Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2000-03-13
2001-05-29
Dentz, Bernard (Department: 1625)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C544S405000, C546S281400, C548S214000, C548S365700, C549S014000, C549S059000, C549S060000, C549S069000
Reexamination Certificate
active
06239282
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relate to a process for preparing a 2-alkyl-3-aminothiophene derivative useful as an agricultural fungicide or intermediate thereof, and novel 3-aminothiophene derivatives.
2. Description of the Related Art
Japanese Patent Application Laid-Open (JP-A) No. 9-235282 (EP-A 0737682 A1) describes that a certain kind of 2-alkyl-3-aminothiophene derivative has strong control effect against various plant disease damages. For producing this 2-alkyl-3-aminothiophene derivative, there is envisaged a method in which an alkyl group is directly introduced into 2-position of a 3-aminothiophene derivative. For example, Tetrahedron Letters, 34, 5715 to 5718 (1993) teaches that 2-alkyl-3-aminothiophene is obtained by reacting 3-aminothiophene with various aldehydes in the presence of p-toluenesulfonic acid and selenophenol.
(wherein, R′ represents an alkyl group.) However, in this literature, there is utterly no description in which 2-alkyl-3-aminothiophene having a secondary alkyl group is synthesized. For obtaining a 2-alkyl-3-aminothiophene derivative having a secondary alkyl group using a synthesis method described in this literature, 3-aminothiophene derivative has to be reacted with ketones. However, when the present inventors substituted an aldehyde for the ketone and conducted this reaction, 3-aminothiophene was decomposed and the intended 2-alkyl-3-aminothiophene derivative or 2-alkenyl-3-aminothiophene derivative could not be obtained (Reference Example 1). Further, this literature includes a problem as an industrial production method since the reaction uses as a reducing agent selenophenol which is not easily obtained industrially.
Further, Tetrahedron 4, 9055 to 9066 (1998) teaches that when an aldehyde having branching at &agr;-position is reacted with 3-aminothiophene or 3-aminothiophene derivative, an primary alkenyl group is introduced. However, this literature includes utterly no description regarding reactions using a ketone.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a process for industrially preparing a compound having a secondary alkyl group among 2-alkyl-3-aminothiophene derivatives useful as an agricultural and horticultural fungicide or intermediate thereof by reacting a 3-aminothiophene derivative with a ketone.
The present inventors have studied for solving the above-described problems and found that when a 3-aminothiophene derivative in which an amino group at 3-position is substituted with an amide bond or carbamate bond is reacted with various ketones in the presence of an acid, a secondary alkenyl group is introduced into 2-position of the 3-aminothiophene derivative, and when this alkenyl group is reduced by an industrially possible method, it can be converted to an alkyl group easily, completing the invention.
Namely, the aspect of the present invention relates to following (1) to (6).
(1) A process for preparing a 2-alkyl-3-aminothiophene derivative represented by the formula (1):
wherein, R represents a hydrogen atom, alkyl group or alkoxy group which may be substituted, aromatic or non-aromatic hydrocarbon ring which may be substituted, aromatic or non-aromatic heterocyclic ring which may be substituted, each of R
1
, R
2
, R
3
and R
4
independently represents a hydrogen atom or straight or branched alkyl group having 1 to 12 carbon atoms, and R
1
and R
2
, R
3
and R
4
, R
1
and R
3
, R
1
and R
4
, R
2
and R
3
or R
2
and R
4
may together form a cycloalkyl group,
comprising reacting a compound represented by the formula (2):
wherein, R is as defined above,
with a compound represented by the formula (3):
wherein, each of R
1a
, R
2a
, R
3a
and R
4a
independently represents a hydrogen atom, straight or branched alkyl group having 1 to 12 carbon atoms or straight or branched alkenyl group having 1 to 12 carbon atoms, and R
1a
and R
2a
, R
3a
and R
4a
, R
1a
and R
3a
, R
1a
and R
4a
, R
2a
and R
3a
or R
2a
and R
4a
may together form a cycloalkyl group or cycloalkenyl group,
in the presence of an acid, and reducing the resulting reaction mixture.
