bluuebunny/crossref_metadata_2025_split huggingface dataset:
Conformational preference of substituted naphthalenes: 1—Aldehyde derivatives of naphthalene
Authors: Salman Salman R. 
Published: May 2005

AbstractLong‐range proton‐proton coupling constants between the aldehyde proton and the ring protons were used to deduce the conformational preference of 1‐naphthaldehyde, 2‐naphthaldehyde, 2‐hydroxy‐1‐naphthaldehyde, 2‐methoxy‐1‐naphthaldehyde and 1‐bromo‐2‐naphthaldehyde. Molecular orbital calculations at the CNDO/2 and INDO level were used to calculate the stability and the long‐range proton‐proton couplings of different conformers of 1‐ and 2‐naphthaldehyde. The Z conformer was found to be more stable in 1‐naphthaldehyde and the E conformer was more stable in 2‐naphthaldehyde.
1H and 13C NMR studies of binuclear lanthanide(III):—silver(I) shift or relaxation reagents: Competition between several bonding sites in olefinic, aromatic and heteroaromatic compounds
Authors: Audit M. , Demerseman P. , Goasdoue N. , Platzer N. 
Published: May 2005

AbstractThe relative abilities of weak Lewis bases to complex binuclear lanthanide(III)—silver(I) reagents were checked by inter‐ or intra‐ molecular competitions. Preferential complexation at one particular site was shown to be determined mainly by the occurrence of well localized π electrons, by the relief of strain effects or by the lack of steric hindrance. In benzofuran and methoxybenzene derivatives oxygen never interacts directly with the silver reagent and plays a role mainly through electronic effects. Unlike oxygen, sulphur in benzo[b]thiophene is the preferred site of complexation with the silver reagent. On complexation with binuclear shift reagents (lanthanide = Eu, Pr, Yb) the 1H NMR shifts were shown to result from several mechanisms. Better insight into the precise location of the reagent is obtained in 13C NMR by the use of the binuclear relaxation reagent Ag(tfa)‐Gd(fod)3.
High resolution mass spectrometry in molecular studies. Part XVII. Evidence for ring contractions in molecular ions: The fragmentation of N‐acetylmorpholine
Authors: Tesarek J. M. , Richter W. J. , Burlingame A. L. 
Published: May 2005

AbstractIn comparing N‐acetylmorpholine to closely related systems, two major differences in fragmentation are observed. M‐15 and M‐43 fragments, although quite common to such systems, are unusual with respect to their genesis. Formation of the M‐15 fragment by loss of C‐3 instead of the anticipitated loss of C‐2 or C‐8 is evident from shifts in the spectra of deuterated analogs. The M‐43 species arises from total loss of the N‐acyl substituent rather than the usual two‐step loss of ketene plus a ring hydrogen. These data are presented in support of mechanistic rationale involving radical induced ring contraction to a common intermediate molecular ion. Techniques of high resolution mass spectrometry and isotope labeling have been employed to substantiate certain mechanistic details.
The metastable spectra of cis‐ and trans‐butenes
Authors: Daly N. R. , McCormick A. , Powell R. E. 
Published: May 2005

AbstractA new type of ion detector has been developed that can be made to operate in two ways. It can detect all ions, or it can be made to detect only those within a preselected energy range. Its use on a mass spectrometer to examine the metastable spectra of cis‐ and trans‐butenes is described.
The primary fragmentation step of isoxazole upon electron impact. A correlation with photochemistry
Authors: Nakata Hisao , Sakurai Hiroshi , Yoshizumi Hideo , Tatematsu Akira 
Published: May 2005

AbstractThree isomeric compounds, I, II and III, were prepared and their mass spectra recorded. Comparisons of the spectra showed that the fragmentation of I proceeds only by way of II, and that II itself is transformed in part to III upon electron impact. It is suggested that selective ionization of each one of the two isolated functional groups in II may afford two isomeric radical ions, IIa and IIb. A possible interrelation to the photochemistry of these compounds is also discussed.
Einfluss funktioneller Gruppen auf die Massenspektren von 17β‐Hydroxysteroiden
Authors: Spiteller‐Friedmann Margot , Spiteller Gerhard 
Published: May 2005

