31356-11-3Relevant academic research and scientific papers
Unusual Olefinic C-H Functionalization of Simple Chalcones toward Aurones Enabled by the Rational Design of a Function-Integrated Heterogeneous Catalyst
Yatabe, Takafumi,Jin, Xiongjie,Mizuno, Noritaka,Yamaguchi, Kazuya
, p. 4969 - 4978 (2018)
Flavonoids, which are ubiquitous plant secondary metabolites obtained from chalcones, mostly possess 6-membered C-rings derived from 6-endo-trig cyclization of chalcones. However, aurones, which are a class of flavonoids that rarely occur naturally, possess unusual 5-membered C-rings biosynthesized from chalcones by mainly performing B-ring oxidation. Therefore, the chemical catalytic transformation from simple chalcones into aurones is attractive, because it overcomes the drawback of known limited enzyme catalysis. The catalytic transformation, however, has not yet been reported because of the preferential 6-membered ring formation as with the biosynthesis and the need for rare intramolecular olefinic C-H functionalization. Here, we developed the catalytic olefinic C-H functionalization of simple chalcones toward various aurones enabled by the rational design of a function-integrated heterogeneous catalyst - a Pd-on-Au bimetallic nanoparticle catalyst supported on CeO2 - using O2 in air as the sole oxidant without any additives. In this system, the four conditions that were required for the challenging transformation toward aurones were achieved by the respective components of the catalyst: (a) a supported Pd catalyst: a catalyst for the olefinic C-H functionalization of chalcones toward aurones, (b) an Au promoter: an improvement in the catalytic activity by stabilizing Pd(0), (c) a CeO2 support: the inhibition of the 6-endo-trig cyclization utilizing the adsorption of chalcones, and (d) a Pd-on-Au structure: the inhibition of Au-catalyzed flavone synthesis. This catalytic transformation will promote not only the pharmaceutical study of aurones but also the rational design of a heterogeneous catalyst for the development of organic reactions that are not yet realized by homogeneous catalysts or biocatalyst.
A robust three-component synthesis of dispiroheterocycles containing aurone scaffold via 1,3-dipolar cycloaddition reaction of azomethine ylides: regioselectivity and mechanistic overview using DFT calculations
Esmaeeli, Zohreh,Khodabakhshi, Mohammad Reza,Mirjafary, Zohreh,Saeidian, Hamid
, (2021/09/09)
Highly regioselective synthesis of 12 new dispiroheterocycles containing aurone scaffold was reported via a three-component 1,3-dipolar cycloaddition reaction of azomethine ylide and (Z)-2-benzylidene-6-methoxybenzofuran-3(2H)-one derivatives in excellent yields (60–94%). The structures of all the desired products were fully confirmed by 1H NMR, 13C NMR, and FT-IR spectral data and CHN elemental analysis. In the second part of the paper, the 1,3-dipolar cycloaddition reaction between N-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-N-methylmethanideaminium II as a 1,3-dipole and 2-benzylidene-6-methoxybenzofuran-3(2H)-one III as a dipolarophile was studied theoretically using density functional theory (DFT) at the B3LYP/6–31 + + G(d, p) computational level to shed light on the regioselective and mechanistic aspects. Two possible routes for the reaction were considered, and the regioselectivity was also studied. The DFT results showed that the high regioselectivity is in complete agreement with the experimental results.
Transition-metal-free synthesis of polysubstituted pyrrole derivatives via cyclization of methyl isocyanoacetate with aurone analogues
Wang, Zhi-Peng,He, Yun,Shao, Pan-Lin
supporting information, p. 5422 - 5426 (2018/08/12)
Presented herein is an unprecedented transition-metal-free cyclization of methyl isocyanoacetate with aurone analogues catalyzed by NaOH. Various 2,3,4-trisubstituted pyrroles were obtained in excellent yields (up to 99%). The high efficiency of this synthetic procedure, coupled with the operational simplicity and atom economy, makes it an attractive method for the synthesis of polysubstituted pyrroles.
Catalytic Asymmetric [3 + 2] Cycloaddition Reaction between Aurones and Isocyanoacetates: Access to Spiropyrrolines via Silver Catalysis
Wang, Zhi-Peng,Xiang, Sichuan,Shao, Pan-Lin,He, Yun
, p. 10995 - 11007 (2018/07/21)
The first enantioselective formal [3 + 2] cycloaddition of aurone analogues with isocyanoacetates was developed via chiral Ag-complex catalysis. A variety of optically enriched spiro-1-pyrrolines were obtained in excellent yields, diastero- and enantioselectivities (up to 99% yield, >20:1 dr, >99% ee). This synthetic approach represents an extremely simple, efficient, and atom-economical method for spiro-1-pyrrolines synthesis.
"On water" synthesis of aurones: First synthesis of 4,5,3',4',5'-pentamethoxy-6-hydroxyaurone from Smilax riparia
Venkateswarlu, Somepalli,Murty, Gandrotu Narasimha,Satyanarayana, Meka
, p. 303 - 314 (2017/06/19)
A simple and green method for the synthesis of aurones by condensation of benzofuranone with aromatic aldehyde in neat water has been developed. The main advantages of this protocol include good yields, absence of catalyst, reagent, organic solvent, work-up and chromatographic purification. 4,5,3',4',5'-Pentamethoxy-6-hydroxyaurone, isolated from Smilax riparia was synthesized for the first time from 3-benzyloxy-4,5-dimethoxybenzaldehyde in five steps. {figure presented}.
