Organic compounds -- part of the class 532-570 series – Organic compounds – Imidic acids – chalcogen analogs or salts thereof
Reexamination Certificate
2001-09-20
2003-07-22
McKane, Joseph K. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Imidic acids, chalcogen analogs or salts thereof
C562S802000, C564S183000
Reexamination Certificate
active
06596902
ABSTRACT:
BACKGROUND OF THE INVENTION
2-Aryl-5-(perfluoroalkyl)pyrrole compounds are useful as insecticidal and acaricidal agents. In addition, those compounds are also useful for the preparation of other insecticidal and acaricidal agents. In particular, 2-aryl-5-(perfluoroalkyl)pyrrole compounds are key intermediates in the preparation of arylpyrrole compounds such as chlorfenapyr. Accordingly, there is an ongoing search to discover new methods for the preparation of 2-aryl-5-(perfluoroalkyl)pyrrole compounds.
U.S. Pat. No. 5,145,986 discloses that 2-aryl-5-(trifluoromethyl)pyrrole compounds may be prepared by reacting an N-(substituted benzyl)-2,2,2-trifluoroacetimidoyl chloride compound with an &agr;-halo-&agr;,&bgr;-unsaturated nitrile, ester or nitro compound in the presence of a base. However, the process described in U.S. Pat. No. 5,145,986 is not entirely satisfactory because the required &agr;-halo-&agr;,&bgr;-unsaturated nitrile, ester or nitro compound is prepared in a two step—halogenation/dehydrohalogenation—process.
U.S. Pat. Nos. 5,446,170 and 5,426,225 disclose that 2-aryl-5-(trifluoromethyl)pyrrole compounds may be obtained in several steps from the appropriate aldehyde. The processes described in U.S. Pat. Nos. 5,446,170 and 5,426,225 require the use of an aminonitrile intermediate which is obtained via the Strecker synthesis from the appropriate aldehyde. However, the use of the Strecker synthesis is not entirely satisfactory because of cyanide containing waste streams.
It is, therefore, an object of the present invention to provide a new process for the preparation of 2-aryl-5-(perfluoroalkyl)pyrrole compounds which avoids the use of &agr;-halo-&agr;,&bgr;-unsaturated nitrile, ester and nitro compounds and the Strecker synthesis.
It is also an object of this invention to provide a new process for the preparation of arylpyrrole compounds such as chlorfenapyr.
A further object of the present invention is to provide new intermediate compounds which are useful in the processes described hereinbelow.
Those and other objects of the present invention will become more apparent from the detailed description thereof set forth below.
SUMMARY OF THE INVENTION
The present invention provides a new process for the preparation of 2-aryl-5-(perfluoroalkyl)pyrrole compounds having the structural formula I
wherein
W is hydrogen or C
m
F
2m+1
;
Y is CN, NO
2
or CO
2
R;
R is C
1
-C
4
alkyl;
m and n are each independently an integer of 1, 2, 3, 4, 5, 6, 7 or 8;
A is
L is hydrogen or halogen;
M and Q are each independently hydrogen, halogen, CN, NO
2
, C
1
-C
4
alkyl, C
1
-C
4
haloalkyl, C
1
-C
4
alkoxy, C
1
-C
4
haloalkoxy, C
1
-C
4
alkylthio, C
1
-C
4
haloalkylthio, C
1
-C
4
-sulfinyl, C
1
-C
4
haloalkylsulfinyl, C
1
-C
4
alkylsulfonyl, C
1
-C
4
haloalkylsulfonyl or when M and Q are on adjacent positions they may be taken together with the carbon atoms to which they are attached to form a ring in which MQ represents the structure —OCH
2
O—, —OCF
2
O— or —CH═CH—CH═CH—;
R
1
, R
2
and R
3
are each independently hydrogen, halogen, NO
2
, CHO or R
2
and R
3
may be taken together with the atoms to which they are attached to form a ring in which R
2
R
3
is represented by the structure
R
4
R
5
R
6
and R
7
are each independently hydrogen, halogen, CN or NO
2
; and
X is O or S
which process comprises reacting an N-[1-chloro-1-(perfluoroalkyl)methyl]arylimidoyl chloride compound having the structural formula II
wherein A and n are as described above with a dieneophile compound having the structural formula III
wherein W and Y are as described above and a base in the presence of a solvent.
The present invention further provides novel compounds having the structural formulas II, IV and V
wherein n and A are as described hereinabove.
