Flavan derivatives. XXV. Mass spectra of 3-hydroxyflavanones, flavan-3-ols, and flavan-3,4-diols

1968 ◽  
Vol 21 (12) ◽  
pp. 3025 ◽  
Author(s):  
JW Clark-Lewis
Keyword(s):  
Mass Spectra ◽  
Hydrogen Transfer ◽  
Diels Alder ◽  
Hydroxyl Group ◽  
Mass Spectral Data ◽  
Insertion Technique ◽  
Mass Spectral ◽  
Marked Enhancement ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns

Mass spectral data are reported for eight 3-hydroxyflavanones, ten flavan-3-ols, and twelve flavan-3,4-diol derivatives. The principal fragmentation of each of these three classes of compound yields ions derived by retro Diels-Alder fission of the heterocyclic nucleus, accompanied in the case of 3-hydroxyflavanones and flavan-3-ols by hydrogen transfer from the 3-hydroxyl group to the A ring fragment. Deuteration experiments with flavan-3-ols confirmed the origin of the hydrogen atom transferred. Flavan-3,4-diols show two characteristic fragmentation patterns depending on the insertion technique. Mass spectra obtained by indirect insertion of flavan-3,4-diols showed a very marked enhancement of the intensities of the M-18 and M-18-28 peaks, and of their fragmentation ions, compared with spectra obtained by direct insertion.

Mass Spectra of Some Carbamates and Related Ureas. II

1968 ◽  
Vol 51 (2) ◽  
pp. 347-365 ◽  
Author(s):  
W R Benson ◽  
J N Damico
Keyword(s):  
Spectral Data ◽  
Relative Abundance ◽  
Mass Spectra ◽  
The Other ◽  
Methyl Isocyanate ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Sulfur Containing

Abstract Mass spectral data for fourteen carbamates, live dithiocarbamates, one thiocarbamate, and eight phenylureas are given with some interpretations. Among the compounds examined were some sulfur-containing aliphatic oxime carbamates; these lost the sulfur moieties more easily than the methyl isocyanate moiety. In the aryl IV-methylcarbamate series, the CH3NCO moiety appears to be lost most easily, as it is in pyrolysis. When l-(2-chlorophenyI)-3- methylurea is fragmented, unexpectedly the [HNC0]+ ion is found in high relative abundance. However, the remaining ureas undergo fragmentation in a manner similar to their related carbamates. Although the two ethylene bisdithiocarbamates give essentially identical fragmentation patterns, the spectra of the other four thio- and dithiocarbamates show sufficient differences so that they may be distinguished from one another.

Mass Spectra of β-Keto Esters

1972 ◽  
Vol 50 (16) ◽  
pp. 2707-2710 ◽  
Author(s):  
Larry Weiler
Keyword(s):  
Mass Spectra ◽  
Carbonyl Groups ◽  
Mass Spectral Fragmentation ◽  
Mass Spectral ◽  
Keto Esters ◽  
Fragmentation Patterns

The mass spectra of several γ-substituted β-keto esters have been recorded and interpreted. The fragmentation patterns are compared to those of α-substituted β-keto esters and are found to be very useful in differentiating the α- and γ-substituted isomers. The mass spectral fragmentation schemes are dominated by cleavages α to the carbonyl groups and by McLafferty rearrangements.

scholarly journals Novel archaeal macrocyclic diether core membrane lipids in a methane-derived carbonate crust from a mud volcano in the Sorokin Trough, NE Black Sea

Archaea ◽  
2003 ◽  
Vol 1 (3) ◽  
pp. 165-173 ◽  
Author(s):  
Alina Stadnitskaia ◽  
Marianne Baas ◽  
Michael K. Ivanov ◽  
Tjeerd C. E. Van Weering ◽  
Jaap S. Sinninghe Damsté
Keyword(s):  
Black Sea ◽  
Mass Spectra ◽  
Membrane Lipids ◽  
Mud Volcano ◽  
The Novel ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Carbonate Formation ◽  
Carbonate Crust ◽  
Archaeal Lipids

A methane-derived carbonate crust was collected from the recently discovered NIOZ mud volcano in the Sorokin Trough, NE Black Sea during the 11th Training-through-Research cruise of the R/V Professor Logachev. Among several specific bacterial and archaeal membrane lipids present in this crust, two novel macrocyclic diphytanyl glycerol diethers, containing one or two cyclopentane rings, were detected. Their structures were tentatively identified based on the interpretation of mass spectra, comparison with previously reported mass spectral data, and a hydrogenation experiment. This macrocyclic type of archaeal core membrane diether lipid has so far been identified only in the deep-sea hydrothermal vent methanogenMethanococcus jannaschii. Here, we provide the first evidence that these macrocyclic diethers can also contain internal cyclopentane rings. The molecular structure of the novel diethers resembles that of dibiphytanyl tetraethers in which biphytane chains, containing one and two pentacyclic rings, also occur. Such tetraethers were abundant in the crust. Compound-specific isotope measurements revealed δ13C values of –104 to –111‰ for these new archaeal lipids, indicating that they are derived from methanotrophic archaea acting within anaerobic methane-oxidizing consortia, which subsequently induce authigenic carbonate formation.

