Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Reexamination Certificate
2001-11-05
2003-09-23
Shippen, Michael L. (Department: 1621)
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
C568S426000, C568S436000, C568S437000, C568S592000, C568S811000
Reexamination Certificate
active
06624336
ABSTRACT:
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a process for producing tetrafluorobenzenemethanols represented by formula (4)
(wherein m represents 1 or 2, n represents 0 or 1, and m+n=2) useful as an intermediate of pesticide or medicine and a process for producing an intermediate in the production of the tetrafluorobenzenemethanols.
More specifically, the present invention relates to a process for producing tetrafluorobenzenemethanols, tetrafluorobenzenecarbaldehyde dialkylacetals and tetrafluorobenzenecarbaldehydes which are useful as intermediates in the production of cyclopropanecarboxylic acid esters having excellent insecticidal action by a series of reactions using tetrafluorocyanobenzene as a starting material, and also relates to a novel tetrafluorobenzenecarbaldehyde dimethylacetal.
BACKGROUND ART
It is known that 2,2-dimethyl-3-halogenovinyl-cyclopropanecarboxylic acid esters of a benzyl alcohol substituted by from 1 to 4 fluorines and from 0 to 2 chlorines have good insecticidal action (see, German Patent Publication (OLS) No. 2,658,074). In particular, it is known that cyclopropanecarboxylic acid esters of 2,3,5,6-tetrafluorobenzyl alcohol are an excellent insecticide because these have good insecticidal action but at the same time, are low in the toxicity to mammals as compared with cyclopropanecarboxylic acid esters of pentafluorobenzyl alcohol (see, German Patent Publication (OLS) No. 3,705,224).
With respect to the process for producing tetrafluorobenzenemethanol represented by formula (4), a method of reducing a halogen-substituted benzoic acid derivative by a metal hydride such as NaBH
4
and LiAlH
4
has been proposed.
For example, German Patent Publication (OLS) No. 3,714,602 discloses a method where 2,3,5,6-tetrafluorobenzoic acid is reacted with NaBH
4
and then treated with an alkylating agent to produce 2,3,5,6-tetrafluorobenzyl alcohol. German Patent Publication (OLS) Nos. 2,658,074, 2,714,042 and 2,661,074 disclose a method of reducing polyfluorobenzoyl fluoride by NaBH
4
to produce polyfluorobenzyl alcohol and a method of reducing polyfluorobenzoyl fluoride by LiAlH
4
to produce polyfluorobenzyl alcohol in which one or more fluorine substituent is defluorinated.
In British (Unexamined) Patent Publication No. 2,127,013, 2,3,5,6-tetrafluoroterephthaloyl chloride and NaBH
4
are reacted to produce 2,3,5,6-tetrafluorobenzenedimethanol.
Furthermore, in European (Unexamined) Patent Publication No. 31,199, 1,2,4,5-tetrafluorobenzene and n-butyl lithium are reacted, carbon dioxide is subsequently allowed to act thereon, thereby forming 2,3,5,6-tetrafluorobenzoic acid, and this is reduced by LiAlH
4
to produce 2,3,5,6-tetrafluorobenzyl alcohol.
These methods all use an expensive hydrogenated metal reagent in a stoichiometric amount and cannot be an industrially advantageous method.
In addition, for producing tetrafluorobenzenemethanol represented by formula (4), a method using an electrolytic reduction has also been proposed. For example, in JP-A-1-119686 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”), pentafluorobenzoic acid is electrolytically reduced using a solid metal or solid alloy for the cathode and an aqueous solution of sulfuric acid, hydrochloric acid, phosphoric acid or sulfonic acid for the electrolytic solution, thereby producing 2,3,5,6-tetrafluorobenzyl alcohol together with 2,3,5,6-tetrafluorobenzaldehyde.
In JP-A-63-206491, a pentafluorobenzoic acid is electrolytically reduced using a solid metal or solid alloy for the cathode and a sulfuric acid aqueous solution for the electrolytic solution, thereby producing 2,3,5,6-tetrafluorobenzyl alcohol as a mixture with pentafluorobenzyl alcohol.
