Intermediates for producing 5,7-dichloro-4-hydroxyquinoline

Details Intermediates for producing 5,7-dichloro-4-hydroxyquinoline Intermediates for producing 5,7-dichloro-4-hydroxyquinoline

1996-09-03

1998-03-24

Ivy, C. Warren

Organic compounds -- part of the class 532-570 series

Organic compounds

Heterocyclic carbon compounds containing a hetero ring...

560 43, 560 44, C07D215233, C07C22930

Patent

active

057314403

DESCRIPTION:

BRIEF SUMMARY
This application is the national phase of PCT/JP95/00293, filed Feb. 27, 1995.


TECHNICAL FIELD

The present invention relates to a process for producing 5,7-dichloro-4-hydroxyquinoline (hereinafter, referred to as DCHQ) by decarboxylating 5,7-dichloro-3-carboxy-4-hydroxyquinoline (hereinafter, referred to as DCQA) in the presence of an acid; to a process for producing DCQA by hydrolyzing 3-cyano- or 3-ethoxycarbonyl-5,7-dichloro-4-hydroxyquinoline in the presence of an acid; to a process for producing DCHQ by successively decarboxylating DCQA formed in the above hydrolysis in the presence of an acid; and to certain intermediates for those manufacturing processes.


BACKGROUND ART

Japanese Unexamined Patent Publication No. Hei 1-246263 (JP Laid Open Appln. No. 246263/1989) discloses that 5,7-dichloro-4-(4-fluorophenoxy)quinoline shows an excellent plant fungicidal activity as an agrohorticultural bactericide. With respect to a process for producing said 5,7-dichloro-4-(4-fluorophenoxy)quinoline, there is disclosed a manufacturing process wherein a reaction product of 3,5-dichloroaniline and Meldrum's acid is heated to produce DCHQ, the resulting DCHQ is made to react with phosphorus oxychloride to produce 4,5,7-trichloroquinoline and the resulting 4,5,7-trichloroquinoline is made to react with 4-fluorophenol. In the manufacture of DCHQ in the above-mentioned process, it is usually conducted that 3,5-dichloroaniline is made to react with Meldrum's acid to produce 2,2-dimethyl-4,6-dioxo-5-(3,5-dichloroanilinomethylene)-1,3-dioxane and the resulting 2,2-dimethyl-4,6-dioxo-5-(3,5-dichloroanilinomethylene)-1,3-dioxane is thermally cyclized to give DCHQ. In addition to said process, it is also conducted, for example, that 3,5-dichloroaniline is made to react with diethyl ethoxymethylenemalonate to produce 5,7-dichloro-3-ethoxycarbonyl-4-hydroxyquinoline, the resulting 5,7-dichloro-3-ethoxycarbonyl-4-hydroxyquinoline is hydrolyzed with an aqueous solution of sodium hydroxide to produce DCQA and the resulting DCQA is decarboxylated on heating at 240.degree.-250.degree. C. to give DCHQ.
However, in the prior art processes, there are difficulties in their industrial utilizations that (i) especially in hydrolysis of 5,7-dichloro-3-ethoxycarbonyl-4-hydroxyquinoline, although the reaction time is short, the produced DCQA is of a very fine crystal whereby its separation is difficult resulting in a poor productivity; and (ii) the process requires a large quantity of heating medium for decarboxylation of DCQA. In addition, it is difficult to obtain a large amount of Meldrum's acid in low cost. Therefore, there has been a demand for a manufacturing process which is suitable for industrial utilization using a material available easier than Meldrum's acid.
The present inventors have conducted an investigation for overcoming the difficulties in the prior art processes, particularly the drawback which is inherent in the prior art process where diethyl ethoxymethylenemalonate is used, with particular attention for an improvement in effectively conducting the hydrolysis of 5,7-dichloro-3-ethoxycarbonyl-4-hydroxyquinoline and the decarboxylation of DCQA and also in conducting the decarboxylation of DCQA without the use of heating medium whereupon a process for producing DCHQ which is suitable for industrial utilization has been achieved.


DISCLOSURE OF THE INVENTION

One aspect of the present invention is:
(i) a process for producing 5,7-dichloro-4-hydroxyquinoline (DCHQ) which comprises decarboxylating 5,7-dichloro-3-carboxy-4-hydroxyquinoline (DCQA) in the presence of sulfuric acid or phosphoric acid;
(ii) a process for producing DCHQ which comprises hydrolyzing 3-cyano- or 3-ethoxycarbonyl-5,7-dichloro-4-hydroxyquinoline in the presence of hydrochloric acid, sulfuric acid or phosphoric acid followed by subjecting the resulting 5,7-dichloro-3-carboxy-4-hydroxyquinoline (DCQA) to a decarboxylation as mentioned in the above process (i); and
(iii) a process for producing DCHQ according to the above-mentioned process (ii) in whi

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patent: 4380632 (1983-04-01), Steffen
patent: 4412076 (1983-10-01), Baudouin
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Savini L, Massarelli P, Pellerano C, Bruni G. Farmaco 48 (6), 805-25 (Abstract), 1993.
March J. Advanced Organic Chemistry. Second Eidtion. McGraw-Hill Book Company. New York. p. 514, 1977.

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