scholarly journals Electron Impact Ionization Mass Spectra of 3-Amino 6-Chloro2-methyl Quinazolin-4-(3H)-one Derivative

2021 ◽  
pp. 1-5
Author(s):  
Osarumwense Peter Osarodion ◽  
◽  
Omotade Treasure Ejodamen ◽  
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Impact Ionization ◽  
Cyclic Compound ◽  
Electron Impact Ionization ◽  
Ionization Mass ◽  
Fragmentation Pattern ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Characteristic Fragmentation

Looking at the previous studies on quinazolinones derivatives, only limited information’s are available on their mass spectral along with the preparation of novel quinazolin-4-(3H)-one derivatives The condensation of Methyl-2-amino-4-Chlorobenzoate with acetic anhydride yielded the cyclic compound 2-methyl 7-Chloro-1, 3-benzo-oxazine-4-one (1) which further produce 3-Amino-2-Methyl 7-Chloro quinazolin-4(3H)-ones (2) via the reaction with hydrazine hydrate. The compounds synthesized were unequivocally confirmed by means of Infrared, Nuclear Magnetic Resonance (1H and 13C), Gas Chromatography-Mass spectrophotometry and Elemental analysis. Discussion: The molecular ion of m/z 235 fragments to give m/z 220 by loss of –NH group. The ion of m/z 220 was broken to give m/z 206 by losing CH2 group and fragment to m/z 177 by loss of HCO. This fragmented to m/z 162 by loss of –CH3 group and then m/z 136 by loss of CN group. The loss of O gave m/z 120 which fragment to give m/z 93 by loss of –HCN and finally gave m/z 65 by loss of CO group. Conclusion: The electron impact ionization mass spectra of compound 2show a weak molecular ion peak and a base peak of m/z 235resulting from a cleavage fragmentation. Compound 2 give a characteristic fragmentation pattern. From the study of the mass spectra of compound 2, it was found that the molecular ion had fragmented to the m/z 220. The final fragmentation led to ion of m/z 93 and ion of mass m/z 65, respectively

Glandular Trichomes and the Yolatiles Obtained by Steam Distillation of Quercus robur Leaves

1993 ◽  
Vol 48 (9-10) ◽  
pp. 736-744 ◽  
Author(s):  
Ralf Engel ◽  
Paul-Gerhard Gülz ◽  
Thorsten Herrmann ◽  
Adolf Nahrstedt
Keyword(s):  
Electron Microscopy ◽  
Quercus Robur ◽  
Mass Spectra ◽  
Steam Distillation ◽  
Glandular Trichomes ◽  
Retention Indices ◽  
Mass Spectral Data ◽  
Mass Spectral ◽  
Kováts Indices ◽  
Scanning Electron

Glandular trichomes in form of long stretched tubes are present on the lower leaf side of Quercus robur as shown by scanning electron microscopy. The glands contain an essential oil, which was isolated by steam distillation together with volatile waxy components of the leaves in an amount of 0.025% of fresh leaves. The product of steam distillation was analyzed by GC-MS. Identification of com pounds is based on comparison of their mass spectral data with those of authentic samples in combination with retention indices and MS data using the SeKoMS (Search Kovats Indices and Mass Spectra) Library. Altogether 184 components of the product of steam distillation were separated, 155 of which could be identified, another 7 were tentatively assigned. Three groups of substances according to their chemical composition are found: hexenyl derivatives and some acetals (32%); terpenes including monoterpenes (4% ), sesquiterpenes and diterpenes (21%); and alkane derivatives (35%). The residual 8% consist of benzyl alcohol, com pounds which stem from the degradation of carotenes, and miscellaneous constituents

scholarly journals Chemical and biochemical studies on 18-hydroxyoestrone

1974 ◽  
Vol 137 (2) ◽  
pp. 263-272 ◽  
Author(s):  
John K. Findlay ◽  
Lothar Siekmann ◽  
Heinz Breuer
Keyword(s):  
Mass Spectra ◽  
Strong Acid ◽  
Hydroxyl Group ◽  
Hydroxyl Groups ◽  
No Formation ◽  
Polar Metabolites ◽  
Characteristic Fragmentation ◽  
Liquid Chromatographic

