PYRIMIDINE NUCLEOSIDE DERIVATIVES AND SALTS THEREOF

摘要

A novel pyrimidine nucleoside derivative represented by the following formula (1) and a salt thereof, as well as a pharmaceutical composition comprising the same as an active ingredient have excellent antiviral properties and are useful as antiviral therapeutic agents: [wherein R represents a nitrogen-containing heterocyclic ring which may have any one of a C1-C3 alkyl group or a C1-C3 alkoxy group as a substituent, or a C1-C6 alkyl group which has one primary amino group as a substituent].