- Pyrazolyl asarin derivative and preparation method and application thereof
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The invention discloses a pyrazolyl asarin derivative, a preparation method thereof and application of the pyrazolyl asarin derivative as a bacteriostatic agent, the chemical structure of the pyrazolyl asarin derivative is shown as a general formula (f), and R is selected from hydrogen, C1-C5 alkyl, cyano, nitro or halogen. Compared with the prior art, the novel pyrazolyl asarin derivative provided by the invention has good antibacterial activity, and the compound is cheap and easy to obtain. Part of target asarin derivatives particularly have relatively strong inhibitory activity on fusarium graminearum, valsa mali, watermelon fusarium wilt and pumpkin fusarium wilt, and are expected to be used for preparing novel natural product bacteriostatic agents.
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Paragraph 0022; 0030; 0036; 0041-0042
(2021/08/11)
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- Discovery of Natural Product-Based Fungicides (III): Semisynthesis and Biological Activity of N-Phenylpyrazole Sarisan Hybrids as Antifungal Agents
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Many phytopathogenic fungi can easily infect crops, resulting in crop yield reductions. In continuation of our efforts to develop natural product (NP)-based antifungal agents, a series of N-phenylpyrazole sarisan hybrids 6a–v were prepared via I2-mediated oxidative cyclization, and their structures were determined by various spectral analyses including IR, 1H-NMR and ESI-MS. Among all N-phenylpyrazole sarisan hybrids, compounds 6a, 6b, 6e, 6i, 6j and 6r exhibited more encouraging antifungal action against at least two phytopathogenic fungi than the reference fungicide hymexazol. Especially, 6a displayed really encouraging and broad-spectrum antifungal activity against F. graminearum, V. mali, and F. oxysporum f.sp.niveum with the EC50 values of 12.6±0.9, 18.5±0.2, and 37.4±1.8 μg/mL, respectively. Moreover, the structure-activity relationships (SARs) were also observed. Additionally, compounds 6a and 6e also exhibited relative low toxicity on normal LO2 cells. This study indicates that these N-phenylpyrazole sarisan hybrids would shed light on developing novel NP-based antifungal agents.
- Cao, Jiangping,Cheng, Wanqing,Guo, Yong,Han, Meiyue,Hou, Enhua,Wang, Xiaoguang,Yang, Ruige
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- Domino Processes of Arynes Reacting with Three Classes of Nucleophiles for Organic Syntheses
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Synthetic application of arynes is broadened by their reactions with neutral N-, S-, and O-containing nucleophiles to produce three types of compounds. Accordingly, 1,2-dihydroquinolines are synthesized from Schiff bases, alkynes, and arynes through a Diels-Alder reaction. Epoxides are prepared from thioethers and arynes along with aldehydes or ketones through a Johnson-Corey-Chaykovsky reaction. Phenolic ethers are produced from allyl ethers and arynes through a Claisen-type rearrangement. These target molecules, including natural products γ-asarone, asaricin, and a cholesteryl phenolic ether, are formed through reactions initiated by arynes. These new reactions share a prevailing feature of domino processes, which are carried out in a single flask and afford the desired products in good to high yields.
- Hwu, Jih Ru,Panja, Avijit,Gupta, Nitesh K.,Hu, Yu-Chen,Tan, Kui-Thong,Lin, Chun-Cheng,Hwang, Kuo-Chu,Hsu, Ming-Hua,Huang, Wen-Chieh,Tsay, Shwu-Chen
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p. 683 - 693
(2021/01/18)
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- Discovery of Natural Product-Based Fungicides (II): Semisynthesis and Biological Activity of Sarisan Attached 3-Phenylisoxazolines as Antifungal Agents
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Many phytopathogenic fungi cause severe damage to crop yields. In continuation of our research aimed at the discovery and development of natural products-based fungicides, a series of thirty-one sarisan attached 3-phenylisoxazolines were synthesized and evaluated for their antifungal activities against five phytopathogenic fungi (B. cinerea, C. lagenarium, A. solani, F. solani, and F. graminearum). Among all title sarisan derivatives, compounds IV2, IV14 and IV23 showed potent antifungal activity against some phytopathogenic fungi. In particular, compound IV2 exhibited a broad-spectrum and more potent antifungal activity against A. solani, F. solani, and F. graminearum than the commercial fungicide Hymexazol. In addition, compounds IV2, IV14 and IV23 also displayed relative low toxicity on normal NRK-52E cells. This work will give some insights into the development of sarisan derivatives as new fungicide candidates in plant protection.
- Liu, Zhiyan,Cao, Jiangping,Yan, Xiaoting,Cheng, Wanqing,Wang, Xiaoguang,Yang, Ruige,Guo, Yong
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- Expeditious synthesis of bioactive allylphenol constituents of the genus Piper through a metal-free photoallylation procedure
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Nine bioactive allylphenol (anisole) derivatives (e.g. eugenol, safrole and asaricin) present in several plants of the genus Piper have been synthesized in medium to high yield via aryl cation intermediates. This expeditious metal-free procedure involves the irradiation of the corresponding chlorophenols or chloroanisoles in a polar solvent (MeCN or, better, TFE or aqueous acetonitrile) in the presence of allyltrimethylsilane. Estragole has also been synthesized starting from the corresponding fluoroderivative and diazonium salt, though in a lower yield. The Royal Society of Chemistry 2005.
- Protti, Stefano,Fagnoni, Maurizio,Albini, Angelo
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p. 2868 - 2871
(2007/10/03)
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- Total Synthesis of Isoflavones: Jamaicin, Calopogonium Isoflavone-B, Pseudobaptigenin, and Maxima Substance-B. Friedel-Crafts Acylation Reactions with Acid-Sensitive Substrates
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The Friedel-Crafts acylation reaction was studied on several acid-sensitive substrates.Under the proper conditions of varying Lewis acids, solvents, and reaction temperatures, the acylation indeed took place, thus obviating the necessity for functional group protection-deprotection sequences.By use of these procedures, the naturally occuring isoflavones jamaicin (1), calopogonium isoflavone-B (2), maxima substance-B (30), and pseudobaptigenin (31) were synthesized and characterized.
- Schuda, Paul Francis,Price, William A.
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p. 1972 - 1979
(2007/10/02)
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- Selective Demethylative Cyclisation of 2-Methoxy-allylbenzenes
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Treatment of 3-substituted 2-methoxyallylbenzenes with dry HBr in CHCl3 causes selective demethylative cyclisation to give 7-substituted 2-methyl-2,3-dihydrobenzofurans.The reaction involves mutual participation of allyl and 2-methoxyl groups and is sterically accelerated by substituents vicinal to OCH3.The reaction does not take place in high dielectric solvents such as DMF or DMSO.A propable mechanism envisaging a non-classical ionic transition state is proposed and the synthetic utility of this reaction is also demonstrated.
- Devakumar, C.,Mukerjee, S. K.
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p. 368 - 372
(2007/10/02)
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