Method for producing pest control agent
To supply a derivative having a 2-acyliminopyridine structure and being represented by the following formula (I) in an amount required as a pest control agent stably and at a low cost, provided is a method comprising the steps of: acylating an amino group at position 2 of a compound represented by formula (A) by use of an acylating agent, to thereby produce a compound represented by formula (B); and further alkylating a nitrogen atom at position 1 of the compound represented by formula (B): [where Ar represents a phenyl group or a 5- to 6-membered heterocycle, R 1 represents a C 1-6 alkyl group, and Y represents a hydrogen atom; a halogen atom; a hydroxyl group; a C 1-6 alkyl group which may be substituted with a halogen atom; a C 1-6 alkyloxy group which may be substituted with a halogen atom; a cyano group; a formyl group; or a nitro group].
1. A method for producing a compound represented by the following formula (I):
wherein Ar is a 6-chloro-3-pyridyl group, R 1 represents an optionally substituted C 1-6 alkyl group, and Y is a hydrogen atom:
the method comprising, as shown in the following reaction formula:
the steps of:
acylating an amino group at position 2 of a compound represented by formula (A), wherein Y is a hydrogen atom, with an acylating agent represented by R 1 COR 2 , wherein R 1 represents an optionally substituted C 1-6 alkyl group, and R 2 represents (1) a trifluoroacetoxy group, (2) a C 1-6 alkyloxy group optionally substituted with a halogen atom or a benzyloxy group, wherein a phenyl group of the benzyloxy group is optionally substituted with a halogen atom, a methyl group, a cyano group, a nitro group, or a methoxy group, (3) a C 1-6 alkylcarbonyloxy group which is optionally substituted with a halogen atom (provided that a trifluoroacetoxy group is excluded) or a phenylcarbonyloxy group wherein a phenyl group of the phenylcarbonyloxy group is optionally substituted with a halogen atom, a methyl group, a cyano group, a nitro group, or a methoxy group, (4) a hydroxyl group, or (5) a halogen atom; wherein the acylation is carried out in the presence of a base and in the presence or absence of at least one compound selected from the group consisting of a condensation agent, phosphorus pentoxide, sulfuric acid, polyphosphoric acid, thionyl chloride, phosphorus oxychloride, oxalyl dichloride, p-toluenesulfonic acid, boron trifluoride, a metal halide, a metal sulfate, a metal nitrate, and a metal oxide, wherein the metal is iron, cobalt, copper, nickel, zinc, aluminum, lithium, or magnesium; to thereby produce a compound represented by formula (B); and
alkylating a nitrogen atom at position 1 of the compound represented by formula (B) with Ar—CH 2 —R 4 ; wherein Ar is a 6-chloro-3-pyridyl group, and R 4 represents a halogen atom, a C 1-6 alkylsulfoxy group which is optionally substituted with a halogen atom, or a phenylsulfoxy group which is optionally substituted with a halogen atom or a methyl group.
2. A method for producing a compound represented by the following formula (I):
wherein Ar represents a phenyl group or a pyridyl group, optionally substituted with a halogen atom, an alkyl group or a haloalkyl group; R 1 represents a C 1-6 alkyl group optionally substituted with a halogen atom;
and Y represents a hydrogen atom;
the method comprising combining together at once to form a mixture:
(i) a compound represented by formula (A):
wherein Y represents a hydrogen atom;
(ii) an acylating agent represented by R 1 COR 2 , wherein R 1 represents a C 1-6 alkyl group optionally substituted with a halogen atom, and R 2 represents a trifluoroacetoxy group, an ethoxy group, a hydroxyl group, or chlorine atom;
and
(iii) an alkylating agent Ar—CH 2 —R 4 , wherein Ar represents a phenyl group or a pyridyl group, optionally substituted with a halogen atom, an alkyl group or a haloalkyl group and R 4 represents a halogen atom, a C 1-6 alkylsulfoxy group which is optionally substituted with a halogen atom, or a phenylsulfoxy group which is optionally substituted with a halogen atom or a methyl group;
and reacting the mixture, in the presence of a base and in the presence or absence of at least one compound selected from the group consisting of a condensation agent, phosphorus pentoxide, sulfuric acid, polyphosphoric acid, thionyl chloride, phosphorus oxychloride, oxalyl dichloride, p-toluenesulfonic acid, boron trifluoride, a metal halide, a metal sulfate, a metal nitrate, and a metal oxide, wherein the metal is iron, cobalt, copper, nickel, zinc, aluminum, lithium, or magnesium.
3. The method according to claim 1 , wherein R 1 is a trifluoromethyl group.
4. The method according to claim 1 , wherein
R 1 is a trifluoromethyl group, and
R 2 is a trifluoroacetoxy group, an ethoxy group, a hydroxyl group, or a chlorine atom.
5. The method according to claim 1 , wherein
R 1 COR 2 is at least one acylating agent selected from the group consisting of trifluoroacetic anhydride, trifluoroacetic acid, ethyl trifluoroacetate, trifluoroacetyl chloride, and mixed acid anhydrides, and is used in an amount of 1.0 to 5.0 equivalents to the compound represented by formula (A).
6. The method according to claim 1 , wherein
R 1 COR 2 is trifluoroacetic anhydride, and is used in an amount of 1.0 to 1.5 equivalents to the compound represented by formula (A).
7. The method according to claim 1 , wherein
R 1 COR 2 is ethyl trifluoroacetate, and is used in an amount of 1.0 to 5.0 equivalents to the compound represented by formula (A).
8. The method according to claim 1 , wherein
R 1 COR 2 is trifluoroacetyl chloride, and is used in an amount of 1.0 to 3.0 equivalents to the compound represented by formula (A).
9. The method according to claim 1 , wherein
R 1 COR 2 is trifluoroacetic acid, and is used in an amount of 1.0 to 3.0 equivalents to the compound represented by formula (A), wherein the acylation is carried out in the presence of at least one compound selected from the group consisting of thionyl chloride, phosphorus oxychloride, p-toluenesulfonic acid, boron trifluoride, a metal halide, a metal sulfate, a metal nitrate, and a metal oxide, wherein the metal is iron, cobalt, copper, nickel, zinc, aluminum, lithium, or magnesium.