JPS6035343B2 - 2-methylbenzimidazole derivatives and insecticides containing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to 2-methylbenzimidazole derivatives.

The 2-methylbenzimidazole derivative of the present invention is a novel compound represented by the following general formula (R in the formula represents a lower alkyl group such as a methyl group or an ethyl group).
7-dimethyl-7-alkoxy-2-octenyl)-2
-Methylbenzimidazole.

The present inventor has discovered that the novel compound of the present invention has an extremely excellent insecticidal effect.

The invention therefore also relates to insecticides containing the novel compounds of the invention as active ingredients.

The compound of the present invention is produced as follows. The invention will now be explained in more detail by way of example.

Example 1 1-(3,7-dimethyl-2,6-octadienyl)-
Production of 2-methylbenzimidazole (formula B) 0.01
An equimolar amount of 2-methylbenzimidazole was added to dry dimethylformamide containing a molar amount of sodium hydride and dissolved.

After 1 hour, 0.01 mole of Geranilc.

Lido was added and the mixture was further incubated at room temperature for 3 hours. After that, water was added to the reaction solution, and the product was extracted with ether. The ether layer was washed with brine, dried over anhydrous sodium hydroxide, the solvent was removed under reduced pressure, and the residue was purified by column chromatography on silica gel. Elution was first performed with hexane, followed by a mixed solvent with a hexane to ethyl chloride ratio of 3:1. The target product has a hexane to ethyl oxalate ratio of 3:1.
It was eluted with a mixed solvent of The solvent was removed under reduced pressure to obtain a compound of formula 0. Yield 79%. Figure 1 shows the N of the compound of formula B.
The MR spectrum is shown. Elemental analysis value C Day N Actual value 80.03 9.09 10.31 Theoretical value 80.55 9.01 10.44 (C,8
24N2) Example 2, Preparation of 1-(3,7-dimethyl-7-methoxy-2-octenyl)-2-methylbenzimidazole (formula 1, where R is methyl group) 0.01 mole of mercury acetate in 6 parts of dry methanol was suspended, and a compound of formula 0 dissolved on dry methanol 6 was added at room temperature, and the mixture was allowed to stand at room temperature.

After 24 hours - add 10' of sodium hydroxide solution,
Then, 10 parts of a sodium hydroxide solution containing sodium borohydride (0.015 mol) was added, and the mixture was stirred at room temperature for 5 hours.

The reaction product was extracted with ether, and the ether layer was washed with brine and dried over anhydrous sodium sulfate. The solvent was distilled off under reduced pressure and the residue was purified by silica gel column chromatography. For elution, first use a mixed solvent with a hexane to ether ratio of 1:1, then use a mixed solvent with a hexane to ethyl oxanate ratio of 2:1, and then use a mixed solvent with a hexane to ethyl chlorate ratio of 1:2. A solvent was used. The target product was eluted at a hexane-ethyl acetate ratio of 1:2. The solvent was removed under reduced pressure to obtain a compound of Formula 1 with R being a methyl group. Yield 37%. FIG. 2 shows the NMR spectrum of this product. Elemental analysis value C Day N Actual value 75.52 9.36 8.91 Theoretical value 75.96 9.39 9.32 (C, Rainbow 28
N20) Example 3 Production of 1-(3,7-dimethyl-7-ethoxy-2-octenyl)-2-methylbenzimidazole (formula 1, where R is an ethyl group) Example 2 except that dry ethanol was used instead of dry methanol A compound of Formula 1, in which R is an ethyl group, was obtained by carrying out exactly the same operation as in the method described above.

Yield 26%. FIG. 3 shows the NMR spectrum of this product. Elemental analysis value C Day N Actual value 75.68 9.64 8.91 Theoretical value 76.40 9.62 8.91 (C2 Rainbow 3 States 20) Example 4 The insecticidal effect of the compound of the present invention was tested on house flies.

The results are shown in Table 1 below. As for house flies, female adult flies that are organophosphate sensitive (WHO, SSS) and resistant (of the third Yume no Shima strain) were used. The test was carried out by topically applying an acetone solution (1 cup) of the compound of the present invention. The mortality rate after 2 minutes was determined, and the effect was indicated by the amount at which 50% of house flies died (LD law value).

Table 1 As is clear from Table 1 above, the compound of the present invention was less effective against susceptible house flies than the organophosphorus insecticide fenitrothion, but exhibited twice the activity of malathion.

It also showed strong insecticidal activity against organophosphate-resistant house flies, and fenitrothion about 60% also showed strong insecticidal activity. It will be understood that various changes and modifications may be made to the invention without departing from its broader spirit and scope.

[Brief explanation of the drawing]

FIG. 1 is an NMR spectrum diagram of an intermediate of the compound of the present invention,
FIGS. 2 and 3 are NMR spectra of the compounds of the present invention, respectively. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] 1 1-(3.7- Dimethyl-7-alkoxy-2-octenyl)-2-methylbenzimidazole. 2. 1-(3,7-dimethyl-7-alkoxy- An insecticide characterized by containing 2-octenyl)-2-methylbenzimidazole as an active ingredient.