An effective synthesis of scalemic 3,5,5-trisubstituted pyrrolin-4-ones
摘要:
A new two-step method employs the intramolecular cyclization of metalated imino esters for the construction of scalemic 3,5,5-trisubstituted pyrrolin-4-ones (4). The imino esters in turn derive from alpha-disubstituted amino acids, the latter readily available via a new protocol exploiting the enantioretentive alkylation of oxazolidinones.
An effective synthesis of scalemic 3,5,5-trisubstituted pyrrolin-4-ones
摘要:
A new two-step method employs the intramolecular cyclization of metalated imino esters for the construction of scalemic 3,5,5-trisubstituted pyrrolin-4-ones (4). The imino esters in turn derive from alpha-disubstituted amino acids, the latter readily available via a new protocol exploiting the enantioretentive alkylation of oxazolidinones.
Enantioretentive alkylation of oxazolidinone aluminum enolates with epoxides: Preparation of uncoded homoserine analogs
作者:Amos B. Smith、Alexander Pasternak、Akihisa Yokoyama、Ralph Hirschmann
DOI:10.1016/0040-4039(94)88404-8
日期:1994.11
The alkylation of Karady/Seebach oxazolidinoneenolates with epoxides, promoted by 2.1 equivalents of diethylaluminum chloride, furnishes ring-opened adducts in moderate-to-good yields with high diastereoselectivity. The method provides an effective approach to uncodedhomoserineanalogs and expands the utility of readily available oxazolidinones in asymmetric synthesis.
De Novo Design, Synthesis, and X-ray Crystal Structures of Pyrrolinone-Based .beta.-Strand Peptidomimetics
作者:Amos B. Smith、Mark C. Guzman、Paul A. Sprengeler、Terence P. Keenan、Ryan C. Holcomb、John L. Wood、Patrick J. Carroll、Ralph Hirschmann
DOI:10.1021/ja00101a017
日期:1994.11
The de novo design and synthesis of a novel non-peptide scaffolding for beta-strand/sheet mimics are described. The scaffold consists of repeating 3,5,5-trisubstituted pyrrolinone (enaminone) units punctuated with appropriate amino acid side chains. The iterative construction of the pyrrolinones exploits a highly efficient cyclization of metalloimines, the latter derived from C-terminal aldehydes and readily available alpha-substituted alpha-amino ester building blocks. As predicted by interactive computer modeling and confirmed by X-ray crystallography, the polypyrrolinones present the side chains and carbonyl hydrogen-bond accepters in a solid-state conformation which mimics polypeptide beta-sheets. Importantly, the enaminone NH protons form hydrogen bonds both intramolecularly, stabilizing the beta-strand conformation, and intermolecularly, promoting sheet formation. The presence or absence of the nitrogen protecting group controlled antiparallel versus parallel sheet formation.
Pyrrolinone-Based HIV Protease Inhibitors. Design, Synthesis, and Antiviral Activity: Evidence for Improved Transport
作者:Amos B Smith、Ralph Hirschmann、Alexander Pasternak、Mark C. Guzman、Akihisa Yokoyama、Paul A. Sprengeler、Paul L. Darke、Emilio A. Emini、William A. Schleif
DOI:10.1021/ja00150a011
日期:1995.11
Pyrrolinone-based peptidomimetics, the first mimics of beta-strands, are potent inhibitors of HIV-1 protease. Importantly, the bis(pyrrolinones) described herein proved to be more active in cellular antiviral assays compared with an analogous peptide-derived inhibitor even though they are less effective in inhibiting the isolated protease. These results suggest that pyrrolinone inhibitors offer better transport properties than the corresponding peptide-based peptidomimetics; we attribute this effect to decreased solvation of the mimetics. Structure-activity relationships for the pyrrolinones correlate well with those reported for related peptides, consistent with similar modes of binding.