AbstractAM Beispiel des 17β‐Hydroxy‐5α‐androstans wird der unterschiedliche Einfluß funktioneller Gruppen auf die Bruchstückbildung von Steroiden studiert.Im 17β‐Hydroxy‐5α‐androstan wird durch die Hydroxylgruppe lediglich die in Steroiden vorhandene eigung zur Spaltung der C‐13/C‐17 Bindung unter Ausbildung eines positiven Ladungszentrums an C‐13 vertärkt. Dieser Einfluß der Hydroxylgruppe überwiegt aber nur, solange Substituenten fehlen, die zur Ionisation einen geringeren Energieaufwand benötigen, als zur Ionisation der C‐13/C‐17 Bindung erforderlich ist. Bereits bei Vorhandensein einer Doppelbindung kann sich das Spaltbild stark wandeln.Wenn sich aber in Stellung 17 noch eine zusätzliche Alkygruppe befindet, so erfolgt die Ionisation mit hoher Wahrscheinlichkeit durch Abspaltung eines Elektrons vom Hydroxylsauerstoff in Stellung 17. Es treten daher andere Hauptabbaureaktionen ein als in Molekülionen, die das Ladungszentrum am C‐13 haben. In solchen Verbindungen ist selbst der dominierende Einfluß eines konjugierten Systems auf die Bruchstückbildung weitgehend eingeschränkt. Bei Verätherung der Hydroxylgruppe wird dieser Effekt potenziert.Im Zuge dieser UNtersuchungen wurden einige bisher noch nicht bekannte, für die Anwesenheit bestimmter Strukturelemente im Steroidskelett typische Abbaureaktionen aufgefunden, die ebenfalls kurz diskutiert werden.
Mass spectrometry in structural and stereochemical problems—CLVIII electron impact promoted fragmentation of triphenylmethyl ethers
Authors: Sheikh M. Younus , Duffield A. M. , Djerassi Carl 
Published: May 2005

AbstractThe triphenylmethyl (trityl) moiety is frequently used for the protection of alcohols but the mass spectra of such trityl ethers have hitherto escaped scrutiny. It has now been found that triphenylmethyl derivatives of primary alcohols yield abundant molecular ions which permit the determination of the isotopic purity of the parent alcohol. Upon electron impact the triphenyl‐methyl entity directs the fragmentation of trityl ethers as demonstrated by a detailed study of n‐pentyl trityl ether and its deuterated analogs. Ions formed by migration of phenyl groups were observed in the mass spectra of the trityl ethers investigated as well as in the spectrum of triphenyl‐methane itself.
Zum Mechanismus massenspektrometrischer Fragmentierungsreaktionen.—I Methoxygruppenwanderungen in den Massenspektren der Methyläther von linearen und verzweigten aliphatischen Polyalkoholen
Authors: Grützmacher Hans‐Friedrich , Winkler Johann 
Published: May 2005

AbstractDie Bildung von 1,1‐Dimethoxyalky‐umlagerungsionen in den Massenspektren der Metyläther von linearen Diolen, 1,2,3‐Triolen und Derivaten der verzweigten Polyole Pentaglycerin und Pentaerythrit wird mit Hilfe von Markierungen mit Deuterium und Massefeinbestimmungen untersucht. Methoxygruppenwanderungen treten in den Massenspektren der Dioldimethyläther nicht oder nur in sehr geringem Ausmaß auf. Die Massenspektren der 1,2,3‐Trioltrimethyläther besizen aber charakteristische Peaks der umlagerungsionen +CH(OCH3)2 und +CR(OCH3)2. Diese Ionen entstehen durch eine 1,3‐Wanderung einer Methoxygruppe, wahrscheinlich bei einem einstufigen Zerfall der Molekül‐Ionen unter Bildung von Methyl‐alkenyl‐äther und H‐Atom bzw. Alkylradikal als neutrale Fragmente. Gorße Peaks der Umlagerungsionen +CH(OCH3)2 werden in den Massenspektren von Verbindungen des Typs
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gefunde. Bei diesen Verbindungen wandert eine Methoxygruppe beim weiteren Zerfall von Radikal‐Ionen, die durch Abspaltung von HY aus den Molekül‐Ionen entstehen. Wanderungen von Hydroxy‐ und Acetoxy‐Gruppen werden ebenfalls beobachtet, aber keine Wanderung von Cl‐Atomen.
Zur Weiteren Kenntnis des Chlorophylls und des Hämins—XIX. Zur McLafferty‐Umlagerung in gerad‐ und in Ungeradelektronischen Systemen
Authors: Budzikiewicz H. , Haar F. G. V. D. 
Published: May 2005

