DE1542879C3 - Use of derivatives of 23-dihydro-2 ^ -dimethyl-7-benzofuranyl carbamate as nematocides - Google Patents

Description

where R is methyl or ethyl, as or in a nematicide.

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The invention relates to the subject matter according to the patent claim.

The preparation, for which no protection is claimed here, and nematicidal activity of the compounds used according to the invention are illustrated in the following specific examples. All parts are, unless otherwise indicated, parts by weight, and all temperatures are in ^0C.

example 1

Manufacture and nematicidal properties

of 2,3-dihydro-2,2-dimethy] -7-benzo-

furanyl N-methyl carbamate

This compound was made by a new process in which 2-methallyloxyphenol was used Formation of a 7-benzofuranol was cyclized and rearranged simultaneously, followed by esterification to Formation of the carbamate.

The 2-methallyloxyphenol used as the starting material was prepared as follows:

To a stirred mixture of 322 parts of pyrocatechol in 300 parts of dry acetone were slowly added 401 parts of potassium carbonate and 481 parts of potassium iodide under a nitrogen atmosphere. The mass was heated to reflux temperature and 262 parts of methallyl chloride were slowly added. The mixture was refluxed for 30 hours, allowed to cool and left to stand for 18 hours, after which it was filtered and the filtrate was concentrated under reduced pressure. The remaining oil was extracted with chloroform, and the chloroform solution was washed with water, dried and concentrated. The remaining oil was distilled, with 213 parts of 2-methallyloxyphenol with a boiling point of 78.5 to 83.0 ° / 0.55 mm, η ^! i = 1.5300.

a) 2,3-Dihydro-2,2-dimethyl-7-benzofuranol

A round bottom flask containing 131 parts of 2-methallyloxyphenol was slowly heated with stirring. An exothermic reaction occurred at 200 ° and the temperature of the mixture in the flask rose rapidly to 275 °. The temperature was kept at 275 ° by external cooling. The thick syrup was distilled under reduced pressure, colorless liquid 2,3-dihydro-2,2-dimethyl-7-benzofuranol with a b.p. 78 to 80 ° / 0.35 to 0.40 mm, π " = 1, 5401 resulted.

b) 2,3-dihydro-2,2-dimethyl-7-benzo
furanyl N-methyl carbamate

A cold solution of 16.4 parts of 2,3-dihydro-2,2-dimethyl-7-benzofuranol in 14 parts of ether was mixed with 5.8 parts of methyl isocyanate and 0.1 part of triethylamine treated. The mixture was stirred at room temperature, a white crystalline product precipitating out. Separation of the solid gave 17.5 parts ι ο 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methylcarbamate from m.p. 151 to 152 °. Recrystallization from methylcyclohexane gave an analytically pure sample.

Analysis: C] ₂ Hi ₅ NO ₂
Calculated: N 6.33%;
found: N 6.57%.

Nematode control was measured as follows:

By mixing approx. 1000 larvae of the root-knot nematode (Meloidogyna incognita var. Acrita) in 1 Liter loam sand soil was made into a soil infected with nematodes. In this infected earth was such an amount of the compound under study in the form of a 5% dust on attapulgite clay mixed in so that a concentration of 25 ppm was obtained. This mixture was in one The greenhouse was kept in a moist state for 4 to 7 days, then young tomato plants were placed in the Soil planted and allowed to grow for 4 to 6 weeks. As soon as a corresponding growth has been achieved, the roots of the tomato plants were washed free from the soil and the extent of the infection was determined Comparison with a plant determined in a soil infected with nematodes, which does not contain any chemical Had undergone treatment, had grown. The connection resulted in complete suppression with no knots at the roots.

Example 2

Manufacture and nematicidal properties

of 2,3-dihydro-2,2-dimethyl-7-benzo-

furanyl-N-ethyl carbamate

According to the process described in Example 1 b), 16.4 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranol were obtained reacted with 7.8 g of freshly distilled ethyl isocyanate and gave 16.4 g of 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-ethyl carbamate from m.p. 103 to 104.5 °. A sample was recrystallized from methylcyclohexane for analysis and melted at 104-105 °.

Analysis: C13H17NO3
Calculated: N 5.96%;
found: N 6.24%.

