Process for producing benzofuran derivative

摘要

A novel process for efficiently and easily producing a compound represented by the formula: wherein ring A is a benzene ring that may be optionally further substituted in addition to the group represented by W, or a salt thereof; which comprises reacting a compound represented by the formula: wherein R¹ and R² are the same or different and each is a hydrogen atom, an optionally substituted hydrocarbon group or an optionally substituted heterocyclic group, Y is a halogen atom, ring A is a benzene ring that may be optionally further substituted in addition to the group represented by Y and ring B is an optionally substituted benzene ring, or a salt thereof, with a compound represented by the formula: WH wherein W is wherein ring C is an optionally substituted benzene ring, ring D is an optionally substituted 5- to 7-membered nitrogen-containing heterocyclic ring, R³ is a hydrogen atom, an aliphatic hydrocarbon group containing an aromatic group or an acyl group, and R⁴ is a hydrogen atom, an optionally substituted hydrocarbon group or an acyl group, or a salt thereof and thereafter, if necessary, deprotecting the resultant product, which is suitable for industrial production.