456-04-2Relevant academic research and scientific papers
Facile Synthesis of α-Haloketones by Aerobic Oxidation of Olefins Using KX as Nonhazardous Halogen Source
Luo, Zhibin,Meng, Yunge,Gong, Xinchi,Wu, Jie,Zhang, Yulan,Ye, Long-Wu,Zhu, Chunyin
supporting information, p. 173 - 177 (2020/01/02)
An operationally simple and safe synthesis of α-haloketones using KBr and KCl as nonhazardous halogen sources is reported. It involves an iron-catalysed reaction of alkenes with KBr/KCl using O2 as terminal oxidant under the irradiation of visible-light. This strategy avoids the risks associated with handling halo-contained electrophiles (Cl2, Br2, NCS, NBS). The process is tolerant to several functional groups, and extended to a range of substituted styrenes in up to 89% yield. A radical reaction pathway is proposed based on control experiments and spectroscopy studies.
Efficient acceptorless photo-dehydrogenation of alcohols and: N -heterocycles with binuclear platinum(ii) diphosphite complexes
Zhong, Jian-Ji,To, Wai-Pong,Liu, Yungen,Lu, Wei,Che, Chi-Ming
, p. 4883 - 4889 (2019/05/16)
Although photoredox catalysis employing Ru(ii) and Ir(iii) complexes as photocatalysts has emerged as a versatile tool for oxidative C-H functionalization under mild conditions, the need for additional reagents acting as electron donor/scavenger for completing the catalytic cycle undermines the practicability of this approach. Herein we demonstrate that photo-induced oxidative C-H functionalization can be catalysed with high product yields under oxygen-free and acceptorless conditions via inner-sphere atom abstraction by binuclear platinum(ii) diphosphite complexes. Both alcohols (51 examples), particularly the aliphatic ones, and saturated N-heterocycles (24 examples) can be efficiently dehydrogenated under light irradiation at room temperature. Regeneration of the photocatalyst by means of reductive elimination of dihydrogen from the in situ formed platinum(iii)-hydride species represents an alternative paradigm to the current approach in photoredox catalysis.
Iodine-DMSO-promoted divergent reactivities of arylacetylenes
Rather, Suhail A.,Kumar, Atul,Ahmed, Qazi Naveed
supporting information, p. 4511 - 4514 (2019/04/26)
An unprecedented set of efficient, economical, atom-economic and exceedingly selective I2-DMSO-promoted methods is described for the generation of different structures. The reaction represents the first of its kind, involving the use of different iodine concentrations, temperatures, acids and salt to adjust the selectivity for the synthesis of different alkenes, α-functionalized ketones and α-ketomethylthioesters.
A new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antibacterial agents: Design, synthesis and evaluation acting on microbes, DNA, HSA and topoisomerase IV
Wang, Liang-Liang,Battini, Narsaiah,Bheemanaboina, Rammohan R. Yadav,Ansari, Mohammad Fawad,Chen, Jin-Ping,Xie, Yun-Peng,Cai, Gui-Xin,Zhang, Shao-Lin,Zhou, Cheng-He
, p. 166 - 181 (2019/07/02)
This work did a new exploration towards aminothiazolquinolone oximes as potentially multi-targeting antimicrobial agents. A class of novel hybrids of quinolone, aminothiazole, piperazine and oxime fragments were designed for the first time, conveniently synthesized as well as characterized by 1H NMR, 13C NMR and HRMS spectra. Biological activity showed that some of the synthesized compounds exhibited good antimicrobial activities in comparison with the reference drugs. Especially, O-methyl oxime derivative 10b displayed excellent inhibitory efficacy against MRSA and S. aureus 25923 with MIC values of 0.009 and 0.017 mM, respectively. Further studies indicated that the highly active compound 10b showed low toxicity toward BEAS-2B and A549 cell lines and no obvious propensity to trigger the development of bacterial resistance. Quantum chemical studies have also been conducted and rationally explained the structural features essential for activity. The preliminarily mechanism exploration revealed that compound 10b could not only exert efficient membrane permeability by interfering with the integrity of cells, bind with topoisomerase IV–DNA complex through hydrogen bonds and π-π stacking, but also form a steady biosupramolecular complex by intercalating into DNA to exert the efficient antibacterial activity. The supramolecular interaction between compound 10b and human serum albumin (HSA) was a static quenching, and the binding process was spontaneous, where hydrogen bonds and van der Waals force played vital roles in the supramolecular transportation of the active compound 10b by HSA.
The Mn-catalyzed paired electrochemical facile oxychlorination of styrenes: Via the oxygen reduction reaction
Tian, Siyu,Jia, Xiaofei,Wang, Ling,Li, Baoying,Liu, Siyuan,Ma, Li,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 12104 - 12107 (2019/10/14)
Reported herein is the electrochemical engendering of chlorine radicals by a manganese catalyst with a controllable pattern, and inexpensive MgCl2 as the chlorine source. In combination with the oxygen reduction reaction, chloroacetophenones were synthesized with abundant styrene as the feedstock in good to excellent yields.