Following the procedure described in Example 1, the compound showed 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-ethyl carbamate good root-knot nematode control at 100 ppm.

The new compounds obtained in this way can optionally be used with the customary additives and extenders for nematicidal agents. Like most pesticides, they will generally not used undiluted. Usually they will either of the accessories and vehicles incorporated, normally for the relief of the

Dispersion of active ingredients are used, taking into account the known fact that the mixture composition and the type of application of an active ingredient can influence the effectiveness of the material. These connections can be, for example, as Sprays, in the form of dust or granules, can be applied to the area in which a nematode control is carried out is desired, the choice of the type of application of course with the type of pest and the environment varies. So these compounds can be used as granules with large particle size, as powdery dust, as wettable powders, as emulsifiable concentrates, as Solutions and the like can be formulated.

Mixtures of the active ingredients with finely divided solids, such as talc, attapulgite clay, Kieselguhr, pyrophyllite, chalk, diatomaceous earth, calcium phosphates, Calcium and magnesium carbonates, sulfur, lime, flours and other organic and inorganic solids, which act as dispersants and carriers for the active ingredient, are called these finely divided solids have an average particle size of less than about 50 μ. A typical one here Usable formulation contains 10.0 parts of active ingredient, 30.0 parts of bentonite clay and 60.0 parts of talc.

The compounds can be dissolved or emulsified in suitable liquids to form liquids Concentrates and by mixing with talc, clays and other known solid carriers that are used in Pesticides used are made into solid concentrates. The concentrates are compositions that contain about 5 to 50% active ingredient and the remainder of inert Material consists of dispersants, emulsifiers and wetting agents. The concentrates are for practical use with water or a other liquid to aqueous sprays or with an additional solid carrier for use as dust '/ thinned Typical carriers for solid concentrates (also called wettable powders) are, for example, fuller's earth, Kaolin clays, silica and other highly absorbent, easily wettable inorganic extenders. Contains a solid concentrate composition suitable for use according to the invention 25.0 parts of active ingredient, 72.0 parts of bentonite clay and 1.5 parts each File sodium lignosulfonate and sodium lauryl sulfonate as a wetting agent.

Suitable liquid concentrates include the emulsifiable ones Concentrates, which are homogeneous liquid or) branch-like compositions, which in Yasser or another dispersant easily disperse and which only consists of the active ingredient and one Liquid or solid emulsifiers can consist of a liquid carrier such as xylene, heavy may contain aromatic naphthas, isophorone and other non-volatile organic solvents. For use, these concentrates are dispersed in water or another liquid carrier and usually applied as a spray on the area to be treated

The concentration of the active ingredient in the dilution usually used to control nematodes usually ranges from about 2 to 0.001%. Many variations in spray and dust compositions The prior art can be used by referring to the known or obvious Prior art compositions utilize the compounds of the invention.

Typical wetting, dispersing or emulsifying agents used in nematicidal compositions include, for example, the alkyl and alkyryl sulfonates and sulfates and their sodium salts, the Alkyl amide sulfonates including the fatty methyl taurides, the alkylaryl polyether alcohols, sulfated higher alcohols, polyvinyl alcohols, polyethyleneoxy-

de, sulfonated animal and vegetable oils, sulfonated Petroleum oils, fatty acid esters of polyhydric alcohols and the ethylene oxide addition products of such Esters and the addition products of long-chain mercaptans and ethylene oxide. Many other types of useful surfactants are commercially available. The surfactant makes im generally, when used, comprises between 1 and 15% by weight of the pesticidal composition.

Other suitable formulations for use in the present invention include simple solutions of Active ingredient in a dispersant in which it is completely soluble at the desired concentration, for example in acetone or other organic solvents. Granular compositions in which the active ingredient carried by relatively coarse particles are of particular benefit nematicidal applications.

The nematicidal compositions can be mixed with other active ingredients including other nematicides, Insecticides, fungicides, plant growth regulators, fertilizers, etc. can be formulated and applied.

When used according to the invention, the active ingredients can also be applied to the soil or the leaves of Plants are applied that grow on a nematode-infested soil.

Claims (1)

Claim:
Use of a compound of the formula CH ₃
O-C-NHR il ο