| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a process for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents. <P>SOLUTION: The process includes reacting a β-(substituted-amino)amide, a β-(substituted-amino)acid ester, or a β-(substituted-amino)thiolcarbonic acid ester with a silylating agent and a cyclizing agent. The cyclizing agent is selected from the group consisting of alkali metal carboxylates, quaternary ammonium carboxylates, quaternary ammonium hydroxides, quaternary ammonium alkoxides, quaternary ammonium aryloxides and hydrates thereof, or the reaction product of: (i) at least one quaternary ammonium halide and at least one alkali metal carboxylate; or (ii) at least one quaternary ammonium chloride, quaternary ammonium bromide, or quaternary ammonium iodide and at least one alkali metal fluoride. <P>COPYRIGHT: (C)2012,JPO&INPIT |
