368-71-8Relevant articles and documents
Photocatalytic Oxidative [2+2] Cycloelimination Reactions with Flavinium Salts: Mechanistic Study and Influence of the Catalyst Structure
Hartman, Tomá?,Reisnerová, Martina,Chudoba, Josef,Svobodová, Eva,Archipowa, Nataliya,Kutta, Roger Jan,Cibulka, Radek
, p. 373 - 386 (2021/02/01)
Flavinium salts are frequently used in organocatalysis but their application in photoredox catalysis has not been systematically investigated to date. We synthesized a series of 5-ethyl-1,3-dimethylalloxazinium salts with different substituents in the positions 7 and 8 and investigated their application in light-dependent oxidative cycloelimination of cyclobutanes. Detailed mechanistic investigations with a coumarin dimer as a model substrate reveal that the reaction preferentially occurs via the triplet-born radical pair after electron transfer from the substrate to the triplet state of an alloxazinium salt. The very photostable 7,8-dimethoxy derivative is a superior catalyst with a sufficiently high oxidation power (E=2.26 V) allowing the conversion of various cyclobutanes (with Eox up to 2.05 V) in high yields. Even compounds such as all-trans dimethyl 3,4-bis(4-methoxyphenyl)cyclobutane-1,2-dicarboxylate can be converted, whose opening requires a high activation energy due to a missing pre-activation caused by bulky adjacent substituents in cis-position.
Synthesis of riboflavines, quinoxalinones and benzodiazepines through chemoselective flow based hydrogenations
Baumann, Marcus,Baxendale, Ian R.,Hornung, Christian H.,Ley, Steven V.,Rojo, Maria Victoria,Roper, Kimberley A.
, p. 9736 - 9759 (2014/08/05)
Robust chemical routes towards valuable bioactive entities such as riboflavines, quinoxalinones and benzodiazepines are described. These make use of modern flow hydrogenation protocols enabling the chemoselective reduction of nitro group containing building blocks in order to rapidly generate the desired amine intermediates in situ. In order to exploit the benefits of continuous processing the individual steps were transformed into a telescoped flow process delivering selected benzodiazepine products on scales of 50 mmol and 120 mmol respectively.
Synthesis and biological evaluation of 5-substituted derivatives of benzimidazole
Vasic, Vesna P.,Penjisevic, Jelena Z.,Novakovic, Irena T.,Sukalovic, Vladimir V.,Andric, Deana B.,Kostic-Rajacic, Sladana V.
, p. 277 - 282 (2014/04/17)
A series of eight novel 5-substituted derivatives of benzimidazole was synthesized by condensation of the corresponding diamine with ethyl 4-[4- -(2-chlorophenyl)piperazin-1-yl]butanoate in refluxing 4 M hydrochloric acid. In vitro antibacterial activity against ten strains, namely Bacillus subtilis, Clostridium sporogenes, Streptosporangium longisporum, Micrococcus flavus, Sarcina lutea, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Salmonella enteritidis and Proteus vulgaris and antifungal activity against two fungal strains, namely Candida albicans and Saccharomyces cerevisiae, were evaluated. Of all the compounds screened for activity, 2-{3-[4-(2-chlorophenyl) piperazin-1-yl]propyl}-5-iodo-1H-benzimidazole and 2-{3-[4-(2-chlorophenyl) piperazin-1-yl]propyl}-5-methyl-1H-benzimidazole were associated with higher antifungal activity than commercial drugs.
