wherein A1 has the same meaning as in formula (IV-I) are reacted by stirring under heating for 2 to 18 hours in an organic solvent, such as toluene, xylene, chlorobenzene and chloroform, in the presence of an acid catalyst, such as p-toluene sulfonic acid, camphorsulfonic acid and a pyridinium p-toluene sulfonic acid, and water by-produced is azeotropically removed, so as to easily produce the bis