Abstract

A catalyst is for use in a reaction using an oxygen-atom-containing reactant and includes a nitrogen-containing heterocyclic compound of the following formula (1): ##STR1##wherein each of R1 and R2 is, identical to or different from each other, a hydrogen atom, a halogen atom, an alkyl group, a haloalkyl group, an aryl group, a cycloalkyl group, a hydroxyl group, an alkoxy group, a carboxyl group, an alkoxycarbonyl group, or an acyl group, and R1 and R2 may be combined to form a double bond or to form an aromatic or non-aromatic ring with the adjacent two carbon atoms, where one or two of heterocyclic ring containing three nitrogen atoms indicated in the formula may be further formed on the R1 or R2, or on the double bond or aromatic or non-aromatic ring formed by R1 and R2 ; X is an oxygen atom or a hydroxyl group; and Y is a single bond, a methylene group, or a carbonyl group. This catalyst can introduce an oxygen-atom-containing group into an organic substrate under mild conditions.