A series of carbamate melatonin derivatives was treated with performic acid, providing tricyclic products with a 3-hydroxytetrahydropyrrolo[2,3-b]indole skeleton. An unusual migration of carbamate groups was observed in some cases, and the reaction appeared to be strongly dependent on the type of substituent in the phenyl ring of the phenylcarbamate group. Theoretical calculations suggest that the reaction is kinetically controlled. 相似文献
The characterization of the inclusion of Waterman–Shiba spaces ΛBV(p) into generalized Wiener classes of functions BV(q;δ) is given. It uses a new and shorter proof and extends an earlier result of U. Goginava. 相似文献
JPC – Journal of Planar Chromatography – Modern TLC - A simple and accurate analytical procedure is proposed for determination of L-ascorbic acid after chromatographic separation.... 相似文献
The paper deals with the 1/f noise as a measure of the submicron MOS transistor degradation. As the reference point of the investigations has been assumed the plot of the 1/f noise drain voltage spectral density SVD versus the channel length L of the long-channel device which in log-log scale is linear (1/L) at slope equals −1. A theoretical analysis and experimental investigations indicate that before stress decrease of the carrier effective mobility, when the MOS transistors channel becomes shorter, causes deviate down of the plot SVD vs. L in comparison with the extrapolated linear plot of the long channel device. During stress the hot-electron effect leads to the out of controll generation of additional interface states near drain edge which influence on deviate up of the plot SVD vs. L in comparison with the value before stress. The measure of the degradation due to the hot-electron effect is difference between SVD after and before stress. It is showed that SVD of the extrinsic transistors do not dependent on the parasitic resistances therefore the considerations concern both of the conventional and LDD-MOS devices. Moreover the fundamental conditions of the measurement have been determined 相似文献
To be or not to be solvated is the decisive parameter that controls the photoinduced hydrogen‐atom transfer in diastereomeric ketone/phenol dyads. A kinetic solvent effect that refers to hydrogen bonding between the phenol and the solvent is suggested to be the main source of the stereoselective discrimination in the hydrogen transfer (see figure).