Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-02-15
2001-05-29
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C564S307000, C534S562000
Reexamination Certificate
active
06239289
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to O-(perfluoroalkyl)dibenzofuranium salt derivatives which are useful as chemicals for introducing a perfluoroalkyl group into an oxygen atom, nitrogen atom and the like (hereinafter referred to as perfluoroalkylating agents), intermediates for their preparation, a preparation method for their intermediates, perfluoroalkylating agents and a perfluoroalkylation method.
PRIOR ART
For the conventional methods for perfluoroalkylating organic compounds, for example, the following synthetic methods for (trifluoromethyl)phenyl ether compounds by trifluoromethylation of phenolic compounds are known:
Method (1) of; preparing methylphenyl ether compounds by methylation of phenolic compounds, then leading to (trichloromethyl)phenyl ether compounds by selective chlorination of the side chains followed by conducting a halogen-exchange reaction with hydrogen fluoride in the presence of a catalyst (antimony pentachloride) [refer to Angew. Chem. Int. Ed. Engl., 16, 735 (1977)],
Method (2) of: heating phenolic compounds with an excess of carbon tetrachloride and hydrogen fluoride at high temperature in an autoclave [refer to J. Org. Chem., 44, 2907 (1979)],
Method (3) of: reacting phenolic compounds with (CF
3
)
2
S (OCF
3
)
2
[refer to Inorg. Chem., 17, 2173 (1978)],
Method (4) of: leading to phenyl thiochloroformate (C
6
H
5
OCSCl) by reacting phenols with thiophosgene, and treating with molybdenum hexafluoride (MoF
6
) [refer to Fr. Demande 2,214,674 (1974) and Chem. Abstr., 82, 155,757 (1975)], and
Method (5) of: leading to phenyl xanthate(C
6
H
5
OCSSCH
3
) by the reaction of phenols with carbon disulfide and methyl iodide followed by reacting this phenyl xanthate with a hydrogen fluoride-pyridine mixture and 1, 3-dibromo-5, 5-dimethylhydantoin [refer to Tetrahedron Lett., 33, 4173 (1992)].
Further, as for synthetic methods for (trifluoromethyl)trifluoromethane sulfonate as a (trifluoromethyl) sulfonate compound derived from sulfonic acid, the followings are known:
Method (6) of: decomposing the peroxide (CF
3
SO
2
OO SO
2
CF
3
) obtained by electrolysis of trifluoromethanesulfonic acid at low temperature [refer to Inorg. Chem., 4, 1010(1965)],
Method (7) of: heating a mixture of trifluoromethanesulfonic acid and fluorosulfonic acid [refer to Synthesis, 319 (1976) and Inorg. Nucl. Chem. Letters, 16, 195 (1980)],
Method (8) of: reacting silver trifluoromethanesulfonate obtained by reacting trifluoromethanesulfonic acid with silver oxide or silver nitrate, with trifluoromethyl iodide at high temperature in an autoclave [refer to Tetrahedron Lett., 40, 3865 (1979)], and
Method (9) of: heating S-(trifluoromethyl)dibenzothiophenium trifluoromethanesulfonate obtained by reacting trifluoromethanesulfonic acid with 2-(trifluoromethylthio)biphenyl and fluorine gas, or its 3, 7-dinitro derivatives [refer to J. Am. Chem. Soc., 115, 2156 (1993)].
Further, the following synthetic method for alkyl(trifluoromethyl)ethers by trifluoromethylation of alkylalcohols is known:
Method (10) of: obtaining methyl or ethyl(trifluoromethyl) ethers by decomposition of trifluoromethanediazohydroxide at −50 to −55° C. which was produced by reaction of hydroxylamine with trifluoronitrosomethane at −75° C. in methanol or ethanol [refer to J. General Chem. USSR, 38, 685 (1968)].
In addition, the following synthetic method for alkyl(trifluoromethyl)ethers is known:
Method (11) of: reacting alkyltrifluoromethanesulfonates or activated alkylbromide with tris(dimethylamino)sulfonium trifluoromethoxide [for this compound, refer to J. Am. Chem. Soc., 107, 4565 (1985)] [for this method, refer to J. Carbohydrate Chem., 4, 545 (1985) and The Proceeding of the 67th Spring Annual Meeting of the Chemical Society of Japan, II, 3 C2 34, 767 (1994)].
