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排序方式: 共有7823条查询结果,搜索用时 15 毫秒
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Hong‐Xia Feng Yuan‐Yuan Wang Jie Chen Ling Zhou 《Advanced Synthesis \u0026amp; Catalysis》2015,357(5):940-944
An efficient dehydrogenative Diels–Alder (DHDA) reaction of prenyl derivatives with 2,3‐dichloro‐5,6‐dicyanobenzoquinone (DDQ) has been developed under mild conditions, leading to a series of cyclohexene derivatives with good to excellent yields and excellent diastereoselectivity.
114.
Jidan Liu Shaobo Zhuang Qingwen Gui Xiang Chen Zhiyong Yang Ze Tan 《Advanced Synthesis \u0026amp; Catalysis》2015,357(4):732-738
A copper‐mediated, chelation‐assisted ortho C H bond nitration of benzoic acid derivatives using sodium nitrite as the source of the nitro group has been achieved with the aid of an 8‐aminoquinoline directing group. Selective mono‐ or dinitration can be achieved by simply changing the reaction conditions. The method shows excellent functional group tolerance and provides a novel and straightforward route for the preparation of ortho‐nitrated benzoic acids.
115.
Peng Sun Youzhi Wu Tie Yang Xiaoming Wu Jinyi Xu Aijun Lin Hequan Yao 《Advanced Synthesis \u0026amp; Catalysis》2015,357(11):2469-2473
A RhIII‐catalyzed tandem C H activation and C N bond formation reaction between oximes and diazo compounds for the synthesis of heterocycle‐fused pyridine N‐oxides has been developed. The reaction exhibits good functional group tolerance and regioselectivity. After simple transformation, the 1‐substituted, 1,3‐disubstituted, 1,4‐disubstituted and 1,3,4‐trisubstituted heterocycle‐fused pyridines were all obtained in high efficiency. Moreover, this strategy has also been expanded to the synthesis of a key intermediate for the construction of one potential anti‐HIV agent.
116.
Ning Jin Changduo Pan Honglin Zhang Pan Xu Yixiang Cheng Chengjian Zhu 《Advanced Synthesis \u0026amp; Catalysis》2015,357(6):1149-1153
An efficient rhodium(III)‐catalyzed direct C7 alkynylation of indoline C H bonds with the alkynylated hypervalent iodine reagents has been developed. This reaction proceeds smoothly under mild conditions over a wide structural scope with high site‐selectivity and excellent functional‐group tolerance. N‐Acetyl as well as other N‐acyls served as effective directing groups (DG). This procedure allows for the synthesis of a variety of 7‐alkynyl‐substituted indolines in good to excellent yield. More significantly, C7‐alkynylated indoles through further transformations have been successfully accessed.
117.
Sho Kano Huilong Yang John McGrady Tomonori Ihara Hazuku Tatsuya Hiroaki Abe 《Journal of Nuclear Science and Technology》2019,56(3):300-309
The radiation-induced surface activation (RISA) effect will be applied to the core design in supercritical light water reactor (SCWR) in order to achieve a high performance with excellent economy and safety. The purpose of the present study is to investigate the RISA effect in the candidate fuel cladding materials in SCWR such as PNC1520. The change of weldability due to RISA effect and the related microstructure analysis were performed in oxidized PNC1520 and 304 stainless steel with various oxidization periods. The phases contained in the surface oxide layer of the present specimen were identified as Fe2CrO4, γ-Fe2O3, and Fe2O3. The lifetime of 13.8 days for wettability improving factor was confirmed in the ultraviolet (UV) irradiation. Meanwhile, the long life of 13.8 days and short life of 0.8 days for wettability improving factors were identified in the γ-ray irradiation. Based on the fact that the band gap energies of Fe2CrO4, γ-Fe2O3, and Fe2O3 were, respectively, 2.1, 2.0, and 2.2 eV, and the photo energies of UV and γ-ray irradiation were 4.48 eV and 13.3 MeV, it is therefore clarified that the hydrophilization on the oxide layer is ascribed to the RISA effect. 相似文献
118.
Haigang Ma Yujiao Gao Yonggang Wang Yi Dai Hongxiang Ma 《International journal of molecular sciences》2022,23(7)
Mitogen-activated protein kinase (MAPK) cascades play crucial roles in almost all biological processes in plants. They transduce extracellular cues into cells, typically through linear and sequential phosphorylation and activation of members of the signaling cascades. However, accumulating data suggest various regulatory mechanisms of plant MAPK cascades in addition to the traditional phosphorylation pathway, in concert with their large numbers and coordinated roles in plant responses to complex ectocytic signals. Here, we highlight recent studies that describe the uncanonical mechanism of regulation of MAPK cascades, regarding the activation of each tier of the signaling cascades. More particularly, we discuss the unusual role for MAPK kinase kinases (MAPKKKs) in the regulation of MAPK cascades, as accumulating data suggest the non-MAPKKK function of many MAPKKKs. In addition, future work on the biochemical activation of MAPK members that needs attention will be discussed. 相似文献
119.
Wei Hu Robert B. Clark Wayne R. Giles Colleen Kondo Henggui Zhang 《International journal of molecular sciences》2022,23(8)
A number of distinct electrophysiological mechanisms that modulate the myogenic spontaneous pacemaker activity in the sinoatrial node (SAN) of the mammalian heart have been investigated extensively. There is agreement that several (3 or 4) different transmembrane ionic current changes (referred to as the voltage clock) are involved; and that the resulting net current interacts with direct and indirect effects of changes in intracellular Ca2+ (the calcium clock). However, significant uncertainties, and important knowledge gaps, remain concerning the functional roles in SAN spontaneous pacing of many of the individual ion channel- or exchanger-mediated transmembrane current changes. We report results from patch clamp studies and mathematical modeling of the hyperpolarization-activated current, If, in the generation/modulation of the diastolic depolarization, or pacemaker potential, produced by individual myocytes that were enzymatically isolated from the adult mouse sinoatrial node (SAN). Amphotericin-mediated patch microelectrode recordings at 35 °C were made under control conditions and in the presence of 5 or 10 nM isoproterenol (ISO). These sets of results were complemented and integrated with mathematical modeling of the current changes that take place in the range of membrane potentials (−70 to −50 mV), which corresponds to the ‘pacemaker depolarization’ in the adult mouse SAN. Our results reveal a very small, but functionally important, approximately steady-state or time-independent current generated by residual activation of If channels that are expressed in these pacemaker myocytes. Recordings of the pacemaker depolarization and action potential, combined with measurements of changes in If, and the well-known increases in the L-type Ca2+ current, ICaL, demonstrated that ICaL activation, is essential for myogenic pacing. Moreover, after being enhanced (approximately 3-fold) by 5 or 10 nM ISO, ICaL contributes significantly to the positive chronotropic effect. Our mathematical model has been developed in an attempt to better understand the underlying mechanisms for the pacemaker depolarization and action potential in adult mouse SAN myocytes. After being updated with our new experimental data describing If, our simulations reveal a novel functional component of If in adult mouse SAN. Computational work carried out with this model also confirms that in the presence of ISO the residual activation of If and opening of ICaL channels combine to generate a net current change during the slow diastolic depolarization phase that is essential for the observed accelerated pacemaking rate of these SAN myocytes. 相似文献
120.