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141.
Synthesis of 1‐silacyclopent‐2‐ene derivatives using 1,2‐hydroboration, 1,1‐organoboration and protodeborylation 下载免费PDF全文
The reaction of di(alkyn‐1‐yl)vinylsilanes R1(H2C═CH)Si(C≡C―R)2 (R1 = Me ( 1 ), Ph ( 2 ); R = Bu (a), Ph (b), Me2HSi (c)) at 25°C with 1 equiv. of 9‐borabicyclo[3.3.1]nonane (9‐BBN) affords 1‐silacyclopent‐2‐ene derivatives ( 3a , 3b , 3c , 4a , 4b ), bearing one Si―C≡C―R function readily available for further transformations. These compounds are formed by consecutive 1,2‐hydroboration followed by intramolecular 1,1‐carboboration. Treated with a further equivalent of 9‐BBN in benzene they are converted at relatively high temperature (80–100°C) into 1‐alkenyl‐1‐silacyclopent‐2‐ene derivatives ( 5a , 5b 6a , 6b ) as a result of 1,2‐hydroboration of the Si―C≡C―R function. Protodeborylation of the 9‐BBN‐substituted 1‐silacyclopent‐2‐ene derivatives 3 , 4 , 5 , 6 , using acetic acid in excess, proceeds smoothly to give the novel 1‐silacyclopent‐2‐ene ( 7 , 8 , 9 , 10 ). The solution‐state structural assignment of all new compounds, i.e. di(alkyn‐1‐yl)vinylsilanes and 1‐silacyclopent‐2‐ene derivatives, was carried out using multinuclear magnetic resonance techniques (1H, 13C, 11B, 29Si NMR). The gas phase structures of some examples were calculated and optimized by density functional theory methods (B3LYP/6‐311+G/(d,p) level of theory), and 29Si NMR parameters were calculated (chemical shifts δ29Si and coupling constants nJ(29Si,13C)). Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
142.
Changing behaviours and attitudes towards more sustainable individual energy consumption is a difficult topic to address. After identifying the most recurrent factors influencing the bad energy consumption, society's environmental short-sightedness, a lack of individual responsibility and a tendency to put responsibility upon firms, institutions, and governments, the authors evaluated the effect that business practices can have on individual behaviour. By qualifying as highly credible sources of information, positioning themselves as examples to follow, and providing its employees with the necessary smart and innovative technology, business communities can have a major impact on changing individual behaviours towards more sustainable energy consumption. 相似文献
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Triggering the Directional Selectivity of a Ring‐Closure Reaction Leads to Pyridoazacarbazoles with Anticancer Properties 下载免费PDF全文
Tamara N. Steinhauer Daniel S. Längle Dr. Christopher Meier Dr. Ulrich Girreser Dr. Lars Stenzel Prof. Dr. Dieter Heber Prof. Dr. Bernd Clement 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(18):6668-6672
We herein describe a facile and versatile synthetic route to the tetracyclic system of 6‐substituted 5,6‐dihydro‐11H‐pyrido[3,2‐i]‐1‐azacarbazoles with promising anticancer properties. These derivatives are built up by an elegant one‐step base‐catalyzed synthetic procedure from commercially available building blocks. One additional step provides the corresponding skeleton hitherto unknown in the literature. The possibility to synthesize a large library of compounds with various substitution patterns utilizing this method underlines the importance of this synthetic procedure. 相似文献
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The techniques of integration by parts and differential reduction differ in the counting of master integrals. This is illustrated using as an example the two-loop sunset diagram with on-shell kinematics. A new algebraic relation between the master integrals of the two-loop sunset diagram that does not follow from the standard integration-by-parts technique is found. 相似文献
149.
Latest environmental regulations require a very deep desulfurization to meet the ultra-low sulfur diesel (ULSD, 15 ppm sulfur) specifications. Due to the disadvantages of hydrotreating technology on the slashing production conditions, costs and safety as well as environmental protection, the ultrasound-assisted oxidative desulfurization (UAOD) as an alternative technology has been developed. UAOD process selectively oxidizes sulfur in common thiophenes in diesel to sulfoxides and sulfones which can be removed via selective adsorption or extractant. SulphCo has successfully used a 5000 barrel/day mobile “Sonocracking” unit to duplicate on a commercial scale its proprietary process that applies ultrasonics at relatively low temperatures and pressures. The UAOD technology estimate capital costs less than half the cost of a new high-pressure hydrotreater. The physical and chemical mechanisms of UAOD process are illustrated, and the effective factors, such as ultrasonic frequency and power, oxidants, catalysts, phase-transfer agent, extractant and adsorbent, on reaction kinetics and product recovery are discussed in this review. 相似文献
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Sylvain Maclot Michael Capron Rémi Maisonny Arkadiusz Ławicki Dr. Alain Méry Dr. Jimmy Rangama Prof. Dr. Jean‐Yves Chesnel Sadia Bari Prof. Dr. Ronnie Hoekstra Dr. Thomas Schlathölter Prof. Dr. Bruno Manil Prof. Dr. Lamri Adoui Dr. Patrick Rousseau Prof. Dr. Bernd A. Huber 《Chemphyschem》2011,12(5):881-881