Organic compounds -- part of the class 532-570 series – Organic compounds – Amino nitrogen containing
Patent
1992-08-25
1993-09-28
Hollrah, Glennon H.
Organic compounds -- part of the class 532-570 series
Organic compounds
Amino nitrogen containing
564155, C07C23307
Patent
active
052488225
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention provides bis-(5-acetamino-2-chloro-4-fluorobenzene)disulfide which is useful as an intermediate material for a thiadiazabicyclononane-type agricultural chemical such as a herbicide.
BACKGROUND ART
As a thiadiazabicyclononate-type agricultural chemical, a compound which has a structure of the following formula: ##STR2## and which is used as an active substance for a herbicide, is, for example, known (see Japanese Unexamined Patent Publication No. 264489/1988). The compound of this formula (2) (hereinafter represented also as the compound (2), the same applies to other compounds) is produced by using 5-amino-2-chloro-4-fluoro-thiophenol represented by the formula (3) (see U.S. Pat. No. 4,613,675) as the starting material: ##STR3##
Heretofore, as a method for obtaining the above compound (3), the following method is known which is a combination of the methods disclosed in Japanese Unexamined Patent Publications No. 172958/1985 and No. 33148/1987: ##STR4##
However, the above conventional method had problems with respect to the safety and toxicity, etc. such that it was necessary to use fumming sulfuric acid containing 60% of SO.sub.3 which was not easy to use for industrial operation, and besides, phosgene was generated during the reaction using carbon tetrachloride as a solvent. Further, for the reduction of the chlorosulfonyl group, a large amount of a reducing agent as well as an excess amount of an acid was required to be used. Therefore, such a method was not satisfactory as an industrial method.
On the other hand, as a method for obtaining the above compound (3), the following method is also known involving a disulfide compound as an intermediate (see Unexamined Patent Publication No. 221254/1990). ##STR5##
However, in the above method, the diazotization operation is cumbersome. Besides, the yield is low, a side reaction proceeds mainly in the nitration, and the yield is also low. Thus, using the disulfide compound as an intermediate does not provide good results, and this method can not necessarily be regarded as a good method.
The present invention has been made for a purpose of overcoming the above mentioned difficulties of the prior art and to provide a novel disulfide compound which can readily be led to the 5-amino-2-chloro-4-fluoro-thiophenol of the above formula (3) in good yield.
DISCLOSURE OF THE INVENTION
In order to accomplish the above object, the present invention provides a bis-(5-acetoamino-2-chloro-4-fluorobenzene)disulfide compound represented by the formula (1): ##STR6##
Now, with reference to the following reaction formula, the bis-(5-acetamino-2-chloro-4-fluorobenzene)disulfide compound of the present invention represented by the formula (1) and a method for leading the disulfide compound (1) to the above mentioned 5-amino-2-chloro-4-fluoro-thiophenol (3), will be described. ##STR7##
Namely, as the operation to obtain bis-(5-acetamino-2-chloro-4-fluorobenzene)disulfide (1) as the disulfide compound of the present invention, 4-chloro-2-fluoroacetanilide (4) and sulfur monochloride are reacted in the presence of a Lewis acid at a temperature of from 0.degree. to 100.degree. C., preferably from 20.degree. to 50.degree. C.
The Lewis acid to be used in the above operation, may, for example, be aluminum chloride, iron chloride or zinc chloride. Among them, aluminum chloride is preferably used to attain a good yield.
Further, as a solvent, it is possible to use a solvent inert to the reaction to smoothly conduct the reaction. As such a solvent, an organic solvent such as a halogenated hydrocarbon, may, for example, be preferred, and dichloromethane, chloroform or dichloroethane may be used.
The amount of sulfur monochloride to be used in the above operation, is 0.5 mol or more, preferably from 0.6 to 2.5 mols, per mol of the compound (4). Further, the amount of the Lewis acid is from 1 to 5 mols, preferably from 2 to 2.5 mols, per mol of the compound (4). On the other hand, when an organic solvent is used, it may be at least an amount where stirr
REFERENCES:
patent: 4613675 (1986-09-01), Lee
Hollrah Glennon H.
Ihara Chemical Industry Co. Ltd.
Lambkin Deborah
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