180261-48-7Relevant academic research and scientific papers
β-Cyclodextrin as a scaffold for supramolecular chemistry, to reverse the regioselectivity of nitrile oxide cycloadditions
Meyer, Adam G.,Easton, Christopher J.,Lincoln, Stephen F.,Simpson, Gregory W.
, p. 9069 - 9075 (1998)
β-Cyclodextrin has been used as a molecular scaffold, whereby tethering dipolarophiles to the cyclodextrin and then allowing preassociation of the modified cyclodextrins with aromatic nitrile oxides, as host-guest complexes, controls the relative orientations of the dipoles and the dipolarophiles in their cycloadditions. In this manner it has been possible to reverse the usual regioselectivity of cycloadditions of nitrile oxides, as illustrated by reactions with a terminal alkene, a terminal alkyne, and a 1,2-disubstituted alkene. For example, in aqueous solution, 4-tertbutylbenzonitrile oxide reacted with 6(A)-deoxy-6(A)-propynamido-β-cyclodextrin to give the corresponding 4- and 5-substituted isoxazoles, in a 15:1 ratio. With DMF as the solvent, to reduce the extent of host-guest complexation, the product ratio was 1:1.5. The role of complexation in these reactions is also demonstrated by contrasting these results with that of the reaction of the nitrile oxide with methyl propynoate, which afforded only the 5-substituted cycloaddition product. Molecular recognition by the cyclodextrin scaffolds was demonstrated through treatment of 4-tertbutylbenzonitrile oxide with an equimolar mixture of 6(A)-deoxy-6(A)-propynamido-β-cyclodextrin and methyl propynoate, in aqueous solution, which gave only the cycloadducts from reaction of the cyclodextrin dipolarophile.
Electrochemical synthesis of 1,2,4-oxadiazoles from amidoximes through dehydrogenative cyclization
Hu, Aixi,Jiang, chan,Li, mingfang,Xu, Leitao,Ye, Jiao,Yi, Yangjie
supporting information, p. 10611 - 10616 (2021/12/27)
A convenient and efficient method for the generation of the iminoxy radical through anodic oxidation was developed for the synthesis of 3,5-disubstituted 1,2,4-oxadiazoles fromN-benzyl amidoximes. The transformation proceeds through 1.5-Hydrogen Atom Transfer (1,5-HAT) and intramolecular cyclization. The process features simple operation, mild conditions, broad substrate scope and high functional group compatibility, and provides a facile and practical way for the preparation of 1,2,4-oxadiazoles.
Anodic Oxidation of Aminotetrazoles: A Mild and Safe Route to Isocyanides
Leech, Matthew C.,Petti, Alessia,Tanbouza, Nour,Mastrodonato, Andrea,Goodall, Iain C. A.,Ollevier, Thierry,Dobbs, Adrian P.,Lam, Kevin
supporting information, p. 9371 - 9375 (2021/12/09)
A new electrochemical method for the preparation of isocyanides from easily accessible aminotetrazole derivatives has been developed, which tolerates an unprecedented range of functional groups. The use of chemical, rather than electrochemical, oxidation to afford isocyanides was also demonstrated, which provides access to these compounds for those without electrosynthesis equipment. The practicality of scale-up using flow electrochemistry has been demonstrated, in addition to the possibility of using electrochemically generated isocyanides in further reactions.
SO2F2-Mediated one-pot cascade process for transformation of aldehydes (RCHO) to cyanamides (RNHCN)
Ding, Chengrong,Ge, Shuting,Wei, Junjie,Zhang, Guofu,Zhao, Yiyong
, p. 17288 - 17292 (2020/05/18)
A simple, mild and practical cascade process for the direct conversion of aldehydes to cyanamides was developed featuring a wide substrate scope and great functional group tolerability. This method allows for transformations of readily available, inexpensive, and abundant aldehydes to highly valuable cyanamides in a pot, atom, and step-economical manner with a green nitrogen source. This protocol will serve as a robust tool for the installation of the cyanamide moiety in various complicated molecules.
Design, synthesis of novel 4,5-dihydroisoxazole-containing benzamide derivatives as highly potent FtsZ inhibitors capable of killing a variety of MDR Staphylococcus aureus
Song, Di,Bi, Fangchao,Zhang, Nan,Qin, Yinhui,Liu, Xingbang,Teng, Yuetai,Ma, Shutao
supporting information, (2020/09/11)
Antibiotic resistance among clinically significant bacterial pathogens, such as methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant S. aureus (VRSA) is becoming a prevalent threat to public health, and new antibacterial agents with novel mechanisms of action hence are in an urgent need. As a part of continuing effort to develop antibacterial agents, we rationally designed and synthesized two series of 4,5-dihydroisoxazol-5-yl and 4,5-dihydroisoxazol-3-yl-containing benzamide derivatives that targeted the bacterial cell division protein FtsZ. Evaluation of their activity against a panel of Gram-positive and -negative pathogens revealed that compound A16 possessing the 4,5-dihydroisoxazol-5-yl group showed outstanding antibacterial activity (MIC, ≤0.125–0.5 μg/mL) against various testing strains, including methicillin-resistant, penicillin-resistant and clinical isolated S. aureus strains. Besides, further mouse infection model revealed that A16 could be effective in vivo and non-toxic to Hela cells. Finally, a detailed discussion of structure-activity relationships was conducted, referring to the docking results. It is worth noting that substituting a 4,5-dihydroisoxazole ring for the isoxazole ring not only broadened the antibacterial spectrum but also resulted in a significant increase in antibacterial activity against S. aureus strains. Taken together, these results suggest a promising chemotype for the development of new FtsZ-targeting bactericidal agents.
