- Broadening antifungal spectrum and improving metabolic stablity based on a scaffold strategy: Design, synthesis, and evaluation of novel 4-phenyl-4,5-dihydrooxazole derivatives as potent fungistatic and fungicidal reagents
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5-phenylthiophene derivatives exhibited excellent antifungal activity against Candida albicans, Candida tropicalis and Cryptococcus neoformans. However, optimal compound 7 was inactive against Aspergillus fumigatus and unstable in human liver microsomes in vitro with a half-life of 18.6 min. To discover antifungal agents with a broad spectrum and improve the metabolic properties of the compounds, the scaffold hopping strategy was adopted and a series of 4-phenyl-4,5-dihydrooxazole derivatives were designed and synthesized. It was especially encouraging that compound 22a displayed significant antifungal activities against eight susceptible strains and seven FLC-resistant strains. Furthermore, the potent compound 22a could prevent the formation of fungalbiofilms and displayed satisfactory fungicidal activity. In addition, the metabolic stability of compound 22a was improved significantly, with the half-life of 70.5 min. Compound 22a was almost nontoxic to mammalian A549, MCF-7, HepG2, and 293T cells. Moreover, pharmacokinetic studies in SD rats showed that compound 22a exhibited pharmacokinetic properties with a bioavailability of 15.22% and a half-life of 4.44 h, indicating that compound 22a is worthy of further study.
- Cheng, Maosheng,Cui, Hengxian,Jiang, Hong,Liu, Lei,Su, Xin,Sun, Yin,Wu, Tianxiao,Yin, Wenbo,Zhang, Yuxin,Zhao, Dongmei,Zhao, Liyu
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- Integrating Hydrogen Production and Transfer Hydrogenation with Selenite Promoted Electrooxidation of α-Nitrotoluenes to E-Nitroethenes
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Developing an electrochemical carbon-added reaction with accelerated kinetics to replace the low-value and sluggish oxygen evolution reaction (OER) is markedly significant to pure hydrogen production. Regulating the critical steps to precisely design electrode materials to selectively synthesize targeted compounds is highly desirable. Here, inspired by the surfaced adsorbed SeOx2? promoting OER, NiSe is demonstrated to be an efficient anode enabling α-nitrotoluene electrooxidation to E-nitroethene with up to 99 % E selectivity, 89 % Faradaic efficiency, and the reaction rate of 0.25 mmol cm?2 h?1 via inhibiting side reactions for energy-saving hydrogen generation. The high performance can be associated with its in situ formed NiOOH surface layer and absorbed SeOx2? via Se leaching-oxidation during electrooxidation, and the preferential adsorption of two -NO2 groups of intermediate on NiOOH. A self-coupling of α-carbon radicals and subsequent elimination of a nitrite molecule pathway is proposed. Wide substrate scope, scale-up synthesis of E-nitroethene, and paired productions of E-nitroethene and hydrogen or N-protected aminoarenes over a bifunctional NiSe electrode highlight the promising potential. Gold also displays a similar promoting effect for α-nitrotoluene transformation like SeOx2?, rationalizing the strategy of designing materials to suppress side reactions.
- Chong, Xiaodan,Liu, Cuibo,Wang, Changhong,Yang, Rong,Zhang, Bin
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supporting information
p. 22010 - 22016
(2021/09/02)
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- Conversion of nitroalkanes into carboxylic acids via iodide catalysis in water
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We report a new method for the conversion of nitroalkanes into carboxylic acids that achieves this transformation under very mild conditions. Catalytic amounts of iodide in combination with a simple zinc catalyst are needed to give good conversions into the corresponding carboxylic acids.
- Marcé, Patricia,Lynch, James,Blacker, A. John,Williams, Jonathan M. J.
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supporting information
p. 1013 - 1016
(2016/01/16)
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- Organocatalytic, diastereo- and enantioselective synthesis of nonsymmetric cis -stilbene diamines: A platform for the preparation of single-enantiomer cis -imidazolines for protein-protein inhibition
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The finding by scientists at Hoffmann-La Roche that cis-imidazolines could disrupt the protein-protein interaction between p53 and MDM2, thereby inducing apoptosis in cancer cells, raised considerable interest in this scaffold over the past decade. Initial routes to these small molecules (i.e., Nutlin-3) provided only the racemic form, with enantiomers being enriched by chromatographic separation using high-pressure liquid chromatography (HPLC) and a chiral stationary phase. Reported here is the first application of an enantioselective aza-Henry approach to nonsymmetric cis-stilbene diamines and cis-imidazolines. Two novel mono(amidine) organocatalysts (MAM) were discovered to provide high levels of enantioselection (>95% ee) across a broad range of substrate combinations. Furthermore, the versatility of the aza-Henry strategy for preparing nonsymmetric cis-imidazolines is illustrated by a comparison of the roles of aryl nitromethane and aryl aldimine in the key step, which revealed unique substrate electronic effects providing direction for aza-Henry substrate-catalyst matching. This method was used to prepare highly substituted cis-4,5-diaryl imidazolines that project unique aromatic rings, and these were evaluated for MDM2-p53 inhibition in a fluorescence polarization assay. The diversification of access to cis-stilbene diamine-derived imidazolines provided by this platform should streamline their further development as chemical tools for disrupting protein-protein interactions.
