5533-03-9Relevant academic research and scientific papers
Mccrearamycins A–D, Geldanamycin-Derived Cyclopentenone Macrolactams from an Eastern Kentucky Abandoned Coal Mine Microbe
Wang, Xiachang,Zhang, Yinan,Ponomareva, Larissa V.,Qiu, Qingchao,Woodcock, Ryan,Elshahawi, Sherif I.,Chen, Xiabin,Zhou, Ziyuan,Hatcher, Bruce E.,Hower, James C.,Zhan, Chang-Guo,Parkin, Sean,Kharel, Madan K.,Voss, S. Randal,Shaaban, Khaled A.,Thorson, Jon S.
, p. 2994 - 2998 (2017)
Four cyclopentenone-containing ansamycin polyketides (mccrearamycins A–D), and six new geldanamycins (Gdms B–G, including new linear and mycothiol conjugates), were characterized as metabolites of Streptomyces sp. AD-23-14 isolated from the Rock Creek underground coal mine acid drainage site. Biomimetic chemical conversion studies using both simple synthetic models and Gdm D confirmed that the mccrearamycin cyclopentenone derives from benzilic acid rearrangement of 19-hydroxy Gdm, and thereby provides a new synthetic derivatization strategy and implicates a potential unique biocatalyst in mccrearamycin cyclopentenone formation. In addition to standard Hsp90α binding and cell line cytotoxicity assays, this study also highlights the first assessment of Hsp90α modulators in a new axolotl embryo tail regeneration (ETR) assay as a potential new whole animal assay for Hsp90 modulator discovery.
SELECTIVE HYDRODEOXYGENATION OF AROMATIC COMPOUNDS
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Paragraph 0228-0231; 0238; 0245-0246; 0249; 0255, (2021/07/02)
Disclosed are methods of selective hydrodeoxygenation of aromatic compounds by using catalyst systems comprising N-heterocyclic carbene (NHC) and 4-pyridinol-derived pincer ligands and metal complexes containing these ligands.
Determining the Catalyst Properties That Lead to High Activity and Selectivity for Catalytic Hydrodeoxygenation with Ruthenium Pincer Complexes
Boudreaux, Chance M.,Das, Sanjit,Delucia, Nicholas A.,Papish, Elizabeth T.,Qu, Fengrui,Vannucci, Aaron K.,Yao, Wenzhi
, (2020/03/13)
Ten ruthenium pincer complexes were evaluated as catalysts for the hydrodeoxygenation (HDO) reaction on a lignin monomer surrogate, vanillyl alcohol. Four of these complexes are reported herein with the synthesis and full characterization data for all and single-crystal X-ray diffraction data for three complexes bearing OH/O-, NMe2, and Me substituents on the pincer. A systematic study of these CNC pincer complexes revealed that the π-donor substituent on the pyridine ring plays a key role in enhancing the yield of the desired deoxygenated product. While OMe, OH, and NMe2 are all effective as π-donor substituents on the central pyridine ring in the pincer, the highest conversion to products and the best selectivity was observed with OH substituents and added sodium carbonate as a base. Base serves to deprotonate the OH group and form 1O- as observed spectroscopically. Furthermore, efforts to use other catalysts have revealed that free or labile sites are needed on the ruthenium center and an electronically rich and nonbulky CNC pincer is optimal. At low catalyst loadings (0.01 mol %), the OH-substituted catalyst 1OH in the presence of base serves as a homogeneous catalyst and is able to achieve quantitative and selective conversion of vanillyl alcohol to desired the HDO product, creosol, with up to 10000 turnovers. With this knowledge in hand, we can design the next generation of homogeneous catalysts with increased reactivity toward all of the oxygenated sites on lignin-derived monomers.
Nickel-catalyzed intelligent reductive transformation of the aldehyde group using hydrogen
Tong, Xinli,Guo, Pengfei,Liao, Shengyun,Xue, Song,Zhang, Haigang
, p. 5828 - 5840 (2019/11/11)
The selective transformation of the aldehyde group (-CHO) in multifunctional oxygenates is a key challenge in the development of sustainable biomass feedstock. Herein, a smart Ni-MFC catalyst was developed from a 2D Ni-based metal-organic framework (MOF), which efficiently promoted the transformation of -CHO in the presence of H2 to a methyl group (-CH3) via the reductive etherification and hydrogenolysis of the C-O ether bond in methanol. Moreover, the catalytic process could be controlled to directionally produce methyl ether (-CH2OR) using the reductive etherification protocol. For the catalytic reduction of vanillin, the Ni-MFC-700 catalyst guaranteed the full conversion of vanillin and 96.5% yield of the desired 2-methoxy-4-methylphenol (MMP), while the Ni-MFC-500 catalyst afforded about 82.7% yield of 4-(methoxymethyl)-2-methoxyphenol in methanol solvent. This is a novel and promising approach for the valorization of multifunctional oxygenates and biomass-derived platform compounds.
