Mass spectrometry in structural and Stereochemical problems—XXXIV Aromatic methyl and ethyl ethers

The behavior under electron impact of a series of aromatic methoxy and ethoxy compounds has been observed. The more common fragmentation processes are interpreted and in some cases the differences among spectra of positional isomers can be explained.     

Piecewise monotone interpolation

In reaction to a recent paper by E. Passow in this Journal, it is shown that broken line interpolation as a scheme for piecewise monotone interpolation is hard to improve upon. It is also shown that a family of smooth piecewise polynomial interpolants, introduced by Swartz and Varga and noted by Passow to be piecewise monotone, converges monotonely, for fixed data, to a piecewise constant interpolant as the degree goes to infinity. Finally, piecewise monotone interpolation by splines with simple knots is discussed.     

Quantitative analysis for polycyclic aromatic hydrocarbons by spectral decomposition of molecular fluorescence

Analysis of the molecular fluorescence spectra of several polycyclic aromatic hydrocarbons (PAH) by the technique of spectral decomposition is discussed. Peak characterization parameters obtained by this technique are utilized to obtain quantitative measurement of a mixture containing benzidiae and dibenzochrysene in solution. Application of the technique to a large number of reference compounds is discussed as an aid to routine identification of suspected carcinogens and other compounds containing fluorophores.     

Syntheses of heterocyclic fused thiazolecarboxylic acids I

A number of thiazolo 5-carboxylic acid derivatives were prepared which were fused to other heterocycles such as 1,2,4-benzothiadiazine, quinazoline, and pyrimidine rings at the 2,3-position of the thiazole ring. In several instances unexpected products were obtained, depending on the reaction conditions. The chemistry of these reactions and the identification of the products are discussed.     

Terpenoids-LXXIV: The sesquiterpenes from the soft coral sinularia mayi

Eleven sesquiterpene hydrocarbons, one [sinularene 11] with a new non-famesolic skeleton, and two new sesquiterpene diols from S. mayi were identified or structurally elucidated. Four 4,7-aromadendranediols were synthesized for reference purposes from spathulenol 23 and the stereochemistry assigned by ¹³C spectroscopy.     

Oxidative rearrangement of imidazoles with dimethyldioxirane

Tetrahydrobenzimidazoles, on treatment with dimethyldioxirane, rearrange to provide 5-imidazolones exclusively. These rearrangements proceed with a broad range of substrates and with good to excellent levels of diastereoselectivity. [reaction: see text]