## Abstract The benzene‐induced solvent effects upon the proton chemical shifts of various pyrazines, pyrimidines and their __N__‐oxides are described. Larger chemical shift effects, implying closer benzeneheterocycle association, are noted in the __N__‐oxides as compared to the non‐oxidized hetero
Negative-ion mass spectra of some pyridines, pyrazines and their N-oxides
✍ Scribed by William W. Paudler; Sharon A. Humphrey
- Publisher
- John Wiley and Sons
- Year
- 1970
- Tongue
- English
- Weight
- 267 KB
- Volume
- 4
- Category
- Article
- ISSN
- 1076-5174
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✦ Synopsis
The negative-ion mass spectra of some pyridines, pyrazines and their N-oxides are reported. All of the compounds examined fragment by generation of CN-ions. The alkylated derivatives readily form [M -11 anions. Most of the N-oxides yield 0and OH-ions. Polar substituents control the fragmentation processes involving the heterocyclic ring to which they are bonded.
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A series of anomeric unsaturated C-glycosides were studied by negative ion mass spectrometry following keV ion bombardment. The compounds bearing an acidic hydrogen show a prominent [M -HIpeak; in the other cases, the [ M -H Ipeak is of very low intensity. A retro-Diels-Alder fragmentation and the a
Polypbenols, catecholamines and their oxidation products have a variety of physiological effects and are key components of insect cuticle and other biological structures. Three dihydroxybenzene isomers were easily differentiated using negative ion electrospray mass spectrometry (ESMS) or tandem mass
## Abstract The 70 eV negative ion mass spectra of a series of phosphoranes exhibit significant peaks for ions resulting from skeletal rearrangements. The primary fragmentation reactions of the molecular anions, which involve reduction of the phosphorus from the penta‐ to the ter‐valent state, have