848 or a derivative thereof.

5. A process for the preparation of a compound I as claimed in claim 1, where R1 is cyano, wherein a 2,3-dihydrobenzofurylaldehyde of the formula IV

IV

is reacted with a halide of a carboxylic acid of the formula IIIb IIIb where Hal is halogen, in a conventional manner in the presence of an alkali metal cyanide or of an alkaline earth metal cyanide.

6. A process for the preparation of a compound IV as claimed in claim 5, wherein a 2,3-dihydrobenzofuryl halide of the formula V

V

where X is halogen, is metallized in a conventional manner and then formulated, likewise in a conventional manner.

7. A process for the preparation of a compound II as claimed in claim 4, where Z is hydroxyl, wherein a compound of the formula IV is reduced in a conventional manner or is reacted in a conventional manner with an organometallic compound MR1, where M is an alkali metal, an alkaline earth metal or a transition metal and R1 i8 not hydrogen.

8. A process for the preparation of a compound II as claimed in claim 4 where Z is halogen, wherein a compound of the formula II as claimed in claim 4 where Z is hydroxyl is reacted with a halogenating agent in a - 31 - O.Z. 0050/41848 conventional manner.

9. A pesticide containing a compound of the formula I as claimed in claim 1 and inert additives.

10. A method for controlling pests, wherein the pests and/or their habitat are or is treated with an effective amount of a compound of the formula I as claimed in claim 1.