| 摘要 |
PURPOSE:To obtain the optically active isomer of the titled compound having antibacterial activity, in high yield, via a novel intermediate, by using an optically active (4S)-4-alkoxycarbonylmethyl-2-azetidinone as a starting material. CONSTITUTION:The compound of formulaI(R<1> is lower alkyl; R<3> is H or protective group) is hydrolyzed, activated and made to react with the magnesium salt of formula II (R<31> is protective group) to obtain the compound of formula III, which is converted to the diazo compound of formula IV by treating with an azide in an inert organic solvent under ice cooling. The diazo compound is cyclized by heating and refluxing in an inert organic solvent in the presence of a catalyst. After activating the 3-position oxo group of the resultant compound of formula V, the compound is made to react with the compound of formula VI (R<4> is H or protective group), and if necessary, the protective group is eliminated to obtain the objective compound of formula VII. The intermediates of formula III-V are novel compounds. |
