| 摘要 |
<p>Compounds of formula (I) <CHEM> wherein R<1> represents a hydrogen atom or a C1-4 alkyl group optionally substituted by one to three halogen atoms; R<2> and R<3>, which may be the same or different, each represents a hydrogen atom or a carboxyl blocking group; R<4> represents a hydrogen atom or an amino protecting group; R<5> and R<6> each represents a hydroxy or substituted hydroxy group or R<5> and R<6> together represent a cyclic protected diol group; Z is -S- or -SO- ( alpha - or beta -) and the dotted line bridging the 2-, 3-, and 4-positions indicate that the compound is a ceph-2-em or ceph-3-em compound; and salts and solvates thereof.</p> |
