Organophosphorus compounds. VII. Electron-impact fragmentations of esters of phosphonic acids

1966 ◽  
Vol 19 (7) ◽  
pp. 1187 ◽  
Author(s):  
JL Occolowitz ◽  
JM Swan
Keyword(s):  
Electron Impact ◽  
Phosphorus Atom ◽  
Mass Spectra ◽  
Organophosphorus Compounds ◽  
Ester Group ◽  
Base Peak ◽  
Phosphonic Acids ◽  
Hydrocarbon Group ◽  
Carbon Fragment ◽  
Hydro Carbon

The mass spectra of some dialkyl and diaryl esters of a variety of alkyl-, alkenyl-, alkynyl-, and aryl-phosphonic acids are discussed. The spectra are in many cases similar to those observed for simple dialkyl alkylphosphonates, but with some important differences depending on the nature of the hydrocarbon group attached directly to the phosphorus atom. Some unusual rearrangements are observed, involving migration of a hydro-carbon fragment from the ester group to the hydrocarbon moiety attached to phosphorus, with simultaneous expulsion of a phosphinyl radical. Thus diethyl vinylphosphonate gives an ion [C4H7]+; diethyl 2-phenylvinylphosphonate gives a base peak at m/e 131 due to PhCH=CHCHCH3; diphenyl 2-phenylvinylphosphonate gives an ion [C14H12O]+', and from this, an ion [C14H10]+ which can be formulated as the molecular ion of phenanthrene.

The Mass Spectra of Some Organophosphorus Pesticide Compounds

1966 ◽  
Vol 49 (5) ◽  
pp. 1027-1045
Author(s):  
Joseph N Damico
Keyword(s):  
Alkyl Group ◽  
Mass Spectra ◽  
Organophosphorus Pesticide ◽  
Ester Group ◽  
Base Peak ◽  
Mass Measurements ◽  
Model Compounds ◽  
Hydrogen Migration ◽  
Accurate Mass Measurements ◽  
Individual Parent

Abstract The mass spectra of 23 pentavalent organophosphorus pesticide esters were investigated. Rearrangements and fragmentation by simple cleavage are postulated from analogy with similar compounds, from the presence of chlorine atoms with their readily-recognizable isotopic distribution when applicable, from elemental compositions determined by accurate mass measurements, and, in a few cases, from model compounds. The compounds are divided into four groups: phosphorodithioates, phosphorothionates, phosphorothiolates, and phosphates. The base peaks are formed by rearrangements and simple cleavage. Rearrangement ions are formed by (I) hydrogen migration from the alkyl ester group to the thiophosphite-oxygen skeleton; (2) migration of hydrogen from the Z moiety (aryl or alkyl group) to the phosphorus-oxygen skeleton; (3) migration of hydrogen from the Z moiety to the thiophosphite-oxygen skeleton; (4) migration of hydrogen from the ester group bonded to phosphorus to the Z moiety; and (5) alkyl migration to the Z moiety. The base peak does not characterize the different groups or compounds within a group. However, beta-cleavage (relative to the Z moiety) producing relatively intense peaks (with the charge on the Z moiety) is characteristic of a given group. These data may be useful in identifying metabolites isolated from crops field sprayed with an individual parent organophosphorus pesticide.

The Behavior of 1-Phenyl-2-benzimidazolinethione and 1-Phenyl-2-benzimidazolinone upon Electron Impact and Pyrolysis

1974 ◽  
Vol 52 (13) ◽  
pp. 2359-2366 ◽  
Author(s):  
Denis C. K. Lin ◽  
Michael L. Thomson ◽  
Don C. DeJongh
Keyword(s):  
Mass Spectrum ◽  
Electron Impact ◽  
Mass Spectra ◽  
Path Loss ◽  
Starting Material ◽  
Base Peak ◽  
Pyrolysis Products

The mass spectra of 1-phenyl-2-benzimidazolinethione (3) and 1-phenyl-2-benzimidazolinone (4) have been compared with their pyrolysis products and similarities have been found. In the 70 eV mass spectrum of 3, the base peak results from the loss of H•; at low ionizing voltages, this path and a competing path, loss of S, are the only ones which remain. At 650° in a stream of N2, 1-phenylbenzimidazole (8, 20%) formed from the loss of S and benzimidazo-[2,1-b]benzothiazole (5, 11%) formed by loss of H2. The major fragmentation paths in the mass spectrum of 4 are loss of CHO• and NCO•. At 950°, phenazine (6, 35%) formed by loss of CH2O, and carbazole (7, 14%) formed by loss of HNCO. In each pyrolysis, 65–70% of the starting material was recovered or accounted for.

