Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1991-01-09
1992-12-29
Lee, Mary C.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
560176, C07D21308, C07D 6966
Patent
active
051753006
DESCRIPTION:
BRIEF SUMMARY
DESCRIPTION
1. Technical Field
This invention relates to a process for preparing pyridine-2,3-dicarboxylic acid compounds. More particularly, it relates to a process for preparing pyridine-2,3-dicarboxylic acid compounds which are useful as an intermediate for manufacturing agricultural chemicals and pharmaceuticals.
2. Background Art
Heretofore, as the method of preparing pyridine-2,3-dicarboxylic acid compounds known are:
(1) Oxidation with nitric acid of quinolines and quinolinols which are synthesized by Skraup reaction from aniline and glycerine with concentrated sulfuric acid and nitrobenzene. (J. Chem. Soc. page 4433, 1956);
(2) Reacting an .alpha.,.beta.-unsaturated hydrazone compound and a maleic acid compound in an inert solvent to obtain 1-(substituted amino)-1,4-dihydropyridine-2,3-dicarboxylic acid derivative. Then, heating the resultant derivative to eliminate the substituted amino group in the 1-position. (Japanese Patent Application Unexamined Publication No. 246369/1985).
(3) Treating a 1-(substituted amino)-1,2,3,4-tetrahydropyridine-2,3-dicarboxylic acid derivative with acid and/or by heat to convert into a 1,4-dihydropyridine-2,3-dicarboxylic acid derivative, and then oxidizing it. (Japanese Patent Application Unexamined Publication No. 47482/1986).
(4) Oxidizing quinoline with excess hypochlorites in the presence of ruthenium oxide. (Japanese Patent Application Unexamined Publication No. 212563/1986).
(5) Condensing and cyclizing .alpha.-halo-.beta.-keto-esters and .alpha.,.beta.-unsaturated aldehydes or ketones in the organic solvent in the presence of more than 2 mole equivalent of ammonium salt. (Japanese Patent Application Unexamined Publication No. 106081/1987).
As the method of synthesizing pyridinemonocarboxylic acid derivatives known is such a method as subjecting ethyl 2-methly-1,4-dihydronicotinate which is produced by condensation and cyclization of .alpha.,.beta.-unsaturated aldehydes such as acrolein and crotonaldehyde with ethyl .beta.-aminocrotonate to oxidation with nitric acid in a mixed acid. (J. Org. Chem. Soc. Vol. 21, page 800, 1956).
However, the above method (1) not only has many reaction processes but also requires drastic oxidation with nitric acid, and involves possible hazards. Also, the pyridine-2,3-dicarboxylic acids, which are apt to cause decarboxylation, result in low yields by the oxidation with nitric acid, and, in addition, produce a large quantity of acidic waste liquid. Thus, the method (1) is not suited to the industrial manufacture of pyridine-2,3-dicarboxylic acids.
The methods (2) and (3) mentioned above have many reaction processes leading to decreased total yields, and require the use of expensive starting materials. Particularly, they require elimination process of the substituted amino group in the intermediate. This decreases the yield and becomes a problem on resource saving. Therefore, it is difficult to manufacture pyridine-2,3-dicarboxylic acid derivatives industrially by the method (2) or (3).
In the method (4), there are problems that a large excess of the oxidant must be used and that a large quantity of waste liquid is produced requiring expenses for its disposal.
In the method (5), .alpha.-halo-.beta.-keto-ester used as a raw material cannot be produced in good yield with conventional known manufacturing methods, causing high cost of raw material. It is, therefore, difficult to manufacture pyridine-2,3-dicarboxylic acid derivatives industrially by the method (5).
Accordingly, it is an object of this invention to provide a process for preparing pyridine-2,3-dicarboxylic acid compounds in high yield from starting materials inexpensive and readily available.
DISCLOSURE OF INVENTION
A process for preparing pyridine-2,3-dicarboxylic acid compounds of the invention is a process for preparing pyridine-2,3-dicarboxylic acid compounds represented by the following formula (1). ##STR2## wherein R.sup.1 and R.sup.2 are, identical or different, a lower alkyl group, and R.sup.3 is a hydrogen atom or a lower alkyl group, which comprises,
1) a
REFERENCES:
patent: 4723011 (1988-02-01), Doehwer et al.
patent: 4973695 (1990-11-01), Yamashita et al.
Journal of the American Society, vol. 7, Jan.-Apr. 1950, pp. 5221-5225; L. H. Conover et al.: "Thiazole Analogs of Pyridoxine".
Journal of the Chemical Society, vol. 438, Part III, 1949, pp. 2049-2054, the Chemical Society, London, GB; G. W. Holton et al.: "Experiments on the Synthesis of Rotenone and its Derivatives", Part XVI. The Synthesis of Abutic Acid and its Analogues: P. 2050: "Experimental Part".
Kodama Mitsuhiro
Yamashita Takaharu
Lee Mary C.
McKane Joseph K.
Sugai Chemical Ind. Co., Ltd.
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