ライフサイエンスコーパス: oxonium

1 Protonation of these species by the oxonium acid [H(OEt(2))(2)](+)[BAr'(4)](-) at low temper

2 oss of positive charge due to destruction of oxonium and pyridine, possibly caused the reduced phosph

3 derivative 12 is O/C diprotonated to give an oxonium-annulenium dication.

4 signature ion for CBCC peptides, the cyclic oxonium-biotin fragment ion that is generated upon fragm

5 A concerted 1,2-hydride shift/oxonium formation, followed by elimination, leads to for

6 improved by enrichment method, nanoLC-MS and oxonium glycan ions.

7 rboxylic and phenolic groups, a reduction of oxonium groups and the transformation of pyridine to pyr

8 of a stabilized carbocation from an allylic oxonium intermediate and subsequent trapping by a chiral

9 id-assisted formation of reactive iminium or oxonium intermediates enables the use of a mildly nucleo

10 ations on the O-methyl-2,3-dimethyl-2-butene oxonium ion along with transition states and intermediat

11 th the isomerization of the O-methylethylene oxonium ion and its tetramethyl-substituted analogue hav

12 These oxonium ion Bronsted acids are convenient reagents for t

13 thase in which an SN1-like reaction produces oxonium ion character at C-1 of PRPP which undergoes an

14 The hydride reduction of the intermediate oxonium ion EtO(SiEt(3))(2)(+), 9, occurs via attack by

15 urations of the substrates evidently control oxonium ion formation and their subsequent preferred mod

16 se from a bromonium ion induced transannular oxonium ion formation-fragmentation could also be isolat

17 Bromonium ion induced transannular oxonium ion formation-fragmentation gave the macrocyclic

18 by a face-selective chloronium ion initiated oxonium ion formation-fragmentation process followed by

19 ent exploration of their putative biomimetic oxonium ion formation-fragmentations reactions revealed

20 s includes proton transfer reactions through oxonium ion formation.

21 systems, and these suffer reduction prior to oxonium ion formation.

22 erences, determined through both peptide and oxonium ion fragments, of the desialylated Abeta1-15 or

23 Methanol complexation with the formed oxonium ion group gives rise to a "Zundel-like", shared

24 The putative oxonium ion intermediate 17 formed by an intramolecular

25 The oxonium ion intermediates are generated through Lewis ac

26 in situ generation of benzhydryl cation and oxonium ion intermediates from activated alkyl halides.

27 C5' substituent shields the beta-face of the oxonium ion involved in the coupling reaction while the

28 additional sequences in which the generated oxonium ion is trapped by an internal nucleophile were d

29 ion to generate comprehensive and untargeted oxonium ion maps of precursor masses assigned to fragmen

30 Oxatriquinane, a fused, tricyclic alkyl oxonium ion of unprecented stability, was synthesized in

31 lar modeling, in vitro enzymatic assays, and oxonium ion patterns, we propose that the observed O-lin

32 By calculating the diagnostic oxonium ion ratio of Gal2ABNeuAc and 2ABNeuAc fragments,

33 opening as compared to the O-methylethylene oxonium ion species, leading to a lower probability of i

34 o result from the ring-opening of a bicyclic oxonium ion that follows the nucleophilic capture by the

35 The photoredox cycle furnishes an oxonium ion that is captured by an internal nucleophile

36 ntification of the glycopeptides compared to oxonium ion transitions which allowed us to quantify the

37 nsely substituted 4-alkoxy quinolines via an oxonium ion triggered alkyne carboamination sequence inv

38 e neighboring imido group, and the resulting oxonium ion undergoes subsequent deprotonation to produc

39 ticularly, the initial state (benzyl alcohol oxonium ion) is less stabilized than the dehydration tra

40 at the oxygen atom for the O-methylethylene oxonium ion, 15.7 kcal/mol, agrees well with the experim

41 POCOP)Ir(H)(2) (5) and diethyl(triethylsilyl)oxonium ion, [Et(3)SiOEt(2)](+)[B(C(6)F(5))(4)](-) (7),

42 owever, addition of a silyl enol ether to an oxonium ion, followed by a one-pot debenzylation/spiroke

43 ddition of the alkene to the aryl 2-oxadiene oxonium ion, followed by an intramolecular aromatic subs

44 constructed via reductive cyclization of the oxonium ion, or oxy-Michael cyclization.

45 ttack of the nucleophile on the intermediate oxonium ion.

46 These oxonium-ion-containing spectra were then compared with t

47 The GIG tool extracts precursor masses, oxonium ions and glycan fragments from tandem (liquid ch

48 dal inversion(7) and the perception that all oxonium ions are highly reactive.