Vilsmeier-Haack reagent mediated synthetic transformations with an immobilized iridium complex photoredox catalyst
Zhi, Peng,Xi, Zi-Wei,Wang, Dan-Yan,Wang, Wei,Liang, Xue-Zheng,Tao, Fei-Fei,Shen, Run-Pu,Shen, Yong-Miao
supporting information, p. 709 - 717 (2019/01/10)
An immobilized iridium complex photocatalyst Ir(ppy)2(PDVB-py) was synthesized by immobilization of the iridium complex onto the nanoporous vinylpyridine-divinylbenzene copolymer (PDVB-py). Its application for the synthesis of amides, nitriles, and anhydrides was reported via reactions under the action of the visible-light-driven in situ generated Vilsmeier-Haack reagent from CBr4 in DMF. The results showed that this heterogeneous photocatalyst has extremely high activity and excellent stability to be recycled five times.
Leaving Group Assisted Strategy for Photoinduced Fluoroalkylations Using N-Hydroxybenzimidoyl Chloride Esters
Zhang, Weigang,Zou, Zhenlei,Wang, Yuanheng,Wang, Yi,Liang, Yong,Wu, Zhengguang,Zheng, Youxuan,Pan, Yi
supporting information, p. 624 - 627 (2018/12/13)
Redox-active esters (RAEs) as alkyl radical precursors have been extensively developed for C?C bond formations. However, the analogous transformations of fluoroalkyl radicals from the corresponding acid or ester precursors remain challenging because of the high oxidation potential of the fluoroalkyl carboxylate anions. The newly developed N-hydroxybenzimidoylchloride (NHBC) ester provides a general leaving group assisted strategy to generate a portfolio of fluoroalkyl radicals, and can be successfully applied in photoinduced decarboxylative hydrofluoroalkylation and heteroarylation of unactivated olefins. In addition, DFT calculations revealed that the NHBC ester proceeds by the fluorocarbon radical pathway, whereas other well-known RAEs proceed by the nitrogen radical pathway.
Betulinic acid derivatives: a new class of α-glucosidase inhibitors and LPS-stimulated nitric oxide production inhibition on mouse macrophage RAW 264.7 cells
Gundoju, Narayanarao,Bokam, Ramesh,Yalavarthi, Nageswara Rao,Azad, Rajaram,Ponnapalli, Mangala Gowri
supporting information, p. 2618 - 2622 (2018/04/30)
Chemical manipulation studies were conducted on betulinic acid (1), twenty-one new rationally designed analogues of 1 with modifications at C-28 were synthesized for their evaluation of inhibitory effects on α-glucosidase and LPS-stimulated nitric oxide production in mouse macrophage RAW 264.7 cells. Compound 2 (IC50 = 5.4 μM) exhibited an almost 1.4-fold increase in α-glucosidase inhibitory activity on yeast α-glucosidase while analogues 5 (IC50 16.4 μM) and 11 (IC50 16.6 μM) exhibited a 2-fold enhanced inhibitory activity on NO-production than betulinic acid.
Continuous Platform to Generate Nitroalkanes On-Demand (in Situ) Using Peracetic Acid-Mediated Oxidation in a PFA Pipes-in-Series Reactor
Tsukanov, Sergey V.,Johnson, Martin D.,May, Scott A.,Kolis, Stanley P.,Yates, Matthew H.,Johnston, Jeffrey N.
supporting information, p. 971 - 977 (2018/08/28)
The synthetic utility of the aza-Henry reaction can be diminished on scale by potential hazards associated with the use of peracid to prepare nitroalkane substrates and the nitroalkanes themselves. In response, a continuous and scalable chemistry platform to prepare aliphatic nitroalkanes on-demand using the oxidation of oximes with peracetic acid and direct reaction of the nitroalkane intermediate in an aza-Henry reaction is reported. A uniquely designed pipes-in-series plug-flow tube reactor addresses a range of process challenges, including stability and safe handling of peroxides and nitroalkanes. The subsequent continuous extraction generates a solution of purified nitroalkane, which can be directly used in the following enantioselective aza-Henry chemistry to furnish valuable chiral diamine precursors with high selectivity, thus completely avoiding isolation of the potentially unsafe low-molecular-weight nitroalkane intermediate. A continuous campaign (16 h) established that these conditions were effective in processing 100 g of the oxime and furnishing 1.4 L of nitroalkane solution.
Design, synthesis and structure-based optimization of novel isoxazole-containing benzamide derivatives as FtsZ modulators
Bi, Fangchao,Song, Di,Zhang, Nan,Liu, Zhiyang,Gu, Xinjie,Hu, Chaoyu,Cai, Xiaokang,Venter, Henrietta,Ma, Shutao
, p. 90 - 103 (2018/10/04)
Antibiotic resistance among clinically significant bacterial pathogens is becoming a prevalent threat to public health, and new antibacterial agents with novel mechanisms of action hence are in an urgent need. Utilizing computational docking method and structure-based optimization strategy, we rationally designed and synthesized two series of isoxazol-3-yl- and isoxazol-5-yl-containing benzamide derivatives that targeted the bacterial cell division protein FtsZ. Evaluation of their activity against a panel of Gram-positive and -negative pathogens revealed that compounds B14 and B16 that possessed the isoxazol-5-yl group showed strong antibacterial activity against various testing strains, including methicillin-resistant Staphylococcus aureus and penicillin-resistant S. aureus. Further molecular biological studies and docking analyses proved that the compound functioned as an effective inhibitor to alter the dynamics of FtsZ self-polymerization via a stimulatory mechanism, which finally terminated the cell division and caused cell death. Taken together, these results could suggest a promising chemotype for development of new FtsZ-targeting bactericidal agent.
