Diphenylether derivatives and use thereof as an acaricide

Compounds of the formula ##STR1## wherein R represents CN, SCH.sub.3, Cl, Br or CF.sub.3 and n represents 0 or 1, have very excellent acaricidal activity.

BACKGROUND OF THE INVENTION 
It is shown in West German Offenlegungsschrift No. 2,307,248 that 
derivatives of 4-nitro diphenylether have an excellent acaricidal 
activity. The derivatives of diphenylether of the present invention have 
no nitro substituent on the phenyl ring and yet have an acaricidal 
activity superior to that of said derivatives of 4-nitro diphenyl ether. 
Furthermore the compounds of the present invention have an excellent 
residual efficacy. 
DETAILED DESCRIPTION OF THE INVENTION 
The present invention relates to new derivatives of diphenylether 
represented by the formula 
##STR2## 
wherein R is CN, SCH.sub.3, Cl, Br or CF.sub.3 and n is 0 or 1, an 
acaricidal composition comprising 0.5-90 % by weight of the new 
derivatives of diphenylether and 99.5-10 % by weight of adjuvants and a 
method for exterminating acarids comprising applying to acarids and their 
eggs an effective amount of the new derivatives of diphenylether. 
The new derivative of diphenylether of the present invention is prepared by 
condensing a compound of the formula 
##STR3## 
wherein n is 0 or 1 or an alkali metal salts thereof with a compound of 
the formula 
##STR4## 
wherein X is an halogen such as chlorine or bromine, R is the same meaning 
as defined hereinbefore in an inert organic solvents. 
When the starting materials are not the alkalimetal salts of the compound 
of the formula [II] the condensation is conducted in the presence of an 
alkali metal hydroxide such as sodium hydroxide or potassium hydroxide or 
metal powder such as Cu powder. 
The present compounds of the formula 
##STR5## 
are also prepared by oxidizing the compound of the formula 
##STR6## 
with an oxidizing agent such as hydrogen peroxide. 
The preferred compounds are compounds of the formula [I] wherein R is p-CN, 
p-SCH.sub.3, p-Cl, p-Br, p-CF.sub.3 or m-CF.sub.3 and n is 0 or 1. 
The method for the preparation is illustrated by the following Preparation 
Examples.

PREATION EXAMPLE 1 
4-Methyl-3-n-propylthiophenyl 4-methylthiophenyl ether. 
4-Methyl-3-(n-propylthio)phenol (4.0 g, 0.02 mole) and 85.5 % potassium 
hydroxide (1.4 g, 0.02 mole) were dissolved in N,N-dimethylacetamide (40 
ml) above 90.degree. C. 4-Bromomethylthiobenzene (4.0 g, 0.02 mole) and Cu 
powder (0.5 g, 0.008 mole) were added to this solution below 90.degree. C 
and the mixture was stirred at 120.degree. - 160.degree. C for 14 hr. 
After cooling, the reaction mixture was poured into water (100 ml) and 
extracted twice with benzene. The combined organic layers were washed with 
5 % sodium hydroxide solution, 5 % hydrochloric acid solution, and water, 
then dried over sodium sulfate. The solvent was removed, and the residue 
was distilled under reduced pressure. The yield of 
4-methyl-3-n-propylthiophenyl 4-methylthiophenyl ether was 4.1 g (61.5 %), 
colorless oil, bp 188.degree. - 190.degree. C/2 mmHg. Anal. Found: C, 
67.12; H, 6.59. Calcd. for C.sub.17 H.sub.20 OS.sub.2 : C, 67.06; H, 6.62 
% 
PREATION EXAMPLE 2 
4-Methyl-3-n-propylsulfinylphenyl 3-trifluoromethylphenyl ether 
(A) Preparation of 4-methyl-3-n-propylthiophenyl 3-tri fluoromethylphenyl 
ether 
4-Methyl-3-(n-propylthio)phenol (8.4 g, 0.05 mole) and 85.5 % potassium 
hydroxide (3.3 g, 0.05 mole) were dissolved in N,N-dimethylacetamide (50 
ml) above 90.degree. C. 3-Bromotrifluoromethylbenzene (11.2 g, 0.05 mole) 
and Cu powder (0.5 g, 0.008 mole) were added to this solution below 
90.degree. C and the mixture was stirred at 110.degree.-160.degree. C for 
14 hr. After cooling, the reaction mixture was poured into water (150 ml) 
and extracted twice benzene. The combined organic layers were washed with 
5 % sodium hydroxide solution, 5 % hydrochloric acid solution, and water, 
then dried over sodium fulfate. The solvent was removed, and the residue 
was purified by column chromatography on silica gel using n-hexane benzene 
(2 : 1). The yield of 4-methyl-3-n-propylthiophenyl 
3-trifluoromethylphenyl ether was 8.9 g (54.8 %), colorless oil, 
n.sub.D.sup.25 1.5319. Anal. Found: C, 62.61; H, 5.33. Calcd. for 
C.sub.17 H.sub.17 F.sub.3 OS : C, 62.56; H, 5.25 %. 