AbstractEs wird gezeigt, daß in Porphin‐Derivaten die McLafferty‐Umlagerung bevorzugt in geradelektronischen Systemen abläuft. und zwar mit großer relative Häufigkeit ausgehend von M2+, jedoch weniger begünstigt in Ionen, die durch Radikalabspaltung entstanden sind. Von dieser Beobachtung ausgehend wird ein allgemeines Schema für die McLafferty‐Umlagerung vorgeschlagen.
Amino‐acid sequence study in peptides by mass spectometry‐II. Investigation of pentadeuterobenzoyl‐peptide methyl esters
Authors: Kamerling J. P. , Heerma W. , Penders Th. J. , Vliegenthart J. F. G. 
Published: May 2005

AbstractThe utility of benzoyl and pentadeuterobenzoyl derivatives of peptide methyl esters for mass spectrometric analysis was investigated. The mass spectra of the glu‐his and the val‐tyr‐pro derivatives are discussed. Treatment of the peptide methyl esters with the mixed benzoic‐ethyl‐carbonic anhydride did in some cases lead to benzoyl derivatives as well as to ethoxycarbonyl derivatives.
Bildung ionischer NO‐ und NO2‐Komplexe von aromaten in der Gasphase
Authors: Schulz W. , Drost H. , Klotz H.‐D. 
Published: May 2005

AbstractEs wurde versucht, die bei der Nitrierung von Aromaten entstehenden NO+‐bzw. NO2+‐Intermediärkomplexe durch Ion‐Molekül Reaktionen in der Gasphase zu erzeugen. Die utersuchungen erfolgten am Benzol. Pyridin und Toluol mit NO+, NO2+ sowie CH3NO2+ und CH2ONO2+ als ‘Nitrierungs’‐Ionen. Es ließen sich sowohl aromatische NO+‐Komplexe anchweisen mit wechselndem reaktionsquerschnitt. Die ermittelten unteren Grenzen der Bindungsenergien von 16 kcal/Mol für den NO+‐Komplex und 29 kcal/Mol für den NO2+‐Komplex legen es nahe, die nachgewiesenen Komplexe asl σ‐Komplexe anzusehe, was als weiterer Hinweis für Analogie von elektrophilen Substitutionsreaktionen und Ion‐Molekül‐Reaktionen gewertet wird.
Fragmentations in the mass spectra of 2‐oxo‐3‐indolyl derivatives
Authors: Ballantine J. A. , Fenwick R. G. , Alam M. 
Published: May 2005

AbstractThe mass spectra of a series of isatin, oxindole and 2‐oxo‐3‐indolyl derivatives have been investigated using high resolution and deuterium labelling techniques. The fragmentations involve the sequential loss of a number of neutral molecules and the results show that the concept of charge localisation can be applied with success to explain the fragmentation processes even in these polyheteroatom species.
Energetics of the electron‐impact fragmentation of alkoxybenzenes and alkylthiobenzenes
Authors: Gillis R. G. , Long G. J. , Moritz A. G. , Occolowitz J. L. 
Published: May 2005

AbstractUsing energetic considerations, ketonic structures are postulated for the [Molefin]+ fragments derived from alkoxybenzenes, alkylthiobenzenes and 9‐ethoxyanthracene. Experimentally determined heats of formation for the tautomeric molecular ions derived from anthrone and 9‐anthrol differ by 37 Kcal. mole−1.
Mass spectra of branched long‐chain aliphatic alcohols
Authors: Dolejš L. , Beran P. , Hradec J. 
Published: May 2005

AbstractThe mass‐spectral behaviour of long‐chain aliphatic primary alcohols of the normal, iso‐and anteiso‐series have been discussed. The mass‐spectral fragmentation of individual alcoholic types have been found to be structurally specific. The mass spectra of some deuterio derivatives have shown, however, the complicated nature of the fragmentation processes.
Bond‐forming reactions occurring in azines upon electron impact
Authors: Cooks R. G. , Tam S. W. 
Published: May 2005

