Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates <i>via</i> C–H Bond Activation

Gadakh, Sunita K.; Dey, Soumen; Sudalai, Arumugam

doi:10.1021/acs.joc.5b01713

Cited by 43 publications

(18 citation statements)

References 62 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…26, 116.54, 118.02, 123.53, 127.43, 128.33, 128.75, 129.29, 139.38, 143.25, 145.29, 154.73, 161.01. HR MS (FAB + , m-NBA): calcd for C 15 Synthesis of AC. The identical procedure used for the synthesis of PC was employed for the synthesis of AC, using 9-anthrylboronic acid in place of phenylboronic acid.…”

Section: Synthetic Methodsmentioning

confidence: 99%

Synthetic control over intra- and intermolecular charge transfer can turn on the fluorescence emission of non-emissive coumarin

et al. 2016

View full text Add to dashboard Cite

Conjugated molecules bearing carbonyl groups typically exhibit weak fluorescence emission due to the presence of a non-radiative n-p* transition state. Strong fluorescence emission from n-p* chromophores has been sought through the use of synthetic approaches that incorporate strong electron donors, such as amines, into the conjugated structures. As an alternative to these existing approaches, we investigated two charge-transfer strategies using a series of 1-benzopyran-2-one (coumarin) derivatives. The first strategy involved attaching chromophoric aryl moieties at the 7 position of coumarin. This molecular control produced two effects: the n-p* transition state was destabilized and an intramolecular charge-transfer (ICT) state was generated. The photoluminescence quantum yields (PLQYs) of the bichromophoric dyads increased with the p-conjugation length of the aryl groups, and a PLQY as high as 0.80 was achieved. The second strategy facilitated exciplex fluorescence in poly(N-vinylcarbazole) (PVK) films within which coumarin derivatives have been molecularly dispersed. A thermodynamic analysis based on electrochemical data indicated that exciplex generation involved electron transfer from PVK to photoexcited coumarin molecules. Exciplex fluorescence was uniquely advantageous in its ability to tune the fluorescence emission color upon addition of electron donors having oxidation potentials less positive than that of PVK. Mechanistic studies, including femtosecond laser flash photolysis, were conducted to identify the molecular parameters that governed the two fluorescence properties. A mechanistic understanding may provide useful insights into the development of electrofluorescent materials that harness triplet as well as singlet excitons. † Electronic supplementary information (ESI) available: Fig. S1-S18 display the predicted isodensity plot of the molecular orbitals, the Lippert-Mataga plot, cyclic and differential pulse voltammograms, UV-vis absorption spectra, photoluminescence spectra obtained at 78 K, photoluminescence decay traces, transient absorption spectra, and copies of 1 H and 13 C NMR spectra; Tables S1 and S2 list the summary of the TD-DFT calculation results and the photophysical data for PMMA films doped with the coumarin compounds. See

show abstract

Section: Synthetic Methodsmentioning

confidence: 99%

Synthetic control over intra- and intermolecular charge transfer can turn on the fluorescence emission of non-emissive coumarin

et al. 2016

View full text Add to dashboard Cite

show abstract

“…Phenols react with beta-keto esters to give coumarins [27]. If phenolic acetates are used, then, acrylates are used [28]. Aromatic alkynoate undergoes cyclisation with aldehydes to form 3-acyl-4-arylcoumarins [29] (Figure 11).…”

Section: Synthesis Of Coumarinsmentioning

confidence: 99%

The Oxygen-Containing Fused Heterocyclic Compounds

Venkatachalam¹,

N²

2020

Heterocycles - Synthesis and Biological Activities

View full text Add to dashboard Cite

The oxygen-containing heterocycles are an important class of compounds in organic chemistry. These compounds are used as drugs (coumarin and oxazole), solvent (tetrahydrofuran), flavors, and fragrances (lactones). The fusion of aromatic ring to the oxygen-heterocycle will change the electron density; thereby, the physical/chemical/biological properties will alter. Also, the preparation of these fused molecules will require a different strategy/method/reaction condition. The topics covered in this chapter are the general synthetic methods and uses of fused heterocyclic compounds containing oxygen as a heteroatom. The derivatization of the primary scaffold is excluded from this chapter. Some of the fused compounds are coumarin (benzopyrans) and piclozotan (benzoxazepines).

show abstract

“…Rh-catalyzed C–H bond activation has also been applied to the synthesis of 4-arylcoumarins. Gadakh et al developed a Rh-catalyed ortho -C–H bond activation of phenolic acetate 26 with acrylate 27 in HCO 2 H [ 69 ]. This methodology worked well even in the presence of a strong electron-withdrawing group.…”

Section: Synthetic Routes Toward Central 2-pyrone Of 4-arylcoumarimentioning

confidence: 99%

Recent Advances in Synthesis of 4-Arylcoumarins

et al. 2018

View full text Add to dashboard Cite

4-Arylcoumarins (4-aryl-2H-1-benzopyran-2-one), also known as neoflavones, comprise a minor subclass of naturally occurring flavonoids. Because of their broad-spectrum biological activities, arylcoumarins have been attracting the attention of the organic and medicinal chemistry communities, and are considered as an important privileged scaffold. Since the development of Pechmann condensation, a classical acid-catalyzed condensation between phenol and β-keto-carboxylic acid, several versatile and efficient synthetic approaches for 4-arylcoumarins have been reported. This review summarizes recent advances in the synthesis of the 4-arylcoumarin scaffold by classifying them based on the final bond-formation type. In particular, synthetic methods executed under mild and highly efficient conditions, such as solvent-free reactions and transition metal catalysis, are highlighted.

show abstract

Rh-Catalyzed Synthesis of Coumarin Derivatives from Phenolic Acetates and Acrylates via C–H Bond Activation

Cited by 43 publications

References 62 publications

Synthetic control over intra- and intermolecular charge transfer can turn on the fluorescence emission of non-emissive coumarin

Synthetic control over intra- and intermolecular charge transfer can turn on the fluorescence emission of non-emissive coumarin

The Oxygen-Containing Fused Heterocyclic Compounds

Recent Advances in Synthesis of 4-Arylcoumarins

Contact Info

Product

Resources

About