Abstract: The problem of the present invention is to provide a production method for safely synthesizing a nitrogen-containing heterocyclic N-oxide compound in high yield. Another problem of the present invention is to provide a novel N-oxide compound. There is provided a method for producing a nitrogen-containing heterocyclic N-oxide compound of Formula (2), such as 2,2,7,9-tetramethyl-2H-pyrano[2,3-g]quinoline N-oxide, by oxidizing a nitrogen-containing heterocyclic compound of Formula (1), such as 2,2,7,9-tetramethyl-2H-pyrano[2,3-g]quinoline with a persulfate.

Abstract: A method for producing a high-purity nitrogen-containing heterocyclic compound includes: a process (a) and a process (b): (a) a process of mixing a mixture containing a compound and as an impurity compound with a solvent and a metal salt, and (b) a process of obtaining a mixture in a solution state in which the content of the compound has decreased compared to that in the mixture in the process (a) by filtering a mixed solution obtained in the process (a), or a process of obtaining a mixture in which the content of the compound has decreased compared to that in the mixture in the process (a) by further evaporating the solvent or crystallizing following the filtering; (where R1 and R2 are each independently a hydrogen atom, a C1-6 alkyl group, etc., R3 is a hydrogen atom, a C1-6 alkyl group, etc., X is a hydrogen atom, etc.).

Abstract: The problem of the present invention is to provide a production method for safely synthesizing a nitrogen-containing heterocyclic N-oxide compound in high yield. Another problem of the present invention is to provide a novel N-oxide compound. There is provided a method for producing a nitrogen-containing heterocyclic N-oxide compound of Formula (2), such as 2,2,7,9-tetramethyl-2H-pyrano[2,3-g]quinoline N-oxide, by oxidizing a nitrogen-containing heterocyclic compound of Formula (1), such as 2,2,7,9-tetramethyl-2H-pyrano[2,3-g]quinoline with a persulfate.

Abstract: A method for producing a high-purity nitrogen-containing heterocyclic compound includes: a process (a) and a process (b): (a) a process of mixing a mixture containing a compound and as an impurity compound with a solvent and a metal salt, and (b) a process of obtaining a mixture in a solution state in which the content of the compound has decreased compared to that in the mixture in the process (a) by filtering a mixed solution obtained in the process (a), or a process of obtaining a mixture in which the content of the compound has decreased compared to that in the mixture in the process (a) by further evaporating the solvent or crystallizing following the filtering; (where R1 and R2 are each independently a hydrogen atom, a C1-6 alkyl group, etc., R3 is a hydrogen atom, a C1-6 alkyl group, etc., X is a hydrogen atom, etc.