| 摘要 |
A multi-step stereospecific process for preparing (3S,4R,5R)-1-(allyloxycarbonyl)-methyl-3-(1-hydroxyethyl)-4-beta-napht hoxythi ocarbonylthio-2-azetidinone, stereoisomers thereof or hydroxy protected analogs thereof from anhydropenicillin. The azetidinones are intermediates useful for producing penems which are a known group or antibacterial compounds. The process involves protecting the hydroxy group of anhydropenicillin with a readily removable hydroxy protecting group, then reacting the resulting compound by treatment with oxygen and cuprous chloride in methanol, followed by reaction with ozone to produce a hydroxy protected dithiobis azetidinone and convert the methylidene groups originally in the 2-position of anhydropenicillin and in the bis-compound, to a (methoxycarbonyl)-carbonyl group. The resulting compound is converted to the unprotected dithiobis compound by reaction with ammonium hydroxide, then allyliodoacetate followed by an acid. Reaction of the resulting compound with zinc and a mineral acid followed by reaction with 0-2-naphthalenylcarbonochloridothioate converts the unprotected dithiobis compound to 1-(allyloxycarbonyl)methyl-3-(1-hydroxyethyl)-4-beta-naphthoxy (thiocarbonyl)thio-2-azetidinone.
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