- Vara, Brandon A.,Mayasundari, Anand,Tellis, John C.,Danneman, Michael W.,Arredondo, Vanessa,Davis, Tyler A.,Min, Jaeki,Finch, Kristin,Guy, R. Kiplin,Johnston, Jeffrey N.
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p. 6913 - 6938
(2014/08/18)
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- Kinetic study of proton-transfer reactions of phenylnitromethanes. Implication for the origin of nitroalkane anomaly
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Measurements of rate constants and substituent effects for three important elementary steps of proton-transfer reactions of phenylnitromethane were reported. The Hammett ? values for the deprotonation of ArCH2NO 2 with OH-
- Ando, Kenichi,Shimazu, Yu,Seki, Natsuko,Yamataka, Hiroshi
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supporting information; experimental part
p. 3937 - 3945
(2011/07/08)
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- Nitration of alkanes with nitric acid by vanadium-substituted polyoxometalates
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The nitration of alkanes by using nitric acid as a nitrating agent in acetic acid was efficiently promoted by vanadium-substituted Keggin-type phosphomolybdates such as [H4PVMo11O40], [H5PV2Mo10O40], and [H 6PV3Mo9O40] as catalyst precursors. A variety of alkanes including alkylbenzenes were nitrated to the corresponding nitroalkanes as major products in moderate yields with formation of oxygenated products under mild reaction conditions. The carbon-carbon bond cleavage reactions hardly proceeded. ESR, NMR, and IR spectroscopic data show that the vanadium-substituted polyoxometalate, for example, [H4PVMo 11O40], decomposes to form free vanadium species and [PMo12O40]3- Keggin anion. The reaction mechanism involving a radical-chain path is proposed. The polyoxometalates initially abstract the hydrogen of the alkane to form the alkyl radical and the reduced polyoxometalates. The reduced polyoxometalates subsequently react with nitric acid to produce the oxidized form and nitrogen dioxide. This step would be promoted mainly by the phosphomolybdates, [PMo12O 40]n-, and the vanadium cations efficiently enhance the activity. The nitrogen dioxide promotes the further formation of nitrogen dioxide and an alkyl radical. The alkyl radical is trapped by nitrogen dioxide to form the corresponding nitroalkane.
- Shinachi, Satoshi,Yahiro, Hidenori,Yamaguchi, Kazuya,Mizuno, Noritaka
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p. 6489 - 6496
(2007/10/03)
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- [VO(H2O)5]H[PMo12O40]- catalyzed nitration of alkanes with nitric acid
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[VO(H2O)5]H[PMo12O40], which contains vanadyl counter cations and PMo12O40 3-, can act as a catalyst for the nitration of various alkanes including alkylbenzenes using nitric acid as a nitrating agent in acetic acid at 356 K.
- Yamaguchi, Kazuya,Shinachi, Satoshi,Mizuno, Noritaka
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p. 424 - 425
(2007/10/03)
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- An efficient nitration of light alkanes and the alkyl side-chain of aromatic compounds with nitrogen dioxide and nitric acid catalyzed by N-hydroxyphthalimide
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Nitration of light alkanes and the alkyl side-chain of aromatic compounds with NO2 and HNO3 was successfully achieved by the use of N-hydroxyphthalimide (NHPI) as a catalyst under relatively mild conditions. For example, the nitration of propane with NO2 catalyzed by NHPI at 100 °C for 14 h gave 2-nitropropane in good yield without formation of 1-nitropropane and cleaved products such as nitroethane and nitromethane. Various aliphatic nitroalkanes, which are difficult to prepare by conventional methods, could be selectively obtained by means of the present methodology by using NHPI as the key catalyst. In addition, the side-chain nitration of alkylbenzenes such as toluene was selectively carried out to lead to α-nitrotoluene without the ring nitration. The present reaction provides an efficient selective method for the nitration of light alkanes and alkylbenzenes, which has been very difficult to carry out so far.
- Nishiwaki, Yoshiki,Sakaguchi, Satoshi,Ishii, Yasutaka
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p. 5663 - 5668
(2007/10/03)
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