Synthesis of aryl esters of protected amino acids from aryl sulfonates
摘要:
Aryl esters of Boc- and Fmoc-protected amino acids derived from electron-deficient phenols have been prepared in good yields from aryl 4-nitrobenzenesulfonates in the presence of l-hydroxy-benzotriazole as catalyst. (C) 1999 Published by Elsevier Science Ltd. Ail rights reserved.
Polypeptides. Part V. The use of t-butyl 2,4,5-trichlorophenyl carbonate in the synthesis of N-t-butoxycarbonyl amino-acids and their 2,4,5-trichlorophenyl esters
作者:Wallace Broadbent、J. S. Morley、B. E. Stone
DOI:10.1039/j39670002632
日期:——
t-Butyl2,4,5-trichlorophenylcarbonate, conveniently prepared from phosgene in two stages, reacts cleanly with amino-acids in the presence of bases to give N-t-butoxycarbonylamino-acids (and 2,4,5-trichlorophenol) in excellent yield. By co-extraction of the N-t-butoxycarbonylamino-acid and 2,4,5-trichlorophenol from the acidified reaction mixture, followed by treatment of the extracts with NN′-
Biologically compatible linear block copolymers of polyalkylene oxide
申请人:Sterling Winthrop Inc.
公开号:US05618528A1
公开(公告)日:1997-04-08
A linear block copolymer comprising units of an alkylene oxide, linked to units of peptide via a linking group comprising a --CH.sub.2 CHOHCH.sub.2 N(R)-- moiety, is useful as an imaging agent, drug, prodrug or as a delivery system for imaging agents, drugs or prodrugs.