(B) Preparation of 4-methyl-3-n-propylsulfinylphenyl 
3-trifluoromethylphenyl ether 
Thirty-five percent hydrogen peroxide solution (1.6 g, 0.016 mole) was 
added at 8.degree.-10.degree. C to a mixture of 
4-methyl-3-n-propylthiophenyl 3-trifluoromethylphenyl ether (3.8 g, 0.012 
mole) and glacial acetic acid (30 ml). After 5 hr at room temperature, the 
reaction mixture was poured into water (100 ml) and extracted three times 
with benzene. The combined organic layers were washed with 5 % sodium 
carbonate solution, then water and dried over sodium sulfate. Evaporation 
of the solvent gave 3.8 g (92.5 %) of 4-methyl-3-n-propylsulfinylphenyl 
3-trifluoromethylphenyl ether, colorless oil, n.sub.D.sup.25 1.5350. Anal. 
Found: C, 59.50; H, 5.11. Calcd. for C.sub.17 H.sub.17 F.sub.3 O.sub.2 S : 
C, 59.64; H, 5.01 %. 
The representative compounds are shown in Table 1. 
Table 1. 
______________________________________ 
The formula 
##STR7## 
Compound m.p., b.p. (.degree. C) 
Appear- 
No. R n or n.sub.D.sup.25 
ance 
______________________________________ 
1 p-CN 0 m.p. 52.degree. C 
White 
crystals 
2 p-Cl 0 n.sub.D.sup.25 1.5950 
Colorless 
oil 
3 p-SCH.sub.3 
0 b.p.188-190.degree. C/2mmHg 
" 
4 p-Br 0 n.sub.D.sup.25 1.6081 
" 
5 p-CF.sub.3 
0 n.sub.D.sup.25 1.5415 
" 
6 m-CF.sub.3 
1 n.sub.D.sup.25 1.5350 
" 
7 p-Cl 1 n.sub.D.sup.25 1.5920 
" 
______________________________________ 
The compound of the present invention can be used as an acaricide singly or 
in combination with one or more suitable adjuvants in the form of 
emulsion, wettable powder, dust or granules. The adjuvants include a 
carrier and a supplementary material which is usually employed in 
agricultural chemicals. The carrier may be solid, liquid or gaseous. That 
is to say, the solid carriers are, for example, clay, talc, bentonite, 
white carbon, kaolin, diatomaceousearth and silica. The liquid carriers 
are, for example, water, benzene, kerosene, alcohols, acetone, xylene, 
methylnapthalene, cyclohexane, animal and plant oils, aliphatic acids and 
esters of aliphatic acid. And the gaseous carriers are air, nitrogen, 
carbon dioxide, Freon and the like. 
The supplementary material includes, for example, a spreader, an 
emulsifier, a sticking agent, a wetting or a surface active agent, namely 
polyoxyethylene alkylallyl ether, polyvinyl alcohol, polyoxyethylene 
sorbitan monooleate, alkyldimethyl benzyl ammonium chloride, 
alkylbenzensulfonate, ligninsulfonate, an ester of higher alcohol of 
sulfuric acid, etc. 
The acaricidal composition of the present invention comprise 0.5-90 %, 
preferably, 1-50 % by weight of the compound of the formula [I] and 
99.5-10 %, preferably 99-50 % by weight of the adjuvants. 
