Organic compounds -- part of the class 532-570 series – Organic compounds – Carboxylic acids and salts thereof
Reexamination Certificate
2002-07-16
2004-06-15
Killos, Paul J. (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Carboxylic acids and salts thereof
C562S401000
Reexamination Certificate
active
06750370
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a process for racemizing an optically active vinyl-substituted cyclopropanecarboxylic acid compound.
Optically active vinyl-substituted cyclopropanecarboxylic acid compounds are known as important synthetic pyrethroid insecticides or production intermediates thereof, and a desired optical isomer thereof has been produced by optical resolution of a racemate thereof with an optical resolution agent. In connection with the optical resolution process, the other isomer of the resolved desired compound was racemized to the racemate for the purpose of efficiently utilizing the produced chemicals, and there have been reported, for example, a racemization method of an optically active chrysanthemum-monocarboxylic acid by reacting the optically active acid or its halide with a Lewis acid (e.g. aluminum bromide), and a method of irradiating light in the co-presence of thiol(SH), and the like (JP-A-52-144651, JP-A-60-174744, JP-A-61-5045, JP-A-1-261349).
However, these methods were not necessarily satisfactory as an industrial production process in that a halogen-containing catalyst, which is generally corrosive to reactors, was required, or a powerful electric energy supply for light-irradiation was required.
SUMMARY OF THE INVENTION
According to the present invention, an optically active vinyl-substituted cyclopropanecarboxylic acid compounds including carboxylic acids, carboxylic acid halides and carboxylic acid esters thereof, can be effectively racemized in an industrially advantageous manner.
The present invention provides
a process for racemizing an optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1):
wherein R
1
, R
2
, R
3
and R
4
each independently represent
a hydrogen atom, a halogen atom,
an alkyl group having 1-4 carbon atoms, which may be substituted,
an aryl group, which may be substituted, or
an alkoxycarbonyl group, which may be substituted, or
R
1
and R
2
are bonded to form an alkylene group, which may be substituted (e.g. haloalkylene group such as dihaloethylene group or the like); and
X represents
a hydroxyl group, a halogen atom, an alkoxy group having 1-20 carbon atoms, which may be substituted, or an aryloxy group, which may be substituted,
which process comprises reacting
said optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1) with a nitric compound or a nitrogen oxide.
DETAILED DESCRIPTION OF THE INVENTION
“Racemizing” in the present process means that the optical rotatory power of said optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1) to be reacted is decreased or lost.
A description will be first made to R
1
, R
2
, R
3
and R
4
of formula (1) above.
The alkyl group having 1-4 carbon atoms, which may be substituted, may be straight, branched, or cyclic, and the examples thereof include methyl, ethyl, n-propyl, i-propyl, cyclopropyl, n-butyl, sec-butyl, tert-butyl, and the like.
The alkyl group may be substituted with a group selected from:
a halogen atom such as fluorine, chlorine, bromine, or iodine; and
an alkoxy group (e.g. C1-C4 alkoxy) such as methoxy, ethoxy, n-propoxy, i-propoxy, n-butoxy, sec-butoxy, tert-butoxy, or the like.
Examples of the aryl group, which may be substituted include phenyl, and the aryl group may be substituted with an alkyl group (e.g. C1-C4 alkyl as described above), a halogen atom, or the like.
Examples of the alkoxycarbonyl group, which may be substituted include a (C1-C4)alkoxy-carbonyl group such as methoxycarbonyl, ethoxycarbonyl, n-propoxycarbonyl, i-propoxycarbonyl, n-butoxycarbonyl, sec-butoxycarbonyl, tert-butoxycarbonyl or the like.
Furthermore, these alkoxycarbonyl may be substituted with a halogen atom such as fluorine, chlorine, bromine, or iodine.
Preferably R
1
to R
4
represent a methyl group. Alternatively, R
1
and R
2
preferably represent a halogen atom and R
3
and R
4
represent a methyl group.
Examples of the alkoxy group, which may be substituted, represented by “X” in the formula (1), include an alkoxy group having 1-20 carbon atoms, which may be substituted, and an aryloxy group, which may be substituted.
The alkoxy group may be straight, branched or cyclic.
