申请人:Ciba-Geigy Corporation
公开号:US05274188A1
公开(公告)日:1993-12-28
The invention relates to a novel process for the manufacture of (3R,1'R)-4-acyloxy-3-(1'-hydroxyethyl)-2-azetidinones of formula ##STR1## in which R.sup.1 represents lower alkyl or aryl, by enantioselective reduction of the carbonyl group in a suitable .alpha.-acylaminomethyl-acetoacetic acid ester, cyclisation of the resulting .alpha.-acylaminomethyl-.beta.-hydroxybutyric acid ester to a 5,6-dihydro-1,3,4H-oxazine with inversion of the carbon atom carrying the hydroxy group, equilibration to form the preferred trans-substituted dihydrooxazine, recleaving to form the configuratively uniform .alpha.-aminomethyl-.beta.-hydroxybutyric acid, ring-closure to form the .beta.-lactam and oxidative acylation at C(4) of the .beta.-lactam. Compounds of formula I can be used as starting materials for the manufacture of .beta.-lactam antibiotics. The invention relates also to novel intermediates.
本发明涉及一种新型工艺,用于制造式为##STR1##的(3R,1'R)-4-酰氧基-3-(1'-羟乙基)-2-氮杂环己酮,其中R1代表较低的烷基或芳基,通过对适宜的α-酰氨甲基-乙酰乙酸酯中的羰基基团进行对映选择性还原,将得到的α-酰氨甲基-β-羟基丁酸酯环化成带有羟基的5,6-二氢-1,3,4H-噁嗪,翻转携带羟基的碳原子,平衡形成优选的反式取代二氢噁嗪,再次裂解形成构型一致的α-氨甲基-β-羟基丁酸,环合成β-内酰胺,氧化酰化β-内酰胺的C(4)。式I的化合物可用作β-内酰胺类抗生素的原料。本发明还涉及新型中间体。