Die katalytische Wirkung der Metalle auf Knallgas und die Occlusion des Wasserstoffs

Ohne Zusammenfassung     

Simple, rapid procedure for the synthesis of chloromethyl methyl ether and other chloro alkyl ethers

[Reaction: see text]. Zinc(II) salts catalyze the reaction between acetals and acid halides to provide haloalkyl ethers in near-quantitative yield. Reactions from millimole to mole scale are typically complete in 1-4 h with 0.01 mol % catalyst. The solutions of haloalkyl ethers thus obtained can be utilized directly in reactions in which the presence of the ester byproduct does not interfere. Excess haloalkyl ether is destroyed on workup, thereby minimizing exposure to this class of carcinogenic compounds.     

Intensity perception. XIII. Perceptual anchor model of context-coding

In our preliminary theory of intensity resolution [e.g., see N. I. Durlach and L. D. Braida, J. Acoust. Soc. Am. 46, 372-383 (1969)], two modes of memory operation are postulated: the trace mode and the context-coding mode. In this paper, we present a revised model of the context-coding mode which describes explicitly a process by which sensations are coded relative to the context and which predicts a resolution edge effect [L. D. Braida and N. I. Durlach, J. Acoust. Soc. Am. 51, 483-502 (1972); J. E. Berliner, L. D. Braida, and N. I. Durlach, J. Acoust. Soc. Am. 61, 1256-1267 (1977)]. The sensation arising from a given stimulus presentation is coded by determining its distance from internal references or perceptual anchors. The noise in this process, combined with the sensation noise, constitutes the limitation on resolution in the model. In the revised model the probability density functions of the decision variable are not precisely Gaussian (and cannot be expressed analytically in closed form). This paper outlines the predictions of the model for one-interval paradigms and for fixed-level two-interval paradigms and derives estimates of the values of model parameters.     

The analysis of forward scattering channeling data

The use of large angle forward scattering offers the advantage of performing dechanneling measurements at low beam fluences in comparison to the backscattering technique. Here, we present the method for the analysis of forward scattering channeling data and discuss the advantages of the technique.     

Total synthesis of the epoxy isoprostane phospholipids PEIPC and PECPC

A total synthesis of the naturally occurring hydroxy ketone PEIPC 1, a compound that plays a role in endothelial activation in atherosclerosis, has been completed via a triply convergent preparation of a protected EI derivative 13 from 3,5-diacetoxycyclopentene 7, pentane-1,5-diol, and vinyllithium, using Sharpless epoxidation and enzymatic resolution as key steps. Final coupling with lyso-PC 16 and silyl group deprotection gave PECPC 2 and PEIPC 1, which showed the same activity as natural PECPC and PEIPC. [reaction: see text]     

Improved synthesis of the epoxy isoprostane phospholipid PEIPC and its reactivity with amines

An improved synthesis of the naturally occurring hydroxy ketone 1-palmitoyl-2-(5,6)-epoxyisoprostane E 2- sn-glycero-3-phosphocholine (PEIPC) 1, a compound that plays a role in endothelial activation in atherosclerosis, has been carried out using a PMB ether as the key protecting group. Opening of an intermediate with pentylamine shows that the allylic epoxide is the position of attack by nucleophiles.