Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1997-05-01
1998-04-28
Ivy, C. Warren
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D21338, C07D21326
Patent
active
057446083
DESCRIPTION:
BRIEF SUMMARY
This application is a 371 of PCT/JP96/02535, filed Sep. 6, 1996.
FIELD OF THE INVENTION
The present invention relates to substituted-aminomethyl pyridines which are useful as a precursor for manufacturing important raw materials used for the production of plant protection chemicals.
BACKGROUND ART
Since 3-(aminomethyl)-6-chloropyridines represented by a general formula ##STR3## wherein R.sup.2 is hydrogen or a lower alkyl, R.sup.3 is hydrogen, a lower alkyl or a halogen atom, are known as an important raw material for manufacturing insecticides for agricultural use, many investigations have been made on the methods for the manufacturing said chloropyridines.
For instance, (1) a method to use 6-chloro-3-(chloromethyl)pyridine as a starting material and to convert the chlorine atom substituted on the methyl group therein to an amino group, which method is disclosed in EP 391205, EP 302389, EP 366085, EP 376279, and JP 5286936, and (2) a method to use 6-chloro-3-cyanopyridine as a precursor and to convert the cyano group therein to an aminomethyl group, which method is disclosed in DE 4222152 and WO 9213840, are known as such methods as described above.
However, the method (1) to convert the chlorine atom on the methyl group to an amino group as described above produces some by-products, such as the dimer thereof, and therefore, no satisfactory method to be employed in an industrial scale has been reported up till now. Furthermore, as a method for producing a raw material, 6-chloro-3-(chloromethyl)pyridine, the following methods, (i) chlorination of 6-chloro-3-methylpyridine, which is prepared pursuant to a method described in EP 556683, etc. (see DE 3630046 and DE 4016175), (ii) reduction of 6-chloro-3-(trichloromethyl)pyridine (see EP 512463 and JP 5320132) and (iii) preparation from 6-chloronicotinic acid (see EP 569974, EP 256990, U.S. Pat. No. 4576629 and BP 425030), are typically known. However, in case of the methods (i) and (ii), there is a problem in selectivity of the reaction, namely, it is difficult to allow only the objective first substitution reaction of the chlorine atom on the methyl group and then to stop the subsequent substitution reaction that follows, and the method (iii) has some problems in the cost and so on, since raw materials to be used for the method are expensive and the method requires a higher cost in the reduction process.
In the case of the method(2), it is also problem that elimination of a chlorine atom, the secondary production of dimers, etc. are caused during the reduction procedure of 6-chloro-3-cyanopyridine, and that 6-chloro-3-cyanopyridine can not be efficiently obtained due to the generation of its regioisomers at a time of chlorination of the 6th position of 3-cyanopyridine in the manufacturing process of the raw material.
Therefore, all of the methods previously known have faults that produce many by-products due to any reason of the elimination and the substitution of the chlorine atom, hydrogenation of the pyridine ring, production of the dimer, and so on, since all of the methods publicly-known take a reaction to establish an amino group on the 3rd-positioned methyl group following to the completion of chlorination at the 6th-position.
DISCLOSURE OF THE INVENTION
The inventors of the present invention, have seriously investigated to find an industrially-advantageous method for manufacturing ##STR4## wherein R.sup.2 and R.sup.3 are as described above, and they have found that 3-(aminomethyl)-6-chloropyridines represented by a general formula ##STR5## wherein R.sup.2 and R.sup.3 are as described above, can be efficiently manufactured by using 3-(substituted-aminomethyl)pyridine 1-oxide ##STR6## wherein R.sup.1 is alkyl, aryl, aralkyl or alkoxy, R.sup.2 and R.sup.3 are as described above, as a starting raw material and have accomplished the present invention.
Therefore, the present invention is directed to methods for manufacturing ##STR7## wherein R.sup.2 and R.sup.3 are as described above, characterized in that the said 3-(aminomethyl)-6-chloropyridine
REFERENCES:
patent: 4576629 (1986-03-01), Garst et al.
patent: 5026864 (1991-06-01), Diehr
patent: 5300650 (1994-04-01), Nabata
patent: 5382671 (1995-01-01), Diehr
patent: 5424437 (1995-06-01), Ieno
patent: 5502194 (1996-03-01), Rivadeneira
patent: 5580983 (1996-12-01), Kraus
Hatanaka Kazuhiro
Jun Takahashi
Tsutomu Imagawa
Tsutomu Inoue
Ivy C. Warren
M. Mach D. Margaret
Mason, Jr. Joseph C.
Nippon Soda Co. Ltd.
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