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71.
Low-temperature lithium–iodine exchange between tert-butyllithium and the appropriate iodide has been used to generate 3-oxa-5-hexenyllithium and a variety of 4-oxa-5-hexenyllithiums. The 3-oxa system is inherently unstable and fragments via facile β-elimination to give the anion of allyl alcohol and ethylene. The 4-oxa-5-hexenyllithiums, in contrast, are stable at low temperatures but undergo novel isomerization upon warming to deliver the lithium salt of a 4-alken-1-ol in the formal equivalent of an unprecedented [1,4]-Wittig rearrangement. The rearrangement is most likely mediated by 5-exo-trig ring closure of the 4-oxa-5-hexenyllithium to a (2-tetrahydrofuranyl)methyllithium followed by rapid opening to the alkoxide. 相似文献
72.
Abigail C. Bailey 《代数通讯》2017,45(6):2662-2672
We extend the definition of a piecewise Noetherian ring to the noncommutative case, and investigate various properties of such rings. In particular, we show that a ring with Krull dimension is piecewise Noetherian. Certain fully bounded piecewise Noetherian rings have Gabriel dimension and exhibit the Gabriel correspondence between prime ideals and indecomposable injective modules. 相似文献
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A vinyl-phenylsilane has been used as a masked vinyl organometallic for a cross coupling reaction with phenyl iodide to provide the cine substitution product in high yield. 相似文献
76.
Affolder T Akimoto H Akopian A Albrow MG Amaral P Amidei D Anikeev K Antos J Apollinari G Arisawa T Artikov A Asakawa T Ashmanskas W Azfar F Azzi-Bacchetta P Bacchetta N Bachacou H Bailey S de Barbaro P Barbaro-Galtieri A Barnes VE Barnett BA Baroiant S Barone M Battle C Bauer G Bedeschi F Belforte S Bell WH Bellettini G Bellinger J Benjamin D Bensinger J Beretvas A Berge JP Berryhill J Bhatti A Binkley M Bisello D Bishai M Blair RE Blocker C Bloom K Blumenfeld B Blusk SR Bocci A Bodek A 《Physical review letters》2002,88(7):071806
We present the first general search for new heavy particles, X, which decay via X --> WZ0 --> e(nu)+jj as a function of M(X) and Gamma(X) in pp collisions at square root[s] = 1.8 TeV. No evidence is found for production of X in 110 pb(-1) of data collected by the Collider Detector at Fermilab. General cross section limits are set at the 95% C.L. as a function of mass and width of the new particle. The results are further interpreted as mass limits on the production of new heavy charged vector bosons which decay via W' --> WZ0 in an extended gauge model as a function of the width, Gamma(W'), and mixing factor between the W' and the standard model W bosons. 相似文献
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Bailey PD Boyd CA Bronk JR Collier ID Meredith D Morgan KM Temple CS 《Angewandte Chemie (International ed. in English)》2000,39(3):505-508
By building key structural features into hydrophilic drugs, they can be recognized by the PepT1 transporter system of the small intestine and rendered orally active. The model shown provides, for the first time, a 3D template for all known substrates of PepT1. 相似文献
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Dean P. Stull Thomas A. Scales Randy Daughenbaugh Neil A. Jans David T. Bailey 《Applied biochemistry and biotechnology》1995,54(1-3):133-140
Taxol® (paclitaxel) has been hailed by many as the most promising new cancer treatment in two decades. The FDA requires that paclitaxel intended for human consumption be obtained only from the bark ofTaxus brevifolia, the Pacific yew. As this may become increasingly uneconomical, new strategies must be explored to ensure the continued availability of taxol and related molecules. This article examines the planning that must be engaged in and the contingencies that must be prepared for in this changing arena. 相似文献