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21.
Frank D. King 《Tetrahedron》2007,63(9):2053-2056
A high yielding cyclisation of the readily available N-(4,4-diethoxybutyl)-2-(3,4-dimethoxyphenyl)acetamide to 8,9-bis(methyloxy)-2,3,6,10b-tetrahydropyrrolo[2,1-a]isoquinolin-5(1H)-one is described. The latter can be reduced with either AlH3 or BH3 to (±)-crispine A in an overall yield of 55%. 相似文献
22.
[reaction: see text] Glucuronyl iodide 1 has been studied in detail as a "disarmed" glycosyl donor. In a model reaction, using N-iodosuccinimide (NIS) as a promoter and 2-phenylethanol as acceptor, best results were obtained using NIS with I(2), followed by trimethylsilyltrifluoromethanesulfonate (TMSOTf). When a series of primary and secondary alcohols was glycosylated using these conditions, yields of 60-83% of beta-glucuronides were obtained. Various "nonheavy" metal salts also effectively catalyzed the model reaction but led to significant amounts of alpha-product with less reactive secondary alcohols. 相似文献
23.
Absorption transitions to vibrational levels close to the A state dissociation limit of ICI have been examined using a two-photon sequential absorption technique. The discrete rotational structures of I37 Cl bands to within 0.7 cm?1 of the limit have been selectively excited and analysed. A value of 17557.514 ± 0.030 cm?1 has been obtained for the I(2Po) + Cl(2Po) dissociation energy De, relative to the minimum of the ICI ground state potential well. The two-photon technique can be used to excite and display separately the high resolution absorption spectra of different isotopic species of a molecule which are contained in a mixture. 相似文献
24.
The kick-out model for impurity diffusion in semiconductors is studied. The kick-out mechanism is thought to play an important rôle in a number of applications, including the diffusion of zinc and chromium in gallium arsenide. Asymptotic solutions are derived for both one- and two-dimensional surface source problems. In the one-dimensional case, a mechanism for the destruction of self-interstitials is also incorporated. The calculated diffusion profiles have shapes which are typical of diffusion systems in which the kick-out mechanism is believed to be active. For the two-dimensional problem, contours of constant impurity concentration are calculated and some are found to have the bird's beak shape which is frequently observed in experiments. 相似文献
25.
Demonstration of a fundamental quantum logic gate 总被引:1,自引:0,他引:1
26.
McFarland KS Naples D Arroyo CG Auchincloss P de Barbaro P Bazarko AO Bernstein RH Bodek A Bolton T Budd H Conrad J Drucker RB Harris DA Johnson RA Kim JH King BJ Kinnel T Koizumi G Koutsoliotas S Lamm MJ Lefmann WC Marsh W McNulty C Mishra SR Nienaber P Nussbaum M Oreglia MJ Perera L Quintas PZ Romosan A Sakumoto WK Schumm BA Sciulli FJ Seligman WG Shaevitz MH Smith WH Spentzouris P Steiner R Stern EG Vakili M Yang UK 《Physical review letters》1995,75(22):3993-3996
27.
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29.
Arroyo CG King BJ Bachmann KT Bazarko AO Bolton T Foudas C Lefmann WC Leung WC Mishra SR Oltman E Quintas PZ Rabinowitz SA Sciulli FJ Seligman WG Shaevitz MH Merritt FS Oreglia MJ Schumm BA Bernstein RH Borcherding F Fisk HE Lamm MJ Marsh W Merritt KW Schellman HM Yovanovitch DD Bodek A Budd HS de Barbaro P Sakumoto WK Kinnel T Sandler PH Smith WH 《Physical review letters》1994,72(22):3452-3455
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