Selective dehalogenation process

Details Selective dehalogenation process Selective dehalogenation process

1996-02-01

1998-07-14

Shippen, Michael L.

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

Organic compounds

Carboxylic acid esters

562506, C07C 6974

Patent

active

057806691

DESCRIPTION:

BRIEF SUMMARY
TECHNICAL FIELD

This invention relates to a novel process for producing a starting compound to be used in the preparation of a quinolone derivative (refer to JP-A-2-231475, the term "JP-A" as used herein means an "unexamined published Japanese patent application") which is expected as an excellent antimicrobial agent.


BACKGROUND ART

1,2-cis-2-Fluorocyclopropanecarboxylic acid, which means a compound wherein a carboxylate substituent and a fluorine atom are located on the same side of the cyclopropane ring plane, represented by the following structural formula ##STR3## has been produced by the process described below. Namely, bromofluorocarbene is added to butadiene to thereby give 1-bromo-1-fluoro-2-vinylcyclopropane. Next, this compound is converted into a carboxylic acid compound by oxidizing its vinyl group. Further, the carboxylic acid compound is esterified followed by debromination. After separating 1,2-cis-2-fluorocyclopropanecarboxylate of the cis-configuration from the compound of the trans-configuration, the ester Education, Wakayama University, 33, 33 (1984)!. ##STR4##
However, the above-mentioned process requires a number of reaction steps. In addition, tributyltin hydride (Bu.sub.3 SnH), which is toxic and expensive, is used in the step of debromination. These problems inevitably make this process disadvantageous from an industrial viewpoint.
On the other hand, there has been reported a process for the dechlorination of 2-chloro-2-fluorocyclopropanecarboxylic acid through a catalytic hydorgenolysis reaction in the presence of a base. By this process, however, no 2-fluorocyclopropanecarboxylic acid of the cis-configuration but 2-fluorocyclopropanecarboxylic acid of the trans-configuration alone 49, 127 (1990)!.
It is an object of the present invention to provide a process whereby a 2-fluorocyclopropanecarboxylic acid derivative, in particular, 1,2-cis-2-fluorocyclopropanecarboxylic acid derivative can be produced safely, economically and advantageously from an industrial viewpoint.


DISCLOSURE OF THE INVENTION

Under these circumstances, the present inventors have conducted extensive studies. As a result, they have found out that when a compound represented by the following formula (1) (hereinafter, referred to as the compound (1) and the same will apply to other compounds represented by numbered formulae hereinafter) is subjected to a catalytic hydrogenolysis reaction in the presence of a base under mild conditions, dehalogenation unexpectedly proceeds with retention of the configuration and thus a 1,2-cis-2-fluorocyclopropanecarboxylic acid derivative can be obtained at a high yield. They have further found out that when the compound (3) as will be shown hereinafter is treated under the same conditions, dehalogenation proceeds similarly, thus completing the present invention.
Accordingly, the present invention relates to a process for producing a compound represented by the following formula (2): ##STR5##
wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; which comprises subjecting a compound represented by the following formula (1): ##STR6##
wherein R is as defined above; and X represents a chlorine or bromine atom; to a catalytic hydrogenolysis reaction in the presence of a base.
The present invention further relates to a process for producing a compound represented by the following formula (2): ##STR7##
wherein R represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; which comprises subjecting a compound represented by the following formula (3): ##STR8##
wherein R is as defined above; and X represents a chlorine or bromine atom; to a catalytic hydrogenolysis reaction in the presence of a base.
The present invention furthermore relates to a process for producing the compound (2) which comprises treating the compound (1) or the compound (3) in the presence of 1,2-diaminoethane with the use of a catalyst selected from Raney nickel and palladium/carbon under a hydrogen gas atmosphere of a hydrogen gas pressure ranging from 1 to 50 atm.
The

REFERENCES:
Gassen, Journal of Fluorine Chemistry, vol. 49, pp. 127-139, 1990.

Affiliated with

Also associated with

Rating

Selective dehalogenation process does not yet have a rating. At this time, there are no reviews or comments for this patent.

If you have personal experience with Selective dehalogenation process, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Selective dehalogenation process will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFUS-PAI-O-1883267