Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
2001-10-02
2002-10-29
Solola, T. A. (Department: 1626)
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
Reexamination Certificate
active
06472535
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to processes for the preparation of heteroaromatic thiones. More particularly invention relates to processes for the preparation of triazolinones comprising the step of reacting a triazolinethione with an oxidant in the presence of a base.
BACKGROUND OF THE INVENTION
Heteroaromatic thiones such as triazolinones may be used as herbicides and/or pesticides, or as useful intermediates in the production of herbicides and/or pesticides.
Cebalo et al., U.S. Pat. No. 3,780,052, disclose that substituted triazolinones may be obtained when the corresponding triazolinethiones are reacted with an alkylating agent in the presence of an acid-binding agent, and the resulting alkylthiotriazole derivative is then heated with hydrogen peroxide in the presence of acid.
Linker et al., U.S. Pat. Nos. 5,475,115; 5,639,891 and 5,739,349, disclose that triazolinones may be prepared by reacting alkylsulphonyltriazole derivatives with an aqueous alkali metal hydroxide solution at temperatures between 0° C. and 100° C. under atmospheric pressure to obtain a product, and then acidifying the product.
Haas, et al., U.S. Pat. Nos. 5,508,420 and 5,688,963, disclose that triazolinones may be prepared by reacting triazolinethiones with oxidants at a temperature of from about 0° C. to about 100° C. to obtain triazolesulphonic acids, and reacting the triazolesulphonic acids with water at a temperature of from about 20° C. to about 120° C., optionally in the presence of an acid.
Hong et al., U.S. Pat. No. 5,728,651, disclose the reaction of hydrazones and diphenylphosphoryl azide followed by a ring cyclization to obtain triazolinones.
Some prior art processes require an acidic oxidation of a triazolthione followed by an alkaline hydrolysis, while other prior art processes require an alkaline oxidation of a triazolthione followed by an acidic hydrolysis. Unfortunately changing from acidic to basic, or basic to acidic, conditions may result in the formation of undesirable salts. Further, prior art processes such as the cleavage of triazolesulphonate under acidic conditions require long reflux times.
Thus there is a need of a facile method of synthesizing heteroaromatic thiones, such as triazolinones.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to obviate problems of the prior art.
It is a further object of the present invention to provide processes for the preparation of triazolinones which do not require a change from acidic to basic, or basic to acidic, conditions.
It is a further object of the present invention to provide processes for the preparation of triazolinones which do not require long reflux times. As used herein “long reflux times” refer to reflux times of greater than 10 hours.
These and additional objects are provided by the processes of the invention.
According to one aspect of the invention there are provided processes for preparing a heteroaromatic thione, preferably a triazolinone, which include the step of reacting a triazolinethione with an oxidant in the presence of a base. The processes may be performed at a temperature in the range of from about 60° C. to about 100° C.
According to another aspect of the invention there are provided processes for preparing a triazolinone of the formula:
wherein R
1
represents alkyl having 1 to 6 carbon atoms which is optionally substituted by halogen, cyano or C
1
-C
4
alkoxy, or represents cycloalkyl having 3 to 6 carbon atoms which is optionally substituted by halogen, cyano or C
1
-C
4
-alkyl, and R
2
represents amino, or a radical selected from the group consisting of alkyl, alkenyl, alkinyl, alkoxy, alkylamino or dialkylamino, each of which has up to 6 carbon atoms in the alkyl, alkenyl or alkinyl groups and each of which is optionally substituted by halogen, cyano or C
1
-C
4
-alkoxy, or represents a radical selected from the group consisting of C
3
-C
6
-cycloalkyl, C
3
-C
6
-cycloalkyl-C
1
-C
2
-alkyl or phenyl, each of which is optionally substituted by halogen, cyano, C
1
-C
4
-alkyl, C
1
-C
4
-alkoxy or C
1
-C
4
-alkoxycarbonyl. The process utilizes a triazolinethione of the formula:
The process comprises the step of reacting the triazolinethione with an oxidant at a temperature range of from about 60° C. to about 100° C. in the presence of a base for a time of from about 1 hour to about 6 hours, at a molar ratio of triazolinethione to oxidant to base of from about 1:5:4 to about 1:20:10; or comprises the step of mixing a solvent, a base and the triazolinethione, adding an oxidant and heating the resulting reaction mixture.
