5533-03-9Relevant articles and documents
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.
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.
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.
