PROCESS FOR THE PREPARATION OF A BENZOFURAN DERIVATIVE

摘要

An industrially useful process for producing benzofuran derivatives of formula (1) by formylating a compound of formula (2) (where A1 is a protective group), followed by reaction with a compound of formula (4) (where X1 is a halogen atom), then performing a cyclizing reaction and subsequently performing a reaction for hydroxyl group deprotection.