| 摘要 |
alpha -Arylalkanoic acids or esters, ortho esters or amides thereof are prepared by forming an alpha -hydroxy ketal or thioketal of an aryl alkyl ketone, activating the alpha -hydroxy substituent with an esterifying agent to form the corresponding ketal or thioketal ester substrate, wherein the ester group is sufficiently labile to non-catalytically disassociate from the substrate in a protic or dipolar, aprotic solvent, maintaining the ester substrate in contact with the protic or dipolar, aprotic solvent or mixtures thereof for a time sufficient to form the corresponding alpha -arylalkanoic acid or ester, ortho ester or amide thereof, optionally concomitantly or sequentially hydrolyzing any ester, ortho ester or amide formed to the corresponding alpha -arylalkanoic acid and optionally converting the latter into a salt The rearrangement can be conducted in the absence of water and under acidic conditions to afford high yields of the desired alpha -arylalkanoic acids. |
