Reactions of 5-alpha-hydroxy steroids. VII. The westphalen rearrangement of some 3-beta-substituted-6-beta-acetoxy-5-alpha-hydroxy cholestanes.
Abstract Product analyses and kinetic studies of the reactions of 3β-substituted-6β-acetoxy-5α-hydroxy cholestanes with H 2 SO 4 -Ac 2 O-AcOH reveal a marked dependence of the reactions upon the nature of the 3β-substituent.
The kinetic effects of substituted benzoates on the Westphalen rearrangement
Abstract The rate of the Westphalen rearrangement of 3β,6β-disubstituted 5α-cholestan-5-ols is influenced by substituted benzoates at the 6β position in a manner which can be correlated with Hammett substituent constants (σ), giving a reaction constant (ρ) of −0·35.
Identification of Dihydroxy Aromatic Compounds in a Low-Temperature Pyrolysis Coal Tar by Gas Chromatography−Mass Spectrometry (GC−MS) and Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (FT-ICR MS)
Dihydroxy aromatics in coal tar undergo rapid coupling reactions with each other and with some coal-derived species during coal pyrolysis and liquefaction. However, only limited information on the structure of dihydroxy aromatics is known. In this study, Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS) and gas chromatography−mass spectrometry (GC−MS) were used to characterize the dihydroxy aromatics in a low-temperature pyrolyzed coal tar and its distillate and residue fractions. Negative-ion electrospray ionization (ESI) FT-ICR MS spectra of coal-tar-derived samples had low molecular masses and narrow mass ranges. Negative-ion ESI is extremely selective for the dihydroxy aromatics present in coal tar. The O2 class species had the highest ion intensity among the species in the negative-ion FT-ICR mass spectrum for each sample. Dihydroxy compounds with an aromatic core structure of benzene, indan, biphenyl (and/or acenaphthene), and naphthalene were identified in the distillate fract...