Regiochemistry in Cobalt-Mediated Intermolecular Pauson–Khand Reactions of Unsymmetrical Internal Heteroaromatic Alkynes with Norbornene
作者:Benjamin E. Moulton、Adrian C. Whitwood、Anne K. Duhme-Klair、Jason M. Lynam、Ian J. S. Fairlamb
DOI:10.1021/jo200664m
日期:2011.7.1
comparable (2-phenylethynyl)heteroaromatic compounds with norbornene, mediated by Co2(CO)8 to give cyclopentenone products, were examined in this study. A synthetic protocol utilizing focused-microwave dielectric heating proved indispensable in the efficient synthesis of the PK cyclopentenone products. “π-Deficient” heteroaromatic substrates, e.g., 2-pyrones, and some “π-excessive” heteroaromatics such as
Co 2(CO)8介导的空间可比的(2-苯基乙炔基)杂芳族化合物与降冰片烯的分子间Pauson-Khand(PK)反应得到环戊烯酮产品,在这项研究中进行了检查。事实证明,利用聚焦微波介电加热的合成协议是有效合成PK环戊烯酮产品必不可少的。“π缺陷”杂芳族底物(例如2-吡喃酮)和一些“π过量”杂芳族化合物(例如2-和3-噻吩和2-呋喃)有利于新形成的环戊烯酮环中的β位置。其他π过量的杂芳族化合物(例如2-吡咯或2-吲哚)偏向α位。π-过量的3-吲哚衍生物给出了几乎相等的区域异构体混合物。氮在含吡啶基炔烃底物中的位置也影响PK反应的区域化学结果。拥有近端氮原子的2-吡啶基炔烃相对于4-吡啶基变异体会极大地影响区域选择性,有利于新形成的环戊烯酮环中的β位置。2-嘧啶炔基表现出与2-吡啶炔基相似的行为。不参与与降冰片烯进行PK反应的化合物包括(2-苯基乙炔基)咪唑和相关的苯并咪唑类,它们可促进原位生成的快速分解(μ2-炔)Co
An efficient synthesis of 4-alkenyl/alkynyl-6-methyl-2-pyrones via Pd-catalysed coupling on 4-bromo-6-methyl-2-pyrone
作者:Lester R. Marrison、Julia M. Dickinson、Razwan Ahmed、Ian J.S. Fairlamb
DOI:10.1016/s0040-4039(02)02207-4
日期:2002.12
We herein report the efficient syntheses of biologically active 4-alkenyl- and 4-alkynyl-6-methyl-2-pyrones using Pd-catalysed coupling procedures. A palladium on carbon/triphenylphosphine combination is shown to be the most effective catalyst for Sonogashira cross-coupling of several terminal acetylenes with 4-bromo-6-methyl-2-pyrone in yields of up to 95%. (C) 2002 Elsevier Science Ltd. All rights reserved.
Bioactive 4-substituted-6-methyl-2-pyrones with promising cytotoxicity against A2780 and K562 cell lines
作者:Lester R. Marrison、Julia M. Dickinson、Ian J.S. Fairlamb
DOI:10.1016/s0960-894x(02)00824-7
日期:2002.12
Bioactive synthetic 4-substituted-6-methyl-2-pyrones are reported. Various 4-substitutents have been incorporated using Pd-catalysed carbon-carbon bond coupling procedures. Preliminary screening of the 2-pyrones against human ovarian carcinoma (A2780) and human chronic myelogenous leukaemia (K562) cell lines show that 4-alkynyl-6-methyl-2-pyrones have excellent potential as anticancer agents. The pyrones demonstrate broad spectrum antimicrobial activities. (C) 2002 Elsevier Science Ltd. All rights reserved.
2-Pyrones possessing antimicrobial and cytotoxic activities
作者:Ian J.S Fairlamb、Lester R Marrison、Julia M Dickinson、Feng-Ju Lu、Jan Peter Schmidt
DOI:10.1016/j.bmc.2004.01.051
日期:2004.8.1
The 2-pyrone sub-unit is found in a number of natural products possessing broad spectrum biological activity. Such compounds are validated as being capable of binding to specific protein domains and able to exert a remarkable range of biological effects. In an effort to identify synthetic 2-pyrones with interesting biological effects, herein we report the synthesis and biological evaluation of 4-substituted-6-methyl-2-pyrones. Synthetic routes to 4-alkyl/alkenyl/aryl/alkynyl-6-methyl-2-pyrones have been developed utilising Sonogashira, Suzuki and Negishi cross-coupling starting from readily available 4-bromo-6-methyl-2-pyrone. Specific conditions for each organometallic protocol were required for successful cross-coupling. In particular, a triethylamine/acetonitrile-base/solvent mixture was crucial to Sonogashira alkynylation of 4-bromo-6-methyl-2-pyrone, whereas thallium carbonate was a mandatory base for the Suzuki cross-coupling of trialkylboranes. The 2-pyrones demonstrate potent inhibitory activity against Bacillus subtilis, Escherichia coli, Staphylococcus aureus, Schizosaccharomyces pombe and Botrytis cinerea. The growth inhibitory activities of selected 2-pyrones were determined in A2780 human ovarian carcinoma and K562 human chronic myelogenous leukaemia cell lines using an in vitro cell culture system (MTT assay). These studies demonstrate that 4-phenylethynyl-, 4-tetrahydropyranylpropargyl ether- and 4-ethynyl-6-methyl-2-pyrones have excellent potential as a new class of anticancer agents. (C) 2004 Elsevier Ltd. All rights reserved.
Evaluation of α-Pyrones and Pyrimidones as Photoaffinity Probes for Affinity-Based Protein Profiling
作者:Oliver A. Battenberg、Matthew B. Nodwell、Stephan A. Sieber
DOI:10.1021/jo201281c
日期:2011.8.5
of pyrones and pyrimidones was synthesized, and their potential to act as photoaffinityprobes for nondirected affinity-based protein profiling in several crude cell lysates was evaluated. Further “proof-of-principle” experiments demonstrate that a pyrimidone tag on an appropriate scaffold is equally capable of proteome labeling as a benzophenone.