scholarly journals Mass-spectrometric structure elucidation of dog bile azopigments as the acyl glycosides of glucopyranose and xylopyranose

1971 ◽  
Vol 125 (3) ◽  
pp. 811-819 ◽  
Author(s):  
F. Compernolle ◽  
G. P. Van Hees ◽  
J. Fevery ◽  
K. P. M. Heirwegh
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Hydrogen Bromide ◽  
Molecular Ions ◽  
Side Chain ◽  
Hydroxyl Groups ◽  
Methyl Vinyl ◽  
Mass Spectrometry Identification ◽  
Hydrolysis Of ◽  
Derivatives Of

1. The structures of the α2- and α3-azopigments, prepared by diazotization of dog bile with ethyl anthranilate, were shown by mass spectrometry and g.l.c. to correspond to azobilirubin β-d-xylopyranoside and azobilirubin β-d-glucopyranoside respectively. 2. Both azopigments consist of a mixture of two methyl vinyl isomers having structures (IIIa) and (IIIb) for the α2-azopigment and structures (IVa) and (IVb) for the α3-azopigment. Separation of methyl vinyl isomers was obtained by t.l.c. or column chromatography performed on the acetylated azopigments. Hydrolysis of the less polar acetates derived from components (IIIa) and (IVa) gave rise to the azopigment (Ia), whereas hydrolysis of the more polar acetates derived from components (IIIb) and (IVb) gave rise to the azopigment acid (Ib). The positions of methyl and vinyl substituents in compounds (Ia) and (Ib) were assigned on the basis of their n.m.r. spectra. 3. Molecular ions in the mass spectra of the trimethylsilyl and acetyl derivatives of the azopigments indicated the presence of a pentose and a hexose conjugating sugar. 4. The ester functions linking the sugars to the propionic acid side chain of azobilirubin were demonstrated by ammonolysis and identification of the amide of azobilirubin as the aglycone derivative. 5. The sugar moieties were shown to occur as xylopyranose (α2) and glucopyranose (α3), bound at C-1, by application of a sequence of reactions performed on a micro-scale. The sugar hydroxyl groups were acetylated and the 1-acyl aglycone removed selectively by treatment with hydrogen bromide in acetic acid. Hydrolysis of the 1-bromo sugar acetates followed by acetylation afforded the α- and β-xylopyranose tetra-acetates and α- and β-glucopyranose penta-acetates, identified by a combination of g.l.c. and mass spectrometry. 6. The validity of this degradation scheme was confirmed (a) by g.l.c.–mass spectrometry identification of the α- and β-1-propionyl derivatives of glucopyranose tetra-acetate, obtained from the α3-azopigment after final reaction with propionic anhydride; (b) by subjecting the acetates of αβ-glucopyranose, αβ-xylofuranose and αβ-glucofuranose to the same sequence of reactions.

Liquid Secondary Ion Mass Spectrometry and Collision-induced Dissociation Mass Spectrometry of Sulfonamide Derivatives of meso-Tetraphenylporphyrin

1999 ◽  
Vol 03 (03) ◽  
pp. 172-179 ◽  
Author(s):  
M. ROSÁRIO M. DOMINGUES ◽  
M. GRAÇA SANTANA-MARQUES ◽  
A. J. FERRRER-CORREIA ◽  
AUGUSTO C. TOMÉ ◽  
MARIA G. P. M. S. NEVES ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Secondary Ion Mass Spectrometry ◽  
Molecular Ions ◽  
Collision Induced Dissociation ◽  
Fragment Ions ◽  
Ion Mass Spectrometry ◽  
Derivatives Of ◽  
Secondary Ion

Liquid secondary ion mass spectrometry (LSIMS) and collision-induced dissociation (CID) were used for the characterization of sulfonamide derivatives of meso-tetraphenylporphyrin (TPP). The spectra obtained using LSIMS show abundant molecular ions and fragment ions from losses of the sulfonamide moieties. The main fragmentation observed in the LSI mass spectra and in the CID spectra of the protonated or cationized molecules involves the loss of one sulfonamide group. In addition, in the CID spectra of these compounds the fragment ions formed by the elimination of two, three and/or four sulfonamide groups are also observed. The CID spectra of the protonated or cationized molecules of these derivatives do not display the ions formed by the cleavage of the S - N bond which have been reported for other sulfonamide compounds. The LSI mass spectra and CID spectra of sulfonamide derivatives of meso-tetraphenylporphyrin provide an easy and reliable means of identification of the number and nature of sulfonamide groups in the porphyrinic ring.

