SYNTHESIS OF N-CHLOROACETYL DERIVATIVES OF AMINO-ACIDS AND THEIR USE FOR CONJUGATION OF POLYPEPTIDES TO THIOL-CARRYING COMPOUNDS

The synthesis of the .alpha.-N-chloroacetyl derivatives of lysine n-butylamide (4a), lysine 2-methoxyethylamide, phenylalanyllysine n-butylamide and phenylalanyllysine 2-methoxyethylamide is described. The free .epsilon.-NH2 group of these compounds can initiate the growth of a polypeptide by polymerization of amino acid N-carboxyanhydrides, and this polypeptide can be coupled to thiol-carrying compounds via its N-chloroacetyl group, as illustrated by the use of 4a to attach a polyalanine chain to the SH group of cysteine.