Silica supported dodecatungstophosphoric acid (DTP/SiO<sub>2</sub>): An efficient and recyclable heterogeneous catalyst for rapid synthesis of quinoxalines
作者:Madhav J. Hebade、Tejshri R. Deshmukh、Sambhaji T. Dhumal
DOI:10.1080/00397911.2021.1939060
日期:2021.8.18
Abstract A facile synthesis of quinoxalines by the cyclocondensation of substituted phenacyl bromides with o-pheneylenediamines using silica-supported dodecatungstophosphoric acid (DTP/SiO2) as a recyclableheterogeneouscatalyst is unveiled in this research work. This method is practicable due to environmentally benign, easy workup, high yield, less reaction time, low cost, mild reaction condition
Alzheimer's disease (AD) is a progressive brain disorder which occurs due to lower levels of acetylcholine
(ACh) neurotransmitters, and results in a gradual decline in memory and other cognitive processes. Acetycholinesterase
(AChE) and butyrylcholinesterase (BChE) are considered to be primary regulators of the ACh levels in the brain. Evidence
shows that AChE activity decreases in AD, while activity of BChE does not change or even elevate in advanced
AD, which suggests a key involvement of BChE in ACh hydrolysis during AD symptoms. Therefore, inhibiting the activity
of BChE may be an effective way to control AD associated disorders. In this regard, a series of quinoxaline derivatives
1-17 was synthesized and biologically evaluated against cholinesterases (AChE and BChE) and as well as against α-
chymotrypsin and urease. The compounds 1-17 were found to be selective inhibitors for BChE, as no activity was found
against other enzymes. Among the series, compounds 6 (IC50 = 7.7 ± 1.0 µM) and 7 (IC50 = 9.7 ± 0.9 µM) were found to
be the most active inhibitors against BChE. Their IC50 values are comparable to the standard, galantamine (IC50 = 6.6 ±
0.38 µM). Their considerable BChE inhibitory activity makes them selective candidates for the development of BChE inhibitors.
Structure-activity relationship (SAR) of this new class of selective BChE inhibitors has been discussed.
Synthesis of functionalized benzimidazoles and quinoxalines catalyzed by sodium hexafluorophosphate bound Amberlite resin in aqueous medium
作者:Pranab Ghosh、Amitava Mandal
DOI:10.1016/j.tetlet.2012.09.045
日期:2012.11
for the selective synthesis of 1,2-disubstitutedbenzimidazoles and quinoxalines in water–methanol (1:1) mixture with the aid of resin bound hexafluorophosphate ion as catalyst is reported. The method is also effective for the incorporation of quinoxaline nucleus at the A ring of pentacyclic triterpenoid, friedelin. A plausible mechanism for the formation of disubstituted benzimidazole has also been suggested
General Asymmetric Hydrogenation of 2-Alkyl- and 2-Aryl-Substituted Quinoxaline Derivatives Catalyzed by Iridium-Difluorphos: Unusual Halide Effect and Synthetic Application
A general asymmetric hydrogenation of a wide range of 2-alkyl- and 2-aryl-substituted quinoxaline derivatives catalyzed by an iridium–difluorphos complex has been developed. Under mild reaction conditions, the corresponding biologically relevant 2-substituted-1,2,3,4-tetrahydroquinoxaline units were obtained in high yields and good to excellent enantioselectivities up to 95%. With a catalyst ratio
已开发出由铱-二氟配合物催化的各种2-烷基和2-芳基取代的喹喔啉衍生物的一般不对称氢化反应。在温和的反应条件下,可以以高收率和高达95%的良好至优异的对映选择性获得相应的生物学上相关的2-取代-1,2,3,4-四氢喹喔啉单元。催化剂比为S / C = 1000且以克为单位,Ir-二氟膦配合物的催化活性得以保持,并显示出其潜在价值。最后,我们证明了我们的方法在化合物(S)-9的合成中的应用,该化合物是胆固醇酯转移蛋白(CETP)的抑制剂。
Synthesis of libraries of quinoxalines through eco-friendly tandem oxidation–condensation or condensation reactions
作者:Susmita Paul、Basudeb Basu
DOI:10.1016/j.tetlet.2011.09.141
日期:2011.12
A facile and expeditious solid-phase synthesis of libraries of quinoxalines promoted on KF-alumina surface via tandem oxidation–condensation or condensation reactions is reported. The reaction protocol is operationally simple and mild. Moreover, solvent-free reaction condition makes the reaction procedure eco-friendly and economically viable.