When the compound of the present invention is used for an acaricide in the 
form of an emulsion or a wettable powder, the concentration of the 
compound in the acaricide is within a range of 5-70 %, preferably 10-50 % 
by weight, and the acaricide is diluted with water within a range of 
0.1-0.01 % by weight before sprinkling, and the acaricide diluted is 
sprinkled in an amount of 100-1000 liter per 10 ares. 
When used in the form of powder or granule, the concentration is within a 
range of 0.5-5 % by weight and the acaricide is used within a range of 1-5 
kg per 10 ares. 
The compounds of the present invention can be used in admixture with other 
agricultural fungicides, insecticides, plant growth regulators or liquid 
fertilizers. 
The excellent acaricidal activity of the compound of the present invention 
is illustrated by the following Experimental Examples. 
EXPERIMENTAL EXAMPLE 1 
A leaf of summer orange which was cut 2 cm square was put on the agar gel 
which was poured into the petri dish (9 cm in diameter). The leaf was 
enclosed by an adhesive substance to prevent the escape of mites and then 
20 female adults of citrus red mites which were catched in a farm of 
Ageo-shi Saitama-ken, Japan were inoculated per leaf. One day after the 
inoculation, dead and feeble mites were removed from the leaf and then 7 
ml of 25 ppm solution of a acaricidal compound were sprayed per dish. 
After spraying, the dish was kept in the constant temperature room 
controlled at 25.degree. C for 48 hours and then the death or survivor of 
the mites were examined. The results were shown in Table 2. 
Table 2. 
______________________________________ 
Mortality 
Compound (%) 
______________________________________ 
##STR8## 62.5 
##STR9## 80.0 
##STR10## 100.0 
##STR11## 86.6 
##STR12## 16.2 
(The closest compound of west German 
Offenlegungs-schrift 2307248) 
______________________________________ 
EXPERIMENTAL EXAMPLE 2 
Mite-killing tests of the Experimental Example 1 were repeated except that 
the concentration of an acaricidal compound in the solution was changed to 
12.5 ppm. The results were shown in Table 3. 
Table 3. 
______________________________________ 
Mortality 
Compound (%) 
______________________________________ 
##STR13## 100 
##STR14## 85.7 
##STR15## 38.1 
(The closest compound of West German 
Offenlegungs-schrift 2307248) 
______________________________________ 
EXPERIMENTAL EXAMPLE 3 
Each of 2 seed leaves of young kidney-bean which were cultivated in porous 
pots was cut into the pieces of about 2 cm square. The leaves were 
immersed in a 0.01% (by weight) solution of an acaricidal compound. After 
the leaves were left for 1 day in a room as-is, 15 female imagos of two 
spotted spider mites were inoculated per leaf. Two days after inoculation, 
the death or survival of the mites was examined. Test were conducted 2 
replicates. 
The results are shown in Table 4. 
Table 4. 
______________________________________ 
Mortality 
Compound (%) 
______________________________________ 
##STR16## 100 
##STR17## 78.3 
##STR18## 33.3 
(A compound of West German 
Offenlegungs-schrift 2307248) 
______________________________________ 
The results show that the compounds of the present invention show good 
residual efficacy. 
The acaricidal compositions of the present invention are concretely 
illustrated by the following composition Examples. 
COMPOSITION EXAMPLE 1 (EMULSION) 
______________________________________ 
Compound No.3 20 parts by weight 
Xylene 65 parts by weight 
The mixture of calcium alkylbenzenesulfonate and 
the condensation products of alkylphenol and 
ethyleneoxide 
15 parts by weight 
______________________________________ 
The components mentioned above were mixed and pulverized into fine powder. 
When, used, the fine powder was diluted with water and the resultant 
mixture was sprinkled. 
COMPOSITION EXAMPLE 3 (POWDER) 
______________________________________ 
Compound No.8 3 parts by weight 
Clay 48 parts by weight 
Talc 48 parts by weight 
Synthetic hydrated silicic 
1 part by weight 
acid 
______________________________________ 
The components mentioned above were mixed and pulverized into powder. When 
used, the powder was scattered.