Studies in chemical ionization mass spectrometry: Aryl Ketones

Michnowicz, John; Munson, Burnaby

doi:10.1002/oms.1210060306

Cited by 27 publications

(6 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Alkane (RH) elimination gives the benzoyl ion which fragments further by CO loss as expected. The aryl ketones undergo a process noted previously, 16 give abundant ions in both spectra, as shown in Fig. 2.…”

Section: Fxagmentation Of Even Electron Ionssupporting

confidence: 60%

Fragmentation of even electron ions. Protonated ketones and ethers

Sigsby

Day

Cooks

1979

Org. Mass Spectrom.

View full text Add to dashboard Cite

A systematic study of the types of fragmentation undergone by intemdly excited protonated molecules is presented. Two representative functional groups, ethers and ketones, are selected, and both aliphatic and aromatic substituents are examined. The ions are formed by protonation or alkylation in a chemical ionization source, and caused to fragment by collision at high relative kinetic energy. The prevalence of 1,3-reaurangements and the breakdown of the even eleetron fragmentation rule highlight the ion chemistry uncovered here. Specific findings include: (i) electron unpairing reactions associated with -1 radical loss are common. These are probably energetically less favorable simple bond cleavages and are observed in competition with entropically less favorable elimination reactions. (ii) Alkane elimination is a characteristic reaction, which often occurs by a four-centered mechanism. Several variations on this reaction type are encountered. (%) AlLene elimination is another ubiquitous reaction which occurs by a four-centered mechanism in the systems studied here. Competition between atkene and alkane loss is extremely sensitive to the particular system in hand.

show abstract

Section: Fxagmentation Of Even Electron Ionssupporting

confidence: 60%

Fragmentation of even electron ions. Protonated ketones and ethers

Sigsby

Day

Cooks

1979

Org. Mass Spectrom.

View full text Add to dashboard Cite

show abstract

“…There is little systematic data available in the literature on the chemical structures of protonated drug molecules and their fragmentation in ESI‐MS. Proposals have been made regarding the fragmentation of simple molecules such as amines,8 ketones and ethers,9 monosubstituted cyclohexane derivatives,10 X‐Cn‐Y (X,Y: functional groups, Cn: Carbon skeleton)11–14 and xylene derivatives,15 often in the course of methane CI‐MS. In most cases these protonated molecules were studied using CI‐MS16 between 1970–1985, and thus before the appearance of ESI‐MS 17…”

Section: Fragmentation Of Protonated Drug Molecules Generated By Esi mentioning

confidence: 99%

Strategy for structural elucidation of drugs and drug metabolites using (MS)ⁿ fragmentation in an electrospray ion trap

et al. 2003

View full text Add to dashboard Cite

Triple-stage quadrupole (TSQ) electrospray ionization (ESI) tandem mass spectrometry (MS/MS) and ion trap ESI-MS/MScan be used to cleave protonated molecules to produce carbocations and neutral molecules in the positive ion mode. Dissociation products which correspond to protonated forms of neutral fragment molecules can also be trapped and detected. These protonated molecules in turn can cleave via carbocation cleavage, ipso cleavage, onium cleavage or McLafferty or related rearrangements. One can elucidate the structures of metabolites from the differences in m/z ratios of the fragments arising from the original drug compound and its metabolite. This strategy for structural elucidation is further facilitated by estimates of the reactivity of drugs with oxygen diradicals involved in cytochrome P-450 cycles.

show abstract

“…In the early work in Cl mass spectrometry, essentially the same sensitivities were noted for a series of propionate esters, C4 to C7 (20). More recently, the same sensitivities were observed for the Cl spectra of valerophenone with CH4 (reactant ions = CH-,+ and CgHr1) as the reagent gas and with CH4/H20 mixtures (reactant ion = 1I:>0+ ) as the reagent gas (21). For a series of polyamines, similar sensitivities were observed using CH4, N2, and i-C4Hi0 as reagent gases (22).…”

Section: Reportmentioning

confidence: 56%

Chemical Ionization Mass Spectrometry:

1977

Anal. Chem.

View full text Add to dashboard Cite

Studies in chemical ionization mass spectrometry: Aryl Ketones

Abstract: The CI mass spectra of aryl ketones, +COR, were studied and found to give primarily

Cited by 27 publications

References 13 publications

Fragmentation of even electron ions. Protonated ketones and ethers

Fragmentation of even electron ions. Protonated ketones and ethers

Strategy for structural elucidation of drugs and drug metabolites using (MS)ⁿ fragmentation in an electrospray ion trap

Chemical Ionization Mass Spectrometry:

Contact Info

Product

Resources

About

Studies in chemical ionization mass spectrometry: Aryl Ketones

Abstract: The CI mass spectra of aryl ketones, +COR, were studied and found to give primarily

Cited by 27 publications

References 13 publications

Fragmentation of even electron ions. Protonated ketones and ethers

Fragmentation of even electron ions. Protonated ketones and ethers

Strategy for structural elucidation of drugs and drug metabolites using (MS)n fragmentation in an electrospray ion trap

Chemical Ionization Mass Spectrometry:

Contact Info

Product

Resources

About

Strategy for structural elucidation of drugs and drug metabolites using (MS)ⁿ fragmentation in an electrospray ion trap