A new asymmetric organocatalytic synthesis of spirocyclopropaneoxindoles has been developed. The method is based on the Michael addition of N-Boc-protected 3-chlorooxindole to unsaturated 1,4-dicarbonyl compounds, affording trans-substituted spirocyclopropaneoxindolederivatives in high diastereo- and enantioselectivity.
Diversity-Oriented Synthesis of Spiropentadiene Pyrazolones and 1<i>H</i>-Oxepino[2,3-<i>c</i>]pyrazoles from Doubly Conjugated Pyrazolones via Intramolecular Wittig Reaction
作者:Pankaj V. Khairnar、Chi-Yi Wu、Yi-Fang Lin、Athukuri Edukondalu、Yi-Ru Chen、Wenwei Lin
DOI:10.1021/acs.orglett.0c01552
日期:2020.6.19
An efficient method for the diversity-oriented synthesis of spiropentadiene pyrazolones and 1H-oxepino[2,3-c]pyrazoles is reported. The methodology attributes O-acylation of phosphorus zwitterions which were formed by a tandem phospha-1,6-addition of PBu3 to α,β,γ,δ-unsaturated pyrazolones, further generating betaine intermediates that preferentially resulted in the aforementioned cyclic products in
报道了一种高效的方法来合成螺环戊二烯吡唑啉酮和1 H-氧代庚并[2,3- c ]吡唑。该方法学归因于将PBu 3串联磷酸1,6-加成到α,β,γ,δ-不饱和吡唑酮上形成的两性磷的O-酰化作用,进一步产生了甜菜碱中间体,该中间体优先产生上述环状产物以多元化为导向的方式。机理研究表明,甜菜碱的形成是通过分子内维蒂希反应或空前的δ- C-酰化/环化/维蒂希反应提供产物的关键步骤。
Endogenous Enzymes Enable Antimicrobial Activity
作者:Kenton J. Hetrick、Miguel A. Aguilar Ramos、Ronald T. Raines
DOI:10.1021/acschembio.0c00894
日期:2021.5.21
ant bacteria, new strategies to expand the repertoire of antimicrobial compounds are necessary. Prodrugs are an underexploited strategy in this effort. Here, we report on the enhanced antimicrobial activity of a prodrug toward bacteria having an enzyme capable of its activation. A screen led us to the sulfurol ester of the antibiotic trans-3-(4-chlorobenzoyl)acrylic acid. An endogenous esterase makes
Isothiourea-Mediated One-Pot Synthesis of Functionalized Pyridines
作者:Daniel G. Stark、Louis C. Morrill、Pei-Pei Yeh、Alexandra M. Z. Slawin、Timothy J. C. O'Riordan、Andrew D. Smith
DOI:10.1002/anie.201306786
日期:2013.10.25
Acids to bases: The synthesis of 2,4,6-trisubstituted pyridines from (phenylthio)acetic acid and a range of α,β-unsaturated ketimines is reported. This process proceeds by intermolecular Michael addition/lactamization, thiophenol elimination, and N- to O-sulfonyl migration, giving 2-sulfonate-substituted pyridines which are readily derivatized to generate structural diversity.
CoA Adducts of 4-Oxo-4-phenylbut-2-enoates: Inhibitors of MenB from the <i>M. tuberculosis</i> Menaquinone Biosynthesis Pathway
作者:Xiaokai Li、Nina Liu、Huaning Zhang、Susan E. Knudson、Huei-Jiun Li、Cheng-Tsung Lai、Carlos Simmerling、Richard A. Slayden、Peter J. Tonge
DOI:10.1021/ml200141e
日期:2011.11.10
A high-throughput screen led to the discovery of 2-amino-4-oxo-4-phenylbutanoate inhibitors of the 1,4-dihydroxy-2-naphthoyl-CoA synthase (MenB) from the menaquinone biosynthesis pathway in Mycobacterium tuberculosis. However, these compounds are unstable in solution and eliminate to form the corresponding 4-oxo-4-phenylbut-2-enoates that then react with CoA in situ to form nanomolar inhibitors of MenB. The potency of these compounds results from interaction of the CoA adduct carboxylate with the MenB oxyanion hole, a conserved structural motif in the crotonase superfamily. 4-Oxo-4-chlorophenylbutenoyl methyl ester has minimum inhibitory concentrations of 0.6 and 1.5 mu g/mL against replicating and nonreplicating M. tuberculosis, respectively, and it is proposed that the methyl ester penetrates the cell where it is hydrolyzed and reacts with CoA to generate the active antibacterial. The CoA adducts thus represent an important foundation for the development of novel MenB inhibitors and suggest a general approach to the development of potent inhibitors of acyl-CoA binding enzymes.