Condensed-hexacyclic compounds and a process therefor

摘要

Disclosed are a process for the preparation of a compound represented by the formula (1), which comprises treating a compound represented by the formula (2) with methanesulfonic acid and then subjecting the thus-treated compound to recrystallization; and Compound (1) so obtained.This Compound (1) is free of hygroscopicity, excellent in filterability and solubility and easy in handling. Furthermore, according to the preparation process of the present invention, an unnecessary isomer can be converted into the target one and separation of the target isomer can be conducted easily.