1835-11-6Relevant articles and documents
Synthesis of β-O-4-type artificial lignin polymers and their analysis by NMR spectroscopy
Kishimoto, Takao,Uraki, Yasumitsu,Ubukata, Makoto
, p. 2982 - 2987 (2008)
We describe the synthesis and NMR spectroscopic analysis of three artificial lignin polymers containing only the β-O-4 substructure: syringyl-type homopolymer, p-hydroxyphenyl-type homopolymer and guaiacyl/syringyl-type heteropolymer. Using gel permeation chromatography, the weight-average degree of polymerization (DPw) of the three polymers was determined as 19.2, 38.6, and 13.9, respectively. The polymers were prepared based on the synthetic methodology of guaiacyl-type homopolymer, and were fully characterized using 1H-, 13C-, and 1H- 13C NMR spectroscopy of the acetylated and non-acetylated forms. The spectra of guaiacyl/syringyl-type heteropolymers were in good agreement with those of the β-O-4 substructure of milled wood lignin obtained from the hardwood of Japanese white birch. The Royal Society of Chemistry.
Ipomoeassin F Binds Sec61α to Inhibit Protein Translocation
Zong, Guanghui,Hu, Zhijian,O'Keefe, Sarah,Tranter, Dale,Iannotti, Michael J.,Baron, Ludivine,Hall, Belinda,Corfield, Katherine,Paatero, Anja O.,Henderson, Mark J.,Roboti, Peristera,Zhou, Jianhong,Sun, Xianwei,Govindarajan, Mugunthan,Rohde, Jason M.,Blanchard, Nicolas,Simmonds, Rachel,Inglese, James,Du, Yuchun,Demangel, Caroline,High, Stephen,Paavilainen, Ville O.,Shi, Wei Q.
, p. 8450 - 8461 (2019)
Ipomoeassin F is a potent natural cytotoxin that inhibits growth of many tumor cell lines with single-digit nanomolar potency. However, its biological and pharmacological properties have remained largely unexplored. Building upon our earlier achievements
Chromium-Salen Complex/Nitroxyl Radical Cooperative Catalysis: A Combination for Aerobic Intramolecular Dearomative Coupling of Phenols
Nagasawa, Shota,Fujiki, Shogo,Sasano, Yusuke,Iwabuchi, Yoshiharu
, p. 6952 - 6968 (2021/05/29)
We describe an aerobic intramolecular dearomative coupling reaction of tethered phenols using a catalytic system consisting of a chromium-salen (Cr-salen) complex combined with a nitroxyl radical. This novel catalytic system enables formation of various spirocyclic dienone products including those unable to be accessed by previously reported methods efficiently under mild reaction conditions.
Iron-Catalyzed Wacker-type Oxidation of Olefins at Room Temperature with 1,3-Diketones or Neocuproine as Ligands**
Kataeva, Olga,Kn?lker, Hans-Joachim,Linke, Philipp,Puls, Florian
supporting information, p. 14083 - 14090 (2021/05/24)
Herein, we describe a convenient and general method for the oxidation of olefins to ketones using either tris(dibenzoylmethanato)iron(III) [Fe(dbm)3] or a combination of iron(II) chloride and neocuproine (2,9-dimethyl-1,10-phenanthroline) as catalysts and phenylsilane (PhSiH3) as additive. All reactions proceed efficiently at room temperature using air as sole oxidant. This transformation has been applied to a variety of substrates, is operationally simple, proceeds under mild reaction conditions, and shows a high functional-group tolerance. The ketones are formed smoothly in up to 97 % yield and with 100 % regioselectivity, while the corresponding alcohols were observed as by-products. Labeling experiments showed that an incorporated hydrogen atom originates from the phenylsilane. The oxygen atom of the ketone as well as of the alcohol derives from the ambient atmosphere.