2270-59-9Relevant articles and documents
Studies in Cephalotaxus Alkaloids. Stereospecific Total Synthesis of Homoharringtonine
Hiranuma, Sayoko,Shibata, Misako,Hudlicky, Tomas
, p. 5321 - 5326 (1983)
The alkaloid ester homoharringtonine (2) was synthesized stereospecifically via the Reformatsky reaction of methyl α-bromoacetate with cephalotaxyl pyruvate (16) obtained by esterification of cephalotaxine with acid chloride derived from 15.The preparations of 2 and its unsaturated derivative 13 are described in detail.Possible explanations of the steric requirements in the esterification of cephalotaxine and of the steric outcome of the Reformatsky reaction leading to 2 and 13 are advanced.
Total synthesis and biological evaluation of the natural product (-)-cyclonerodiol, a new inhibitor of IL-4 signaling
Langhanki, Jens,Rudolph, Kristina,Erkel, Gerhard,Opatz, Till
, p. 9707 - 9715 (2014)
In a screening program of natural compounds from fungi, the known cyclopentanoid sesquiterpene (-)-cyclonerodiol was identified as a specific inhibitor of the IL-4 induced STAT6 signaling pathway (IC50 = 9.7 μM) which is required for the differentiation of naive CD4 T cells to T helper type 2 (Th2) lymphocytes. As many allergic conditions, including allergic asthma and atopic diseases, are driven by an excessive Th2 response, STAT6 is a promising target for the development of new therapeutics. The compound was synthesized in six steps from (-)-linalool using an epoxide radical cyclization as the key step. This journal is
Progress toward the total synthesis of bacchopetiolone: Application of a tandem aromatic oxidation/Diels-Alder reaction
Berube, Amelie,Drutu, Ioana,Wood, John L.
, p. 5421 - 5424 (2006)
A stereoselective synthesis of the bacchopetiolone (1) carbocyclic core using a tandem phenolic oxidation/Diels-Alder reaction is described.
Towards the total synthesis of vibsanin E, 15-O-methylcyclovibsanin B, 3-hydroxyvibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A
Schwartz, Brett D.,Tilly, David P.,Heim, Ralf,Wiedemann, Stefan,Williams, Craig M.,Bernhardt, Paul V.
, p. 3181 - 3192 (2006)
Studies detailing synthetic approaches to a variety of biosynthetically related vibsanin-type diterpenes (i.e. vibsanin E, 15-O-methylcyclovibsanin B, 3-hydroxy-vibsanin E, furanovibsanin A, and 3-O-methylfuranovibsanin A) are discussed. Biogenetically modelled approaches are coupled with an investigation of classical and modern six- to seven-membered ring-expansion protocols, which gain access to the central core of these natural products. Wiley-VCH Verlag GmbH & Co. KGaA, 2006.
Photoredox-Catalyzed Cascade Reactions Involving Aryl Radical: Total Synthesis of (±)-Norascyronone A and (±)-Eudesmol
Xu, Ze-Jun,Liu, Xu-Yuan,Zhu, Ming-Zhu,Xu, Yu-Liang,Yu, Yue,Xu, Hai-Ruo,Cheng, Ai-Xia,Lou, Hong-Xiang
supporting information, p. 9073 - 9077 (2021/12/06)
Herein, we have developed two types of photoredox-catalyzed cascade reactions using diaryliodonium salts for the concise synthesis of norascyronone A and β-eudesmol. A rationally designed photoredox-catalyzed arylation/cyclization/Friedel-Crafts cascade reaction of enone was exploited to generate the norascyronone polycyclic skeleton. A visible-light-induced radical cyclization/acyloxy-migration reaction was explored to forge the decalin skeleton of eudesmol, and mechanistic studies indicated the reaction was initiated by one-electron oxidation of the enol ester.
Incorporation of a FRET pair within a phosphonate diester
Harmon, Nyema M.,Huang, Xueting,Hsiao, Chia-Hung Christine,Wiemer, Andrew J.,Wiemer, David F.