An efficient synthesis of aurone derivatives by the tributylphosphine-catalyzed regioselective cyclization of o-alkynoylphenols
Saito, Koya,Yoshida, Masahito,Doi, Takayuki
supporting information, p. 141 - 143 (2015/02/19)
An organocatalytic regioselective synthes is of aurones from o-alkynoylphenols was achieved. A catalytic amount of tributylphosphine select ively induced the 5-exo cyclization of o-alkynoylphenols under ambient conditions leading to aurone derivatives in high to excellent yields.
In vitro inhibitory properties of ferrocene-substituted chalcones and aurones on bacterial and human cell cultures
Tiwari, Keshri Nath,Monserrat, Jean-Philippe,Hequet, Arnaud,Ganem-Elbaz, Carine,Cresteil, Thierry,Jaouen, Gerard,Vessieres, Anne,Hillard, Elizabeth A.,Jolivalt, Claude
experimental part, p. 6451 - 6457 (2012/09/21)
Two series of ten chalcones and ten aurones, where ferrocene replaces the C ring and with diverse substituents on the A ring were synthesized. The compounds were tested against two antibiotic-sensitive bacterial strains, E. coli ATCC 25922 and S. aureus ATCC 25923, and two antibiotic-resistant strains, S. aureus SA-1199B and S. epidermidis IPF896. The unsubstituted compound and those with methoxy substitution showed an inhibitory effect on all bacterial strains at minimum inhibitory concentrations ranging between 2 and 32 mg L -1. For four of these compounds, the effect was bactericidal, as opposed to bacteriostatic. The corresponding organic aurones did not show growth inhibition, underscoring the role of the ferrocene group. The methoxy-substituted aurones and the unsubstituted aurone also showed low micromolar (IC50) activity against MRC-5 non-tumoral lung cells and MDA-MB-231 breast cancer cells, suggesting non-specific toxicity.
Synthesis of 2-(p-Chlorobenzyl)-3-aryl-6-methoxybenzofurans as Selective Ligands for Antiestrogen-Binding Sites. Effects on Cell Proliferation and Choresterol Synthesis
Teo, Chin Chin,Kon, Oi Lian,Sim, Keng Yeow,Ng, Siu Choon
, p. 1330 - 1339 (2007/10/02)
A series of nonsteroidal compounds, 2-(p-chlorobenzyl)-3-aryl-6-methoxybenzofurans derived from the 2-(p-chlorobenzyl)-6-methoxy-3(2H)-benzofuranones has been synthesized.The key steps in the synthesis were reactions of 2-(p-chlorobenzyl)-6-methoxy-3(2H)-benzofuranones with the arylorganometallic reagents followed by dehydration of the resulting carbinols.The benzofurans are ligands for antiestrogen-binding sites (AEBS) and display no significant interaction with the estrogen receptor (ER).All bind to AEBS with equivalent or greater affinity than tamoxifen.These compounds decrease thymidine incorporation in AEBS-containing EL4 lymphoid cells and MCF7 breast cancer cells in a concentration-dependent manner between 10-8 and 10-6 M and are generally more inhibitory than tamoxifen.In contrast, they have no effect on thymidine incorporation by an AEBS-deficient variant of the MCF7 cell line, RTx6.The present findings of (1) selective and high affinity binding of the benzofurans to AEBS, (2) their concentration-dependent inhibition of thymidine incorporation in AEBS-containing cells, and (3) their lack of antiproliferative effect in an AEBS-deficient cell line suggest a functional role for AEBS in mediating the antigrowth effect of these compounds.Two of the more active benzofuran compounds also significantly inhibited de novo cholesterol biosynthesis in EL4 cells which lack ER.This effect could be obtained after 5 h of treatment and preceded significant loss of cell viability.This is the first demonstration that selective ligands of AEBS (other than the known nonsteroidal antiestrogens) interfere with cholesterol biosynthesis - an action that may contribute to their antigrowth effect.
Preparative and Regiochemical Aspects of the Palladium-Catalyzed Carbonylative Coupling of 2-Hydroxyaryl Iodides with Ethynylarenes
Ciattini, Pier Giuseppe,Morera, Enrico,Ortar, Giorgio,Rossi, Sabina Strano
, p. 6449 - 6456 (2007/10/02)
The title reaction has been conveniently carried out in DMF at 60 deg C under 1 atm CO pressure using DBU as the base and Pd(OAc)2(DPPF)2 as the catalyst to afford generally mixtures of flavones 4 and aurones 5 in varying yields, depending on the substituents in the both reactants.Factors controlling the regioselectivity for 4 or 5 formation in this and in similar, previously reported, coupling procedures have been examined.
Intramolecular Cyclisation Catalysed by Silver(I) Ion; a Convenient Synthesis of Aurones
Jong, Ting-Ting,Leu, Shang-Jen
, p. 423 - 424 (2007/10/02)
Silver(I) ion catalysed intramolecular cyclisation of (1a-d) at room temperature gives corresponding aurone (2a-d) as the major product with a trace amount of the flavone; compounds (1a-d) could be prepared by the addition of the corresponding lithium acetylide (4a-b) to the substituted salicyl aldehyde (5a-c), followed by MnO2 oxidation.
