Reactions of phenoxide ion in the gas phase

Binkley, Roger W.; Tevesz, Michael J. S.; Winnik, Witold

doi:10.1021/jo00046a037

Cited by 12 publications

(13 citation statements)

References 4 publications

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“…It strongly suggests that the increased acidity of the phenol moiety in rT3 due to the presence of the two iodines on the outer ring is a critical factor in altering the fragmentation pattern of this species relative to the T3 isomer. The loss of CO has previously been observed in the high‐energy CID studies of phenoxide anions32 and is favoured due to the formation of the aromatic cyclopentadienyl anion. Such a precedent might suggest that in this instance that decarbonylation of the bottom ring arises from the exothermic abstraction of the phenol proton as outlined in Scheme (a); however, the possibility that CO is lost from the amino acid moiety, as indicated in Scheme (b), cannot be excluded.…”

Section: Resultsmentioning

confidence: 64%

On the Influence of the Local Environment on the CO Stretching Frequencies in Native Myoglobin: Assignment of the B‐States in MbCO

Meuwly

2006

ChemPhysChem

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Section: Resultsmentioning

confidence: 64%

On the Influence of the Local Environment on the CO Stretching Frequencies in Native Myoglobin: Assignment of the B‐States in MbCO

Meuwly

2006

ChemPhysChem

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“…Phenols are known to readily form negative ions in the gas phase, and there are several reports on their negative ion chemical ionization mass spectra [12][13][14]. One report on the fragmentation of phenolic anions in the gas phase is restricted to phenol only [12].…”

Section: The Presence Of the Intermediary [M ϫ H ϫ Ch 3 ]mentioning

confidence: 99%

“…One report on the fragmentation of phenolic anions in the gas phase is restricted to phenol only [12]. Reports on negative ion LC/MS for the identification of propofol using APCI for ionization fail to discuss its fragmentation [15,16].…”

Section: The Presence Of the Intermediary [M ϫ H ϫ Ch 3 ]mentioning

confidence: 99%

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Mass spectral fragmentation of the intravenous anesthetic propofol and structurally related phenols

Bajpai

Varshney

Seubert

et al. 2005

J. Am. Soc. Mass Spectrom.

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Propofol (2,6-diisopropyl phenol) is a widely used intravenous anesthetic. To define its pharmacokinetics and pharmacodynamics, methods for its quantitation in biological matrixes have been developed, but its pattern of mass spectral fragmentation is unknown. We found that fragmentation of the [M Ϫ H] Ϫ ion (m/z 177) of propofol in both APCI MS/MS and ESI MS/MS involves the stepwise loss of a methyl radical and a hydrogen radical from one isopropyl side chain to give the most intense product ion, [M ϪH Ϫ CH 4 ] Ϫ , at m/z 161. This two-step process is also the preferred mode of fragmentation for similar branched alkyl substituted phenols. This mode of fragmentation of the [M Ϫ H] Ϫ ion is supported by three independent lines of evidence: (1) Ϫ product ion. Phenols with a single straight chain alkyl substituent, in contrast, undergo ␤ elimination of the alkyl radical irrespective of the length of the alkyl chain, yielding the most intense product ion at m/z 106. This product ion represents a special case of a stable intermediary radical for the two-step process described for branched side chains, because further elimination of a hydrogen radical from the ␤ carbon is not possible. as a supplement to regional anesthesia and in critically ill patients confined to intensive care units. The patient loses consciousness 30 to 50 s after receiving the drug and remains asleep for about 4 to 6 min [1,2]. Even though a single dose of propofol has a short duration of action and produces fast recovery from anesthesia, propofol is not metabolized in a few minutes. It is present in blood, adipose tissues, liver, and brain for a few hours, its concentration decreasing with time [4].

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“…We propose that m experiences ring opening to form an enolate anion which then ring closes to give the highly delocal- is presumably the result of some hydrogen-atom scrambling process and was not identified. The major component is believed to be the same ion observed in the CAD of a and h. A proposed mechanism which accounts for the unusual ease of formation of an acetylene oxide anion (4) and vinyl ketene from c (via n) is shown in Scheme 7 (an alternative ring fragmentation process which produces ketene and acetylene as the neutral products is thought to be approximately I50 kJ moK ' more endothermic').…”

Section: Resorcinolmentioning

confidence: 98%

Fragmentation of collisionally activated hydroxyphenoxide anions in the gas phase

Binkley

Dillow

Flechtner

et al. 1994

Org. Mass Spectrom.

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Low-energy collisionally activated dissociation of 0-deprotonated dihydroxybenzenes (catechol, resorcinol, hydroquinone) in the gas phase causes both fragmentation to form IC,H,O,J-ions by loss of the remaining oxygen-bound hydrogen atom and intramolecular hydrogen atom migration from 0 to C. The rearranged anions then undergo ring-cleavage reactions which are different in each case. Both catechol and hydroquinone produce fragments which are the result of the loss of two carbon atoms and both oxygen atoms but the proposed mechanisms are different. Resorcinol also produces a fragment which derives from the loss of carbon dioxide. For this process a mechanism is proposed which involves a 6-methylpyranone anion intermediate.

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Reactions of phenoxide ion in the gas phase

Cited by 12 publications

References 4 publications

On the Influence of the Local Environment on the CO Stretching Frequencies in Native Myoglobin: Assignment of the B‐States in MbCO

On the Influence of the Local Environment on the CO Stretching Frequencies in Native Myoglobin: Assignment of the B‐States in MbCO

Mass spectral fragmentation of the intravenous anesthetic propofol and structurally related phenols

Fragmentation of collisionally activated hydroxyphenoxide anions in the gas phase

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