Inductive effect in EI-mass spectra of some 5,6-dihalogenides and 5,6-halohydrins of 5α-cholestan-3β-ol and 3β-acetoxy-5α-cholestane

1982 ◽  
Vol 47 (11) ◽  
pp. 2946-2960 ◽  
Author(s):  
Antonín Trka ◽  
Alexander Kasal
Keyword(s):  
Mass Spectra ◽  
Inductive Effect ◽  
Molecular Ions ◽  
Hydroxyl Group ◽  
Halogen Atoms ◽  
Derivatives Of

Partial EI-mass spectra of 3β-hydroxy- and 3β-acetoxy-5α-cholestanes substituted in positions 5α-, 6β- or 5α,6β- with a hydroxyl group or halogen atoms (fluorine, chlorine, bromine) are presented. The molecular ions of 5α,6β-disubstituted derivatives of 3β-hydroxy-5α-cholestane (or of its 3-acetate) are considerably more stable than the corresponding monosubstituted derivatives if at least one of the pair of the vicinal substituents is chlorine or fluorine. This increase in stability, most striking in 5α- and 6β-fluoro compounds, is explained by the inductive effect.

scholarly journals Confirmation of Indandione Rodenticide Toxicoses by Mass Spectrometry/Mass Spectrometry

1992 ◽  
Vol 4 (4) ◽  
pp. 441-446 ◽  
Author(s):  
W. Emmett Braselton ◽  
Regg D. Neiger ◽  
Robert H. Poppenga
Keyword(s):  
Mass Spectrometry ◽  
High Performance ◽  
Mass Spectra ◽  
Similar Case ◽  
Molecular Ions ◽  
Sample Introduction ◽  
Physical Evidence ◽  
Direct Exposure ◽  
Mass Spectrometry Mass Spectrometry ◽  
Isotope Cluster

Mass spectrometry/mass spectrometry (MS/MS) with collision-activated dissociation (CAD) was utilized to unequivocally distinguish 1,3-indandione rodenticides in 2 cases of anticoagulant toxicosis. Anecdotal evidence provided by the veterinarian in a case involving feedlot cows and physical evidence at the site of occurrence in a similar case involving lambs strongly implicated diphenadione (diphacinone; DP) in both instances. However, high performance liquid chromatography indicated chlorophacinone (CP), not DP, was present in the blood samples obtained from both cows and lambs. Intact 1,3-indandiones exhibit poor gas chromatographic properties, so procedures were developed for analysis by MS/MS using a direct exposure probe for sample introduction. The EI mass spectra of DP and CP contained a base peak at m/z 173, with molecular ions (M+) at m/z 340 and m/z 374 (Cl isotope cluster), respectively. Corresponding MS/MS CAD parent ion spectra of m/z 173 showed an ion of m/z 340 for DP and 374 (Cl cluster) for CP. CAD analysis of the blood extracts showed a parent ion scan of m/z 173 identical to that of CP, with the m/z 374 (Cl cluster). (Additional evidence was obtained by MS/MS examination of the CAD daughter ion spectrum of m/z 374.) Blood extracts from the affected animals revealed CAD daughter ion spectra for m/z 374 identical to that of reference CP. Positive confirmation of CP in both cases led to identification of the source of the toxicant and prevention of further animal exposures.

Mass Spectra of Organo-Metallic Compounds: X. Some Mononuclear Olefinic Derivatives of Metal Carbonyls

1969 ◽  
Vol 23 (5) ◽  
pp. 536-546 ◽  
Author(s):  
R. B. King
Keyword(s):  
Mass Spectra ◽  
Iron Carbonyl ◽  
Vinyl Ketone ◽  
Methyl Vinyl Ketone ◽  
Metal Carbonyls ◽  
Methyl Vinyl ◽  
Tungsten Carbonyl ◽  
Metallic Compounds ◽  
Derivatives Of ◽  
Fragmentation Processes