49 t we interpret in terms of fused and bridged oxonium ions arising from participation by the various b

50 que, which we named 'OxoScan-MS', identifies oxonium ions as glycopeptide fragments and exploits a sl

51 glycopeptides were selected by using glycan oxonium ions as signature ions for glycopeptide spectra.

52 ce comes from full characterization of these oxonium ions by low-temperature NMR spectroscopy support

53 In addition, detection of the oxonium ions enabled unambiguous differentiation of glyc

54 the intermediacy of 1-oxabicyclo[3.1.0]hexyl oxonium ions following participation by the pyranoside r

55 After specific enzymatic labeling, oxonium ions from higher-energy C-trap dissociation (HCD

56 developed and there are few applications of oxonium ions in synthesis beyond their existence as reac

57 tween glycan structures and the intensity of oxonium ions in the spectra of glycopeptides and utilize

58 are no examples of configurationally stable oxonium ions in which the oxygen atom is the sole stereo

59 lling of oxatriquinane alongside other alkyl oxonium ions indicated that the electronic consequences

60 witching for the detection of characteristic oxonium ions of saccharides.

61 Structure- and CE-specific oxonium ions provide sufficient information for the reso

62 Oxonium ions representing the distal subunit were observ

63 Oxatriquinanes are fused, tricyclic oxonium ions that are known to have exceptional stabilit

64 generates mono- or disaccharide ions called oxonium ions that carry information about the structure

65 ce of complex, thermally unstable, tricyclic oxonium ions that have been postulated as key reactive i

66 Protein Prospector can use these diagnostic oxonium ions to find glycopeptides, by showing that a we

67 on of 10 natural products on exposure of the oxonium ions to various nucleophiles.

68 opeptides using the spectral features of the oxonium ions using verification spectral set.

69 Oxatriquinanes are tricyclic oxonium ions which are known to possess remarkable solvo

70 renium ions, which form Meerwein's salt-like oxonium ions with methanol as the active methylating age

71 n moiety produces low molecular weight ions (oxonium ions) that can serve as a structure-specific sig

72 nce for catalysis by boron and not silylated oxonium ions, though Si-F bond formation is the enthalpi

73 However, the stereochemistry of oxonium ions-compounds bearing three substituents on a p

74 s of the precursor masses and characteristic oxonium ions.

75 st mass analyzer sufficient to form abundant oxonium ions.

76 arlier reports concerning crotylsilations of oxonium ions.

77 ETD)-MS(2) upon detection of glycan-specific oxonium is one of the better approaches in current LC-MS

78 ochemical conditions with a TMSOTf-catalyzed oxonium-mediated cyclization gave general access to pyrr

79 ormed ammonium (pK(CD(2))(Cl(2)) 5.7-8.2) or oxonium (pK(CD(2))(Cl(2)) -4.7-1.6) regulates the proton

80 hieno[3,2-c]pyran skeleton predominantly via oxonium-Prins cyclization.

81 The five-membered oxonium ring formation-ring opening mechanism is a poten

82 yloxatriquinane (1), a 3-fold tertiary alkyl oxonium salt, is described.

83 olvolytic stability compared to simple alkyl oxonium salts.

84 ceptional stability compared to simple alkyl oxonium salts.

85 represent the first examples of stable allyl oxonium species.

86 Tris(triphenylphosphinegold) oxonium tetrafluoroborate, [(Ph3PAu)3O]BF4, catalyzes th

87 certain carbophilic metals trigger carbenoid/oxonium type pathway.

88 the tetrahydrofuran in the C1-C9 fragment by oxonium ylide (free or metal-bound) formation and rearra

89 tative 1,2-group shift within an unsaturated oxonium ylide (Stevens rearrangement) accounts for the o

90 es result in tandem reactions, consisting of oxonium ylide formation followed by [2,3]-sigmatropic re

91 te results in a two-step process, an initial oxonium ylide formation followed by a [2,3]-sigmatropic

92 on with the reactant diazo compound inhibits oxonium ylide formation in copper-catalyzed reactions.

93 s for polyether coordination, intramolecular oxonium ylide formation occurs at the terminal oxygen, f

94 isting of five distinct steps: rhodium-bound oxonium ylide formation, [2,3]-sigmatropic rearrangement

95 Rh(II)-catalyzed oxonium ylide formation-[2,3] sigmatropic rearrangement

96 opropanation, carbon-hydrogen insertion, and oxonium ylide generation are compared from reactions of

97 type [1,2]-alkyl shift within the postulated oxonium ylide intermediate.

98 rated alcohol to form key silver-coordinated oxonium ylide intermediates, which triggers selective C-

99 An oxonium ylide rearrangement formed the trisubstituted te

100 basic oxygen atom of tetrahydrofuran to give oxonium ylide species.

101 Oxonium ylides formed in situ from substituted indoles s

102 o four carbon atoms in intermediates such as oxonium ylides, carbenes, carbocations, and free radical