Features of the splitting out of a methyl radical from lycoctonine alkaloids under electron impact
The mass spectra of 53 alkaloids and their derivatives are considered. It is known that the presence of a C6(OCH3)-C7(OH)-C8 (OH) grouping in C19-diterpene alkaloids leads to a high intensity of the (M - 15)+ ions at the expense of the C6(OCH3) group and considerably suppresses the competing processes of forming the [M - OH (OCH3)]+ ions in the alkaloids and the (M - 56)+ ions in the anhydroxy bases. When the above-mentioned grouping is absent, the (M - 15)+ ions are formed mainly by the splitting out of a ĊH3 from a N-ethyl group.
Alkaloids ofNitraria schoberi
Kh. T. Pulatova, S. Abdizhabbarova, Z. F. Ismailov, and S. Yu. Yunusov, Khim. Pgir. Soedin., 59 (1968); V. G. Khodzhaev, S. Kh. Maekh, and S. Yu. Yunusov, Khim. Prir. Soedin., 441 (1973). K. P. Guha, B. Mukherjee, and R. Mukherjee, J. Nat. Prod., 42, 1 (1979). Kh. G. Pulatova, Z. F. Ismailov, and S. Yu. Yunusov, Khim. Prir. Soedin., 426 (1966). Z. F. Ismailov, M. V. Telezhenetskaya, and S. Yu. Yunusov, Khim. Prir. Soedin., 136 ( 1 9 6 8 ) .
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...