The mass spectra of the following olefin derivatives of metal carbonyls have been investigated: (a) Arene—tungsten tricarbonyl complexes of toluene, p-xylene, and mesitylene; (b) The cycloheptatriene—metal tricarbonyl complexes C7H8M(CO)3 (M = Cr and W); (c) The 1,3,5-cyclooctatriene complex C8H10W(CO)3; (d) The cyclooctatetraene—metal tricarbonyl complexes C8H8M (CO)3 (M = Cr or Fe); (e) The 1,5-cyclooctadiene—metal tetracarbonyl complexes C8H12M(CO)4 (M = Mo or W); (f) The tungsten tetracarbonyl complexes of bicyclo[2,2,1] heptadiene and dicyclopentadiene; (g) The 1,3-cyclohexadiene complexes (C6H8)2M(CO)2 (M = Mo or W); (h) The cycloheptadienol complex (C7H9OH)Fe(CO)3; (i) The methyl vinyl ketone complexes (CH3COCH = CH2)3M (M = Mo or W); (j) A product of composition C12H16Fe(CO)2 obtained from allene dimer and Fe3(CO)12. The following fragmentation processes of particular interest were observed: (a) The facile dehydrogenation of ions containing the π-bonded 1,3,5-cyclooctatriene, 1,5-cyclooctadiene, and 1,3-cyclohexadiene ligands with two adjacent CH2 groups; (b) Elimination of neutral C5H6 fragments from tungsten carbonyl ions containing π-bonded bicyclo[2,2,1] heptadiene or dicyclopentadiene ligands; (c) Facile dehydration of iron carbonyl ions with π-bonded cycloheptadienol.

Studies in Mass Spectrometry. VII. Triterpenoids: Ifflaionic Acid

1963 ◽  
Vol 16 (4) ◽  
pp. 683 ◽  
Author(s):  
JS Shannon
Keyword(s):  
Mass Spectrometry ◽  
Methyl Ester ◽  
Functional Groups ◽  
Mass Spectra ◽  
Molecular Ions ◽  
Keto Group ◽  
Chemical Derivatives ◽  
Pentacyclic Triterpenoid

The mass spectra of the methyl ester of the new unsaturated pentacyclic triterpenoid ifflaionic acid (urs-12-en-3-on-30-oic acid) and some of its chemical derivatives are presented. These may be used to assign position C-20 to the carbomethoxy and C-3 or C-7 to the keto group. Mechanistic proposals for, and the effect of functional groups on, the main fragmentation of the molecular ions (cleavage through ring C) are discussed.

Fast Atom Bombardment Mass Spectra of Some N-α-(t-Butoxycarbonyl)-O-(diorganylphosphono)-L-serines and O-(Diorganylphosphono)seryl-Containing Dipeptides and Tripeptides

1994 ◽  
Vol 47 (2) ◽  
pp. 229 ◽  
Author(s):  
JW Perich ◽  
I Liepa ◽  
AL Chaffee ◽  
RB Johns
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
High Intensity ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Molecular Ions ◽  
Operating Conditions ◽  
Negative Ion ◽  
The Matrix ◽  
Positive Ion

Positive and negative ion fast atom bombardment ( f.a.b .) mass spectrometry were found to be useful methods for the analysis and structural characterization of five Nα-(t- butoxycarbonyl )-O-( diorganylphosphono )-L- serines ( organyl = Ph, Et, Me, Bzl , But), especially in the case of the sensitive benzyl and t-butyl phosphono derivatives. Under positive ion operating conditions, high intensity pseudo-molecular ions were obtained in the f.a.b . mass spectra, and the fragmentation pathway of the phenyl, ethyl and methyl derivatives was established by parent/daughter linked scanning studies to involve (a) the two-step loss of the t- butoxycarbonyl group, (b) loss of the amino acid as the neutral fragment from the [MH]+, [MH-56]+, [MH-100]+ and [MH-146]+ ions by a four- centred β-elimination rearrangement, and (c) cleavage of the phosphono phenyl and ethyl groups from only the [(RO)2P(OH)2]+ and [NH=CHCH2PO3R2+H]+ fragments. Parent/daughter linked scanning studies of the benzyl derivative showed that the prominent fragmentation involved loss of the benzyl group as the tropylium ion and that the 'apparent' [MH-90]+ peak observed in its f.a.b. mass spectrum resulted from cleavage of the phosphono benzyl group in the matrix during the bombardment process. In the case of the t-butyl derivative, parent/daughter linked scanning studies showed that the prominent fragmentation involved successive 'in-flight' loss of the phosphono t-butyl groups as isobutene. Negative ion f.a.b. mass spectrometry of the five derivatives gave f.a.b. mass spectra which displayed distinct [M-H]- anions along with high intensity [M-H-R]- and [(RO)2PO2]- fragment anions, the f.a.b . mass spectrum of the t-butyl derivative containing an additional [M-H-But-But]- fragment anion. Parent/daughter linked scanning studies established that the majority of the observed fragment anions resulted from extensive fragmentation of the Boc -Ser(PO3R2)-OH derivatives in the matrix phase followed by sputtering of the resultant fragments into the gas phase. In addition, positive ion f.a.b . mass spectrometry was found to be useful for the analysis of a series of protected O-( diorganylphosphono ) seryl-containing dipeptides and tripeptides ( organyl = Ph, Et, Me, Bzl ). The obtained spectra showed that β-elimination fragmentation of the Ser(PO3R2) residue was more pronounced with the tripeptide series and indicated that there was increased sensitivity of the O-( diorganylphosphono ) seryl residue with replacement of the Boc group by an amino acyl residue at its N-terminus.

