申请人:President and Fellows of Harvard College
公开号:US04937331A1
公开(公告)日:1990-06-26
Epoxyimines, formed from epoxyaldehydes, react via cycloaddition with amino-protected glycyl halides to provide 3-protected-amino-4-(substituted oxiranyl)azetidinones represented by the formula ##STR1## wherein, e.g., R is protected amino; R.sub.1 and R.sub.2 is H, alkyl, phenyl, etc.; and R.sub.3 inter alia a nitrogen-protecting group. Chiral epoxyimines from chiral epoxyaldehydes induce high levels of asymmetric induction during the cycloaddition to provide substantially one diastereomer of the 3,4-disubstituted azetidinone. For example, the epoxyimine formed with (2R,3S)-2-formyl-3-phenyloxirane and 2,4-dimethoxybenzylamine is reacted with phthalimidoacetyl chloride to provide [3R,4R,4(2S,3S]-1-(2,4-dimethoxybenzyl)-3-phthalimido-4-(3-phenyloxiran-2- yl)-2-azetidinone. The epoxy-substituted azetidinones are useful intermediates for .beta.-lactam antibiotic compounds.
环氧亚胺是由环氧醛形成的,通过环加成反应与氨基保护的甘氨酰卤反应,得到由下式表示的3-保护氨基-4-(取代氧环氧基)氮杂环酮:其中,例如,R为保护氨基;R1和R2为H、烷基、苯基等;R3为氮保护基等。手性环氧亚胺来自手性环氧醛,在环加成过程中诱导高水平的对映选择性,从而提供3,4-二取代氮杂环酮的基本上一个对映体。例如,用(2R,3S)-2-甲酰-3-苯氧环氧烷和2,4-二甲氧基苯甲胺形成的环氧亚胺与邻苯二甲酰氯反应,得到[3R,4R,4(2S,3S)-1-(2,4-二甲氧基苯基)-3-邻苯二甲酰氨基-4-(3-苯氧环氧烷-2-基)-2-氮杂环酮。环氧取代的氮杂环酮是β-内酰胺类抗生素化合物的有用中间体。