These and additional aspects, objects and advantages of the invention are more fully described in the following detailed description.
DETAILED DESCRIPTION
Processes in accordance with the present invention may be used to produce heteroaromatic thiones, particularly triazolinones. Triazolinones may be used as herbicides and/or pesticides and/or pharmaceuticals, or as useful intermediates in the production of herbicides and/or pesticides and/or pharmaceuticals.
Suitable triazolinones include 1,2,4 triazol-5-thiones. In one embodiment of the reaction the triazolinone has the formula:
wherein R
1
represents an alkyl having 1 to 6 carbon atoms which may be unsubstituted or substituted by halogen, cyano or C
1
-C
4
-alkoxy, or represents a cycloalkyl having 3 to 6 carbon atoms which may be unsubstituted or substituted by halogen, cyano or C
1
-C
4
-alkyl; and R
2
represents amino, or represents a radical selected from the group consisting of alkyl, alkenyl, alkinyl, alkoxy, alkylamino or dialkylamino, each of which has up to 6 carbon atoms in the alkyl, alkenyl or alkinyl groups and each of which may be unsubstituted or substituted by halogen, cyano or C
1
-C
4
-alkoxy, or represents a radical selected from the group consisting of C
3
-C
6
-cycloalkyl, C
3
-C
6
-cycloalkyl-C
1
-C
2
-alkyl or phenyl, each of which may be unsubstituted or substituted by halogen, cyano, C
1
-C
4
-alkyl, C
1
-C
4
-alkoxy or C
1
-C
4
-alkoxycarbonyl.
In one embodiment R
1
represents methyl, ethyl, n- or i-propyl, or n-, i- or s-butyl, each of which may be unsubstituted or substituted by fluorine, chlorine, bromine, cyano, methoxy or ethoxy, or represents cyclopropyl, cyclopropylmethyl, cyclobutyl, cyclopentyl or cyclohexyl, each of which may be unsubstituted or substituted by fluorine, chlorine, bromine, cyano or methyl; while in another embodiment R
1
represents methyl, ethyl, n- or i-propyl, cyclopropyl or cyclopropylmethyl, each of which is mono-, di-, tri-, tetra-, penta-, hexa- or heptasubstituted by fluorine and/or chlorine.
In one embodiment R
2
represents amino, a radical selected from the group consisting of methyl, ethyl, n- or i-propyl, n-, i- or s-butyl, allyl, propargyl, methoxy, ethoxy, n- or i-propoxy, n-, i- or s-butoxy, methylamino, ethylamino, n- or i-propylamino, n-, i- or s-butylamino, dimethylamino or diethylamino, each of which may be unsubstituted or substituted by fluorine, chlorine, cyano, methoxy or ethoxy, or represents a radical selected from the group consisting of cyclopropyl, cyclobutyl, cyclopentyl or cyclohexyl or phenyl, each of which may be unsubstituted or substituted by fluorine, chlorine, bromine, cyano, methyl, ethyl, n- or i-propyl, methoxycarbonyl or ethoxycarbonyl; while in another embodiment R
2
represents methyl, ethyl, n- or i-propyl, methoxy, ethoxy, methylamino, ethylamino, dimethylamino, cyclopropyl, phenyl or tolyl.
In accordance with one embodiment of the invention, a triazolinone of the formula:
is formed by reacting a triazolinethione of the formula:
and an oxidant in the presence of base. The reaction may occur at a temperature in the range of from about 60° C. to about 100° C., preferably from about 60° C. to about 90° C., more preferably from about 80° C. to about 90° C., and for a time of no more than about 10 hours, preferably less than 10 hours, such as from about 1 hour to about 6 hours, preferably from about 2 to about 3 hours. In one embodiment the reaction occurs for a time of no more than 4 hours, pr
Anderson Rebecca
Bayer Corporation
Harmuth Raymond J.
Solola T. A.
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