Specific examples of the alkoxy group include methoxy, ethyoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, neopentoxy, n-hexyloxy, cyclohexyl, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, n-tridecyloxy, n-tetradecyloxy, n-pentadecyloxy, n-hexadecyloxy, n-heptadecyloxy, n-octadecyloxy, n-nonadecyloxy, n-icosyloxy and the like.
The alkoxy group may be substituted with a group selected from:
a halogen atom such as fluorine, chlorine, bromine, and iodine;
an aryl group, which may be substituted with an alkyl (e.g. C1-C3 alkyl such as methyl, ethyl, or propyl), or phenoxy group, and specific examples of the aryl group include, for example phenyl, naphthyl, or anthracenyl methylphenyl, dimethylphenyl, trimethylphenyl, propylphenyl, and phenoxyphenyl groups;
a heterocyclic group such as furyl, phenoxyfuryl, benzylfuryl, difluoromethylfuryl, propargylfuryl, methylisooxazolyl, trifluoromethylthiazolyl, trifluoromethoxythiazolyl, propinylpyrolyl, propinylpyrazolyl, propinyldioxoimidazolidinyl, indolyl, propinylindolyl, dioxotetrahydroisoindolyl, oxothiazolyl, pyridyl, or trifluoropyridyl group;
an oxo group;
an alkenyl having a double bond or an alkynyl having a triple bond (e.g. C2-C3 alkenyl such as vinyl, propenyl or the like, C2-C3 alkynyl such as ethynyl, propynyl or the like); cyano; nitro; and the like.
The alkoxy group, which may be substituted is preferably a C1-C20 alkoxy group, more preferably a C1-C4 alkoxy group, yet more preferably a C1-C2 alkoxy group.
Examples of the aryloxy group, which may be substituted, include phenoxy, 1-naphthyloxy, 2-naphthyloxy of which aromatic ring may be substituted with alkyl(e.g. C1-C4 alkyl), alkynyl(e.g. C2-C3 alkynyl), alkoxy(e.g. C1-C4 alkoxy), acetyl, formyl, or a halogen atom. Specific examples of the alkyl, alkynyl and alkoxy groups include those specified above.
Specific examples of the optically active vinyl-substituted cyclopropanecarboxylic acid compound of formula (1) include optically active
2,2-dimethyl-3-(1-propenyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropane-carboxylic acid,
2,2-dimethyl-3-(2,2-dichlorovinyl)cyclopropane-carboxylic acid,
2,2-dimethyl-3-(2-chloro-2-fluorovinyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-bromovinyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2,2-dibromovinyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-chloro-3,3,3-trifluoro-1-propenyl)-cyclopropanecarboxylic acid,
2,2-dimethyl-3-{3,3,3-trifluoro-2-(trifluoromethyl)-1-propenyl}cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-phenyl-1-propenyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-phenylvinyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-{(2,2-difluorocyclopropylidene)methyl}-cyclopropanecarboxylic acid,
2,2-dimethyl-3-{2-(tert-butoxycarbonyl)vinyl}-cyclopropanecarboxylic acid,
2,2-dimethyl-3-{2-fluoro-2-(methoxycarbonyl)vinyl}-cyclopropanecarboxylic acid,
2,2-dimethyl-3-{2-fluoro-2-(ethoxycarbonyl)vinyl}-cyclopropanecarboxylic acid,
2,2-dimethyl-3-{2-fluoro-2-(tert-butoxycarbonyl)-vinyl}cyclopropanecarboxylic acid,
2,2-dimethyl-3-[2-{2,2,2-trifluoro-1-(trifluoromethyl)-ethoxycarbonyl}vinyl]cyclopropanecarboxylic acid,
2-methyl-2-ethyl-3-(1-propenyl)cyclopropanecarboxylic acid,
2,2-diethyl-3-(2,2-dichlorovinyl)cyclopropanecarboxylic acid, and
2-methyl-2-phenyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylic acid; optically active chlorides, methyl esters and ethyl esters thereof; and the like.
Preferable examples thereof include, for example, optically active
2,2-dimethyl-3-(1-propenyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(2-methyl-1-propenyl)cyclopropanecarboxylic acid,
2,2-dimethyl-3-(1-propenyl)cyclopropanecarboxylic acid chloride,
2,2-d
Goto Fumisato
Iwakura Kazunori
Souda Hiroshi
Killos Paul J.
Sumitomo Chemical Company Limited
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