1615-02-7Relevant articles and documents
Structural elucidation and bioassays of newly synthesized pentavalent antimony complexes
Iftikhar, Tuba,Rauf, Muhammad Khawar,Sarwar, Sidra,Badshah, Amin,Waseem, Durdana,Tahir, Muhammad Nawaz,Khan, Amjad,Khan, Khalid Mohammad,Khan, Gul Majid
, p. 89 - 96 (2017)
Antimony (V) organometallics (1–5) have been synthesized with general formula [SbR′3(O2CR)2], where R' = phenyl, p-tolyl and O2CR are substituted cinnamates. These complexes have been characterized by FT-IR analysis, multinuclear (1H, 13C) NMR spectroscopy and single crystal X-ray diffraction analysis. The crystal structures of [Sb(phenyl)3(4-ClC6H4C2H2O2C)2] (1) and [Sb(p-tol)3(4-OCH3C6H4C2H2O2C)2].CHCl3 (5) displayed distorted geometry between trigonal bipyramidal and square pyramidal with monomeric structure at a five coordinated Sb center. Starting reagents and complexes were evaluated for anticancer, antileishmanial, antibacterial and alpha amylase inhibition potentials. It was observed that complexes 3, 4 and 5 showed significant (p 0.05) antileishmanial and anticancer activities against Leishmania tropica KWH23 promastigotes and HepG2 cell lines respectively. Antibacterial activity of compound 3 was also significant against E. coli (MIC: 5.55 μg/mL), K. pneumoniae (MIC: 16.66 μg/mL), S. aureus (MIC: 5.55 μg/mL) and P. aeruginosa (MIC: 50 μg/mL). Hence, these new antimony complexes can act as good drug candidates.
Ligand-controlled divergent dehydrogenative reactions of carboxylic acids via C–H activation
Wang, Zhen,Hu, Liang,Chekshin, Nikita,Zhuang, Zhe,Qian, Shaoqun,Qiao, Jennifer X.,Yu, Jin-Quan
, p. 1281 - 1285 (2021/12/10)
Dehydrogenative transformations of alkyl chains to alkenes through methylene carbon-hydrogen (C–H) activation remain a substantial challenge. We report two classes of pyridine-pyridone ligands that enable divergent dehydrogenation reactions through palladium-catalyzed b-methylene C–H activation of carboxylic acids, leading to the direct syntheses of a,b-unsaturated carboxylic acids or g-alkylidene butenolides. The directed nature of this pair of reactions allows chemoselective dehydrogenation of carboxylic acids in the presence of other enolizable functionalities such as ketones, providing chemoselectivity that is not possible by means of existing carbonyl desaturation protocols. Product inhibition is overcome through ligand-promoted preferential activation of C(sp3)–H bonds rather than C(sp2)–H bonds or a sequence of dehydrogenation and vinyl C–H alkynylation. The dehydrogenation reaction is compatible with molecular oxygen as the terminal oxidant.
Larvicidal activity and in silico studies of cinnamic acid derivatives against Aedes aegypti (Diptera: Culicidae)
Bezerra Fran?a, Saraliny,Carine Barros de Lima, Luana,Rychard da Silva Cunha, Cristhyan,Santos Anuncia??o, Daniela,Ferreira da Silva-Júnior, Edeildo,Ester de Sá Barreto Barros, Maria,José da Paz Lima, Dimas
, (2021/07/07)
Cinnamic acid derivatives (CAD's) represent a great alternative in the search for insecticides against Aedes aegypti mosquitoes since they have antimicrobial and insecticide properties. Ae. aegypti is responsible for transmitting Dengue, Chikungunya, and Zika viruses, among other arboviruses associated with morbimortality, especially in developing countries. In view of this, in vitro analyses of n-substituted cinnamic acids and esters were performed upon 4th instar larvae (L4) of Ae. aegypti, as well as, molecular docking studies to propose a potential biological target towards this mosquitoes species. The larvicide assays proved that n-substituted ethyl cinnamates showed a more pronounced activity than their corresponding acids, in which p-chlorocinnamate (3j) presented a LC50 value of 8.3 μg/mL. Thusly, external morphologic alterations (rigid and elongated body, curved bowel, and translucent or darkened anal papillae) of mosquitoes’ group exposed to compound 3j, were observed by microscopy. In addition, an analytical method was developed for the quantification of the most promising analog by using high-performance liquid chromatography with UV detection (HPLC-UV). Molecular docking studies suggested that the larvicide action is associated with inhibition of acetylcholinesterase (AChE) enzyme. Therefore, expanding the larvicidal study with the cinnamic acid derivatives against the vector Ae. aegypti is important for finding search for more effective larvicides and with lower toxicity, since they have already shown good larvicidal properties against Ae. aegypti.
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.