Readily available from d-arabinal and l-rhamnal 2-C:1-N-carbonyl-2-deoxy-β-d-arabino- and -α-l-gluco-pyranosylamines 5, 25 and 26 were transformed into cephems 45 and 49 via a sequence of reactions consisting of alkylation of the β-lactam nitrogen atom, deprotection of pyranoid hydroxy groups, glycolic cleavage of the vic diol grouping, discrimination of carbon atoms which were separated by periodate
可容易地从d-arabinal和1- rhamnal 2-C:1-N -羰基- 2-脱氧β-d-arabino-和-α-L-
葡糖pyranosylamines 5,25和26转化到头孢45和49.通过一系列的反应序列,包括β-内酰胺氮原子的烷基化,
吡喃类羟基的脱保护,vic二醇基团的羟基裂解,通过
高碘酸氧化分离的碳原子的辨别以及形成1,3-恶嗪六元环与β-内酰胺片段稠合。在通过较大的甲
硅烷基取代基或通过内酯化还原和保护羟甲基之一后,实现了在
乙醇裂解步骤中获得的两个醛基的区分。