| 摘要 |
<p>A compound of the formula: wherein A1 is a single bond, a C2-C5 alkylene group or a C1C5 alkylidene group, A2 is a C2-C3 alkylene group or a C1-C3 alkylidene group, A3 is a C2-C4 alkylene group or a C1-C4 alkylidene group, X is -O- or -SOn- (wherein n is an integer of 0 to 2), R1 is a hydrogen atom, a C1-C5 alkyl group, a C3-C5 alkenyl group and R2 is a hydrogen atom, a C1-C5 alkyl group, a C3-C5 alkenyl group, a C2-C5 alkanoyl group, a C2C5 alkoxycarbonyl group, a benzyloxycarbonyl group, or when taken together with the adjacent nitrogen atom, R1 and R2 may form a five or six-membered heterocyclic group, which exhibits excellent antiviral activity with no or weak side effects or toxicities.</p> |
