| abstract |
An anti-viral composition comprising a nitrogen-containing heterocyclic carboxamide derivative of formula I wherein ring A is a pyrazine, pyrimidine, pyridazine or triazine ring optionally substituted with at least one substituent selected from halogen, hydroxy, oxide, phenyl, pyridyl, mercapto and nitro; R 5 is O or OH; R.sup.2.n. is H, C.sub.2-5 .alkynoyl, benzoyl or carbamoylC.sub.1-6alkyl or carboxyC.sub.1-6alkyl, optionally substituted with at least one substituent selected from carboxy and carboxyC.sub.1-6.n.alkyl; and the dotted line represents a single bond or a double bond; or his salt. The nitrogen-containing heterocyclic carboxamide derivative of formula (I) wherein ring A is a pyrazine ring substituted with a halogen atom, a hydroxy group or an oxide group, and the other symbols are as defined above or a salt thereof. |