| 摘要 |
<p>A process for the preparation of the compounds of the formula (I), or salts thereof, wherein R represents a hydrogen atom or difluoromethanesulfonyl, characterized in that compounds of the formula (II), or salts thereof, wherein R has the same definition as aforementioned, and n represents 0 or 1, are reacted in the presence of hydrogen peroxide and acetic acid.</p> |
