Abstract: Compounds represented by the general formula (1) or pharmaceutically acceptable salts thereof, effective in the prevention and/or treatment of infections with microbes: (1) (a) wherein R1 is hydrogen or straight-chain C1-6 alkylcarbonyl; R2 is hydrogen or C1-6 alkylcarbonyl; R3 is hydrogen, C1-6 alkyl, C1-6 alkylcarbonyl, C1-6 alkenyl, C2-6 alkenylcarbonyl, C2-6 alkynyl, or an Ar—B— group (wherein Ar is aryl or a heterocyclic group; and B is C1-6 alkyl, C1-6 alkylcarbonyl, C2-6 alkenyl, C2-6 alkenylcarbonyl, or C2-6 alkynyl); R5, R6, R7 and R8 are each hydrogen, C1-6 alkyl, C2-6 alkenyl, C2-6 alkynyl, or an Ar—B?— group (wherein B? is C1-6 alkyl, C2-6 alkenyl, or C2-6 alkynyl); X is oxygen or —NR4— (wherein R4 is hydrogen, C1-6 alkyl or C1-6 alkyl which may be substituted with Ar); and R4? is hydrogen or a group represented by the general formula (a) (wherein R3? and R4? are each hydrogen or straight-chain or branched C1-6 alkylcarbonyl)

Abstract: A compound represented by the following general formula (1) or a pharmaceutically acceptable salt thereof, which is useful for a prophylactic and/or therapeutic treatment of a microbial infectious disease.