(2) A process for preparing a mixture of 2-alkenyl-3-aminothiophene derivatives containing compounds represented by the formulae (4a), (4b), (4c) and (4d) respectively:
wherein, R represents a hydrogen atom, alkyl group or alkoxy group which may be substituted, aromatic or non-aromatic hydrocarbon ring which may be substituted, aromatic or non-aromatic heterocyclic ring which may be substituted, each of R
1a
, R
2a
, R
3a
and R
4a
independently represents a hydrogen atom, straight or branched alkyl group having 1 to 12 carbon atoms or straight or branched alkenyl group having 1 to 12 carbon atoms, and R
1a
and R
2a
, R
3a
and R
4a
, R
1a
and R
3a
, R
1a
and R
4a
, R
2a
and R
3a
or R
2a
and R
4a
may together form a cycloalkyl group or cycloalkenyl group,
comprising reacting a compound represented by the formula (2):
wherein, R is as defined above,
with a compound represented by the formula (3):
wherein, R
1a
to R
4a
are as define above,
in the presence of an acid.
(3) A process for preparing 2-alkyl-3-aminothiophene represented by the formula (1a):
wherein, R
a
represents a group represented by any of the following (A1) to (A12):
wherein, R
5
represents a trifluoromethyl group, difluoromethyl group, methyl group, ethyl group or halogen atom, R
6
represents a hydrogen atom, methyl group, trifluoromethyl group, halogen atom, methoxy group or amino group, R
7
represents a hydrogen atom, halogen atom, methyl group or methoxy group, R
8
represents a hydrogen atom, methyl group, ethyl group or halogen atom, and n represents an integer from 0 to 2, and herein, in the case of (A9), (A10) or (A11), R
5
is not a halogen atom, each of R
1
, R
2
, R
3
and R
4
independently represents a hydrogen atom or straight or branched alkyl group having 1 to 12 carbon atoms, and R
1
and R
2
, R
3
and R
4
, R
1
and R
3
, R
1
and R
4
, R
2
and R
3
or R
2
and R
4
may together form a cycloalkyl group,
comprising reacting a compound represented by the formula (2):
wherein, R represents a hydrogen atom, alkyl group or alkoxy group which may be substituted, aromatic or non-aromatic hydrocarbon ring which may be substituted or aromatic or non-aromatic heterocyclic ring which may be substituted, with a compound represented by the formula (3):
wherein, each of R
1a
, R
2a
, R
3a
and R
4a
independently represents a hydrogen atom, straight or branched alkyl group having 1 to 12 carbon atoms or straight or branched alkenyl group having 1 to 12 carbon atoms, and R
1a
and R
2a
, R
3a
and R
4a
, R
1a
and R
3a
R
1a
and R
4a
, R
2a
and R
3a
or R
2a
and R
4a
may together form a cycloalkyl group or cycloalkenyl group,
in the presence of an acid, reducing the resulting reaction mixture to obtain a compound represented by the formula (1):
wherein, R, R
1
, R
2
, R
3
and R
4
are as defined above, further hydrolyzing the resultant compound under acidic or alkaline condition to obtain a compound represented by the formula (5):
wherein, R
1
, R
2
1
R
3
and R
4
are as defined above,
and reacting this compound with a compound represented by the formula (8a):
wherein, R
a
is as defined above.
(4) A 3-aminothiophene derivative represented by the formula (6a):
wherein, R
9
represents a hydrogen atom, carboxyl group or alkoxycarbonyl group having 1 to 6 carbon atoms and Ra represents a group represented by any of the following (A11) to (A12):
wherein, R
5
represents a trifluoromethyl group, difluoromethyl group, methyl group, ethyl group or halogen atom, R
6
represents a hydrogen atom, methyl group, trifluoromethyl group, halogen atom, methoxy group or amino group, R
7
represents a hydrogen atom, halogen atom, methyl group or methoxy group, R
8
represents a hydrogen atom, methyl group, ethyl group or halogen atom, and n represents an integer from 0 to 2, and herein, in the case of (A9), (A10)
Ishii Seiichi
Katsuta Hiroyuki
Kodaka Kenji
Tomiya Kanji
Burns Doane Swecker & Mathis L.L.P.
Dentz Bernard
Mitsui Chemicals Inc.
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