Auto-Tandem Catalysis with Frustrated Lewis Pairs for Reductive Etherification of Aldehydes and Ketones
Bakos, Mária,Gy?m?re, ádám,Domján, Attila,Soós, Tibor
supporting information, p. 5217 - 5221 (2017/04/27)
Herein we report that a single frustrated Lewis pair (FLP) catalyst can promote the reductive etherification of aldehydes and ketones. The reaction does not require an exogenous acid catalyst, but the combined action of FLP on H2, R-OH or H2O generates the required Br?nsted acid in a reversible, “turn on” manner. The method is not only a complementary metal-free reductive etherification, but also a niche procedure for ethers that would be either synthetically inconvenient or even intractable to access by alternative synthetic protocols.
Total Synthesis of Avrainvilleol
Wegener, Aaron,Miller, Kenneth A.
, p. 11655 - 11658 (2017/11/10)
The first total synthesis of the marine natural product avrainvilleol is reported. The total synthesis features the first application of the transition-metal-free coupling of a tosyl hydrazone and a boronic acid to the preparation of a complex natural product, and the first example of this coupling with a hindered diortho substituted hydrazone substrate.
α-Halogenation as a Strategy to Functionalize Cyclohexa-2,4-dienones
Chittimalla, Santhosh Kumar,Koodalingam, Manikandan,Gadi, Vinod Kumar,Anaspure, Prasad
supporting information, p. 475 - 480 (2017/02/24)
A facile pyridine-mediated α-halogenation approach to functionalize cyclohexa-2,4-dienones is developed. A range of reactions, including organometallic coupling protocols, have been applied on these newly obtained halogenated cyclohexa-2,4-dienones, and the results are presented herein.
Highly selective hydrogenation and hydrogenolysis using a copper-doped porous metal oxide catalyst
Petitjean, Laurene,Gagne, Raphael,Beach, Evan S.,Xiao, Dequan,Anastas, Paul T.
, p. 150 - 156 (2015/12/31)
A copper-doped porous metal oxide catalyst in combination with hydrogen shows selective and quantitative hydrogenolysis of benzyl ketones and aldehydes, and hydrogenation of alkenes. The approach provides an alternative to noble-metal catalysed reductions and stoichiometric Wolff-Kishner and Clemmensen methods.
Total synthesis of celastrol, development of a platform to access celastroid natural products
Camelio, Andrew M.,Johnson, Trevor C.,Siegel, Dionicio
supporting information, p. 11864 - 11867 (2015/10/06)
Celastroid natural products, triterpenes, have been and continue to be investigated in clinical trials. Celastrol, and for that matter any member of the celastroid family, was prepared for the first time through chemical synthesis starting from 2,3-dimethylbutadiene. A triene cyclization precursor generated in 12 steps underwent a nonbiomimetic polyene cyclization mediated by ferric chloride to generate the generic celastroid pentacyclic core. In the cyclization, engagement of a tetrasubstituted olefin formed adjacent all carbon quaternary centers stereospecifically. With access to the carbocyclic core of the family of natural products, wilforic acid and wilforol A were prepared en route to racemic celastrol.
Metalloporphyrin-catalyzed aerobic oxidation of 2-methoxy-4-methylphenol as a route to vanillin
Jiang, Qing,Sheng, Wenbing,Guo, Xiangdong,Tang, Jie,Guo, Cancheng
, p. 121 - 126 (2013/06/26)
We report the use of simple metalloporphyrins (T(p-Cl)PPMnCl, T(p-Cl)PPCo, T(p-Cl)PPFeCl, T(p-Cl)PPCu or [T(p-Cl)PPFe]2O) as a catalyst for the direct oxidation of 2-methoxy-4-methylphenol to vanillin with molecular oxygen under mild conditions. The research results showed that the type of metalloporphyrin used, catalyst loading, temperature, reaction time, the amount of NaOH, solvent, the amount of solvent and the flow rate of oxygen influenced the conversion of 2-methoxy-4-methylphenol and the selectivity of vanillin. Under the optimal conditions, the conversion of 2-methoxy-4-methylphenol was up to 87% and the selectivity of vanillin reached 74%. A possible mechanism was also proposed for the present oxidation.
