METHOD FOR PREPARING A HYDANTOIN DERIVATIVE SUBSTITUTED IN POSITION 5, METHOD FOR PREPARING AN alpha -AMINO ACID ALKALINE SALT FROM SAID HYDANTOIN DERIVATIVE AND METHOD FOR ESTERIFYING CYCLIC alpha -AMINO ACIDS

摘要

The invention concerns a method for preparing a hydantoin derivative substituted in position 5, from a carbonyl compound selected among aldehydes and ketones. The invention is characterised in that the method consists in reacting the carbonyl compound, in an appropriate solvent for a practically homogeneous reaction liquid phase, while stirring, with an appropriate cyanide compound and an appropriate ammonium compound, with controlled extraction of the carbon dioxide formed during the reaction. The invention also concerns a method for preparing an alpha -amino acid alkaline salt from a hydantoin derivative substituted in position 5 and a method for esterifying cyclic alpha -amino acid.