606-43-9Relevant articles and documents
Cyclobutane-cleavage of anti-head-to-head coumarin and quinolinone homo- and cross-dimers via single- and two-photon-absorption photochemistry
Bieniek, Nikolai,Inacker, Sebastian,Kim, Hee-Cheol,Hampp, Norbert
, (2021/04/19)
The light-driven cleavage of cyclobutane containing systems via [2 + 2] cycloreversion, such as di-coumarin, is an important yet poorly investigated photochemical reaction. Its applications can be found in smart crosslinking polymers or light-activated drug release. We report the increased cleavage efficiencies of the coumarins lactam analog quinolinone for single-photon as well as two-photon-absorption experiments. To investigate the structure-function relationship of the molecular substitution pattern and its influence on the photoactivity, a coumarin-quinolinone cross-dimer was synthesized and investigated towards its cleavage efficiencies in single-photon as well as two-photon photocleavage. The cross-dimer shows a lower cleavage efficiency than both homo-dimers. The presented results are of interest, e.g., for applications utilizing highly efficient cleavage reactions in symmetric or asymmetric molecular frameworks.
An organocatalyst bound α-aminoalkyl radical intermediate for controlled aerobic oxidation of iminium ions
Motaleb, Abdul,Bera, Asish,Maity, Pradip
, p. 5081 - 5085 (2018/07/29)
A catalyst bound α-aminoalkyl radical intermediate from iminium is developed to control its formation and reactivity with aerobic oxygen. The influence of the catalyst was demonstrated via the ease of radical intermediate formation and its subsequent reactivity, including the first catalyst-controlled enantioselective aerobic oxidation with a chiral phosphite catalyst.
Metal-free ring expansion of indoles with nitroalkenes: A simple, modular approach to 3-substituted 2-quinolones
Aksenov, Alexander V.,Smirnov, Alexander N.,Aksenov, Nicolai A.,Aksenova, Inna V.,Matheny, Jonathon P.,Rubin, Michael
, p. 8647 - 8656 (2015/03/03)
3-Substituted 2-quinolones are obtained via a novel metal-free transannulation reaction of 2-nitroolefins with 2-substituted indoles in polyphosphoric acid. This acid-mediated cascade transformation operates via the ANRORC (Addition of Nucleophile, Ring Opening, and Ring Closure) mechanism and can be used in combination with the Fisher indole synthesis to offer a practical three-component hetero-annulation approach to 2-quinolones from arylhydrazines, 2-nitroalkenes, and acetophenone. An alternative entry to this chemistry employing the alkylation of electron-rich arenes and hetarenes with 1-(2-indolyl)-2-nitroalkene has also been demonstrated.
Computational assessment of the electronic structure of 1-azacyclohexa-2,3,5-triene (3δ2-1H-pyridine) and its benzo derivative (3δ2-1H-quinoline) as well as generation and interception of 1-methyl-3δ2-1H-quinoline
Schoeneboom, Jan C.,Groetsch, Stefan,Christl, Manfred,Engels, Bernd
, p. 4641 - 4649 (2007/10/03)
Treatment of a solution of 3-bromo-1-methyl-1,2-dihydroquinoline (9) and [18]crown-6 in furan or styrene with KOtBu followed by hydrolysis afforded a mixture of 1-methyl-1,2-dihydroquinoline (10) and 1-methyl-2-quinolone (11). If the reaction was performed in [D8]THF and the mixture was immediately analysed by NMR spectroscopy, 2-tert-butoxy-1-methyl-1,2-dihydroquinoline (17) was shown to be the precursor of 10 and 11. The structure of 17 is evidence for the title cycloallene 7, which arises from 9 by β elimination of hydrogen bromide and is trapped by KOtBu to give 17 so fast that cyclo-additions of 7 with furan or styrene cannot compete. Since this reactivity is unusual compared to the large majority of the known six-membered cyclic allenes, we performed quantum-chemical calculations on 8, which is the parent compound of 7, and the corresponding isopyridine 6 to assess the electronic nature of these species. The ground state of 6 was no longer an allene (6a) but the zwitterion 6b. In the case of 8, the allene structure 8a is more stable than the zwitterionic form 8b by only ≈1 kcal mol-1. These results suggest a high reactivity of 6 and 8 towards nucleophiles and explains the behaviour of 7. In addition to the ground states, the low-lying excited states of 6 and 8 were considered, which are represented by the diradicals 6c and 8c and, as singlets, lie above 6b and 8a by 19.1 - 24. 8 and 14.4-17.7 kcal mol-1, respectively.
The Oxidation of 1-Alkyl(aryl)quinolinium Chlorides with Rabbit Liver Aldehyde Oxidase
Angelino, S. A. F. G.,Valkengoed, B. H. van,Buurman, D. J.,Plas, H. C. van der,Mueller, F.
, p. 107 - 112 (2007/10/02)
1-Alkyl(aryl)quinolinium chlorides are oxidized by rabbit liver aldehyde oxidase at positions C-2 and C-4.The site and the maximum rate of oxidation are dependent on the size and the steric conformation of the N-1 substituent.The presence of a 3-carboxamido group directs the oxidation completely to position C-4, irrespective of the size of the N-substituent.Application of covalent amination in liquid ammonia as an "enzyme model" for the oxidation of these compounds shows little resemblance.
214. Halochromic Molecules. Chromogenic Compounds by Cyclization of heteroarylium Salts: Synthesis and Acidobasis Behaviour
Ziegler, Hugo,Balli, Heinz
, p. 2165 - 2181 (2007/10/02)
Coloured heteroarylium salts are deprotonated to colourless spiro-compounds.The preparation of these products is described and their structure is explained by 1H-NMR and UV/VIS spectroscopy.An investigati
