(+/-)-alpha-Hydroxy-alpha-(p-Chlorobiphenyl)acetic acid 합성과 분할

Synthesis of (+/-)-alpha-Hydroxy-alpha-(p-Chlorobiphenyl)Acetic Acid and its Resolution

Optically pure (-)-and (+)-alpha-hydroxy-alpha-(p-chlorobiphenyl)acetic acids were prepared. The racemate was synthesized through three steps. By condensation of p-chlorobiphenyl with diethyl ketomalonate in the presence of SnCl4 diethyl alpha-hydroxy-alpha-(p-chlorobiphenyl)malonate (1) was formed and subsequently (+/-)-alpha-hydroxy-alpha-(p-chlorobiphenyl)acetic acid (3) was obtained through hydrolysis and decarboxylation. For the separation of the racemate the classcal resolution method, derivatization of a racemate by reaction with an optically pure compound was employed. In this case the optically pure compounds were [R]-(+)-alpha-methylbenzylamine and [S]-(-)-alpha-methylbenzylamine. Diastereomeric salts between acids and bases could be easily separated by crystallization in absolute ethanol.