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991.
Liu XK Qiu S Xiang YG Ruan YP Zheng X Huang PQ 《The Journal of organic chemistry》2011,76(12):4952-4963
The SmI(2)-mediated radical coupling reactions of β-hydroxylated pyrrolidine/piperidine aza-hemiacetals 8 and 9 and N,S-acetals 6 and 33 with α,β-unsaturated compounds are described. This method allows a rapid access to β-hydroxylated pyrrolidines, piperidines, pyrrolizidinones, and indolizidinones. Starting from N,S-acetal 33 and via a common intermediate 27, the alkaloids hyacinthacine A(2) (2), uniflorine A (3, 6-epi-casuarine), and the unnatural epimer 7-epi-casuarine (37) have been synthesized in four and five steps with overall yields of 34%, 16%, and 13%, respectively. The radical mechanism of the coupling reactions has been confirmed by controlled experiments, which also allowed deducing the anionic mechanism in the coupling between N,S-acetal 6 and carbonyl compounds. This demonstrates that the mechanisms of these SmI(2)-mediated reactions are switchable from Barbier-type anionic to radical by cooperative action of BF(3)·OEt(2) and t-BuOH. 相似文献
992.
Ibarra IA Yang S Lin X Blake AJ Rizkallah PJ Nowell H Allan DR Champness NR Hubberstey P Schröder M 《Chemical communications (Cambridge, England)》2011,47(29):8304-8306
The metal-organic frameworks NOTT-400 and NOTT-401, based on a binuclear [Sc(2)(μ(2)-OH)(O(2)CR)(4)] building block, have been synthesised and characterised; the desolvated framework NOTT-401a shows a BET surface area of 1514 m(2) g(-1) with a total H(2) uptake of 4.44 wt% at 77 K and 20 bar. 相似文献
993.
Xiang Y Qian X Chen Y Zhang Y Chai Y Yuan R 《Chemical communications (Cambridge, England)》2011,47(7):2080-2082
Reagentless, sensitive and multiplexed analysis of gyrB and K-ras gene biomarkers is achieved based on the proximity changes of two different redox-tags to the electrode surface upon DNA hybridizations, and the presence of the two gene biomarkers also acts as inputs and activates the logic gate. 相似文献
994.
TiO(2) films composed of flower-like TiO(2) microspheres with exposed {001} facets were synthesized by a simple one-pot hydrothermal method and exhibited tunable photocatalytic selectivity towards decomposition of azo dyes in water by modifying the surface of TiO(2) microspheres as well as by varying the degree of etching of {001} facets. 相似文献
995.
996.
Mir MH Ong JX Kole GK Tan GK McGlinchey MJ Wu Y Vittal JJ 《Chemical communications (Cambridge, England)》2011,47(42):11633-11635
A pair of trans,trans-muconate ligands have been successfully aligned in two novel Au(I) macrocycles by design from phosphino metal precursors that undergo photochemical cycloaddition reactions quantitatively, resulting in the formation of cyclooctadiene derivatives. 相似文献
997.
Ge HM Yan W Guo ZK Luo Q Feng R Zang le Y Shen Y Jiao RH Xu Q Tan RX 《Chemical communications (Cambridge, England)》2011,47(8):2321-2323
Precursor-fed cultivation of endophytic Chaetomium globosum 1C51 afforded nine novel "unnatural" halogenated chaetoglobosins including those with more preferable immunosuppressive activity. 相似文献
998.
Ying Hui Shao Xiao Ning Ren Zi Ru Liu Xiang Zhang 《Journal of Thermal Analysis and Calorimetry》2011,103(2):617-623
The eutectic ternary phase diagrams of some typical volatilizable energetic materials have been investigated by high pressure
differential scanning calorimeter (PDSC). The ternary H–X phase diagrams for TNT/TNAZ/DNTF (TTD) and TNAZ/DNTF/RDX (TDR) systems were constructed by the correlation of the apparent
fusion heat with the composition (H–X method). And, the ternary T–X phase diagrams (the temperature dependence on composition) for the two ternary systems were constructed by calculating from
the data of the five T–X binary phase diagrams. The eutectic compositions (mol%) of TTD and TDR ternary systems were obtained to be 52.3/27.3/20.4
(H–X method), 53.2/25.8/21.0 (T–X method) and 54.9/39.6/5.5 (H–X method), 55.1/42.2/2.7 (T–X method), respectively. The eutectic temperatures of the ternary systems were obtained by PDSC determination and T–X method calculation to be 76.5 and 76.7 °C, 47.5 and 50.2 °C, respectively. It is shown that the results obtained by two methods
are in agreement and the error in measuring or calculating eutectic compositions and temperatures for the two ternary systems
are within allowable ranges of ±3 mol% and ±3 °C, respectively. Moreover, by means of constructing two ternary H–X phase diagrams with different fixed composition of a component and comparing the apparent fusion heat of eutectics with calculated
one, the results obtained from H–X method for TTD system were proved. The results showed that the gasification or volatilization of easy volatile materials
could be efficiently restrained by high pressure atmosphere, and the perfectly and ideally H–X ternary phase diagrams can be constructed. In comparison with T–X method, H–X method has as a virtue of being quick and simple, especially on constructing ternary phase diagram. 相似文献
999.
1000.