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Selektive enzymatische Schutzgruppenabspaltungen: Der n‐Heptylester als Carboxylschutzgruppe in der Peptidsynthese
Author(s) -
Braun Peter,
Waldmann Herbert,
Vogt Walter,
Kunz Horst
Publication year - 1991
Publication title -
liebigs annalen der chemie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0170-2041
DOI - 10.1002/jlac.199119910130
Subject(s) - chemistry , protecting group , hydrolysis , amino acid , peptide , organic chemistry , stereochemistry , biochemistry , alkyl
Selective Enzymatic Removal of Protecting Groups: n‐Heptyl Esters as Carboxy Protecting Functions in Peptide Synthesis Amino acid heptyl (Hep) esters are accessible as generally crystalline hydro tosylates 3 from the amino acids by azeotropic esterification with 1‐heptanol in high yields. They can be condensed with Z‐, Boc‐, and Aloc‐protected amino acids to give the dipeptides 7–9 in the presence of 1‐ethoxycarbonyl‐2‐ethoxy‐1,2‐dihydroquinoline (EEDQ). From the fully protected dipeptides the N‐terminal protecting groups are cleaved by chemical methods without affecting the Hep esters. On the other hand, the heptyl esters can be hydrolyzed under mild conditions (pH = 7.0, 37°C) and with high yields by means of a lipase from Rhizopus niveus without attacking the N‐terminal urethane groups or the peptide bonds.