Differences in the Formation and Fragmentation of Sodium Adduct Ions between Tertiarybutoxycarbonyl-Protected Prolylproline Diastereomers in Fast Atom Bombardment Mass Spectrometry.

Tsunematsu, Hideaki; Isobe, Ryuichi; Hanazono, Hiroshi; Soeda, Yasuko; Inagaki, Michio; Ito, Naofumi; Higuchi, Ryota; Yamamoto, Magobei

doi:10.1248/cpb.47.1040

Cited by 9 publications

(5 citation statements)

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“…It is difficult to discriminate between a pair of diastereomeric dipeptides or their derivatives by MS and MS/MS of a protonated molecule ion. We have reported that tert ‐butoxycarbonyl(Boc)‐ L ‐prolyl‐ L ‐proline is distinguished from Boc‐ D ‐prolyl‐ L ‐proline by the difference in the formation of the [M + Na] + ions and by collision‐induced dissociation (CID) of these ions on the addition of sodium chloride in positive‐ion FAB‐MS 15. In addition, we have recently reported that Boc‐ L ‐prolyl‐ L ‐proline ethyl ester (Boc‐ L ‐Pro‐ L ‐Pro‐OEt) is distinguished from Boc‐ D ‐Pro‐ L ‐Pro‐OEt by the CID spectra of the [M + Na] + ions in positive‐ion FAB‐MS, and dicussed the effect of the chemical structure of the C‐terminus in Boc‐protected prolylproline on the chiral recognition of these diastereomers 16.…”

Section: Introductionmentioning

confidence: 99%

Differentiation of a pair of diastereomeric tertiarybutoxycarbonylprolylproline ethyl esters by collision‐induced dissociation of sodium adduct ions in electrospray ionization mass spectrometry and evidence for chiral recognition by ab initio molecular orbital calculations

et al. 2003

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The fragmentation of the sodium adduct ions for tert-butoxycarbonyl-L-prolyl-L-proline ethyl ester (Boc-L-Pro-L-Pro-OEt) was compared with that for Boc-D-Pro-L-Pro-OEt in positive-ion electrospray ionization (ESI) mass spectrometry. In the collision-induced dissociation (CID) mass spectra of the [M + Na](+) ions, the abundance of the [M + Na - C(CH(3))(3) + H](+) ion, which is due to the loss of a tert-butyl group from the [M + Na](+) ion for Boc-D-Pro-L-Pro-OEt, was about eight times higher than that for Boc-L-Pro-L-Pro-OEt. In addition, in the CID spectra of the sodium adduct fragment ion ([M + Na - Boc + H](+)), the abundance of the [M + Na - Boc - prolylresidue + H](+) ion, which is due to the loss of prolyl residue from the [M + Na - Boc + H](+) ion for Boc-L-Pro-L-Pro-OEt, was about five times higher than that for Boc-D-Pro-L-Pro-OEt. These results indicate that Boc-L-Pro-L-Pro-OEt was distinguished from Boc-D-Pro-L-Pro-OEt by the CID mass spectra of the sodium adduct ions in ESI mass spectrometry. The optimized geometries of the [M + Na](+) and the [M + Na - Boc + H](+) ions calculated by ab initio molecular orbital calculations suggest that the chiral recognition of these diastereomers was due to the difference of the orientation of a sodium ion to the oxygen and nitrogen atoms in dipeptide derivatives, and to the difference of the total energies between them.

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Section: Introductionmentioning

confidence: 99%

Differentiation of a pair of diastereomeric tertiarybutoxycarbonylprolylproline ethyl esters by collision‐induced dissociation of sodium adduct ions in electrospray ionization mass spectrometry and evidence for chiral recognition by ab initio molecular orbital calculations

et al. 2003

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“…It was obtained as a mixture of conformers, as a white solid (0.74 g, 77%). mp 195–196 °C recrystallized from EtOAc (lit . 196–197 °C); 1 H NMR (600 MHz, CDCl 3 ): δ 4.62 (m, 1H), 4.45 (m, 1H), 4.48–4.43 (m, 1H), 3.77 (m, 1H), 3.61–3.43 (m, 1H), 2.50 (m, 1H), 2.29–1.85 (m, 8H), 1.44–1.40 (m, 9H).…”

Section: Methodsmentioning

confidence: 99%

“…mp 195−196 °C recrystallized from EtOAc (lit. 75 ). The spectral data are in accordance with those reported in the literature.…”

Section: The Journal Of Organic Chemistrymentioning

confidence: 99%

Hybrid Peptide–Thiourea Catalyst for Asymmetric Michael Additions of Aldehydes to Heterocyclic Nitroalkenes

2020

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Bifunctional organocatalysis combining covalent and noncovalent activation is presented. The hybrid peptide− thiourea catalyst features a N-terminal proline moiety for aldehyde activation and a thiourea unit for electrophile activation. This catalyst effectively promotes asymmetric Michael additions of aldehydes to challenging but biologically relevant heterocyclecontaining nitroalkenes. The catalyst can be used under solvent-free conditions. Spectroscopic and density functional theory studies elucidate the catalyst structure and mode of action.

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“…In some cases, differences in the abundances or formation of specific fragment ions can be observed in mass spectra especially when electron ionization (EI) has been applied as an ionization technique. Soft ionization techniques (chemical ionization (CI), fast atom bombardment (FAB), liquid secondary ion mass spectrometry (LSI) or electrospray (ESI)) give abundant protonated or cationized molecules from which stereochemical information can be obtained by collision‐induced dissociation (CID) 3–5. Investigation of fragmentation stereochemistry can be useful for better understanding of the factors influencing differences in the fragmentation of diastereoisomers of new compounds.…”

Section: Methodsmentioning

confidence: 99%

Stereochemical effects in fragmentation of diastereoisomers of protected diethyl 1,2-diamino-alkylphosphonates

Drabik

Błaszczyk

Gajda

et al. 2010

Rapid Commun. Mass Spectrom.

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Diastereoisomers of diethyl 5-substituted (2-thioxo-imidazolidin-4-yl)phosphonates, which can be regarded as protected diethyl 1,2-diaminoalkylphosphonates, have been analyzed by electron ionization mass spectrometry. Significant differences in the fragmentation of cis- and trans-diastereoisomers were found. The stereospecificity of the elimination of diethyl phosphonate and the loss of the diethoxyphosphoryl group were studied using specific labeled compounds and collision-induced dissociation. The relative abundances of ions formed via these fragmentation processes can be used for differentiation of both diastereoisomers.

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Differences in the Formation and Fragmentation of Sodium Adduct Ions between Tertiarybutoxycarbonyl-Protected Prolylproline Diastereomers in Fast Atom Bombardment Mass Spectrometry.

Cited by 9 publications

References 1 publication

Differentiation of a pair of diastereomeric tertiarybutoxycarbonylprolylproline ethyl esters by collision‐induced dissociation of sodium adduct ions in electrospray ionization mass spectrometry and evidence for chiral recognition by ab initio molecular orbital calculations

Differentiation of a pair of diastereomeric tertiarybutoxycarbonylprolylproline ethyl esters by collision‐induced dissociation of sodium adduct ions in electrospray ionization mass spectrometry and evidence for chiral recognition by ab initio molecular orbital calculations

Hybrid Peptide–Thiourea Catalyst for Asymmetric Michael Additions of Aldehydes to Heterocyclic Nitroalkenes

Stereochemical effects in fragmentation of diastereoisomers of protected diethyl 1,2-diamino-alkylphosphonates

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