Reaction of various types of alcohols with a novel type of acylating agent, the isopropenyl esters 2a–e in the presence of a catalytic amount of conc. sulfuric acid or toluene-p-sulfonic acid followed by selective deprotection of the terminal ester gives the monoesters 5a–i in good yields.
Covalent Linkage and Macrocylization Preserve and Enhance Synergistic Interactions in Catalytic Amyloids
作者:Zsofia Lengyel‐Zhand、Liam R. Marshall、Maximilian Jung、Megha Jayachandran、Min‐Chul Kim、Austin Kriews、Olga V. Makhlynets、H. Christopher Fry、Armin Geyer、Ivan V. Korendovych
DOI:10.1002/cbic.202000645
日期:2021.2.2
How might complexity arise from short peptides? Synergisticinteractions between the side chains of catalyticamyloids are locked into place by linkers between the peptides, and these new designs result in faster assembly and asymmetric assemblies. These could serve as a potential link in the evolutionary path between abiotic peptides and complex enzymes.
Total Synthesis of the Epidermal Growth Factor Inhibitor (−)-Reveromycin B
作者:Anthony N. Cuzzupe、Craig A. Hutton、Michael J. Lilly、Robert K. Mann、Kenneth J. McRae、Steven C. Zammit、Mark A. Rizzacasa
DOI:10.1021/jo001646c
日期:2001.4.1
The total synthesis of the epidermal growth factor inhibitor reveromycin B (2) in 25 linear steps from chiral methylene pyran 13 is described. The key steps involved an inverse electron demand hetero-Diels-Alderreaction between dienophile 13 and diene 12 to construct the 6,6-spiroketal 11 which upon oxidation with dimethyldioxirane and acid catalyzed rearrangement gave the 5,6-spiroketal aldehyde
Thermodynamic Analysis of Autonomous Parallel β-Sheet Formation in Water
作者:John D. Fisk、Margaret A. Schmitt、Samuel H. Gellman
DOI:10.1021/ja060942p
日期:2006.6.1
We report the first thermodynamic analysis of parallelβ-sheet formation in a modelsystem that folds in aqueous solution. NMR chemical shifts were used to determine β-sheet population, and van't Hoff anaysis provided thermodynamic parameters. Our approach relies upon the d-prolyl-1,1-dimethyl-1,2-diaminoethane unit to promote parallelβ-sheet formation between attached peptide strands. The development
Rhodium catalyzed cyclization process for bicyclic .beta.-lactams
申请人:University of Notre Dame du Lac
公开号:US05051502A1
公开(公告)日:1991-09-24
1-Carbapenam-2-one-3-carboxylic acid and 1-carba-3-hydroxy-3-cephem-4-carboxylic acid and esters thereof are provided by a process comprising a rhodium C.sub.2 -C.sub.10 carboxylate catalyzed cyclization of an ester of a 4-(1-alkoxy- or 1-substituted alkxoy)-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketobutyric acid and an ester of a 5-(1-alkoxy- or 1-substituted alkoxy-2-oxo-4-azetidinyl)-.alpha.-diazo-.beta.-ketovaleric acid respectively. The process is carried out in an inert organic solvent at a temperature between about 15.degree. C. and about 85.degree.0 C. The 1-carba bicyclic .beta.-lactams are intermediates for preparing antibiotics.