Synthesis of triterpene glycosides
Summary1. The acyl-β-D-glucopyranosides, acyl-β-D-xylopyranosides, and acyl-α-L-arabinopyranosides of oleanolic and ursolic acids have been synthesized for the first time.2. A method for the synthesis of acyl glycosides of triterpene hydroxyacids with hindered carboxy groups has been developed.
Zur Glucosidbildung aus 1‐Acyl‐glucosen
Die Darstellung von D-Glucosiden, vor allem der α-Reihe, wurde an weiteren 1-Acyl-D-glucosen untersucht. Einige kinetische Messungen wurden bei dieser Reaktion durchgefuhrt.
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...