Optical resolution of aminoisobobutyric acid

摘要

A process for resolving amino protected racemic 3-amino-2-methylpropionic acid which comprises the steps of: (1) reacting said amino protected acid with a protected amino group with an enantiomer of a chiral amine to form diastereomeric salts; (2) recrystallizing the diastereomeric salts from ethyl acetate to separate the diastereomeric salts into crystal fractions; and (3) releasing the resolved acid from the diastereomeric salt by treating the diastereomeric salt with a basic solution is disclosed. A process for the preparation of the cryptophycin molecules is also disclosed.