Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1986-07-16
1989-10-10
Gray, Bruce
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568636, C07C 4124
Patent
active
048733733
DESCRIPTION:
BRIEF SUMMARY
FIELD OF INDUSTRIAL APPLICATION
The present invention relates to a process for the preparation of 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-methylpropyl ethers represented by the following formula (I): ##STR3## wherein R stands for a lower alkyl group, and X.sub.1 and X.sub.2 stand for a hydrogen atom or fluorine atom.
A 3-phenoxybenzyl ether type derivative represented by the formula (I) is an excellent pest-controlling agent having very high insecticidal and acaricidal activities, being excellent in the immediate effect and residual effect and being less toxic to not only men and domestic animals but also fish.
PRIOR ART
A process for the preparation of a compound of the formula (I) having an alkoxy group on the benzene nucleus of the neophyl group is disclosed in Japanese Patent Application Laid-Open Specification No. 154427/81, and it is taught that the neophyl derivative can be prepared by condensing a compound represented by the following formula (III): ##STR4## with a 3-phenoxybenzyl halide or alcohol or by condensing a compound represented by the following formula (IV): ##STR5## wherein X stands for a halogen atom, with a 3-phenoxybenzyl alcohol.
The reaction path for the synthesis of the compound of the formula (III) is long, and the process for preparing the compound of the formula (I) from the compound of the formula (III) as the starting material is disadvantageous from the industrial viewpoint.
As the process for preparing the compound of the formula (IV), for example, the above-mentioned laid-open specification discloses a process represented by the following reaction formulas: ##STR6## However, in the case where the 4-position is substituted with a lower alkoxy group, according to the process of the reaction formula (1), a nuclear chlorination reaction is preferentially advanced, and the intended 4-alkoxyneophyl chloride is in only a very poor yield obtained. Furthermore, according to the process of the reaction formula (2), an alkylation reaction at the ortho-position to the alkoxy group is preferentially advanced and a large quantity of an ortho-isomer is formed as a by-product, and since effective separation of the isomers is difficult, the intended 4-alkoxyneophyl chloride having a high purity can be obtained only in a very low yield.
Moreover, the obtained 4-alkoxyneophyl chloride is an unstable compound, and storage and handling thereof on an industrial scale involve various difficulties.
As the improved process for overcoming the foregoing disadvantages, Japanese Patent Application Laid-Open Specification No. 73535/84 proposes a process in which a 4-alkoxyhalogenoneophyl halide having at least one chlorine or bromine atom substituted at the ortho-position to the alkoxy group is used and this compound is reacted with a 3-phenoxybenzyl alcohol to obtain a compound of the formula (II) and a compound of the formula (I) is obtained from this compound of the formula (II).
In this laid-open specification, it is taught that the compound of the formula (I) is obtained by subjecting the compound of the formula (II) to catalytic hydrodehalogenation using hydrogen in a solvent such as methanol in the presence of a hydrogenation catalyst such as palladium and a base as the dehydrohalogenating agent.
The fatal defect of this process is that hydrogen gas is used at the dehalogenating step. Namely, in the case where this process is worked on an industrial scale, special care should be taken to maintain safety and the location is limited because hydrogen gas-supplying equipment is necessary. Moreover, large equipment expenses are necessary and hence the process is disadvantageous also from the economical viewpoint.
In the catalytic hydrogenation reaction using hydrogen, cleaving is readily caused in a compound having an O-benzyl group and a fluorine atom, such as the compound of the formula (II), unless the hydrogenation conditions are strictly controlled. It has been found that this tendency is especially prominent when a palladium type catalyst, which is known to be preferred as a dehalogenation cata
REFERENCES:
patent: 4510071 (1985-04-01), Joyner et al.
patent: 4542243 (1985-09-01), Umemoto et al.
Okamoto et al, "The Transition-Metal Catalyzed Dehalogenation of Aromatic Halides by NaOH-Alcohols. A Facile Method of Destroying Aromatic Polyhalides", Bull. of the Chem. Soc. of Jpn., vol. 54, No. 4, 1981.
Asano Tamotsu
Horie Hironobu
Nishida Takeshi
Takagi Akinobu
Tamura Nobuyasu
Gray Bruce
Mitsui Toatsu Chemicals Inc.
LandOfFree
Process for preparation of 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2- does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Process for preparation of 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2-, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for preparation of 3-phenoxybenzyl 2-(4-alkoxyphenyl)-2- will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1958750