1. 18-Hydroxyoestrone was reduced by NaBH4 in methanol, giving 18-hydroxyoestradiol-17α and 18-hydroxyoestradiol-17β in the ratio 3:7. 2. Treatment of 18-hydroxyoestrone with a strong alkali yielded 18-noroestrone; however, the 18-hydroxyoestradiols did not undergo transformation to their respective 18-nor derivatives. 3. All the 18-hydroxylated oestrogens were stable under acid conditions. They formed Kober chromogens: the chromogenicity of 18-hydroxyoestrone was only one-third that of the 18-hydroxyoestradiols and oestriol. 4. Paper-, thin-layer- and gas–liquid-chromatographic systems for the characterization of these compounds are described. 5. An examination of the mass spectra revealed peaks characteristic of the substituted carbon atoms. Definite assignment of the 17α- and 17β-hydroxyl groups of the epimeric 18-hydroxyoestrogens was possible by characteristic fragmentation of the free steroids. Further, the configuration of 18-hydroxyoestradiol-17β was confirmed by the formation of the dimethylsildioxy derivative of the 3-methylether of the steroid. 6. Both rat and rabbit liver slices reduced 18-hydroxyoestrone to 18-hydroxyoestradiol-17β and some other labile, polar metabolites with properties similar to 2-hydroxylated oestrogens. No formation of 18-hydroxyoestradiol-17α in vitro was observed. 7. The results are discussed with respect to the possible influence of the 18-hydroxyl group on reactions at C-17, as well as the reactions of 18-hydroxylated oestrogens with strong acid (Kober reactions) and alkali.

N=N Vibrational Frequencies and Fragmentation Patterns of Substituted 1-Aryl-3,3-Dialkyl-Triazenes: Comparison with other High-Nitrogen Compounds

1993 ◽  
Vol 47 (7) ◽  
pp. 986-993 ◽  
Author(s):  
F. Zimmermann ◽  
Th. Lippert ◽  
Ch. Beyer ◽  
J. Stebani ◽  
O. Nuyken ◽  
...  
Keyword(s):  
Aromatic Ring ◽  
Mass Spectra ◽  
Valence Vibration ◽  
Vibrational Frequencies ◽  
Substitution Pattern ◽  
Ft Ir ◽  
Characteristic Fragmentation ◽  
Fragmentation Patterns ◽  
Substituted 1 ◽  
Ir And Raman

The influence of substitution pattern and electronic structure on the N=N stretching frequencies of compounds containing three to six linearly connected nitrogen atoms has been investigated by FT-IR and Raman spectroscopy. For a series of 1-phenyl-3,3-dialkyl-triazenes, Phe-N1=N2-N3 R2, shifts in the two valence vibrations of the triazeno group are studied with respect to the type and position of substituents at the aromatic ring, and for various alkyl substituents at N3. The N1=N2 stretching frequency is lowered by electron-withdrawing substituents at the aromatic ring; this effect is most pronounced for para-positioned substituents. A decrease in the N1=N2 bond order, and of the associated valence vibration, is also observed upon introduction of heavier N3-alkyl substituents, due to an inductive effect. Changes in vibrational frequencies are correlated with characteristic fragmentation patterns in the mass spectra of these compounds, where two degradation routes subsequent to ionization at the nitrogen atoms N1 and N2 have been observed. For the investigated pentazadiene derivatives, a weaker dependence of the N=N vibrational frequencies on the substituents is found. Mass spectra are interpreted in terms of two typical fragmentation pathways, involving a McLafferty rearrangement.

Infrared, N.M.R. and mass spectral studies on 3-Amino-4-aryl-5-aryl(or alkyl)imino-4,5-dihydro-1,2,4-thiadiazoles

1975 ◽  
Vol 28 (3) ◽  
pp. 591 ◽  
Author(s):  
CP Joshua ◽  
KN Rajasekharan
Keyword(s):  
Spectral Data ◽  
Structure Elucidation ◽  
Mass Spectra ◽  
Spectral Studies ◽  
Mass Spectral ◽  
Fragmentation Patterns ◽  
Chemical Evidence

Some 3-amino-4-aryl-5-aryl(or alkyl)imino-4,5-dihydro-1,2,4-thiadiazol, previously prepared and assigned structures on chemical evidence, are now confirmed in structure by a detailed study of their spectra. While i.r, and n.m.r, spectral data confirm the nature of the ring present in these compounds, mass spectra confirm the assignment of substituents on the ring. Mass spectra of these compounds exhibit specific fragmentation patterns and consequently are useful in structure elucidation of substituted 4,5-dihydro-1,2,4-thiadiazoles.

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