121247-01-6Relevant articles and documents
Organocatalytic Enantioselective Acyloin Rearrangement of α-Hydroxy Acetals to α-Alkoxy Ketones
Wu, Hua,Wang, Qian,Zhu, Jieping
supporting information, p. 5858 - 5861 (2017/05/12)
We report an unprecedented organocatalytic enantioselective acyloin rearrangement of α,α-disubstituted α-hydroxy acetals. In the presence of a catalytic amount of chiral binol-derived N-triflyl phosphoramide, α-hydroxy acetals rearranged to α-alkoxy ketones in good to high yields with high enantioselectivities. Formation of an ion pair between the in situ generated oxocarbenium ion and the chiral phosphoramide anion was proposed to be responsible for the highly efficient transfer of chirality. Conditions for removal of cyclohexyl and cyclopentyl groups from the corresponding α-alkoxy ketones were uncovered underpinning their potential general utility as hydroxy protecting groups. Conversion of the rearranged products to the enantioenriched α-hydroxy ketone, 1,2-diol, β-amino alcohol and 1,4-dioxane was also documented.
Rh-catalyzed asymmetric hydrogenation of racemic aldimines via dynamic kinetic resolution
Fan, Dongyang,Lu, Jian,Liu, Yang,Zhang, Zhenfeng,Liu, Yangang,Zhang, Wanbin
, p. 5541 - 5547 (2016/08/05)
Catalyzed by a rhodium complex of P-stereogenic diphosphine ligand trichickenfootphos (TCFP), asymmetric hydrogenation of racemic aldimines via dynamic kinetic resolution has been realized for the preparation of chiral arylglycines with good yields and enantioselectivities.
Syntheses, Cholinesterases Inhibition, and Molecular Docking Studies of Pyrido[2,3-b]pyrazine Derivatives
Hameed, Abdul,Zehra, Syeda T.,Shah, Syed J. A.,Khan, Khalid M.,Alharthy, Rima D.,Furtmann, Norbert,Bajorath, Jürgen,Tahir, Muhammad N.,Iqbal, Jamshed
, p. 1115 - 1120 (2015/10/28)
Cholinesterases, acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), have a role in cholinergic deficit which evidently leads to Alzheimer's disease (AD). Inhibition of cholinesterases with small molecules is an attractive strategy in AD therapy. This study demonstrates synthesis of pyrido[2,3-b]pyrazines (6a-6q) series, their inhibitory activities against both cholinesterases, AChE and BChE, and molecular docking studies. The bioactivities data of pyrido[2,3-b]pyrazines showed 3-(3′-nitrophenyl)pyrido[2,3-b]pyrazine 6n a potent dual inhibitor among the series against both AChE and BChE with IC50 values of 0.466 ± 0.121 and 1.89 ± 0.05 μm, respectively. The analogues 3-(3′-methylphenyl)pyrido[2,3-b]pyrazine 6c and 3-(3′-fluorophenyl)pyrido[2,3-b]pyrazine 6f were found to be selective inhibition for BChE with IC50 values of 0.583 ± 0.052 μm and AChE with IC50 value of 0.899 ± 0.10 μm, respectively. Molecular docking studies of the active compounds suggested the putative binding modes with cholinesterases. The potent compounds among the series could potentially serves as good leads for the development of new cholinesterase inhibitors. A series of pyrido[2,3-b]pyrazine (6a-6q) derivatives has been synthesized and evaluated for inhibitory activities against cholinesterases; acetylcholinesterase, and butyrylcholinesterase. Molecular docking of active compounds was also performed to suggest the putative binding modes with cholinesterases.
Synthesis of 2-aroyl-(4 or 5)-aryl-1H-imidazoles and 2-hydroxy-3,6-diaryl- pyrazines via a cascade process
Liu, Cong,Dai, Rong J.,Yao, Guo W.,Deng, Yu L.
, p. 146 - 163 (2014/04/17)
The synthesis of (4 or 5)-aryl-2-aroyl-1H-imidazoles and 2-hydroxy-3,6-diarylpyrazines from aryl methyl ketones via a cascade process of DMSO-HBr oxidation and Debus reaction was investigated. Owing to the simple starting materials, mild conditions, easy operation, high bioactivity of imidazole and pyrazine derivatives, this protocol has great potential in medicinal chemistry.
Iodine-mediated oxidative annulation for one-pot synthesis of pyrazines and quinoxalines using a multipathway coupled domino strategy
Viswanadham, K. K. Durga Rao,Prathap Reddy, Muktapuram,Sathyanarayana, Pochampalli,Ravi, Owk,Kant, Ruchir,Bathula, Surendar Reddy
supporting information, p. 13517 - 13520 (2015/01/09)
An efficient iodine-mediated oxidative annulation of aryl acetylenes-arylethenes-aromatic ketones with 1,2-diamines for the synthesis of pyrazines and regioselective synthesis of quinoxalines is presented. A multipathway coupled domino approach has been developed for the one-pot synthesis of 1,4-diazines with high functional group compatibility.
Quinoxaline derivatives: Novel and selective butyrylcholinesterase inhibitors
Zeb, Aurang,Hameed, Abdul,Khan, Latifullah,Khan, Imran,Dalvandi, Kourosh,Choudhary, M. Iqbal,Basha, Fatima Z.
, p. 724 - 729 (2015/04/14)
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 achymotrypsin 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 ± 1.0μM) 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.
