Conformationally Assisted Lactamizations for the Synthesis of Symmetrical and Unsymmetrical Bis-2,5-diketopiperazines
摘要:
Open-chain N-Cbz-protected-peptidoyl benzotriazolides are converted by a novel lactamization strategy using proline as a turn introducer into both symmetrical (5a-c and 11a-c) and unsymmetrical (19a-e) bis-2,5-diketopiperazines (bis-2,5-DKPs), previously recognized as difficult targets.
Expedient synthesis of N-Z-pyroglutamyl-amino acid derivatives
作者:Alan R. Katritzky、Parul Angrish、Ekaterina Todadze、Ion Ghiviriga
DOI:10.1016/j.bmcl.2007.07.052
日期:2007.11
N-Z-Pyroglutamyl pseudopeptides 3a-c are shown to be conveniently prepared from glutamyl-bis-Bt la by cyclization of an N-terminal glutamic acid residue. Structures are supported by 2D NMR studies and by comparison with the same products prepared by direct coupling of the C-terminus activated N-pGlu 1b and free amino acids 2a-c. () 2007 Elsevier Ltd. All rights reserved.