A process for preparing a 4-acetoxy-3-hydroxyethylazetidin-2-one derivative having the formula (II): ##STR1## wherein R.sup.1 is a protective group for the hydroxyl group, which comprises reacting a .beta.-lactam compound having the formula (I): ##STR2## wherein R.sup.1 is as defined above, and R.sup.2, R.sup.3 and R.sup.4 are a lower alkyl group having 1 to 6 carbon atoms, phenyl group or an aralkyl group, with acetic anhydride in an organic solvent in the presence of a low concentration of a substituted pyridine. According to the present invention, there can be obtained 4-acetoxy-3-hydroxyethylazetidin-2-one derivatives, which are useful intermediates for preparing carbapenem .beta.-lactam antibiotics.
一种制备4-乙酰氧基-3-羟乙基氮杂二环-2-酮衍
生物的方法,其
化学式为(II): ##STR1## 其中R.sup.1是羟基的保护基,包括将具有
化学式(I)的β-内酰胺化合物与
乙酸酐在有机溶剂中,在低浓度的取代
吡啶存在下反应。式(I)中,R.sup.1如上定义,R.sup.2、R.sup.3和R.sup.4是具有1至6个碳原子的低碳基、苯基或芳基烷基。根据本发明,可以获得有用的中间体4-乙酰氧基-3-羟乙基氮杂二环-2-酮衍
生物,用于制备碳青霉烯β-内酰胺抗生素。