Organic compounds -- part of the class 532-570 series – Organic compounds – Heterocyclic carbon compounds containing a hetero ring...
Patent
1993-05-26
1995-01-24
Ramsuer, Robert W.
Organic compounds -- part of the class 532-570 series
Organic compounds
Heterocyclic carbon compounds containing a hetero ring...
C07D23138
Patent
active
053844092
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for producing 5-amino-3-methylpyrazole.
BACKGROUND ART
5-Amino-3-methylpyrazole is a compound well known as an intermediate used in the field of fine chemicals (e.g., photographic chemicals, medicines and agricultural chemicals). It has also been known that the compound can be produced, for example, by the following methods.
(1) A method which comprises reacting acetonitrile with metallic sodium, sodium hydride or the like to obtain diacetonitrile, and reacting diacetonitrile with hydrazine (for example, J. Heterocyclic Chem., 11, 423 (1974)).
(2) A method which comprises reacting crotononitrile with chlorine to obtain 2,3-dichlorobutyronitrile, dehydrochlorinating 2,3-dichlorobutyronitrile in the presence of a base (e.g., potassium t-butoxide) to obtain 2-chloro-2-butenonitrile, and reacting 2-chloro-2-butenonitrile with hydrazine (for example, J. Heterocyclic Chem., 19, 1267 (1982)).
(3) A method which comprises reacting sodium cyanide with propargyl chloride to form 2,3-butadienenitrile and reacting 2,3-butadienenitrile with hydrazine (for example, Ann., 624, 1 (1959)).
However, the method (1) has a problem of using such agents having the danger of spontaneous ignition as metallic sodium and sodium hydride. The method (2) has a problem that crotononitrile, a starting material, is expensive. The method (3) has a problem of using explosive propargyl chloride.
DISCLOSURE OF THE INVENTION
The present inventors have made extensive study to find a process for producing 5-amino-3-methylpyrazole without using such agents and starting material that would cause the problems as mentioned above. As the result, they have found a novel process for producing 5-amino-3-methylpyrazole which comprises reacting 2,3-dichloropropene with hydrocyanic acid to obtain a reaction mixture and reacting the reaction mixture with hydrazine. Thus, they accomplished the present invention.
The first aspect of the present invention relates to a process for producing 5-amino-3-methylpyrazole which comprises the steps of: water and a cuprous salt at a pH of from 3 to 8 to obtain a reaction intermediate containing at least one compound selected from the group consisting of 3-chloro-3-butenonitrile and 2,3-butadienenitrile, and
The second aspect of the present invention relates to a process for producing 5-amino-3-methylpyrazole which comprises the steps of: water and a cuprous salt at a pH of from 3 to 8 to obtain a reaction mixture containing 3-chloro-3-butenonitrile, 2,3-butadienenitrile, and
The third aspect of the present invention relates to a process for producing 5-amino-4-chloro-3-methylpyrazole hydrochloride which comprises the steps of: 3-chloro-3-butenonitrile and 2,3-butadienenitrile with hydrazine to obtain 5-amino-3-methylpyrazole, and acid.
2,3-Dichloropropene used in the first step of the first aspect is known to the art, which aspect relates to a process for producing 5-amino-3-methylpyrazole which comprises the steps of: (a) reacting hydrocyanic acid with 2,3-dichloropropene in the presence of water and a cuprous salt at a pH of 3-8 to obtain a reaction intermediate containing at least one compound selected from the group consisting of 3-chloro-3-butenonitrile and 2,3-butadienenitrile, and used in the reaction of 2,3-dichloropropene with hydrocyanic acid may be, for example, cuprous chloride, cuprous cyanide, and the like. The amount used of the cuprous salt is usually within the range of from 0.01 to 1 equivalent, preferably within the range of from 0.01 to 0.05 equivalent, relative to 2,3-dichloropropene.
Hydrocyanic acid is used in an amount of usually 1-2 equivalents relative to 2,3-dichloropropene.
The reaction is conducted in the presence of water. Water is usually used in an amount of at least 10 times by weight, preferably at least 13 times by weight, relative to the cuprous salt.
Although water is most preferably used as the reaction solvent, polar solvents such as ethylene glycol, dimethylformamide and dimethyl sulfoxide, aromatic hydrocarbon solv
REFERENCES:
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patent: 3920693 (1975-11-01), Ege
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Kawai Takashi
Masaki Shinzaburo
Minamisaka Kazuya
Saito Kenji
Sekiguchi Masahito
Ramsuer Robert W.
Sumitomo Chemical Company Limited
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