Amino-acids and peptides. Part XXX. Facilitation of peptide synthesis by the use of 4-picolyl esters for carboxy-group protection

摘要: The preparation and properties of the dihydrobromides some 4-picolyl esters amino-acids (I), their benzyloxycarbonyl derivatives, are described. may be cleaved by cold alkali, catalytic hydrogenation, sodium in liquid ammonia, electrolytic reduction. A new procedure for facilitation peptide synthesis is reported, which carboxy-terminal residue incorporated as its ester; after each coupling reaction product separated from excess acylating agent, co-products, by-products extraction into an acidic phase, e.g. sulphoethyl-Sephadex. illustrated two syntheses L-leucyl-L-alanylglycyl-L-valine.