Compounds of aziadamantane type: Mass spectrometric study

1989 ◽  
Vol 54 (3) ◽  
pp. 691-698 ◽  
Author(s):  
Sergei D. Isaev ◽  
Nataliya F. Karpenko ◽  
Aleksandr G. Yurchenko ◽  
Luděk Vodička ◽  
Valentin I. Kadentsev ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrometric Study ◽  
Nitrogen Molecule ◽  
Molecular Ions ◽  
Mass Spectrometric ◽  
Spectrometric Study ◽  
Molecular Ion ◽  
Mechanism Of Decomposition ◽  
Derivatives Of ◽  
Type Mass

Azi and hydrazi derivatives of adamantane,adamantanone and diamantane were studied by mass spectrometry. The EI spectra of azi derivatives lack completely molecular ions; the presence of abundant dehydroadamantane or dehydrodiamantane ions corresponds to elimination of nitrogen molecule from the molecular ion. Comparison of the EI ionization with photolysis or pyrolysis allowed to deduce some analogies and to suggest the mechanism of decomposition of the molecular ion.

Differentiation of 2-Alkylthioorotic Acids, Methyl and Ethyl 2-Alkylthioorotates and Hydrazides of 2-Alkylthioorotic Acids by Using Electron Ionization Mass Spectra

2008 ◽  
Vol 14 (1) ◽  
pp. 27-35 ◽  
Author(s):  
Grazyna Bartkowiak
Keyword(s):  
Molecular Mass ◽  
Mass Spectra ◽  
Chemical Species ◽  
Molecular Ions ◽  
Electron Ionization ◽  
Relative Molecular Mass ◽  
Ionization Mass ◽  
Acid Methyl ◽  
Electron Ionization Mass Spectra ◽  
Derivatives Of

Electron ionization mass spectra of 12 derivatives of 2-thioorotic acid have been discussed and general fragmentation routes of their molecular ions have been proposed. The compounds under discussion were three groups of four chemical species (2-alkylthioorotic acid, methyl 2-alkylthioorotate, ethyl 2-alkylthioorotate and 2-alkylthioorotic hydrazide) each with the same relative molecular mass. The comparison of selected ions relative abundances and their correlation with the abundance of molecular ions enable differentiation between isomeric or isobaric species in this class of compounds.

Naphtho[1,8-bc]thiophens. II. Mass spectrometry

1968 ◽  
Vol 21 (1) ◽  
pp. 171 ◽  
Author(s):  
DG Hawthone ◽  
QN Porter
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectra ◽  
Electron System ◽  
Complete Analysis ◽  
Base Peak ◽  
Aromatic System ◽  
Chemical Research ◽  
Fragment Ions ◽  
The Stability ◽  
Derivatives Of

II.* MASS SPECTROMETRY By D. G. HAWTHORN,E~$ and Q. N. PORTER^ [Manzlscript received March 6, 19671 The high-resolution mass spectra of some derivatives of naphtho[l,S-be]- thiophen have been analysed. The base peak in the spectra is usually the naphtho- [1,8-bclthienylium cation (mle 171) or one of its substitution products; this emphasizes the stability of this species. Structures are suggested for most of the other ions observed in the spectra. INTRODUUTION In Part I, which dealt with the synthesis of naphtho[l,8-bclthiophen derivatives, the mass spectra of the 2-methyl-2H- (I; R = CH,) and 2-phenyl-2H- (I; R = Ph) compounds were briefly described. It was suggested that in each case the cleavage shown gave the ion of mle 171, for which the naphthothienylium cation structure ac was proposed. (1) ac; m/e 171 In this paper we present a complete analysis of the spectra of these compounds, and of some related naphtho[l,8-bclthiophen derivatives. For reasons outlined in Part I of this series, it is not possible to write structures for fragment ions from aromatic and heteroaromatic molecules with the confidence with which this can be done for many less-aromatic systems. In writing ionic structures to formalize the observed spectra, the following principles have been used: (i) Where the formation of an odd-electron system is involved, the ion is, if possible, written as a radical cation derivable from an aromatic system. There is * Part I, Aust. J. Chem., 1966, 19, 1909. t Department of Organic Chemistry, University of Melbourne, Vic. 3052. $ Present Address: Division of Applied Mineralogy, CSIRO Chemical Research Labora- tories, Melbourne, Vic. 3001. Aust. J. Chem., 1968, 21, 171-83

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