DETAILED DESCRIPTION OF THE INVENTION
The process of the present invention preferably comprises reacting an N-[1-chloro-1-(perfluoroalkyl)methyl]arylimidoyl chloride compound of formula II with at least about one molar equivalent, preferably about one to four molar equivalents, of a dienophile compound of formula III and at least about one molar equivalent, preferably about one to four molar equivalents, of a base in the presence of a solvent preferably at a temperature range of about 5° C. to 100° C. to form 2-aryl-5-(perfluoroalkyl)pyrrole compounds of formula I.
Alternatively, the formula I compounds may be prepared by forming the formula III dienophile compounds in situ. This process comprises reacting an N-[1-chloro-1-(perfluoroalkyl)methyl]arylimidoyl chloride compound of formula II with preferably about one to four molar equivalents of a substituted haloethane compound having the structural formula VI
wherein W and Y are as described hereinabove and Z is Cl, Br or I, and at least about two molar equivalents, preferably about two to five molar equivalents, of a base in the presence of a solvent preferably at a temperature range of about 5° C. to 100° C. to form 2-aryl-5-(perfluoroalkyl)pyrrole compounds of formula I.
Advantageously, the present invention provides new processes for the preparation of 2-aryl-5-(perfluoroalkyl)pyrrole compounds which avoid the use of &agr;-halo-&agr;,&bgr;-unsaturated nitrile, ester and nitro compounds and the Strecker synthesis.
The formula I compounds of this invention may be isolated by conventional procedures such as dilution of the reaction mixture with water and filtration or, alternatively, extraction with a suitable solvent. Suitable extraction solvents include water-immiscible solvents such as ether, ethyl acetate, toluene, methylene chloride and the like.
Bases suitable for use in this invention include tri-(C
1
-C
6
alkyl)amines such as trimethylamine, triethylamine, tripropylamine, tributylamine, diisopropylethylamine and the like; alkali metal carbonates such as potassium carbonate and sodium carbonate; alkali metal hydroxides such as potassium hydroxide and sodium hydroxide; alkali metal acetates such as potassium acetate and sodium acetate; and heterocyclic tertiary amines including, but not limited to, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU); 1,5-diazabicyclo[4.3.0]non-5-ene (DBN); 1,4-diazabicyclo[2.2.2]-octane; pyridine; substituted pyridines such as 2,6-dimethylpyridine, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine and the like; quinoline; and substituted quinolines. Preferred bases include tri-(C
1
-C
6
alkyl)amines, 1,8-diazabicyclo[5.4.0]undec-7-ene, 1,5-diazabicyclo[4.3.0]non-5-ene, 1,4-diazabicyclo[2.2.2]-octane, potassium carbonate and sodium carbonate.
Solvents suitable for use in the present invention include, but are not limited to, carboxylic acid amides such as N,N-dimethylformamide, N,N-dimethylacetamide and the like; N-substituted pyrrolidinones such as N-methylpyrrolidinone and the like; nitrites such as acetonitrile, propionitrile and the like; halogenated hydrocarbons such as methylene chloride, chloroform, carbon tetrachloride and the like; ethers such as tetrahydrofuran, dioxane and the like; sulfoxides such as dimethyl sulfoxide and the like; and mixtures thereof. Preferred solvents include carboxylic acid amides and nitrites and mixtures thereof. N,N-dimethylformamide and acetonitrile and mixtures thereof are especially preferred for use in the present invention.
Exemplary of halogen hereinabove are fluorine, chlorine, bromine and iodine. The terms “C
1
-C
4
haloalkyl”, “C
1
-C
4
haloalkoxy”, “C
1
-C
4
haloalkylthio”, “
1
-C
1
-C
4
haloalkylsulfinyl” and “C
1
-C
4
haloalkylsulfonyl” are defined as a C
1
-C
4
alkyl, C
1
-C
4
alkoxy, C
1
-C
4
alkylthio, C
1
-C
4
alkylsulfinyl or C
1
-C
4
alkylsulfonyl group substituted with one or more halogen atoms, respectively.
The present invention is especially useful for the preparation of formula I compounds wherein
W is hydrogen;
Y is CN;
n is 1 or 2;
A is
L is hydrogen or halogen; and
M and Q are each independently hydrogen, halogen, C
1
-C
4
haloalkyl or C
1
-C
4
haloalkoxy.
In particular, the present invention is useful for t
BASF - Aktiengesellschaft
Keil & Weinkauf
McKane Joseph K.
Small Andrea D.
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