NOVEL PYRAZINE DERIVATIVES OR SALTS THEREOF, PHARMACEUTICAL COMPOSITIONS CONTAINING THE DERIVATIVES OR THE SALTS AND INTERMEDIATES FOR THE PREPARATION OF BOTH

摘要

Pyrazine derivatives of the general formula [1] or salts thereof exhibit excellent antiviral activities and are useful as remedies for viral infection. In the formula [1], each symbol is as defined in the description. Further, fluoropyrazine derivatives of the general formula [2] or salts thereof are useful as intermediates not only for the preparation of the compounds [1], but for industrial production of fluoropyrazinecarboxamide derivatives such as 6-fluoro-3-hydroxy-2-pyrazinecarboxamide having an antiviral effect. In the formula [2] each symbol is as defined in the description.