However, the said methods have serious defects as follows:
Methods (1), (4) and (5) need multi-step reaction processes and must use highly toxic chlorine gas, hydrogen fluoride, thiophosgene, molybdenum hexafluoride, carbon disulfide and the like;
Method (2) results in a low yield (10%) of (trifluoromethyl)phenyl ether itself; besides it needs high pressure and high temperature using highly toxic hydrogen fluoride as the reaction condition;
In method (3), the synthesis of (CF
3
)
2
S(OCF
3
)
2
used is extremely complex and must handle highly toxic substances (fluorine gas, chlorine gas, fluorophosgene and the like) in the synthesis;
In method (6), in addition to sulfonic acids used being limited, the highly dangerous explosive peroxides must be decomposed under careful control, and further electrolysis at a low temperature where the reaction condition is limited must be used;
In method (7), in addition to sulfonic acids used being limited, the yield of the objective is very low, the isolation is difficult because of generating many byproducts, and it needs a long reaction time at high temperature under conditions of super strong acidity;
Method (8) must use costly silver salts,
Method (9) must use a highly toxic fluorine gas and sulfonic acids are limited to super strong acids. Thus, these conventional methods cannot be widely used as useful synthetic methods for trifluoromethyl compounds.
Further, method (10) has problems related to the handling of the highly toxic gas, trifluoronitrosomethane and the controlling of the reaction due to the necessary decomposition reaction of trifluoromethanediazohydroxide, an unstable intermediate. Furthermore, as this is a reaction with solvent molecules, the range of application is extremely narrow and is not a widely-used method for trifluoromethylation.
Method (11) has problems in the isolation and purification of the objective (trifluoromethyl)ether compounds because many monofluorinated byproducts are generated. In addition, tris(dimethylamino)sulfonium trifluoromethoxide used in this reaction must be synthesized using highly toxic fluorophosgene as the starting material. Accordingly, method (11) is not a useful preparation method for trifluoromethyl compounds.
On the other hand, S-(trifluoromethyl)dibenzothiophenium salts and their analogous compounds are accepted as a useful trifluoromethylating agent [refer to J. Am. Chem. Soc., 115, 2156 (1993) and JP Patent Opening 3-197479]. However, when this agent is used for the trifluoromethylation of phenolic compounds, one drawback is that the yield is extremely low.
Further, (perfluoroalkyl)phenyliodonium trifluoromethanesulfonate (FITS reagent) and their analogs are known as perfluoroalkylating agents that have more than two carbons. However, reacting these with phenols usually fails to give (perfluoroalkyl) phenyl ethers, while a mixture of ortho- and para- (petfluoroalkyl)phenols is obtained by nuclear substitution [refer to Chem. Lett., 1663 (1981)]. Consequently, it has the serious defect that the method cannot be used as a preparation method for (perfluoroalkyl)phenyl ethers.
Considering these previous situations, the present inventors in the previous application have found 2′-(perfluoroalkoxy)biphenyl-2-diazonium salt or its derivatives as a perfluorinating agent which can readily perfluorinate an oxygen atom, nitrogen atom and the like in one step under mild conditions (refer to JP Patent Opening 7-330703: hereinafter, sometimes refer red to as the previous invention).
However, it was found that the yield and the range of application (namely, possible substances for perfluoroalkylation) of the perfluoroalkylation reaction when using 2′-(perfluoroalkoxy)biphenyl-2-diazonium salt and its derivatives as perfluoroalkylating agents for the perfluorination of an oxygen atom, nitrogen atom and the like, still need to be improved.
Further, 4-t-butyl-2′-(perfluoroalkoxy)biphenyl-2-diazonium salt, which is one typical example of the derivatives in the previous invention and the closest compound to the present invention has the problem of storability as a perfluoroalkylating ag
Adachi Kenji
Ishihara Sumi
Umemoto Teruo
Armstrong Westerman Hattori McLeland & Naughton LLP
Daikin Industries Ltd.
McKane Joseph K.
Solola Taofiq A.
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