2400-66-0Relevant articles and documents
Site-Selective trans-Hydrostannation of 1,3- and 1,n-Diynes: Application to the Total Synthesis of Typhonosides E and F, and a Fluorinated Cerebroside Analogue
Mo, Xiaobin,Letort, Aurélien,Ro?ca, Drago?-Adrian,Higashida, Kosuke,Fürstner, Alois
, p. 9667 - 9674 (2018)
Propargyl alcohols are privileged substrates for stereochemically unorthodox trans-hydrostannation reactions catalyzed by [Cp*RuCl]4 (Cp=pentamethylcyclopentadienyl), because an incipient hydrogen bond between the -OH group and the polarized [Ru-Cl] unit assists substrate binding. For this very reason, it is also possible to subject diyne derivatives carrying one -OH group to site-selective stannylation, even if the acetylene units are conjugated and hence, electronically coupled. An unusual temperature dependence was observed in that heating tends to improve site-selectivity, whereas per-stannylation is favored when the reaction is carried out in the cold. This counterintuitive trend can be rationalized based on spectroscopic data; additional support comes from the isolation of the unusual bimetallic complex 11. The bridging fulvene and enynyl ligands in 11 are thought to reflect an interligand redox isomerization process likely triggered by synchronous activation of the 1,3-diyne substrate by two metal centers. The preparative relevance of site-selective trans-hydrostannation is illustrated by the total synthesis of two members of the typhonoside series of glycolipids, which are endowed with neuroprotective properties. Moreover, the preparation of a fluoroalkene sphingosine analogue shows that the tin residue also serves as a versatile handle for late-stage modification of a bioactive target compound.
Synthesis of enantiopure aliphatic acetylene alcohols and determination of their absolute configurations by 1H NMR anisotropy and/or X-ray crystallography
Sekiguchi, Satoshi,Akagi, Megumi,Naito, Junpei,Yamamoto, Yoko,Taji, Hiromi,Kuwahara, Shunsuke,Watanabe, Masataka,Ozawa, Yoshiki,Toriumi, Koshiro,Harada, Nobuyuki
, p. 2313 - 2324 (2008)
The MαNP acid method has been applied to racemic aliphatic acetylene alcohols in order to simultaneously prepare enantiopure alcohols and to determine their absolute configurations by 1H NMR anisotropy. Racemic acetylene alcohols 6-8, 11, and 20 were esterified with MαNP acid (S)-(+)-1 to yield diastereomericMαNP esters which were efficiently separated by HPLC on silica gel with separation factors α in the range 1.60-1.93. The 1H NMR anisotropy factors Δδ [= δ(2nd fr.) - δ(1st fr.)] were calculated from the data of the first- (22a-27a) and second-eluted MαNP esters (22b-27b). The absolute configurations of the first-eluted esters were determined from the distribution of Δδ values in the MαNP sector rule. In the case of MαNP ester 26b, the assigned absolute configuration was confirmed by X-ray crystallography. The solvolysis of MαNP esters yielded enantiopure acetylene alcohols 5-8 with established absolute configurations. Wiley-VCH Verlag GmbH & Co. KGaA, 2008.
Discovery of Anti-TNBC Agents Targeting PTP1B: Total Synthesis, Structure-Activity Relationship, in Vitro and in Vivo Investigations of Jamunones
Hu, Caijuan,Li, Guoxun,Mu, Yu,Wu, Wenxi,Cao, Bixuan,Wang, Zixuan,Yu, Hainan,Guan, Peipei,Han, Li,Li, Liya,Huang, Xueshi
supporting information, p. 6008 - 6020 (2021/05/06)
Twenty-three natural jamunone analogues along with a series of jamunone-based derivatives were synthesized and evaluated for their inhibitory effects against breast cancer (BC) MDA-MB-231 and MCF-7 cells. The preliminary structure-activity relationship revealed that the length of aliphatic side chain and free phenolic hydroxyl group at the scaffold played a vital role in anti-BC activities and the methyl group on chromanone affected the selectivity of molecules against MDA-MB-231 and MCF-7 cells. Among them, jamunone M (JM) was screened as the most effective anti-triple-negative breast cancer (anti-TNBC) candidate with a high selectivity against BC cells over normal human cells. Mechanistic investigations indicated that JM could induce mitochondria-mediated apoptosis and cause G0/G1 phase arrest in BC cells. Furthermore, JM significantly restrained tumor growth in MDA-MB-231 xenograft mice without apparent toxicity. Interestingly, JM could downregulate phosphatidylinositide 3-kinase (PI3K)/Akt pathway by suppressing protein-tyrosine phosphatase 1B (PTP1B) expression. These findings revealed the potential of JM as an appealing therapeutic drug candidate for TNBC.
Acridine Photocatalysis: Insights into the Mechanism and Development of a Dual-Catalytic Direct Decarboxylative Conjugate Addition
Arman, Hadi D.,Dang, Hang T.,Haug, Graham C.,Larionov, Oleg V.,Nguyen, Viet D.,Nguyen, Vu T.,Vuong, Ngan T. H.
, p. 11448 - 11457 (2020/11/17)
Conjugate addition is one of the most synthetically useful carbon-carbon bond-forming reactions; however, reactive carbon nucleophiles are typically required to effect the addition. Radical conjugate addition provides an avenue for replacing reactive nucleophiles with convenient radical precursors. Carboxylic acids can serve as simple and stable radical precursors by way of decarboxylation, but activation to reactive esters is typically necessary to facilitate the challenging decarboxylation. Here, we report a direct, dual-catalytic decarboxylative radical conjugate addition of a wide range of carboxylic acids that does not require acid preactivation and is enabled by the visible light-driven acridine photocatalysis interfaced with an efficient copper catalytic cycle. Mechanistic and computational studies provide insights into the roles of the ligands and metal species in the dual-catalytic process and the photocatalytic activity of substituted acridines.