Antiviral activity is exhibited by compounds having the formula ##STR1## and its pharmaceutically acceptable salts wherein R.sub.1 is ##STR2## wherein R.sub.2 is hydrogen, methyl, fluoro, chloro, bromo, iodo, hydroxy or amino; or trifluoromethyl; R.sub.5 is alkyl; R.sub.6 is hydrogen, alkyl, substituted alkyl, or aryl; and R.sub.7 and R.sub.8 are independently hydrogen, ##STR3##
化合物具有以下结构式##STR1##及其药用盐,其中R.sub.1为##STR2##其中R.sub.2为氢、甲基、
氟、
氯、
溴、
碘、羟基或
氨基;或三
氟甲基;R.sub.5为烷基;R.sub.6为氢、烷基、取代烷基或芳基;而R.sub.7和R.sub.8独立地为氢、##STR3##