Structural assignment of n3-acylated uridine derivatives by means of 13c nmr spectroscopy

Diisopropylethylamine was effective as a base for acylation of 2′,3′,5′-tri-O-acetyluridine with various acid chlorides. The ¹³C NMR spectra of the products and related compounds showed clearly that the acyl groups intoduced to the uracil moiety are attached to the N³-nitrogen.     

Magnetic Susceptibility of Deintercalated Tunnel Compound of KxCr5Se8 and Mössbauer Spectra of Kx(Cr0.95 57Fe0.05)5Se8

Abstract

KCr₅Se₈ has a TIV₅S₈-type structure, containing K ions in one-dimensional tunnels. Deintercalated samples of K_xCr₅Se₈ (0.32 ≤ x ≤ 0.93) were prepared by leaching method using Alc₃/FeCl₃ aqueous solution. These samples showed a broad peak of magnetic susceptibility at ca. 130 K. ⁵⁷Fe-Mössbauer spectra of K_x(Cr_0.95 ⁵⁷Fe_0.05)₅Se₈ (x = 1.0, 0.49) showed a quadrupole doublet at 300 K. Magnetic sextets appeared at 4.2 K in both samples, indicative of magnetic ordering. The observed isomer shift indicated that the charge of Fe is +3 in both samples. It was proposed that Se^2- was partially oxidized by the deintercalation.     

Detection of hydrocarbons in air and purification of exhaust gas under lean-burn conditions using solid electrolytes

Research on Chemical Intermediates - A chemical sensor and an electrochemical reactor without the need for the geometry of two electrode compartments have been fabricated using high...     

Contribution of interstitial diffusion in drug absorption from perfused rabbit muscle: effect of hyaluronidase on absorption.

[3H]Water and [14C]inulin were injected into perfused rabbit muscle with or without hyaluronidase (300 units/ml) and their absorption into venous effluent from muscle was determined. Hyaluronidase accelerated the absorption of both compounds but the enhancement of [14C]inulin was much larger than that for [3H]water. The pharmacokinetic analysis of venous appearance curves based on a physiological diffusion model elucidated that interstitial diffusion of [14C]inulin was remarkably increased by hyaluronidase treatment, suggesting the existence of steric hindrance for it by the polysaccharide network under normal conditions. Enhancement of [3H]water diffusion was also detected although enhancement ratio was about one-half of that of [14C]inulin. Mean time necessary for each process was calculated using the statistical moment concepts. The results suggested predominant contribution of the interstitial diffusion process and secondary and little contribution of local perfusion flow and permeation process across the capillary wall, respectively, in total absorption of [14C]inulin. Effect of hyaluronidase on transcapillary movement of [14C]inulin was studied using an in vitro diffusion experiment with cultured endothelial cell monolayer and no enhancing effect was shown on [14C]inulin transport across the cell monolayer. The contribution of the local perfusion flow, on the other hand, was shown to be almost equivalent to that of the diffusion process in the total absorption of [3H]water.