The principle of simultaneous activation and protection is operative in the reaction of a- amino acids with cyanogen bromide in aqueous solution at neutral pH It is assumed that the initially formed N-cyano derivative invites psrticipation of the carboxy function to yield a highly reactive 5-iminooxazolidone-2 which is opened in an sntermolecular reaction by a second molecule of the a-amino acid to give in good yield N-carbamyl dipeptides In the ...
