Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
1999-08-09
2001-04-24
Higel, Floyd D. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C546S186000, C548S352100, C560S227000, C562S830000, C562S512000, C562S605000, C564S270000
Reexamination Certificate
active
06222046
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a novel fluorine containing compound and a preparation process of the same. More specifically, the invention relates to a novel fluorine containing compound, tetraalkylfluoroformamidinium trifluoroacetate and a preparation process of the compound.
2. Prior Art of the Invention
In a conventional method for preparing trifluoroacetate ester, the compounds such as trifluoroacetic acid, trifluoroacetyl chloride and trifluoroacetic anhydride have been principally used.
The trifluoroacetate ester can be prepared by an esterification reaction using these compounds.
The process for preparing a trifluoroacetate ester by using trifluoroacetic acid includes, for example, a process for preparing the ester by condensation of trifluoroacetic acid with alcohol.
As an example of such process, J. Am. Chem, Soc., 79, 54 (1957) has reported a process for reacting alcohol with excess trifluoroacetic acid in the presence of a sulfuric acid catalyst and successively washing resultant ester with water to obtain trifluoroacetate ester. However, the process leads to partial hydrolysis of ester in the course of washing, and further, it is difficult to recover excess trifluoroacetic acid from an aqueous layer. Thus, application of the process in industry cannot be carried out with ease.
The process for preparing a trifluoroacetate ester by using trifluoroacetyl chloride includes a process for reaction of trifluoroacetyl chloride with alcohol in the presence of a basic catalyst. The process can prepare trifluoroacetate ester under mild condition in high yields as compared with the above case using trifluoroacetic acid. However, the process also requires a complicated method for recovery and reuse for hydrochloride of the base and has a problem on storage due to hydrolyzability of trifluoroacetyl chloride.
The process by use of trifluoroacetic anhydride can prepare trifluoroacetate ester under mild conditions due to high reactivity of trifluoroacetic anhydride. However, trifluoroacetic anhydride is expensive and thus application of the process in industry is difficult in view of economy.
SUMMARY OF THE INVENTION
The object of the invention is to provide a novel fluorine-containing compound, tetraalkylfluoroformamidinium trifluoroacetate, which is useful for a trifluoroacetoxylation reaction and a preparation process of the compound.
As a result of an intensive investigation in order to solve these subjects, the present inventors have found a novel compound represented by the formula (1):
wherein R
1
to R
4
are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group and can be the same or different, R
1
and R
2
or R
3
and R
4
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, and R
1
and R
3
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, and that the novel compound is excellent as a novel anion carrier, that is, a trifluoroacetoxylation agent and is useful for preparation of trifluoroacetate ester. And further, they have found that the application of the novel compound to a trifluoroacetoxylation reaction can be carried out in high safety and with ease without requiring specific equipment or technique.
The compound represented by the formula (1) can be prepared by reacting an alkali metal salt of trifluoroacetic acid with a compound represented by the formula (4);
wherein R
1
to R
4
are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group and can be the same or different, R
1
and R
2
or R
3
and R
4
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, R
1
and R
3
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, one of the fluorine atoms can form an ion pair as anion.
Thus, no specific equipment or technique is required at all and preparation can be carried out with safety in industry.
Further, the compound represented by the formula (4) can be prepared from an intermediate compound represented by the formula (5);
wherein R
1
to R
4
are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group and can be the same or different, R
1
and R
2
or R
3
and R
4
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, and R
1
and R
3
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, and a chlorine anion can covalently bond with the carbon atom having a chlorine atom. Urea is the raw material of the intermediate compound of the formula (5).
The inventors have also found that, after finishing the trifluoroacetoxylation reaction, the trifluoroacetoxylation agent can be recovered in the form of a urea derivative and reused in economy.
That is, one aspect of the invention is:
1) A compound represented by the formula (1);
wherein R
1
to R
4
are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group and can be the same or different, R
1
and R
2
or R
3
and R
4
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms, and R
1
and R
3
can bond to form a ring containing a nitrogen atom or a nitrogen atom and other hetero atoms.
2) A compound according to 1) wherein the compound represented by the formula (1) is a compound represented by the formula (2);
wherein a is an integer of 2 or 3.
3) A compound according to 1) wherein the compound represented by the formula (1) is 2-fluoro-1,3-dimethylimidazolinium trifluoroacetate represented by the formula (3);
4) A preparation process of a compound represented by the formula (1);
wherein R
1
to R
4
are the same as above, comprising reacting a compound represented by the formula (4);
wherein R
1
to R
4
are the same as above, and one of the fluorine atoms can form an ion pair as anion, with an alkali metal salt of trifluoroacetic acid.
5) A preparation process according to 4) wherein the compound represented by the formula (1) is a compound represented by the formula (2);
wherein a is an integer of 2 or 3, and the compound represented by the formula (4) is a compound represented by the formula (4-1);
wherein a is an integer of 2 or 3.
6) A preparation process according to 4) wherein the compound represented by the formula (1) is a compound represented by the formula (3):
and the compound represented by the formula (4) is a compound represented by the formula (4-2);
7) A trifluoroacetoxylation agent according to one of 1) to 3).
The present invention has enabled to provide a novel fluorine containing compound, tetraalkylfluoroformamidinium trifluoroacetate which is safe, ease to handle, very useful in industry and can be used for an industrial production of trifluoroacetate ester.
The compound of the invention can eliminate various problems in the conventional preparation processes of fluorine compounds and is effective for the preparation of fluorine compound in industry.
PREFERRED EMBODIMENT OF THE INVENTION
The invention will be illustrated in detail hereafter.
The compound of the invention, that is, the compound which is useful as the trifluoroacetoxylation agent of the invention is tetraalkylfluoroformamidinium trifluoroacetate represented by the above formula (1), preferably the compound represented by the formula (2), more preferably the compound represented by the formula (3).
In the formula (1), R
1
to R
4
are a substituted or unsubstituted, saturated or unsaturated alkyl group or a substituted or unsubstituted aryl group, preferably an alkyl or aryl group having 1 to 6 carbon atoms. The alkyl group can be a straight-chain or branched-chain and includes, for example, a methyl, ethyl, n-propyl, isopropyl, n-butyl, i-butyl, t-butyl, n-pentyl, n-hexyl, cyclohexyl, phenyl, naphthyl, methylphenyl, ethylphenyl and dimethylphenyl grou
Fukumura Kouki
Goto Ken-ichi
Hayashi Hidetoshi
Nagata Teruyuki
Naruse Junko
Burns Doane Swecker & Mathis L.L.P.
Higel Floyd D.
Mitsui Chemicals Inc.
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