Thermodynamic equilibration of dihydropyridone enolates: application to the total synthesis of (+/−)-epiuleine
作者:Edward S. Tasber、Robert M. Garbaccio
DOI:10.1016/j.tetlet.2003.10.030
日期:2003.12
as its vinyltriflate (3). This enolate interconversion is dependent on the dihydropyridone C-2 substituent and can be interpreted in terms of conformational analysis. This novel scaffold (3) opens another avenue for the strategic deployment of dihydropyridones into both natural product synthesis and drug discovery. To this end, this method is highlighted by its use as a key step in a total synthesis
Catalytic Enantioselective Addition of Dialkylzinc Reagents to<i>N</i>-Acylpyridinium Salts
作者:M.â Ãngeles Fernández-Ibáñez、Beatriz Maciá、Mariaâ Gabriella Pizzuti、Adriaanâ J. Minnaard、Benâ L. Feringa
DOI:10.1002/anie.200904981
日期:2009.11.23
A pinch of salt: The first catalyticaddition of dialkylzincreagents to N‐acylpyridinium salts with good yields and excellent enantioselectivities uses a copper–(S)‐L complex as the catalyst. The versatility of the method is illustrated in the formal synthesis of the alkaloid (R)‐coniine. Bn=benzyl, Tf=trifluoromethanesulfonyl.
Pyridine-derived triflating reagents: An improved preparation of vinyl triflates from metallo enolates.
作者:Daniel L. Comins、Ali Dehghani
DOI:10.1016/s0040-4039(00)60957-7
日期:1992.10
Metallo enolates of ketones are trapped with an N-(2-pyridyl)triflimide at low temperatures to give vinyl triflates.
C-3 Acetoxylation of N-acyl-2,3-dihydro-4-pyridones
作者:Daniel L. Comins、David A. Stolze、Faresh Thakker、Cheryl L. McArdle
DOI:10.1016/s0040-4039(98)01195-2
日期:1998.8
Stereoselective acetoxylation at the C-3 position of N-acyl-2-alkyl-2, 3-dihydro-4-pyridones was effected with Pb(OAc)(4) in refluxing toluene. (C) 1998 Elsevier Science Ltd. All rights reserved.
Methyl-substitution of an iminohydantoin spiropiperidine β-secretase (BACE-1) inhibitor has a profound effect on its potency
作者:Melissa Egbertson、Georgia B. McGaughey、Steven M. Pitzenberger、Shaun R. Stauffer、Craig A. Coburn、Shawn J. Stachel、Wenjin Yang、James C. Barrow、Lou Anne Neilson、Melody McWherter、Debra Perlow、Bruce Fahr、Sanjeev Munshi、Timothy J. Allison、Katharine Holloway、Harold G. Selnick、ZhiQiang Yang、John Swestock、Adam J. Simon、Sethu Sankaranarayanan、Dennis Colussi、Katherine Tugusheva、Ming-Tain Lai、Beth Pietrak、Shari Haugabook、Lixia Jin、I.-W. Chen、Marie Holahan、Maria Stranieri-Michener、Jacquelynn J. Cook、Joseph Vacca、Samuel L. Graham
DOI:10.1016/j.bmcl.2015.06.082
日期:2015.11
The IC50 of a beta-secretase (BACE-1) lead compound was improved similar to 200-fold from 11 mu M to 55 nM through the addition of a single methyl group. Computational chemistry, small molecule NMR, and protein crystallography capabilities were used to compare the solution conformation of the ligand under varying pH conditions to its conformation when bound in the active site. Chemical modification then explored available binding pockets adjacent to the ligand. A strategically placed methyl group not only maintained the required pKa of the piperidine nitrogen and filled a small hydrophobic pocket, but more importantly, stabilized the conformation best suited for optimized binding to the receptor. (C) 2015 Elsevier Ltd. All rights reserved.