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排序方式: 共有229条查询结果,搜索用时 15 毫秒
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Jing Zhou Shihua Song Feng Jiang Chunling Fu Prof. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(42):9948-9958
Herein, we report the total synthesis of traumatic lactone and rhizobialide by utilizing allenoic acid to construct the lactone ring. The key starting materials, allenoic acids, could be prepared by the ATA (allenation of terminal alkynes) of a terminal alkyne with an aldehyde that contained a protected hydroxyl group followed by hydrolysis. Importantly, the asymmetric synthesis could be realized just by replacing racemic diphenylprinol with (R)- or (S)-diphenylprinol to deliver the optically active allenoate. 相似文献
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The ZnO catalysts supported on Silicalite‐1 zeolites with different crystallite sizes (0.08, 0.35, 1 and 1.7 μm, respectively) and 5% Zn were synthesized via an incipient wetness method. The catalysts were characterized by XRD, N2 adsorption, SEM, TEM‐EDX, DRIFT spectra and NH3‐TPD, and their catalytic performance in isobutane dehydrogenation assisted by CO2 was investigated. The catalytic activity is strongly dependent on the crystallite size of Silicalite‐1 support. The ZnO/S‐1‐0.35 catalyst with ca. 0.35 μm crystallite size displays the highest activity, affording an initial isobutane conversion of 51.0% and 74.5% isobutene selectivity. This can be attributed to a higher amount of acid sites present on this catalyst as well as the largest amount of nest silanols possessed by the S‐1‐0.35 support. 相似文献
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Dr. Binjie Guo Dr. Xin Huang Prof. Dr. Chunling Fu Prof. Dr. Shengming Ma 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(51):18343-18348
A mild and efficient method using readily available 1‐aryl‐2,3‐allenols and unprotected‐N indoles, Au+‐catalyzed cyclization, and aromatization to afford the final [4C+2C] products, carbazoles 4, with an excellent selectivity, is reported. The reaction demonstrates excellent regioselectivity and allows the N?H unit to undergo reactivity unprotected. A mechanism involving a spiropolycyclic intermediate has been proposed and synthetic application is also demonstrated. 相似文献
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The Pd(OAc)2/TFP-catalyzed cyclization reaction of 2,3-allenamides in the presence of propargylic carbonates provides an efficient route to β-allenyl furanimine derivatives. Preliminary mechanistic study showed that this reaction was probably initiated by Pd(0) species. 相似文献
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鞘氨醇(sphingosine)是生物体内合成鞘脂的母体化合物, 是生物膜中的重要组分之一. 通过分析表面压力和平均分子面积(π-A)等温线数据分别研究了鞘氨醇与二棕榈酰基磷脂酰胆碱(DPPC)和二棕榈酰基磷脂酰乙醇胺(DPPE)二元组分单层膜的热力学特性, 并在恒定膜压下制备不同摩尔比例的混合脂膜用原子力显微镜进行观测. 实验结果表明: (1)鞘氨醇与DPPC组成的系统中, XD-Sph=0.2, 0.4, 0.6时, 过量分子面积与过量吉布斯自由能在所研究的表面压力下表现为负值, 而当XD-Sph=0.8时, 表现为正值; (2)鞘氨醇与DPPE组成的系统中, 当表面压力 π<25 mN8226;m-1时, 过量分子面积与过量吉布斯自由能在所研究的组分比例下表现为负值, 当π≥25 mN8226;m-1时为正值. 混合单层膜的分子面积与表面吉布斯自由能决定了分子间的相互作用, 当为负值时分子间相互作用表现为吸引力, 出现凝聚现象; 为正值时分子间相互作用表现为排斥力, 促使单层膜出现相分离现象. 过量吉布斯自由能值越小, 单层膜的热稳定性越高. 弹性系数曲线分析和AFM图片观测进一步验证了理论分析的结果. 相似文献
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Yixiong?Hao Pingdan?Yan Xing?Zhang Huawei?Shen Chunling?Gu Hongqin?Zhang Minghao?Zhang Hua?XiangEmail author 《Mikrochimica acta》2017,184(11):4341-4349
The authors describe a signal amplification strategy for highly sensitive detection of the prostate-specific antigen (PSA). This is accomplished by a combination of two methods, viz. (a) improved surface-initiated enzymatic polymerization (SIEP), and (b) the use of nanoflowers prepared from C60 fullerene and Methylene Blue (C60/MB) modified with a long single-strand DNA. C60/MB acts as a novel electrochemical indicator. The C60/MB nanoflowers improve the load of MB and promote the electron transfer. The integration of the SIEP technique and the C60/MB nanomaterial also results in improved loading of MB on the nucleic acid. Ultimately, dual cascade signal amplification is accomplished. The biosensor was constructed as follows: (a) Gold nanospheres were modified with antibody 2 (Ab2) and a thiolated oligonucleotide (referred to as S0). (2) S0 is then extended by the SIEP reaction. (3) The redox indicator C60/MB is then connected to the extended guanine-rich ssDNA which then yields the amperometric signal. (4) A sandwich immunoassay is performed by capturing the nanoprobe oy type Ab2-Au-S0 on the gold electrode modified with multi-walled carbon nanotubes (MWCNTs) and protein A. Current is measured by using differential pulse voltammetry (DPV). The synergic effect of the biofunctional nanomaterial and the signal amplification strategy greatly improves the performance of this immunoassay. Under optimized conditions and at a working voltage of typically ?0.18 V (vs Ag/AgCl), the assay has a linear range that extends from 15 pg·mL?1 to 8 ng·mL?1 of PSA. The detection limit is as low as 1.7 pg·mL?1 (at an S/N ratio of 3). In our perception, this dual amplification scheme has a wide scope in that it may become applicable to numerous other immunoassays. 相似文献
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