Structures of [M-44]+ ions in the electron impact and fast atom bombardment mass spectra of the β-blocker nipradilol with a nitrate ester group

1990 ◽  
Vol 25 (3) ◽  
pp. 146-150 ◽  
Author(s):  
Michiaki Yoneda ◽  
Kazuo Tsujimoto ◽  
Mamoru Ohashi ◽  
Masami Shiratsuchi ◽  
Yasushi Ohkawa
Keyword(s):  
Electron Impact ◽  
Mass Spectra ◽  
Fast Atom Bombardment ◽  
Ester Group ◽  
Nitrate Ester ◽  
Β Blocker

scholarly journals MEKANISME REAKSI FRAGMENTASI SENYAWA KIMIA DALAM KULIT BUAH ALPUKAT (Persea americana Mill.)

2019 ◽  
Vol 2 (2) ◽  
pp. 61
Author(s):  
Irma Antasionasti ◽  
Sri Sudewi ◽  
Imam Jayanto ◽  
Jainer Pasca Siampa
Keyword(s):  
Mass Spectrometry ◽  
Gas Chromatography ◽  
Electron Impact ◽  
Mass Spectra ◽  
Persea Americana ◽  
Gas Chromatography Mass Spectrometry ◽  
Fragmentation Reaction ◽  
Base Peak ◽  
Chromatography Mass Spectrometry ◽  
Fragmentation Mechanisms

ABSTRACTInvestigation of the fragment structure of ions and fragmentation reaction is crucial and needs to be done to reconstruct the chemical structure of the examined sample. Therefore, it is necessary to study the fragmentation mechanisms of chemical compound that identified from avocado peel to study the rules of the fragmentation reaction that occurs Sample analysis was examined using Gas Chromatography-Mass Spectrometry (GC-MS) with ionization Electron Impact (EI). Two compounds foun in avocado peel are 1,2,4-trihidroksiheptadek-12,16-diyne and 1,2,4-trihidroksiheptadek-16-yne-18-ene following the principle of even electron positive (EE+) which tends to always form even electron positive (EE+) and even electron neutral (EE0). The fragmentation mechanisms in both compounds are σ bond dissociation reaction and i cleavage which forms even electron positive (EE+) and even electron neutral (EE0). The fragmentation mechanism of the compounds in avocado peel can be estimated through interpretation of GC-MS mass spectra with base peak m/z 87. Keywords : Persea americana Mill.; GC-MS; fragmentation; 1,2,4-trihidroksiheptadek-12,16-diyne; 1,2,4-trihidroksiheptadek-16-yne-18-ene ABSTRAKPenyidikan struktur ion-ion fragment serta reaksi fragmentasinya sangat penting dan perlu dilakukan untuk dapat merekonstruksi kembali struktur kimia sampel yang diperiksa. Oleh karena itu, perlu diketahui mekanisme fragmentasi senyawa kimia yang diidentifikasi dari sampel kulit buah alpukat untuk mengetahui kaidah reaksi fragmentasi yang terjadi. Analisis sampel dilakukan menggunakan Gas-Chromatography-Mass Spectrometry (GC-MS) dengan cara ionisasi Electron Impact (EI). Dua senyawa yang terkandung dalam kulit buah alpukat yaitu senyawa 1,2,4-trihidroksiheptadek-12,16-diena dan senyawa 1,2,4-trihidroksiheptadek-16-ena-18-una mengikuti kaidah fragmentasi ion elektron genap positif (EE+) cenderung untuk selalu membentuk ion elektron genap positif (EE+) dan molekul elektron genap netral (EE0). Mekanisme fragmentasi pada kedua senyawa tersebut terjadi melalui reaksi dissosiasi ikatan σ dan reaksi pemutusan induktif membentuk ion elektron genap positif (EE+) dan molekul elektron genap netral (EE0). Mekanisme fragmentasi senyawa dalam kulit buah alpukat dapat diperkirakan melalui interpretasi spektrum massa GC-MS dengan base peak m/z 87. Kata kunci: Persea americana Mill.; GC-MS; fragmentasi; 1,2,4-trihidroksiheptadek-12,16-diena; 1,2,4-trihidroksiheptadek-16-ena-18-una

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.

Asymmetric Synthesis of Organophosphorus Compounds using H-P reagents derived from Chiral Alcohols

2021 ◽  
Author(s):  
Tomasz K. Olszewski ◽  
Joseph Gbubele
Keyword(s):  
Asymmetric Synthesis ◽  
Phosphorus Atom ◽  
Organophosphorus Compounds ◽  
Chiral Alcohols

Chiral organophosphorus compounds, especially those containing C-stereogenic carbons in the proximity of the phosphorus atom, are known for their unique properties and have found wide applications that span from medicinal...

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