Application of N-cyclohexyloxycarbonyl (Choc) protection in Boc chemistry on solid phase provides a new possibility for the preparation of protected peptide fragments. A Choc/OcHex protection scheme allows also the assembly of cyclic lactam peptides linked to the resin through the C-terminus. Choc protection is stable under the 1M TMSOTf-thioanisole/TFA cleavage condition at 0 degrees C, but it is removable by anhydrous HF. We have utilized cyclohexyloxycarbonyl as an orthogonal protecting group for the synthesis of a i) bicyclic epitope peptide of glycoprotein D of HSV 1 on BHA resin and ii) fully protected hexapeptide involved in protein transport on Merrifield resin. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.
Structure-Based Design, Synthesis, and Biological Evaluation of Irreversible Human Rhinovirus 3C Protease Inhibitors. 2. Peptide Structure−Activity Studies
作者:Peter S. Dragovich、Stephen E. Webber、Robert E. Babine、Shella A. Fuhrman、Amy K. Patick、David A. Matthews、Siegfried H. Reich、Joseph T. Marakovits、Thomas J. Prins、Ru Zhou、Jayashree Tikhe、Ethel S. Littlefield、Ted M. Bleckman、Michael B. Wallace、Thomas L. Little、Clifford E. Ford、James W. Meador、Rose Ann Ferre、Edward L. Brown、Susan L. Binford、Dorothy M. DeLisle、Stephen T. Worland
DOI:10.1021/jm9800696
日期:1998.7.1
The structure-based design, chemical synthesis, and biological evaluation of various peptide-derived human rhinovirus (HRV) 3C protease (3CP) inhibitors are described. These compounds are comprised of an ethyl propenoate Michael acceptor moiety and a tripeptidyl binding determinant. The systematic modification of each amino acid residue present in the binding determinant as well as the N-terminal functionality is described. Such modifications are shown to provide irreversible HRV-14 3CP inhibitors with anti-3CP activities (k(obs)/[I]) ranging from 60 to 280 000 M-1 s(-1) and antiviral EC50's which approach 0.15 mu M. An optimized inhibitor which incorporates several improvements identified by the structure-activity studies is also described. This molecule displays very rapid irreversible inhibition of HRV-14 3CP (k(obs)/[I] = 800 000 M-1 s(-1)) and potent antiviral activity against HRV-14 in cell culture (EC50 = 0.056 mu M). A 1.9 Angstrom crystal structure of an S-alkylthiocarbamate-containing inhibitor complexed with HRV-8 3CP is also detailed.
Azole Endothelin Antagonists. 3. Using Δ log <i>P</i> as a Tool To Improve Absorption
作者:Thomas W. von Geldern、Daniel J. Hoffman、Jeffrey A. Kester、Hugh N. Nellans、Brian D. Dayton、Samuel V. Calzadilla、Kennan C. Marsh、Lisa Hernandez、William Chiou、Douglas B. Dixon、Jinshyun R. Wu-Wong、Terry J. Opgenorth
DOI:10.1021/jm9505932
日期:1996.1.1
The oral absorption profile of a family of azole-based ET(A)-selective antagonists has been improved through a rational series of structural modifications which were suggested by analysis of the physicochemical parameter Delta log P. Comparison of urea 2 with a series of well-absorbed compounds using Delta log P analysis suggested that 2 has an excess capacity for forming hydrogen bonds with solvent. A series of urea modifications were explored as a means of reducing H-bonding capacity while maintaining affinity for the ET(A)-receptor. The correlation between Delta log P values and absorption in an intraduodenal (id) bioavailability model was good; this strategy uncovered replacements for each of the urea NH groups which simultaneously improve both potency and drug absorption. A combination of these optimized modifications produces carbamate 16h, a highly-selective ET(A) antagonist with a potency/bioavailability profile consistent with an oral route of administration.