AbstractSkeletal rearrangement processes of the general type \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm ABC}^{\mathop {\rm + }\limits_{\rm .} } {\rm } \to {\rm AC}^{\mathop {\rm + }\limits_{\rm .} } {\rm + B} $\end{document} in which HCN is eliminated and also bond‐forming reactions involving intramolecular aromatic substitution occur in aromatic azines upon electron impact. In addition, hydrogen rearrangements can lead to abundant benzonitrile and benzalimine molecular ions and their substituted analogues. The abundant [M1] ions are predominantly formed by loss of the methine hydrogen preceded by complete scrambling of the aromatic and methine hydrogens. The similarities between the processes occurring in azines and those in anils, both in their normal bond cleavages and in some bond‐forming reactions are emphasized.
Gas chromatographic—mass spectrometric studies of long chain hydroxy acids.—III.1 The mass spectra of the methyl esters trimethylsilyl ethers of aliphatic hydroxy acids. A facile method of double bond location
Authors: Eglinton G. , Hunneman D. H. , McCormick A. 
Published: May 2005

AbstractTrimethylsilylation has proved to be extremely useful in the gas chromatography and the mass spectrometry of hydroxy acid methyl esters. The characteristic mass spectral fragmentation patterns have shown these derivatives to be superior in some respects to others for structural elucidation; in particular, hydroxylation followed by trimethylsilylation provides a useful method of double bond location in unsaturated fatty acid esters.A preliminary presentation of this method has been given by G. Eglinton at the Lecture etting in Combined Gas Chromatography—Mass Spectrometry at the school of Pharmacy, London, August 9, 1967. It has come to the authors' attention that this method simultaneously developed by Dr. P. Capella, Institute di Industria Agrarie, University of Bologna, Italy1c (P. Capella and C. M. Zorzut, Anal. Chem. 41, 1458 (1968).)
Mass spectrometry of steroid systems.—XX The application of the ionization efficiency curves to some stereochemical problems
Authors: Sadovskaya V. L. , Zaretskii V. I. , Wulfson N. S. , Sizoy V. F. 
Published: May 2005

AbstractThe dependence of the cleavage of some cis/trans‐isomers in the terpenoid and steroid series on the energy of the ionizing electrons have been studied.
Mass spectra of substituted thioglycollic acids and esters. Skeletal rearrangement upon electron‐impact
Authors: Bowie J. H. , Madsen J. Ø. , Lawesson S.‐O. , Cooks R. G. 
Published: May 2005

AbstractThe mass spectra of thioglycollic acids and esters are reported and discussed. The spectra of compounds of the type X·CH(Y)·S·CH2·COOR(X > Y) contain skeletal rearrangement fragments with the composition R·Y·C2H3SO+. Ions produced by simple cleavage processes may be usefully correlated with structure.
Fragmentation of organic compounds on electron‐impact—VI. Dideuteriooctanes
Authors: Weinberg D. S. , Scoggins M. W. 
Published: May 2005

AbstractEleven isomeric octenes were converted to the corresponding dideuterio derivatives and the mass spectra recorded. The cracking patterns of the various dideuterioctanes are unique and the distribution of peaks representing the higher molecular weight ions can be predicted using a simple fragmentation model. The application of this technique to the determination of the position of the double bond in olefins of known carbon skeleton is discussed.
Mass spectrometry in structural and stereochemical problems—CLXXI: Factors governing the preferential loss of small vs. Large radicals in the α‐fission of aliphatic amines
Authors: Brown C. A. , Duffield A. M. , Djerassi Carl 
Published: May 2005

AbstractA study of the α‐cleavage processes of aliphatic amines (using RLCH2N(R)CH2Rs and RLCH(NR)RsRL represents the larger Rs the smaller alkyl group throughout this paper and both, unless indicated to the contrary, have similar degrees of lsubstitution on the α‐carbon atom.
as typical substrates) at several ionizing voltages indicates that the loss ratio of large and small alkyl radicals, [M  RL]/[M  Rs], decreases with ionizing voltage. This ratio, greater than 1·0 at 70 eV, may become less than unity at low voltage (15 eV, 10 eV) in some cases. Comparison of similarly structured compounds with nitrogen or oxygen as the heteroatom suggests that the effects of ionizing voltage are lessened when the fragment is of greater stability (e.g. amine vs. ether or imine vs. ketone). The effects of lowering the ionizing voltage became much less pronounced as the alkyl groups become larger or similar in size.
Mass spectrometry in structural and stereochemical problems—CLXXIV:1 Electron‐impact induced fragmentation of some aryl‐ and alkylsulfonylthioureas
Authors: Duffield A. M. , Djerassi Carl , Neidlein R. , Heukelbach E. 
Published: May 2005

