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排序方式: 共有646条查询结果,搜索用时 0 毫秒
1.
Jia-Li Jiang 《Tetrahedron letters》2006,47(6):953-955
ReBr(CO)5-catalyzed addition of Et2NH and CO2 to terminal alkynes afforded anti-Markovnikov adducts of alkenyl carbamates in good to excellent yield and high regioselectivity. 相似文献
2.
《Journal of Coordination Chemistry》2012,65(1-3):249-259
Abstract The photochemical insertion of phenylacetylene with the “tied-back” dinuclear complex [(η5-C5H4)2SiMe2]Fe2(CO)2(μ-CO)2 (4) yields, by X-ray structural analysis, a dimetallacyclopentenone product entirely analogous to that obtained from the photochemical reaction of the alkyne with (η5 - C5H5)2Fe2(CO)2(μ-CO)2 (1). This result is interpreted as evidence for an alternative pathway for photochemical alkyne addition to 1. Attempts to identify the photochemical intermediates from 4 have been unsuccessful. A competition study between 1 and 4 indicates that photochemical alkyne insertion into 1 is preferred by approximate ratio of 2:1 over insertion into 4. 相似文献
3.
4.
This work mainly addresses terminal constrained robust hybrid iterative learning model predictive control against time delay and uncertainties in a class of complex batch processes with input and output constraints. In this work, an equivalently novel extended two-dimensional switched system is first constructed to represent the process model by introducing state difference, output error and new relaxation variable information. Then, a hybrid predictive updating controller is proposed and an optimal performance index function including terminal constraints is designed. Under the condition that the switching signal meets certain conditions, the solvable problem of model predictive control is realized by Lyapunov stability theory. Meanwhile, the design scheme of controller parameters is also given. In addition, the robust constraint set is adopted to overcome the disadvantage that the traditional asymptotic stability cannot converge to the origin when it involves disturbances, such that the system state converges to the constraint set and meets its expected value. Finally, the effectiveness of the proposed algorithm is verified by controlling the speed and pressure parameters of the injection molding process. 相似文献
5.
Biswanath Das Yallamalla Srinivas Chittaluri Sudhakar Kongara Damodar Ravirala Narender 《合成通讯》2013,43(2):220-227
Bromination of alkenes and alkynes has efficiently been carried out at room temperature in short reaction times using KBr and diacetoxy iodobenzene in CH2Cl2-H2O (1:1) to prepare the corresponding trans-dibromo compounds in excellent yields. 相似文献
6.
Design,synthesis and anti-influenza virus activities of terminal modified antisense oligonucleotides
Four novel terminal modified antisense oligonucleotides (ODNs) were designed, synthesized and tested for their anti-influenza virus activity. Initial biological studies indicated that lipophilic and rimantadin emodificated Flutide exhibited more potent anti-H1N1 activity than Flutide. Among them, lipophilic modificated ODN (Flutide-I) showed the most antiviral activity. The EC50 value of Flutide-I for inhibiting H1N1 induced cytopathic effect (CPE) and H1N1 RNA were respectively (0.26 ± 0.16) μM and (0.11 ± 0.03) μM. The cytotoxicity of these compounds has also been assessed. No significant cytotoxicities were found for any of these compounds with the concentrations up to 20 μM. 相似文献
7.
Dr. Tao Xu Dr. Chi Wai Cheung Prof. Dr. Xile Hu 《Angewandte Chemie (International ed. in English)》2014,53(19):4910-4914
Iron catalysis has been developed for the intermolecular 1,2‐addition of perfluoroalkyl iodides to alkynes and alkenes. The catalysis has a wide substrate scope and high functional‐group tolerance. A variety of perfluoroalkyl iodides including CF3I can be employed. The resulting perfluoroalkylated alkyl and alkenyl iodides can be further functionalized by cross‐coupling reactions. This methodology provides a straightforward and streamlined access to perfluoroalkylated organic molecules. 相似文献
8.
In the presence of zinc chloride, the in situ generated β‐enamino ester from the reaction of morpholine, piperidine and pyrrolidine with methyl propiolate reacted, with aromatic aldehydes and thiourea in ethanol resulting in the functionalized tetrahydropyrimidin‐2‐thiones in satisfactory yields and with good diastereoselectivity. When aromatic aldehydes bearing electron‐withdrawing group were used in the reaction, the 4‐hydroxytetrahydropyrimidin‐2‐thione derivatives were obtained as the main product. 相似文献
9.
Julia Leitl Dr. Andrew R. Jupp Dr. Evi R. M. Habraken Verena Streitferdt Dr. Peter Coburger Dr. Daniel J. Scott Prof. Dr. Ruth M. Gschwind Prof. Dr. Christian Müller Dr. J. Chris Slootweg Prof. Dr. Robert Wolf 《Chemistry (Weinheim an der Bergstrasse, Germany)》2020,26(35):7788-7800
Salt metathesis of 1-methyl-2,4,6-triphenylphosphacyclohexadienyl lithium and chlorobis(pentafluorophenyl)borane affords a 1-phospha-7-bora-norbornadiene derivative 2 . The C≡N triple bonds of nitriles insert into the P−B bond of 2 with concomitant C−B bond cleavage, whereas the C≡C bonds of phenylacetylenes react with 2 to form λ4-phosphabarrelenes. Even though 2 must formally be regarded as a classical Lewis adduct, the C≡N and C≡C activation processes observed (and the mild conditions under which they occur) are reminiscent of the reactivity of frustrated Lewis pairs. Indeed, NMR and computational studies give insight into the mechanism of the reactions and reveal the labile nature of the phosphorus–boron bond in 2 , which is also suggested by detailed NMR spectroscopic studies on this compound. Nitrile insertion is thus preceded by ring opening of the bicycle of 2 through P−B bond splitting with a low energy barrier. By contrast, the reaction with alkynes involves formation of a reactive zwitterionic methylphosphininium borate intermediate, which readily undergoes alkyne 1,4-addition. 相似文献
10.
Igor B. Sivaev Nadezhda Yu. Kulikova Maxim V. Vichuzhanin Zoya A. Starikova Vladimir I. Bregadze 《Journal of organometallic chemistry》2008,693(3):519-525
Practical method of synthesis of the 1,4-dioxane derivative of the closo-dodecaborate anion was developed. The cleavage of the dioxonium ring in [B12H11O(CH2CH2)2O]− with acetylenic alcohols gave rise to the preparation of closo-dodecaborate derivatives with terminal acetylene group. These compounds can be introduced into click reactions with phenylazide leading to the corresponding triazoles. The structures of (Bu4N)[B12H11O(CH2CH2)2O] and (Bu4N)2[B12H11(OCH2CH2)2OCH2CCH] · 0.5HOCH2CCH were determined by single-crystal X-ray diffraction. 相似文献