Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols

Yoshida, Masahito; Fujino, Yuta; Saito, Katsuharu; Doi, Takayuki

doi:10.1016/j.tet.2011.09.063

Cited by 60 publications

(26 citation statements)

References 44 publications

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“…α NF was purchased from Sigma-Aldrich (St. Louis, MO) and recrystallized from hot C 2 H 5 OH (mp 157-158 °C, lit 158-160 °C (Yoshida, Fujino, Saito, & Doi, 2011)) (melting points uncorrected). H 2 O was purified using a Milli-Q system (Millipore, Billerica, MA), and the CH 3 OH solvent used to dissolve P450 3A4 substrates was spectrophotometric or luminescence grade (Sigma-Aldrich).…”

Section: Methodsmentioning

confidence: 99%

7,8-benzoflavone binding to human cytochrome P450 3A4 reveals complex fluorescence quenching, suggesting binding at multiple protein sites

Marsch

Carlson

Guengerich

2017

Journal of Biomolecular Structure and Dynamics

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Human cytochrome P450 (P450) 3A4 is involved in the metabolism of one-half of marketed drugs and shows cooperative interactions with some substrates and other ligands. The interaction between P450 3A4 and the known allosteric effector 7,8-benzoflavone (α-naphthoflavone, αNF) was characterized using steady-state fluorescence spectroscopy. The binding interaction of P450 3A4 and αNF effectively quenched the fluorescence of both the enzyme and ligand. The Hill Equation and Stern-Volmer fluorescence quenching models were used to evaluate binding of ligand to enzyme. P450 3A4 fluorescence was quenched by titration with αNF; at the relatively higher [αNF]/[P450 3A4] ratios in this experiment, two weaker quenching interactions were revealed (Kd 1.7-2.5 μM and 6.5 μM). A range is given for the stronger interaction since αNF quenching of P450 3A4 fluorescence changed the protein spectral profile: quenching of 315 nm emission was slightly more efficient (Kd 1.7 μM) than the quenching of protein fluorescence at 335 and 355 nm (Kd 2.5 and 2.1 μM, respectively). In the reverse titration, αNF fluorescence was quenched by P450 3A4; at the lower [αNF]/[P450 3A4] ratios here, two strong quenching interactions were revealed (Kd 0.048 μM and 1.0 μM). Thus, four binding interactions of αNF to P450 3A4 are suggested by this study, one of which may be newly recognized and which could affect studies of drug oxidations by this important enzyme.

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Section: Methodsmentioning

confidence: 99%

7,8-benzoflavone binding to human cytochrome P450 3A4 reveals complex fluorescence quenching, suggesting binding at multiple protein sites

Marsch

Carlson

Guengerich

2017

Journal of Biomolecular Structure and Dynamics

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“…However, the intramolecular cyclization of o ‐(alkynon‐1‐yl)phenols with K 2 CO 3 occurred competitively by 6‐ endo and 5‐ exo ring cyclization to give flavones and aurones, respectively . The use of triflic acid and a catalytic 4‐(dimethylamino)pyridine predominantly induced 6‐ endo cyclization to provide flavones forming γ‐benzopyranones. The 1,4‐addition of an excess of secondary amines to O ‐TBS protected alkynones in CH 3 OH afforded the corresponding enaminoketones, which underwent cyclization and subsequent elimination to produce flavones under reflux conditions .…”

Section: Methodsmentioning

confidence: 99%

Novel Synthesis of Flavones by Regioselective Cyclization of 1‐(2‐Hydroxyphenyl)‐3‐phenyl‐2‐propyn‐1‐ones Derived from 2‐Hydroxybenzoic Acids

Lee

2017

Bulletin Korean Chem Soc

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“…However, the use of strong acidic or basic conditions, high temperature, long reaction times, poor functional‐group tolerance, and low yield confines its synthetic utility . The regioselective cyclization of the enone system is one of the prominent methods for the preparation of this type of heterocyclic scaffold …”

Section: Introductionmentioning

confidence: 99%

Solvent‐Switchable Regioselective Synthesis of Aurones and Flavones Using Palladium‐Supported Amine‐Functionalized Montmorillonite as a Heterogeneous Catalyst

et al. 2016

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We report the use of Pd0APTES@K10 (APTES=(3‐aminopropyl)triethoxysilane) as a heterogeneous catalyst for the regioselective synthesis of aurones and flavones from the carbonylative cyclization of 2‐iodophenol with terminal alkynes. This work emphasizes the role of the solvent on the mode of cyclization, that is, 5‐exo or 6‐endo. The 5‐exo products (aurones) were predominant over the 6‐endo products (flavones) in 1,2‐dimethoxyethane (DME), and a reversal of regioselectivity was observed in DMF to favor the 6‐endo product. This protocol provides a simple one‐pot access to a wide variety of aurone and flavone derivatives under mild reaction conditions. The heterogeneous Pd0APTES@K10 catalyst was characterized using several techniques. Furthermore, the catalyst could be reused in up to four consecutive cycles without a significant loss in catalytic activity.

show abstract

Regioselective synthesis of flavone derivatives via DMAP-catalyzed cyclization of o-alkynoylphenols

Cited by 60 publications

References 44 publications

7,8-benzoflavone binding to human cytochrome P450 3A4 reveals complex fluorescence quenching, suggesting binding at multiple protein sites

7,8-benzoflavone binding to human cytochrome P450 3A4 reveals complex fluorescence quenching, suggesting binding at multiple protein sites

Novel Synthesis of Flavones by Regioselective Cyclization of 1‐(2‐Hydroxyphenyl)‐3‐phenyl‐2‐propyn‐1‐ones Derived from 2‐Hydroxybenzoic Acids

Solvent‐Switchable Regioselective Synthesis of Aurones and Flavones Using Palladium‐Supported Amine‐Functionalized Montmorillonite as a Heterogeneous Catalyst

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