摘要:
In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
摘要:
In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
摘要:
In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
摘要:
In an illustrative embodiment, the present invention describes the synthesis of the following compound and similar compounds, in high stereochemical purity by a novel stereoselective alkylation process:
摘要:
A process is provided for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents, comprising 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 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, wherein a quaternary ammonium moiety of the cyclizing agent is unsubstituted or substituted by one to four groups independently selected from the group consisting of alkyl, arylalkyl and arylalkyl-alkyl.
摘要:
A process is provided for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents, comprising 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 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, wherein a quaternary ammonium moiety of the cyclizing agent is unsubstituted or substituted by one to four groups independently selected from the group consisting of alkyl, arylalkyl and arylalkyl-alkyl.
摘要:
This invention provides a process for preparing the hypocholesterolemic compound comprising: (a) reacting p-fluorobenzoylbutyric acid with pivaloyl chloride and acylating the product with a chiral auxiliary to obtain a ketone of formula IV: (b) reducing the ketone of formula IV in the presence of a chiral catalyst to an alcohol: (c) reacting the chiral alcohol of step (b), an imine and a silyl protecting agent, then condensing the protected compounds to obtain a &bgr;-(substituted-amino)amide of formula VII: (d) cyclizing the &bgr;-(substituted-amino)amide of formula VII with a silylating agent and a fluoride ion catalyst to obtain a protected lactam of the formula VIII: and removing the protecting groups. The intermediates of formulas VII and VIII are also claimed.
摘要:
A process is provided for preparing azetidinones useful as intermediates in the synthesis of penems and as hypocholesterolemic agents, comprising 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 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, wherein a quaternary ammonium moiety of the cyclizing agent is unsubstituted or substituted by one to four groups independently selected from the group consisting of alkyl, arylalkyl and arylalkyl-alkyl.
摘要:
The present invention relates to an improved process for preparing himbacine analogs. The compounds are useful as thrombin receptor antagonists. The improved process may allow for at least one of easier purification by crystallization, easier scalability, and improved process yield on the desired enantiomer.An example of a step in the synthesis of such a himbacine analog is as follows:
摘要:
The present invention relates to an improved process for preparing himbacine analogs. The compounds are useful as thrombin receptor antagonists. The improved process may allow for at least one of easier purification by crystallization, easier scalability, and improved process yield on the desired enantiomer.An example of a step in the synthesis of such a himbacine analog is as follows: