CuI–Zn(OAc) 2 catalyzed C(sp 2 )–H activation for the synthesis of pyridocoumarins through an uncommon Cu I –Cu III switching mechanism: A fast, solvent-free, combo-catalytic, ball milling approach

Kausar, Nazia; Das, Asish R.

doi:10.1016/j.tetlet.2017.05.074

Cited by 24 publications

(10 citation statements)

References 49 publications

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“…More importantly, the 2p binding energies of Cu atom in ring-closed isomer 4c (951.9 eV for 2p 1/2 and 932.3 for 2p 3/2 ) are almost identical to the values of 4 (952.0 eV for 2p 1/2 and 932.3 for 2p 3/2 ). The lack of satellite peaks typical of shake-up features at higher binding energies further excludes the possibility of Cu(II) or Cu(III) species 26 and confirms the Cu(I) state 27 in ring-closed product 4c. Likewise, the 4f binding energies (76.0 eV for 4f 5/2 and 72.7 eV for 4f 7/2 ) of Pt atoms in both complex 4 and its ring-closed isomer 4c…”

Section: Photochromic Mechanism Studiesmentioning

confidence: 66%

Achieving T-Type Photochromism through Generating Copper(I) Metallacyclopentadiene Biradical

Zhang

Wang

et al. 2022

CCS Chem

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Photochromism due to organometallic ring-closure through CC linkage has not been attained ever before. In this work, we report an initial approach to achieve T-type photochromism by creating metallacyclopentadiene biradical under light irradiation. A class of CuPt 2 phenylacetylide compounds were prepared with distinguished photochromic recyclability and durability, which involve the formation of thermally sensitive copper(I)-butadienyl five-membered ring through copper(I)participated ring-closure. Upon UV light irradiation, metallacyclopentadiene with copper(I) center chelated by 1,3-butadiene-1,4-diyl biradical is generated through photochemical C-C linkage of two face-to-face oriented ethynyl units in close proximity, which gives rise to a drastic change in UV-Vis absorption spectrum. When UV light irradiation is ceased, decoloration occurs through thermal cycloreversion, which endows photochromic CuPt 2 complexes with self-recovery characteristics.Electron paramagnetic resonance (EPR) spectral study confirms a biradical feature of the ring-closed isomer. The thermal decoloration half-lives at ambient temperature are regulated from seconds to hours by increasing F substituents in phenylethynyl ligands.

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Section: Photochromic Mechanism Studiesmentioning

confidence: 66%

Achieving T-Type Photochromism through Generating Copper(I) Metallacyclopentadiene Biradical

Zhang

Wang

et al. 2022

CCS Chem

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“…Recently, A. R. Das and his co‐workers have developed a combo‐catalytic, rapid, solvent‐free, ballmilling method for the synthesis of pyridocoumarins 32 , starting from 3‐amino coumarin 1 , aldehyde (both aryl and heteroayl) 9 and phenyl acetylene 10 via CuI‐catalyzed C(sp2)‐H activation and functionalization (Scheme ). The reaction goes through in‐situgenerated aryl‐Copper(III) intermidiate.…”

Section: Synthesis Of Pyridocoumarinsmentioning

confidence: 99%

A Concise Review on Pyridocoumarin/Azacoumarin Derivatives: Synthesis and Biological Activity

Patra¹

2019

ChemistrySelect

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Coumarins are important due to their versatile bio‐activity. Synthesised pyridocoumarin derivatives show remarkable biological activities including antifungal, antibacterial, antitumor, antiHIV, and antimicrobial activity. The present review aims to review a vast body of literature on different synthetic methodology mainly aza‐Diels Alder reaction, metal catalyzed cyclization and multicomponent reaction and bioactivity of pyridocoumarin derivatives as published during the period from 1997 up to 2017. The synthesised compounds have been reported in literature either by construction of pyridine, pyran or of both ring starting from suitable precursors.

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“…A green ball‐milling protocol was devised for the synthesis of pyridocoumain derivatives using a bimetallic CuI‐Zn(OAc) 2 catalyst system (Scheme ) . Starting with 3‐aminocoumarin, aldehyde and phenylacetylene, the desired product was obtained with 89% yield in 35 min under solvent‐free conditions.…”

Section: Synthesis Of Heterocycles Based On Ring Sizementioning

confidence: 99%

Recent Advances and Perspectives in the Synthesis of HeterocyclesviaZinc Catalysis

et al. 2018

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Among the various metal catalysts, zinc salts have enormous potential due to their availability, low toxicity, eco‐friendliness and inexpensive nature. Biologically zinc is an essential element in our daily lives and it possesses a wide range of applications in pharmaceutical as well as material sciences. In synthetic organic chemistry, the main role of zinc salts is as a Lewis acid catalyst. The importance of the synthesis of heterocycles is attested by the vast number of applications of these compounds in the chemical and pharmaceutical industries. The environmentally benign nature of zinc, its abundance and the Lewis acid character of most of its compounds make it a suitable catalyst for heterocycle synthesis. This is the first review exclusively on zinc‐catalyzed heterocycle synthesis and deals with the recent applications, especially using tandem/domino or one‐pot reaction strategies and covers the literature from 2008 to 2018.

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CuI–Zn(OAc) 2 catalyzed C(sp 2 )–H activation for the synthesis of pyridocoumarins through an uncommon Cu I –Cu III switching mechanism: A fast, solvent-free, combo-catalytic, ball milling approach

Cited by 24 publications

References 49 publications

Achieving T-Type Photochromism through Generating Copper(I) Metallacyclopentadiene Biradical

Achieving T-Type Photochromism through Generating Copper(I) Metallacyclopentadiene Biradical

A Concise Review on Pyridocoumarin/Azacoumarin Derivatives: Synthesis and Biological Activity

Recent Advances and Perspectives in the Synthesis of HeterocyclesviaZinc Catalysis

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