The isolation of 11-oxotetrahydrorhombifoline from Ormosia coutinhoi and a study of its mass spectrum

1967 ◽  
Vol 45 (7) ◽  
pp. 751-757 ◽  
Author(s):  
Stewart McLean ◽  
A. G. Harrison ◽  
D. G. Murray
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Equilibrium Theory ◽  
Side Chain ◽  
Fragmentation Reaction ◽  
Quasi Equilibrium ◽  
Molecular Ion ◽  
Dihydro Derivative ◽  
A Minor

11-Oxotetrahydrorhombifoline (I) has been isolated from the alkaloidal extract of the bark of Ormosia coutinhoi, and its dihydro derivative II has been prepared. An examination of the mass spectra of these compounds and of their 3,3-d2 derivatives has led to the elucidation of the course of the major electron impact induced fragmentations undergone by the molecules. The main fragmentation of I leads to loss of C3H5 from the side chain to form an ion of m/e 221, with a minor path involving a central fission of the molecular ion to form an ion of m/e 150. The mass spectrum of II shows that the loss of C3H7 to form the ion of m/e 221 is a minor process, the main fragmentation reaction involving a central fission to form an ion of m/e 152 analogous to the ion of m/e 150 from I. This change in the spectrum is shown to be consistent with predictions based on the quasi-equilibrium theory of mass spectra.

Mass spectra of 4,4-dimethyl-A-homocholestane-3,5- and 3,4a diols and their derivatives

1982 ◽  
Vol 47 (12) ◽  
pp. 3328-3338
Author(s):  
Antonín Trka ◽  
Helena Velgová
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Neutral Fragment ◽  
Molecular Ion ◽  
Impact Fragmentation ◽  
Fragmentation Processes

Partial mass spectra of the following 4,4-dimethyl-A-homocholestane derivatives are given: 3,5-epoxides I and II, 3,5-diols III-VI, 3-methoxy-5-ols VII-IX, 3-acetoxy-5-ol X, 3,4a-diols XI-XIV, 3-acetoxy-4a-ols XV-XVIII and 4,4-[2H6]-dimethyl-3,4a-diol XIX, and their electron impact fragmentation investigated. The mass spectra of epoxides I and II, diols III-VI and acetate X are very similar. Considerable differences in mass spectra of methoxy derivatives VII-IX are explained by two mechanisms of elimination of CH3OH from M+. The same similarity of the fragmentation processes and the mass spectra is also observed in diols XI-XIV and acetates XV-XVIII. For the formation of the characteristic ion m/z 288 a fragmentation scheme containing an usual cleavage of the rings A, B, and C is proposed. On the basis of comparison with the mass spectrum of the 4,4-[2H6]dimethyl analogue XIX it was shown that the ion m/z 361 in the mass spectra of diols XI-XIV is formed by elimination of the neutral fragment C6H13 from A-ring of the molecular ion, the last process being accompanied by the 3-hydroxyl transfer from A-ring to the rest of the molecular ion.

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

Improved Rate Expression in the Quasi‐Equilibrium Theory of Mass Spectra

1962 ◽  
Vol 37 (6) ◽  
pp. 1276-1283 ◽  
Author(s):  
Marvin Vestal ◽  
Austin L. Wahrhaftig ◽  
William H. Johnston
Keyword(s):  
Mass Spectra ◽  
Equilibrium Theory ◽  
Quasi Equilibrium ◽  
Rate Expression

Mass spectral investigations on selenium compounds. II. The behaviour of meta-and para-substituted benzeneseleninic acids and of meta-nitrophenyl selenocyanate under electron impact

1982 ◽  
Vol 35 (7) ◽  
pp. 1365 ◽  
Author(s):  
A Benedetti ◽  
C Preti ◽  
L Tassi ◽  
G Tosi
Keyword(s):  
Mass Spectrometry ◽  
Mass Spectrum ◽  
Electron Impact ◽  
Molecular Ions ◽  
Selenium Compounds ◽  
Molecular Ion ◽  
Mass Spectral ◽  
Low Intensity ◽  
Fragment Ions

Substituted benzeneseleninic acids of the type XC6H4SeO2H (X = m-Cl, p-Cl, m-Br, p-Br, p-Me, m-NO2, p-NO2) have been investigated by mass spectrometry. The fragmentation modes and the fragment ions are discussed and compared with those obtained from the mass spectrum of m-nitro-phenyl selenocyanate, O2NC6H4SeCN. Generally, as regards the acids, besides very weak peaks due to the molecular ions, a number of peaks at higher mass numbers and of greater intensity is observed; these peaks are in multiplets typical of the presence of two selenium atoms, and they correspond to the disubstituted diphenyl diselenides of the type XC6H4SeSeC6H4X. m-Nitrophenyl selenocyanate shows an intense molecular ion peak and the relative fragmentation, while the peak due to the diselenide is of very low intensity.

