The Mass Spectra of Phenyl Methyl Ethers

1963 ◽  
Vol 16 (2) ◽  
pp. 219 ◽  
Author(s):  
CS Barnes ◽  
JL Occolowitz
Keyword(s):  
Hydrogen Atom ◽  
Electron Impact ◽  
Methyl Ether ◽  
Mass Spectra ◽  
Methyl Radical ◽  
Formaldehyde Molecule ◽  
Ether Oxygen

Fragmentation of a phenyl methyl ether under electron impact normally occurs by fission of either C-O bond to give ions due to loss from the parent of a methyl radical or, with rearrangement of one hydrogen, a formaldehyde molecule. In the latter case a hydrogen atom may be subsequently lost if a stable tropylium ion may thereby result. If there are present ortho- or para-substituents which are capable of forming a quinonoid structure involving the ether oxygen after removal of a methyl radical, then loss of formaldehyde does not occur.

The mass spectra of some naturally occurring oxygen heterocycles and related compounds

1964 ◽  
Vol 17 (9) ◽  
pp. 975 ◽  
Author(s):  
CS Barnes ◽  
JL Occolowitz
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Methyl Radical ◽  
Naturally Occurring ◽  
Oxygen Heterocycles ◽  
Related Compounds ◽  
Oxygen Atoms

The mass spectra of some naturally occurring and synthetic α- and γ-pyrones, benzofurans, and 2,2-dimethylchromenes have been determined. Under electron impact compounds derived from coumarin lose oxygen atoms as CO, usually forming a stable benzofuran ion. 2,2-Dimethylchromenes lose a methyl radical to give a stable benzopyrylium ion, while the most prominent fission of flavanoid compounds occurs by breaking both bonds β to the A ring.

Supplemental Measurements in Probing Electron Impact-Induced Decompositions via Mass Spectra of Labeled Compounds

1968 ◽  
Vol 22 (1) ◽  
pp. 30-33 ◽  
Author(s):  
Seymour Meyerson
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Isotope Labeling ◽  
Operating Conditions ◽  
Voltage Source ◽  
Labeled Compounds ◽  
Methyl Radical ◽  
Source Temperature ◽  
Fragment Ions ◽  
Different Parts

The value of isotope labeling in probing the chemistry underlying mass spectra is well established. The usefulness of this approach and the reliability of conclusions reached thereby can be greatly increased by checking dependence of label retentions in fragment ions on operating conditions. For example, varying the ionizing voltage, source temperature, or repeller potential alters the relative contributions of the two competing processes by which methylcyclopentane loses a methyl radical to form isomeric C5H9+ ions. The ions resulting from the two processes are derived from different parts of the original molecule and so can be distinguished by appropriate labeling.

AN ELECTRON IMPACT STUDY OF METHYL PHENYL ETHERS

1964 ◽  
Vol 42 (8) ◽  
pp. 2008-2017 ◽  
Author(s):  
F. Meyer ◽  
A. G. Harrison
Keyword(s):  
Electron Impact ◽  
Methyl Ether ◽  
Mass Spectra ◽  
Impact Study ◽  
Deuterium Labelling ◽  
Appearance Potential ◽  
Phenyl Ethers ◽  
Methyl Phenyl

The mass spectra of anisole, anisole-methoxy-d3, meta and para methylanisole, meta and para methyl-d3-anisole, and meta and para niethylanisole-methoxy-d3 have been recorded. From the deuterium labelling and appearance potential studies, the main fragmentation paths on electron impact have been elucidated. The energetics of formation of the CH3OC7H6+ ion from the methylanisoles, benzyl methyl ether, 7-methoxycycloheptatriene, and the ethylanisoles have been studied.