AbstractThe mass spectra of five aryl (I to V) and four alkylsulfonylthioureas (VI toIX) have been recorded and mechanistic rationalizations are suggested for their principal fragmentation processes. The aryl analogs exhibited peaks in their mass spectra corresponding to skeletal rearrangements with elimination of SO2 from their molecular ions but this fragmentation was absent in those alkylsulfonylthioureas (VI to IX) examined.
Mass spectra of some quinoline hydroxamic acids and related compounds
Authors: Coutts R. T. , Hindmarsh K. W. 
Published: May 2005

AbstractThe mass spectra of some 3‐ and 4‐substituted quinoline hydroxamic acids and related compounds have been interpreted, and proposed fragmentations substantiated by means of deuterium‐labeling and accurate mass determinations. All compounds examined gave abundant molecular ions; most showed strong [M  16]+ ions and weak [M  17]+ ions. The expulsion of CO and HCN molecules and H and HCO radicals were common subsequent decompositions. The spectrum of 4‐hydroxy‐2‐methylquinazoline‐3‐oxide (VII) was unique and showed that nitric oxide was expelled from the molecular ion.
Mass spectra of indazolones and pyrazolones—II: 5‐pyrazolones
Authors: Desmarchelier J. M. , Johns R. B. 
Published: May 2005

AbstractThe mass spectral fragmentations of 3‐methyl‐5‐pyrazolone (I), 3‐methyl‐5‐pyrazolone‐1‐d1 (II), 3‐methyl‐5‐pyrazolone‐1,4,4‐d3 (III), 1‐acetyl‐3‐methyl‐5‐pyrazolone (IV), 3‐methyl‐5‐ethoxy‐pyrazole (V), 3,4‐dimethyl‐5‐pyrazolone (VI), 1,3‐dimethyl‐5‐pyrazolone (VII), 1‐acetyl‐5‐acetoxy‐3,4‐dimethylpyrazole (VIII), 1,2,3‐trimethyl‐5‐pyrazolone (IX), 3,4,4‐trimethyl‐5‐pyrazolone (X), 3,4,4‐trimethyl‐5‐pyrazolone‐1‐d1 (XI), 3‐phenyl‐5‐pyrazolone (XII), 2‐acetyl‐3‐phenyl‐5‐pyrazolone (XIII) and 5‐acetoxy‐3‐phenylpyrazole (XIV) are reported. Comparison is made between the mass spectra of 5‐pyrazolones and 3‐indazolones. As for the latter compounds initial loss of ·N2R is preferred to loss of ·CHO, and is followed by loss of CO. The [M  1]ions are intense in the C‐methyl substituted pyrazolones, and unlike the 3‐indazolones, the pyrazolones do not show any significant loss of HCN from these ions. The mass spectra distinguish between certain isomeric 5‐pyrazolones.
The structure of [YC6H5O]+· ions in the spectra of aryl alkyl ethers
Authors: McLafferty F. W. , Schiff L. J. 
Published: May 2005

AbstractThe [YC6H5O]+· ions from YC6H4OC2H5 appear to correspond in structure to the molecular ions of the analogous substituted phenols, [YC6H4OH]+·.
Studies in organic mass spectrometry—VI. The fragmentation of enol derivatives of acyclic β‐diketones
Authors: Vandewalle M. , Schamp N. , Francque M. 
Published: May 2005

AbstractThe mass spectra of enol derivatives of β‐diketones, such as enol ethers and enaminies are discussed. Their behaviour under electron‐impact is in accordance with the fragmentation we suggested for an acyclic β‐diketone in the enol form.Rearrangement of the enol functional group is observed in the spectra. This process is a general one, as it show not only migration of oxygen and nitrogen in the enol ethers and enamines, but also migeration of sulphur and chlorine in the thio‐ether and in 4‐chloro‐3‐pentene‐2‐one.Enol derivatives are suitable compounds for determining the branching of alkyl chains in β‐diketones.
High resolution mass spectrometry—V: Cyclic esters of aliphatic α‐hydroxy acids
Authors: Goulden J. D. S. , Millard B. J. 
Published: May 2005