AN ELECTRON IMPACT STUDY OF SOME C8HI0 ISOMERS

1965 ◽  
Vol 43 (1) ◽  
pp. 211-218 ◽  
Author(s):  
F. Meyer ◽  
P. Haynes ◽  
Stewart McLean ◽  
A. G. Harrison
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Major Part ◽  
The Other ◽  
Fragmentation Pattern ◽  
Impact Study ◽  
Deuterium Labelling ◽  
Appearance Potential ◽  
Alkyl Benzenes

The mass spectra of 1-, 2-, and 6-methylspiro[2.4]hepta-1,3-diene have been measured and found to be very similar to the spectra of 7-methylcycloheptatriene and the isomeric alkyl benzenes. It is concluded that in all cases the major part of the fragmentation occurs by identical paths involving identical intermediates. This conclusion is supported by deuterium labelling and appearance potential data. On the other hand the mass spectrum of 2,5-dimethyl-1,5-hexadien-3-yne, an acyclic C8H10 isomer, shows a number of significant differences in its fragmentation pattern. These differences are reflected in the energetics of ion formation and it is concluded that in this case the fragmentation proceeds through different intermediates.

Spectres de masse d'hydrazino-2 benzo- et naphtothiazoles et d'hydrazones des méthyl-3 benzo- et naphtothiazolinones-2

1975 ◽  
Vol 53 (23) ◽  
pp. 3677-3680 ◽  
Author(s):  
Jean-Claude Richer ◽  
Philippe Lapointe ◽  
Martine Beljean ◽  
Michel Pays
Keyword(s):  
Mass Spectrum ◽  
Mass Spectra ◽  
Base Peak ◽  
Molecular Ion ◽  
Ion Fragmentation ◽  
Fragment Ions ◽  
Sampling Probe ◽  
Electron Impact Mass ◽  
Impact Mass ◽  
Hydrazone Form

Electron impact mass spectra are reported for the hydrazones of 3-methyl-2-benzothiazolinone (1), of 4-, 5-, 6-, and 7-chloro-3-methylbenzo-2-thiazolinones (2, 3, 4, and 5) and of 3-methyl-naphtho[2,1-d]-2-thiazolinone (6), as well as for 2-hydrazinobenzothiazole (7), for 4-, 5-, 6-, and 7-chloro-2-hydrazinobenzothiazoles (8, 9, 10, and 11) and for 2-hydrazinonaphtho[2,1-d]thiazole (12). The results obtained in the two series are compared. The 2-hydrazone and 3-methyl-benzo-2-thiazolinone and its derivatives all form a base peak corresponding to the molecular ion; fragmentation proceeds mainly by successive losses of·NH2, HCN, HCN, and then CS. Initial losses of N2H2, NH·, and NH3 are minor fragmentation routes.In the case of 2-hydrazinobenzothiazole and its derivatives, the base peak is still that of the molecular ion; however, the relative proportions of the various fragment ions vary with the position of sampling probe inside the apparatus. Thus it is concluded that the observed mass spectrum is that of a mixture of the possible hydrazone-hydrazine tautomers. The principal fragmentations involve the initial loss of NH3 (leading to a stabilized ion), of NH2· (probably from the hydrazone form), and of N2H2.(Journal Translation)

MASS SPECTRA OF OXYGENATED QUINOLINES

1966 ◽  
Vol 44 (7) ◽  
pp. 781-788 ◽  
Author(s):  
D. M. Clugston ◽  
D. B. MacLean
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Fragmentation Mechanism ◽  
Significant Extent ◽  
Fragmentation Pathways ◽  
Molecular Ion ◽  
One Step ◽  
The Stability ◽  
Hydroxy Compounds ◽  
Fragmentation Patterns

The mass spectra of the monohydroxyquinolines, the monomethoxyquinolines, N-methyl-2-quinolone, and N-methyl-4-quinolone have been recorded. The isomeric hydroxy compounds vary somewhat in the stability of the molecular ion, but all show the same fragmentation mechanism. Two general fragmentation patterns are discernible in the spectrum of each of the monomethoxyquinolines, but there is considerable variation among the isomers in the extent to which the two patterns occur. In addition, 8-methoxyquinoline undergoes a peculiar fragmentation wherein all three methyl hydrogens are lost. The 3-methoxy compound is unusual in that loss of 43 mass units from the molecular ion occurs in one step. Deuterium- and 13C-labelling experiments have proved to be useful in interpreting the fragmentation pathways. The spectra of the two N-methylquinolones prove that O to N methyl rearrangement does not occur to any significant extent upon electron impact.

Sign in / Sign up

Export Citation Format

Share Document