Amino acids and peptides. XXIII. Synthesis of N alpha-protected amino acid 6-chloro-2-pyridyl esters and their evaluation for peptide synthesis.
6-Chloro-2-pyridyl esters (OPyCl) of N alpha-benzyloxycarbonyl and tert-butyloxycarbonylamino acids were synthesized by the N,N'-dicyclohexylcarbodiimide (DCC) method from the acids and 6-chloro-2-hydroxypyridine in dimethylformamide (DMF). The reactivity of the 6-chloro-2-pyridylester with amino group is much higher than that of the corresponding 2-pyridyl ester (OPy) and p-nitrophenyl esters (ONp) in dioxane and DMF, and a peptide bond is formed without acylation at the side chain hydroxyl group of amino acids. Z-Asp(OBzl)-OPyCl reacted with amino acid methyl esters in dioxane to give the corresponding dipeptide without any detectable aspartimide formation.
Tsuboi
S
S
Okada
Y
Y
D000596:Amino Acids / Q000032:analysis*; D055598:Chemical Phenomena; D002621:Chemistry; D010455:Peptides / Q000032:analysis / Q000138:chemical synthesis*; D011725:Pyridines / Q000138:chemical synthesis*
D000596:Amino Acids; D010455:Peptides; D011725:Pyridines