Massenspektrometrische Untersuchung von Amiden. VI—Mechanismus der Methyl-Abspaltung aus Crotonsä;urepiperidid

By the investigation of ²H labelled compounds, it has been established that in the case of crotonoyl piperidyl only the hydrogens of the methyl group participate in the elimination of CH₃·.     

Ungewöhnliche Methyl-Abspaltungen aus Nicht Endständigen Kohlenstoffpositionen Bei p-Methylstyrol

The mechanism of methyl elimination has been investigated with the help of ¹³C-labelled p-methylstyrene. Not only terminal C atoms participate in this process; however, neither complete nor partial C scrambling ensues prior to the fragmentation.     

Elektronenstossinduzierte Fragmentierung von Acetylenverbindungen. XI—Energetische Betrachtungen zum Mas Senspektro-Metrischen Zerfall Einiger Offenkettinger und Isomerer Cyclischer Kohlenwasserstoffe

The enthalpy of formation of stable ions of some C₈H₆, C₁₀H₁₀ and C₁₂H₁₀ hydrocarbons have been calculated by means of AP/IP measurements and their correlation with thermochemical data. It has further been shown that under electron-impact-induced fragmentation aromatic and isomeric acetylenic compounds give open chain as well as cyclic ion structures.     

Elektronenstossinduzierte Fragmentierung von Acetylenverbindungen—VIII:. Struktur der stabilen und instabilen Ionen [C9H9]+ aus isomeren C9H10-Kohlenwasserstoffen

The appearance potentials of [C₉H₉]⁺ have been estimated and the enthalpy of formation, calculated from the data, is correlated with different structural proposals. Open chain structures can be eliminated in favour of aromatic ones (vinyltropylium or indanyl cation). The structure of the unstable [C₉H₉]⁺ ions is investigated by means of ¹³C-labelled compounds. The results are also in agreement with the acceptance of aromatic structures.     

A Short Stereoselective Total Synthesis of Racemic Patchouli Alcohol. Preliminary communication

A stereoselective four-step synthesis of racemic patchouli alcohol starting from the known 2,6,6-trimethyl-2,4-cyclohexadien-1-one [1] and 3-methylpent-4-en-1-ol [2] is described.     

Thermal and Photochemical Rearrangements of Divinylcyclopropanes to Cycloheptadienes. - A model for the biosynthesis of the cycloheptadiene derivatives found in a seaweed (Dictyopteris). Preliminary communication

The activation parameters of the thermal rearrangements of the trans-divinylcyclopropanes 1 and 2 , and of cis-divinylcyclopropane 3 to give cycloheptadiene 5 have been determined. In addition it has been shown that trans-divinylcyclopropane-cycloheptadiene rearrangements also occur under irradiation by a mercury lamp in benzene at 40°. These low-temperature in vitro rearrangements suggest that the biosynthesis of the cycloheptadienes in Dictyopteris (dictyopterenes C′ and D′) may proceed by the same reaction(s).     

Scalar nonlinear Boltzmann equation for gas-mixtures

A scalar form of the nonlinear Boltzmann equation for a spatially homogeneous and isotropic gas-mixture is given. Integrations are carried out explicitly on the assumption that the particles scatter like rigid spheres of different mass. A closed analytic representation has been found for the resulting scalar hard-sphere scattering kernel, which reveals two basic symmetries that govern energy conservation and anH-theorem.     

Elektronenstossinduzierte CH4-Abspaltung aus dem Fragment [C7H9]+ von p-Methyl-1-phenyläthanol-1

High resolution mass spectroscopy of ²H-labelled compounds shows that the [C₇H₉]⁺ ion formed from p-methyl(1)phenylethanol-(1) by loss of CH₃· and CO lost methane preferentially from a three-membered ring structure. Other pathways only play a minute part in the fragmentation.