1239977-75-3Relevant academic research and scientific papers
Pharmacophore-Directed Retrosynthesis Applied to Ophiobolin A: Simplified Bicyclic Derivatives Displaying Anticancer Activity
Tao, Yongfeng,Reisenauer, Keighley N.,Masi, Marco,Evidente, Antonio,Taube, Joseph H.,Romo, Daniel
, p. 8307 - 8312 (2020)
Pharmacophore-directed retrosynthesis applied to ophiobolin A led to bicyclic derivatives that were synthesized and display anticancer activity. Key features of the ultimate defensive synthetic strategy include a Michael addition/facially selective protonation sequence to set the critical C6 stereocenter and a ring-closing metathesis to form the cyclooctene. Cytotoxicity assays toward a breast cancer cell line (MDA-MB-231) confirm the anticipated importance of structural complexity for selectivity (vs MCF10A cells) while C3 variations modulate stability.
Novel One-Pot Synthetic Method for Propargyl Alcohol Derivatives from Allyl Alcohol Derivatives
Kutsumura, Noriki,Inagaki, Mai,Kiriseko, Akito,Saito, Takao
, p. 1844 - 1850 (2015/06/30)
An efficient one-pot procedure for the synthesis of propargyl alcohol derivatives from allyl alcohol derivatives has been developed. The key to this transformation from a C-C double bond to a C-C triple bond is that hydrogen bromide elimination from 1,2-dibromoalkanes that contain a neighboring oxygen functional group is promoted by the inductive electron-withdrawing effect of the oxygen functional group. In the one-pot reaction, tetrabutylammonium hydroxide was the best base, and the addition of molecular sieves 13X also promoted the reaction.
A modular synthesis of functionalized pyridines through lewis-acid-mediated and microwave-assisted cycloadditions between azapyrylium intermediates and alkynes
Linder, Igor,Gerhard, Markus,Schefzig, Luise,Andrae, Michal,Bentz, Christoph,Reissig, Hans-Ulrich,Zimmer, Reinhold
supporting information; experimental part, p. 6070 - 6077 (2011/12/02)
In this report we describe the synthesis of differentially functionalized pyridine derivatives 3 and the related 3-bromo-substituted pyridines 11. Dissociation of 6H-1,2-oxazine precursors (1a, 1b, 5, 6, or 12) in situ, mediated by boron trifluoride-diethyl ether, generates the azapyrylium intermediates A, which undergo hetero-Diels-Alder reactions with various mono- and disubstituted alkynes 2. In general, these pyridine syntheses proceeded with high efficiencies and were very flexible with respect to all positions in the pyridine cores. For the 3-phenyl-substituted pyridine derivatives 3a-3j and 11a-11f the best results were obtained by a new microwave-assisted protocol, which is clearly superior to the previously used conventional procedure at low temperature in dichloromethane. Furthermore, 3-(trifluoromethyl)- and 3-acryloyl-substituted 6H-1,2-oxazines reacted cleanly under microwave irradiation conditions to furnish the expected pyridine derivatives 3k and 3l in respectable yields. The 3-bromo-substituted pyridines 11 were further functionalized through palladium-catalyzed couplings such as Suzuki or Sonogashira reactions, which led smoothly to tri- or tetrasubstituted pyridine derivatives such as 19-21 and 23. Reductive debromination of 11e afforded the pyridine 17 in excellent yield, whereas oxidation of the pyridinyl thioether 3g with oxone led to the corresponding sulfoxide 24. Our method thus establishes a new and versatile approach to highly substituted pyridine derivatives. A simple method for the modular synthesis of substituted pyridines is disclosed. Microwave-assisted reactions between azapyrylium intermediates (generated in situ) and alkynes afforded the corresponding pyridine derivatives in good to excellent yields. The functional group tolerance in this process is very good and allows a variety of subsequent reactions.
