To obtain the subject compound useful as an intermediate for producing an antiallergic agent, etc., in an industrially advantageous way be reacting a 3,5-dihydroxynaphthoate derivative with a specific pyridine derivative in the presence of a phosphorane compound.

This naphthoate derivative, expressed by formula IV, used as an intermediate for producing a useful compound as an antiallergic agent, etc., is easily obtained in high yield by reacting a 3,5-dihydroxynaphthoate derivative expressed by formula I [R' is a (substituted) 1-6C alkyl, an aromatic hydrocarbon group or an aromatic heterocyclic group] with a pyridine derivative expressed by formula II [(n) is an integer of 1-6) in the presence of a phosphorane compound expressed by formula III (R2 is an electophilic group; R3-R5 is each a 1-6C alkyl, an aromatic hydrocarbon or an aromatic heterocyclic group].