AbstractThe main fragmentation sequences of glycollide and its homologues are initiated by fission of a COO bond, leading to the formation of fragment ions of low, m/e, such as [R1CO]+ and [CR1R2CCO]+. When a hydrogen atom is present on a ring carbon atom, 1,3 hydrogen migration occurs to produce [CHR2OH]+. In case where a ring carbon atom carries an alkylchain ⩾ C2H5, a McLafferty rearrangement occurs with the adjacent carbonyl group. When both ring carbon atoms are dimethyl substituted, a 1,4 hydrogen migration must be invoked to account for the observed fragmentation sequence.
A mass‐spectral study of exo‐ and endo‐2‐norbornyl bromide and exo and endo‐8‐bromobicyclo[3.2.1]octane by photoionization
Authors: DeJongh D. C. , Shrader S. R. , Isakson R. G. , LeBel N. A. , Beynon J. H. 
Published: May 2005

AbstractThe photoionization, as well as the electron‐impact, mass spectra of exo‐and endo‐norbornyl bromide and of exo‐and endo‐8‐bromobicyclo[3.2.1]octane show that exo‐Br loss is more facile than endo‐Br loss in formation of C7H11⊕ and C8H13⊕, respectively. The relative intensity values are compared with solvolysis data from the same systems.
Terpenoids—CXXXVII: Fragmentation of constunolide and its derivatives under electron‐impact
Authors: Sathe R. N. , Kulkarni G. H. , Kelkar G. R. , Das K. G. 
Published: May 2005

AbstractAn attempt has been made to correlate the fragmentation modes and structure of costunolide and some lactones derived from it, containing a ten‐membered carbocyclic system. The possible origins for the major fragments have been determined, using high resolution mass spectrometry and deuterium labelling.
The mass spectra of sydnones
Authors: Goudie R. S. , Preston P. N. , Palmer M. H. 
Published: May 2005

AbstractThe mass spectra of thirty sydnoes have been interpreted; the types investigated include 3‐aryl, 3‐alkyl‐, substituted 3‐alkylsydnones; and bis sydnones. A characteristic fragmentation mode involves initial loss of NO and CO from the molecular ion, but peaks corresponding to alkylcarbonium ions dominate the spectra of 3‐alkylsydnones; a cyclic mechanism is suggested for weak transitions involving loss of sydnone neutral molecule from the molecular ion. A mechanism is proposed for loss of chlorine radical from the molecular ion of 3‐(2,4‐dichlorophenethyl)sydnone. An unusual feature in the mass spectrum of trimethylenebis sydnone is rationalised on the basis of a precursor 1,2,3‐oxadiazole ion. The effect of substituents in the aryl ring on the fragmentation of 3‐arylsydnones is discussed.
Electron‐impact induced fragmentation of some natural products containing bis‐2,2‐dimethylchromene and bis‐2,2‐dimethylchroman ring systems
Authors: Duffield A. M. 
Published: May 2005

AbstractDerivatives of eriostoic and eriostemoic acids (II and III) and their tetrahydro analogs (VI and IX) which contain the bis‐2,2‐dimethylchromene and the bis‐2,2‐dimethylchroman ring systems respectively, fragment subsequent to electron‐impact in characteristic fashion. The former yield mass spectra dominated by the loss of a methyl radical from their molecular ions while the latter exhibit preferential fragmentation of the heterocyclic ring system. In particular the hydrogen transfer process accompanying elemination of C4H7 from the parent ion of bis‐2,2‐dimethylchromans was investigated by deuterium labeling studies. Fragment ions containing the bis‐2,2‐dimethylchroman ring undergo further fragmentation by the loss of C4H8 rather than C4H7. An unusual elimination of CH5 (accompanied by the appropriate metastable ion) from the molecular ions of the 3,5‐dinitrobenzoate esters (XIV and XV) was observed in their mass spectra.
The mass spectra of 2‐alkyl N‐methyl pyrrolidines
Authors: Osman S. , Dooley C. J. , Foglia T. 
Published: May 2005

AbstractThe mass spectra of a series of 2‐alkyl N‐methyl pyrrolidines have been examined and fragments which may be pyrrole type structures are apparent. These ions are most prominent in the spectra of the long chain alkyl derivatives.
The mass spectra of some 1,3,2‐oxazaborolidines
Authors: Brooks C. J. W. , Middleditch B. S. , Anthony G. M. 
Published: May 2005

AbstractLow resolution mass spectra of a series of alkylphenyl‐1,3,2‐oxazaborolidines are reported. The characteristic fragmentations are shown to be an aid to the elucidation of the substituents in the 1,3,2‐oxazaborolidine ring by means of a ‘substituent shift’ technique.