主权项 |
1. A method of producing an imidazole compound represented by the general formula (II′): or a salt thereof, wherein ring C′ represents a benzene ring optionally having substituent(s) or a monocyclic aromatic heterocyclic ring optionally having substituent(s); R0 represents a hydrogen atom, an aralkyl group optionally having substituent(s), an acyl group, or an acyloxy group; R1, R2, and R3, are same as or different from each other and each represents a hydrogen atom, an alkyl group optionally having substituent(s), an alkoxy group optionally having substituent(s), or an amino group optionally having substituent(s); and Y represents a nitrogen atom or CH, the method comprising: oxidizing, in a reactor, an imidazole compound represented by the general formula (I′): or a salt thereof, wherein ring C′, R0, R1, R2, R3, and Y have the same meaning as defined above; monitoring, by an oxidation reduction potential meter attached to the reactor, an electric potential of an oxidation reaction solution for producing the imidazole compound represented by the general formula (II′) by an oxidation reaction; detecting, by the oxidation reduction potential meter attached to the reactor, a predefined decrease of the electric potential of the oxidation reaction solution, wherein the decrease of the electric potential of the oxidation solution is measured from the point at which the electric potential of the oxidation reaction solution reaches its highest electric potential; and determining an end point for the oxidation reaction on the basis of detecting the predefined decrease of the electric potential, wherein the imidazole compound represented by the general formula (II′) or a salt thereof is lansoprazole or a salt thereof or an optically active substance thereof, wherein the predefined decrease of the electric potential is 70 mV. |