The consecutive loss of two H₂O molecules from protonated 1,2‐ and 1,3‐ cyclohexanediols in the gas phase: An example for the incidence of skeletal rearrangement in chemical ionization mass spectrometry

Effects of stereoisomerism on the electron impact fragmentation of some compounds with an eburnane skeleton1

“…l1 Compound 6 was studied as a model. Although a number of papers dealing with the 5b P 6 eburnane-type compounds have appeared (e.g. , they are all concerned with naturally occurring 3H-a epimers only.…”

Stereochemical differentiation of cyclic glycols by ion-molecule reactions in a quadrupole mass spectrometer using dimethyl ether acetonitrile and 2-S-pyrrolidinemethanol

“…There are many examples of investigations concerning stereochemical effects for cyclic diols in positive chemical ionization (PCI) with ammonia or isobutane as the reagent gas 5–9. They can serve as model compounds for more complex natural products that contain multiple hydroxy groups such as sugars, steroids and prostaglandins.…”

“…Cis ‐ and trans ‐1,2‐cyclohexanediols have quite similar PCI spectra because of the flexibility of the cyclohexane ring that minimizes stereochemical preferences for proton bridging 5–7…”

Eliminierung von Aceton und Bildung von protoniertem Aceton bei der chemischen Ionisation von [2.2.6.6]-Tetramethylcyclohexanon/ Elimination of Acetone and Formation of Protonated Acetone from [2,2,6,6]-Tetramethylcyclohexanone under the Condition of Chemical Ionisation

“…By means of appropriately D and 13 C labelled precursors it is shown that the proton catalysed degradation of [2,2,6,6]-tetramethyl cyclohexanone {e.g. elimination of acetone and formation of protonatecl acetone from [MH]+) proceeds via two distinct pathways.…”

“…Wagner-Meerwein-Umlagerungen in der Gasphase unter den Bedingungen der Chemischen Ionisation (Cl) [1] sind in jüngster Zeit mehrfach diskutiert worden [2] Die Herstellung der 13 C-markierten Ketone la und lb erfolgte nach Schema 3. [1-13 C]-Cyclohexanon (4 a) [4] 0,75 g 3 wurden mit 25 mg BaC03 vermengt und innerhalb 1 h im Metallbad auf 320 °C erhitzt [5], Nach weiteren 2 h wurde 10 min auf 340 °C erhitzt, das erhaltene Destillat mit Ether verdünnt, über MgS04 getrocknet und das Lösungsmittel abdestilliert.…”