CV-driven Optimization: Cobalt-Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR
Tian, Siyu,Lv, Shide,Jia, Xiaofei,Ma, Li,Li, Baoying,Zhang, Guofeng,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 5626 - 5633 (2019/11/22)
Instead of screening reaction conditions by yield-based chemical trial-and-error, potential-based cyclic voltammetry was alternatively employed for optimization of electrochemical oxychlorination of alkenes. With this unconventional screening method, the catalyst system including catalysts, molar ratio of chloride sources and solvents were identified in a rational, time- and energy-efficient manner. The optimal catalytic system in combination with oxygen reduction reaction enabled broad substrate scopes for the desired transformation by taking advantages of persistent radical effect. UV-vis and CV titration experiments confirmed the in-situ formed catalytic species [CoCl5]. Moreover, cyclic voltammetry was applied to obtain mechanistic insights in our reaction system. (Figure presented.).
Novel carbazole-triazole conjugates as DNA-targeting membrane active potentiators against clinical isolated fungi
Zhang, Yuan,Tangadanchu, Vijai Kumar Reddy,Bheemanaboina, Rammohan R. Yadav,Cheng, Yu,Zhou, Cheng-He
, p. 579 - 589 (2018/06/20)
A series of carbazole-triazole conjugates were designed, synthesized and characterized by IR, NMR, and HRMS spectra. Biological assay showed that most of the synthesized compounds exhibited moderate and even strong antifungal activities, especially 3,6-dibromocarbazolyl triazole 5d displayed excellent inhibitory efficacy against most of the tested fungal strains (MIC = 2–32 μg/mL) and effectively fungicidal ability towards C. albicans, C. tropicals and C. parapsilosis ATCC 22019 (MFC = 4–8 μg/mL). Its combination use with fluconazole could enhance the antifungal efficacy, and compound 5d also did not obviously trigger the development of resistance in C. albicans even after 10 passages. Preliminary mechanism study revealed that the active molecule 5d could depolarize fungal membrane potential and intercalate into DNA to possibly block DNA replication, thus possibly exhibiting its powerful antifungal abilities. Conjugate 5d could interact with HSA, which was constructive for the further design, modification and screening of drug molecules. Docking investigation demonstrated a non-covalent binding of 5d with CYP51 through hydrogen bond and hydrophobicity. These results strongly suggested that compound 5d could act as a potential template for the development of promising antifungal drugs.
Mild Homologation of Esters through Continuous Flow Chloroacetate Claisen Reactions
Ganiek, Maximilian A.,Ivanova, Maria V.,Martin, Benjamin,Knochel, Paul
supporting information, p. 17249 - 17253 (2018/12/05)
The selective chloromethylenation of functionalized esters using chloroacetic acid (CA) and LiHMDS (HMDS=hexamethyldisilazide) in a continuous-flow setup is reported. This Claisen homologation is for the first time extended to bis-chloromethylenation using dichloroacetic acid (DCA), thus giving access to under-explored α,α′-bis-chloroketones. The use of flow conditions enables efficient generation and reaction of the unstable chloroacetate dianion intermediates, leading to unprecedented mild and scalable reaction conditions at an economical reagent stoichiometry (?10 °C, 1 min, 1.0–2.4 equiv dianion). The clean reaction profiles allow subsequent use of the unpurified crude products, which is demonstrated in the synthesis of various heterocycles of broad interest. Furthermore, we report a novel, catalyst-free substitution of the obtained monochloro ketone products with (hetero)aryl zinc enolates to give valuable 1,4-diketones.
Iridium-Catalyzed Asymmetric Hydrogenation of Halogenated Ketones for the Efficient Construction of Chiral Halohydrins
Yin, Congcong,Wu, Weilong,Hu, Yang,Tan, Xuefeng,You, Cai,Liu, Yuanhua,Chen, Ziyi,Dong, Xiu-Qin,Zhang, Xumu
supporting information, p. 2119 - 2124 (2018/04/30)
Iridium-catalyzed asymmetric hydrogenation of prochiral halogenated ketones was successfully developed to prepare various chiral halohydrins with high reactivities and excellent enantioselectivities under basic reaction condition (up to >99% conversion, 99% yield, >99% ee). Moreover, gram-scale experiment was performed well in the presence of just 0.005 mol% (S/C=20 000) Ir/f-amphox catalyst with 99% yield and >99% ee. (Figure presented.).
Cascade Trisulfur Radical Anion (S3?-) Addition/Electron Detosylation Process for the Synthesis of 1,2,3-Thiadiazoles and Isothiazoles
Liu, Bei-Bei,Bai, Hui-Wen,Liu, Huan,Wang, Shun-Yi,Ji, Shun-Jun
, p. 10281 - 10288 (2018/07/25)
Trisulfur radical anion (S3?-) mediated reactions with in situ formed azoalkenes and α,β-usaturated N-sulfonylimines for the construction of 1,2,3-thiadiazoles and isothiazoles has been developed. S3?- is in situ generated from potassium sulfide in DMF. These two approaches provide a new, safe, and simple way to construct 4-subsituted 1,2,3-thiadiazoles, 5-subsituted 1,2,3-thiadiazoles, and isothiazole in good yields. The reactions include the formation of the new C-S and N-S bonds via S3?- addition and electron detosylation under mild conditions.