There have been proposed many other methods using electrolytic reduction, however, similarly to the above-described cases, a benzyl alcohol is produced as a mixture in all methods (see,
J. Electroanal. Chem
., page 215 (1991),
J. Electroanal. Chem
., page 315 (1987),
J. Chem. Soc. Perkin Trans I
, page 189 (1972),
J. Appl. Electrochem
., page 1082 (1992), and
Denki Kagaku Oyobi Kogyo Butsuri Kagaku
(Electrochemistry and Industrial Physical Chemistry), page 83 (1990)).
In any of these methods, the yield is low and the purity of the product is not high. Particularly, pentafluorobenzyl alcohol from which cyclopropanecarboxylic acid ester harmful to human body is derived, cannot be prevented from mixing into the product.
In order to overcome these problems, International Patent Publication No. 9808795 has proposed a process for producing a fluorinated benzyl alcohol, where fluorinated dicyanobenzene is hydrogenolized in the presence of a catalyst, the cyano group only on one side is hydrodecyanated to produce fluorinated benzonitrile, and then the cyano group of the fluorinated benzonitrile is converted into a hydroxymethyl group. In this method, the conversion of cyano group into hydroxymethyl group is attained by a method of reducing the cyano group into an aldehyde group and reducing it into a hydroxymethyl group, a method of reducing the cyano group directly into a hydroxymethyl group, or a method of hydrolyzing the cyano group into a carboxyl group and then reducing the carboxyl group into a hydroxymethyl group.
However, some problems are present in the process of converting the cyano group into a hydroxymethyl group. To speak more specifically, in the method of hydrolyzing the cyano group into a carboxyl group and then reducing the carboxyl group into a hydroxymethyl group, an expensive hydrogenated metal reagent is used in a stoichiometric amount and therefore, this is not an industrially advantageous method. In the method of reducing the cyano group directly into a hydroxymethyl group, the reaction yield is generally low. And, in the method of reducing the cyano group into an aldehyde group and then reducing it into a hydroxymethyl group, 2,3,5,6-tetrafluorobenzyl alcohol is by-produced in the process of reducing the cyano group into an aldehyde group.
The 2,3,5,6-tetrafluorobenzyl alcohol is an objective component but remains in the distillation still at the purification of aldehyde by distillation because it has a high boiling point. Therefore, this side production of 2,3,5,6-tetrafluorobenzyl alcohol causes reduction in the yield. If the 2,3,5,6-tetrafluorobenzyl alcohol having a high boiling point is recovered by distillation together with aldehyde, impurities are mixed and the product is disadvantageously reduced in the purity.
Aldehyde is an intermediate product in the successive reaction for reducing the cyano group into hydroxymethyl group, accordingly, it is very difficult to suppress the generation of benzyl alcohol as a product due to the excessive reaction. In other words, in order to maximize the yield of aldehyde, the end point of reaction must be very strictly controlled. Furthermore, in any method, a reaction solvent, a co-catalyst such as carboxylic acid, and water are used each in a large amount, and this causes problems such as bad productivity, loss of solvent or the like, and increase in the load for recovery.
OBJECT OF THE INVENTION
Therefore, the object of the present invention is to provide industrially useful methods for manufacturing, in a high purity and a high yield, tetrafluorobenzenemethanols represented by formula (4) useful as an intermediate of pesticide or medicine and tetrafluorobenzenecarbaldehyde dialkylacetals and tetrafluorobenzenecarbaldehydes which are an intermediate in the production of the tetrafluorobenzenemethanols.
In particular, the object of the present invention is to provide a process for producing 2,3,5,6-tetrafluorobenzyl alcohol, 2,3,5,6-tetrafluorobenzaldehyde, 2,3,5,6-tetrafluorobenzenedimethanol, 2,3,5,6-tetrafluoroterephthalaldehyde, 2,3,5,6-tetrafluorobenzaldehyde dimethylacetal and 2,3,5,6-tetrafluoroterephthalaldehyde dimethylacetal, which are useful as an intermediate in the production of pyrethroids having good insecticidal action and low toxicity to human body, by an industrially advantageous method.
D
Furukawa Tetsuhiro
Miyata Hideo
Monzen Hiroyuki
Morikawa Kohei
Ohnishi Yutaka
Shippen Michael L.
Showa Denko K.K.
Sughrue & Mion, PLLC
LandOfFree
Process for producing tetrafluorobenzenemethanols 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 producing tetrafluorobenzenemethanols, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Process for producing tetrafluorobenzenemethanols will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3051674