36293-05-7Relevant articles and documents
P(III)-Assisted Electrochemical Access to Ureas via in situ Generation of Isocyanates from Hydroxamic Acids
Meng, Haiwen,Sun, Kunhui,Xu, Zhimin,Tian, Lifang,Wang, Yahui
supporting information, p. 1768 - 1772 (2021/03/26)
An external oxidant-free protocol for the generation of isocyanates from hydroxamic acids assisted by trivalent phosphine under mild electrochemical conditions was reported. The process started with the anodic oxidation of hydroxamic acids, followed by reacting with phosphine to form corresponding alkoxyphosphoniums and subsequent rearrangement with the release of tri-substituted phosphine oxide as the driving force to give isocyanates, which were trapped by N-based nucleophiles to produce various ureas. This method provides a broadly applicable procedure to access isocyanate intermediates under mild electrochemical conditions.
Achiral Derivatives of Hydroxamate AR-42 Potently Inhibit Class i HDAC Enzymes and Cancer Cell Proliferation
Tng, Jiahui,Lim, Junxian,Wu, Kai-Chen,Lucke, Andrew J.,Xu, Weijun,Reid, Robert C.,Fairlie, David P.
, p. 5956 - 5971 (2020/06/05)
AR-42 is an orally active inhibitor of histone deacetylases (HDACs) in clinical trials for multiple myeloma, leukemia, and lymphoma. It has few hydrogen bond donors and acceptors but is a chiral 2-arylbutyrate and potentially prone to racemization. We report achiral AR-42 analogues incorporating a cycloalkyl group linked via a quaternary carbon atom, with up to 40-fold increased potency against human class I HDACs (e.g., JT86, IC50 0.7 nM, HDAC1), 25-fold increased cytotoxicity against five human cancer cell lines, and up to 70-fold less toxicity in normal human cells. JT86 was ninefold more potent than racAR-42 in promoting accumulation of acetylated histone H4 in MM96L melanoma cells. Molecular modeling and structure-activity relationships support binding to HDAC1 with tetrahydropyran acting as a hydrophobic shield from water at the enzyme surface. Such potent inhibitors of class I HDACs may show benefits in diseases (cancers, parasitic infections, inflammatory conditions) where AR-42 is active.
Straightforward formation of carbocations from tertiary carboxylic acids: Via CO release at room temperature
Bartalucci, Niccolò,Pampaloni, Guido,Marchetti, Fabio,Bortoluzzi, Marco,Zacchini, Stefano
supporting information, p. 1574 - 1577 (2019/04/02)
We report an unprecedented mode of reactivity of carboxylic acids. A series of tertiary carboxylic acids, containing at least one phenyl α-substituent, undergo loss of carbon monoxide at room temperature (295 K), by a one pot reaction with 0.5-1 molar equivalents of WCl6 in dichloromethane. A plausible mechanism for the Ph3CCO2H/WCl6 reaction, leading to [CPh3][WOCl5] and Ph3CCl, is proposed on the basis of DFT calculations. The analogous reactions involving CEt(Ph)2CO2H, CMe(Ph)2CO2H and CMe2(Ph)CO2H selectively afforded stable hydrocarbons (alkene or indene, depending on the case), apparently resulting from the rearrangement of elusive tertiary carbocations.
