| 摘要 |
<p>A process for the preparation of compounds of formula (I), wherein R1 represents hydrogen or a hydroxy-protecting group, R2 represents hydrogen, a cation, the pivaloyloxymethyl group or a carboxy-protecting group and R3 represents hydrogen, the acetoxy group, the carbamoyloxy group, a group S-Y whereby Y represents an unsubstituted or substituted heterocycle, or an optionally substituted pyridinium of formula (II), whereby R4 and R5 are the same or different and each represent hydrogen, halogen, alkyl, hydroxy, carboxamido, alkoxycarbonyl amino, monoalkylamino or di-alkylamino or together represent an optionally substituted 5- or 6-membered carbocyclic ring, characterized by reacting a compound of formula (IV), wherein RI represents a hydroxy protecting group and formula (A) represents a 5- or 6-membered heterocycle which may contain in addition to the nitrogen atom one or two further heteroatoms and which may by substituted or anellated with an optionally substituted benzene ring with a compound of formula (III) and if desired deprotecting the obtained end product and optionally converting an obtained product into a salt or vice-versa.</p> |