, (2021/06/16)
Cell-cleavable protecting groups are an effective tactic for construction of biological probes because such compounds can improve problems with instability, solubility, and cellular uptake. Incorporation of fluorescent groups in the protecting groups may afford useful probes of cellular functions, especially for payloads containing phosphonates that would be highly charged if not protected, but little is known about the steric or electronic factors that impede release of the payload. In this report we present a strategy for the synthesis of a coumarin fluorophore and a 4-((4-(dimethylamino)phenyl)diazenyl)benzoic acid (DABCYL) ester chromophore incorporated as a FRET pair within a single phosphonate. Such compounds were designed to deliver a BTN3A1 ligand payload to its intracellular receptor. Both final products and some synthetic intermediates were evaluated for their ability to undergo metabolic activation in γδ T cell functional assays, and for their photophysical properties by spectrophotometry. One phosphonate bearing a DABCYL acyloxyester and a novel tyramine-linked coumarin fluorophore exhibited strong, rapid, and potent cellular activity for γδ T cell stimulation and also showed FRET interactions. This strategy demonstrates that bioactivatable phosphonates containing FRET pairs can be utilized to develop probes to monitor cellular uptake of otherwise charged payloads.
AuCl3-Catalyzed Ring-Closing Carbonyl–Olefin Metathesis
Wang, Rui,Chen, Yi,Shu, Mao,Zhao, Wenwen,Tao, Maoling,Du, Chao,Fu, Xiaoya,Li, Ao,Lin, Zhihua
supporting information, p. 1941 - 1946 (2020/02/11)
Compared with the ripeness of olefin metathesis, exploration of the construction of carbon–carbon double bonds through the catalytic carbonyl–olefin metathesis reaction remains stagnant and has received scant attention. Herein, a highly efficient AuCl3-catalyzed intramolecular ring-closing carbonyl–olefin metathesis reaction is described. This method features easily accessible starting materials, simple operation, good functional-group tolerance and short reaction times, and provides the target cyclopentenes, polycycles, benzocarbocycles, and N-heterocycle derivatives in good to excellent yields.
Visible-Light Mediated Hydrosilylative and Hydrophosphorylative Cyclizations of Enynes and Dienes
Chen, Xiaoyun,Hou, Hong,Shi, Yaocheng,Xu, Yue,Yan, Chaoguo,Yang, Haibo,Zhu, Shaoqun
supporting information, (2020/03/04)
Described herein is a visible-light mediated intermolecular radical cyclization approach to access heterocycles. Heteroatom radicals, such as silicon and phosphorus atom radicals, were generated via direct hydrogen atom abstraction by the photoexcited catalyst species with hydro-silanes and phosphine oxides. The radical addition/cyclization/HAT (hydrogen atom transfer) reaction sequences of 1,6-enynes and 1,6-dienes were highly efficient delivering the desired heterocycles in good yields.
Potent double prodrug forms of synthetic phosphoantigens
Harmon, Nyema M.,Hsiao, Chia-Hung Christine,Huang, Xueting,Schladetsch, Megan A.,Wiemer, Andrew J.,Wiemer, David F.
, (2020/08/24)
Phosphoantigens are ligands of BTN3A1 that stimulate anti-cancer functions of γδ T cells, yet the potency of natural phosphoantigens is limited by low cell permeability and low metabolic stability. Derivatives of BTN3A1 ligand prodrugs were synthesized that contain an acetate-protected allylic alcohol and act as doubly protected prodrugs. A novel set of phosphonates, phosphoramidates, and phosphonamidates has been prepared through a new route that simplifies synthesis and postpones the point of divergence into different prodrug forms. One of the new prodrugs, compound 11, potently stimulates γδ T cell proliferation (72 h EC50 = 0.12 nM) and interferon γ response to loaded leukemia cells (4 h EC50 = 19 nM). This phosphonamidate form was > 900x more potent than the corresponding phosphoramidate, and the phosphonamidate form was also significantly more stable in plasma following acetate hydrolysis. Therefore, prodrug modification of phosphonate butyrophilin ligands at the allylic alcohol can both facilitate chemical synthesis and improve potency of γδ T cell stimulation.
Direct Synthesis of Enones by Visible-Light-Promoted Oxygenation of Trisubstituted Olefins Using Molecular Oxygen
Harada, Shinji,Matsuda, Daiki,Morikawa, Takahiro,Nishida, Atsushi
supporting information, p. 1372 - 1377 (2020/10/02)
A one-step synthesis of enones from olefins is described. The reaction was performed under visible-light irradiation in the presence of molecular oxygen and a photocatalyst. The reaction proceeded with various types of trisubstituted olefins to give enones in good yields with high regioselectivity. In particular, oxygen- and nitrogen-containing functional groups, heteroaromatic rings, and cyclopropanes were tolerated. Mechanistic studies and previous reports indicated that the active oxygen species generated in the reaction system is singlet oxygen.
