Organic compounds -- part of the class 532-570 series – Organic compounds – Oxygen containing
Patent
1998-03-30
1999-11-02
Kumar, Shailendra
Organic compounds -- part of the class 532-570 series
Organic compounds
Oxygen containing
568425, 568426, 568435, C07C 4542
Patent
active
059774142
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention is related to 2,3-dihalogeno-6-trifluoromethylbenzaldehyde useful as intermediates for producing agrohorticultural bactericides, a process for producing the said compounds, and a process for producing 2,3-dihalogeno-6-trifluoromethylbenzamidoxime from the said compounds.
BACKGROUND ART
Known conventional methods to introduce a formyl group into an aromatic ring are to react alkyl lithium, such as n-butyl lithium, with N,N-dimethylformamide (DMF) or N-phenyl-N-methylformamide, to react alkyl lithium with formate, such as methyl formate, and the like.
For example, European Patent Laid-open specifications Nos. 125803 and 174131 describe a method to react 2,5-difluorobenzotrifluoride with n-butyl lithium and N-phenyl-N-methylformamide. However, this formylation reaction usually gives two reaction products, not being selective.
In the case of the reaction of 3,4-dichlorobenzotrifluoride with n-butyl lithium and DMF, 2,3-dichloro-5-trifluoromethylbenzaldehyde is the main product, as described later.
In the Japanese Patent Laid-open No. Hei 3-5436 Gazette, compounds represented by the general formula (Ia), which contain the compounds of this invention, are described. ##STR2##
Conventionally 2,3-dihalogeno-6-trifluoromethylbenzamidoximes have been produced via 2,3-dihalogeno-6-trifluoromethylbenzonitrile (refer to WO/19442 Gazette). However, this method had problems of low yield and long reaction processes.
DISCLOSURE OF THE INVENTION
The present invention is directed to 2,3-dihalogeno-6-trifluoromethylbenzaldehydes, an outstanding industrial process for producing the same, and an excellent industrial process for producing 2,3-dihalogeno-6-trifluoromethylbenzamidoxime by using 2,3-halogeno-6-trifluoromethylbenzaldehyde as a starting material.
The present invention is directed to
(1) the compounds represented by a general formula (I) ##STR3## wherein X.sup.1 and X.sup.2 are the same or different and each independently a fluorine, chlorine or bromine atom,
(2) a process for producing the compounds represented by the general formula (I) ##STR4## wherein X.sup.1 and X.sup.2 are as defined above, characterized in that the compound is obtained by reacting a compound represented by a general formula (II) ##STR5## wherein X.sup.1 and X.sup.2 are as defined above, with n-butyl lithium and formate
and (3) a process for producing 2,3-dihalogeno-6-trifluoromethylbenzamidoxime represented by a general formula (IV) ##STR6## wherein X.sup.1 and X.sup.2 are as defined above, characterized in that the compound is obtained by oximating a compound represented by the above general formula (I) to produce a compound represented by a general formula (III) ##STR7## wherein X.sup.1 and X.sup.2 are as defined above, then subsequently by amide oximating the said compound.
The process (2) of this invention is described below:
A 3,4-dihalogenobenzotrifluoride is reacted with an alkylated lithium, such as n-butyl lithium and formate, in solvents, while cooling at the temperature of -30.about.-70.degree. C.
Solvents to be used in the reaction are not particularly restricted if they are inert, for example, ethers such as tetrahydrofuran (THF), dioxane and diethyl ether, aromatic hydrocarbons such as toluene and xylene, and saturated hydrocarbons such as hexane and pentane. These solvents can be used alone or a mixture thereof.
The examples of formates used for the reaction are methyl formate, ethyl formate, propyl formate, isopropyl formate, butyl formate, t-butyl formate, phenyl formate and benzyl formate. The use of methyl formate and ethyl formate is particularly preferable due to easy handling and production cost.
As the 2,3-dihalogeno-6-trifluoromethylbenzaldehyde compounds of this invention, the following can be given: .delta.ppm from TMS): 7.64 (1H, d, J=8.5 Hz), 7.74 (1H, d, J=8.5 Hz), 10.44 (1H, s) .delta.ppm from TMS): 7.49 (1H, q, J=9.0 Hz), 7.61 (1H, dd, J=9.0 Hz, J=4.8 Hz), 10.39 (1H, s) (CDCl.sub.3, .delta.ppm from TMS) 7.42 (1H, t, J=8.7 Hz), 7.72 (1H, dd, J=8.7 Hz, J=4.8 Hz), 10
REFERENCES:
patent: 4268525 (1981-05-01), Paul
patent: 4939140 (1990-07-01), Larson
patent: 5041683 (1991-08-01), Marhold et al.
Paquette, Encyclopedia of Reagents for Organic Synthesis, vol. 5, pp. 3504-3505, 1995.
Bridges et al, Tetrahedron Letters, vol. 33, No. 49, 1992, pp. 7499-7502.
Kasahara Isamu
Okabe Takashi
Suzuki Tatsumi
Kumar Shailendra
Nippon Soda Co. Ltd.
Padmanabhan Sreeni
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