Mass spectra of 4,4-dimethyl-A-homo-4a,6-cholestadien-3-ols, 4,4-dimethyl-A-homo-5-cholestene-3,4a-diols and their derivatives

1982 ◽  
Vol 47 (10) ◽  
pp. 2768-2778
Author(s):  
Antonín Trka ◽  
Helena Velgová
Keyword(s):  
Carbon Atom ◽  
Electron Impact ◽  
Mass Spectra ◽  
Molecular Ions

Partial electron impact induced mass spectra are given of 3α-hydroxy-, 3β-hydroxy-, 3β-methoxy-, 3α-acetoxy- and 3β-acetoxy-4,4-dimethyl-A-homo-4a,6-cholestadienes, 3α,5α-epoxy-4,4-dimethyl-A-homo-5-cholestane, isomeric 4,4-dimethyl-A-homo-5-cholestene-3α(β),4aα(β)-diols, their 3-acetoxy derivatives and 3-methyl ethers. The fragmentation of the molecular ions of these substances involves the usual elimination of substituents (in the form of H2O, CH3OH, CH3COOH, CH2CO), but the most abundant and characteristic ions are products of the contraction of ring A (to a six- or five-membered one), accompanied by expulsion of a fragment containing the carbon atom C(4) with both methyls.

Crystal structure of tamsulosin hydrochloride, C20H29N2O5SCl

2021 ◽  
pp. 1-7
Author(s):  
Nilan V. Patel ◽  
Joseph T. Golab ◽  
James A. Kaduk ◽  
Amy M. Gindhart ◽  
Thomas N. Blanton
Keyword(s):  
Crystal Structure ◽  
Hydrogen Bond ◽  
Hydrogen Atom ◽  
Powder Diffraction ◽  
Density Functional ◽  
Carbon Chain ◽  
Strong Hydrogen Bond ◽  
Powder Diffraction File ◽  
Ether Oxygen ◽  
Sulfonamide Group

The crystal structure of tamsulosin hydrochloride has been solved and refined using synchrotron X-ray powder diffraction data and optimized using density functional techniques. Tamsulosin hydrochloride crystallizes in space group P21 (#4) with a = 7.62988(2), b = 9.27652(2), c = 31.84996(12) Å, β = 93.2221(2)°, V = 2250.734(7) Å3, and Z = 4. In the crystal structure, two arene rings are connected by a carbon chain oriented roughly parallel to the c-axis. The crystal structure is characterized by two slabs of tamsulosin hydrochloride molecules perpendicular to the c-axis. As expected, each of the hydrogens on the protonated nitrogen atoms makes a strong hydrogen bond to one of the chloride anions. The result is to link the cations and anions into columns along the b-axis. One hydrogen atom of each sulfonamide group also makes a hydrogen bond to a chloride anion. The other hydrogen atom of each sulfonamide group forms bifurcated hydrogen bonds to two ether oxygen atoms. The powder pattern is included in the Powder Diffraction File™ as entry 00-065-1415.

scholarly journals MASS SPECTRA OF SOME FUROQUINOLINE ALKALOIDS

1965 ◽  
Vol 43 (9) ◽  
pp. 2516-2521 ◽  
Author(s):  
D. M. Clugston ◽  
D. B. Maclean
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
The Other ◽  
Methoxyl Group ◽  
Quinoline Ring

The mass spectra of six furoquinoline alkaloids have been recorded and mechanisms have been proposed for their fragmentation upon electron impact. Strong metastable peaks, present in all spectra, have aided in the interpretation of the fragmentation of these alkaloids. The three alkaloids with a methoxyl group in the 8-position of the quinoline ring may be differentiated from the other three by the presence of relatively intense peaks at M-1 and M-29.

Electron impact studies. VI. Mass spectra of esters and thioesters. Skeletal rearrangement on electron impact

1967 ◽  
Vol 20 (4) ◽  
pp. 689 ◽  
Author(s):  
JH Bowie ◽  
RG Cooks ◽  
P Jakobsen ◽  
S Lawesson ◽  
G Schroll
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
High Resolution ◽  
Electron Impact ◽  
Mass Spectra ◽  
Skeletal Rearrangement ◽  
Unsaturated Esters ◽  
Impact Studies ◽  
Unsaturated Alcohols ◽  
Metastable Ions

The mass spectra of representative series of simple alkyl acetoacetates, alkyl acetothioacetates, and some unsaturated esters derived from unsaturated alcohols or phenols are reported and discussed. The fragmentation schemes have been established by high resolution measurements, appropriate metastable ions, and by deuterium and 18O labelling. Many of the spectra show significant skeletal rearrangement fragments arising from either loss of carbon monoxide or carbon dioxide.

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