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Marwa Elsbaey Bai Jie Chiaki Tanaka Hikaru Kato Sachiko Tsukamoto Kazuteru Usui Go Hirai Tomofumi Miyamoto 《Tetrahedron letters》2019,60(33):150948
Two novel epimers, named nuciferols A (1) and B (2), possessing a unique 6.9′, 9.6′, 7′.8″-cyclosesquineolignan skeleton, were isolated from the ethyl acetate fraction of the endocarp of Cocos nucifera. Their planar structure was elucidated by 1D-, 2D-NMR, HRESIMS and their absolute configuration was determined by ECD. Nuciferols A and B showed radical scavenging activity using DPPH assay, and only nuciferol B showed neuroprotective effects against t-BHP induced cell death in N2a cells. 相似文献
143.
Profens, including pranoprofen, fenoprofen, flurbiprofen, ketoprofen and ibuprofen (Ib), were derivatized by a water-soluble benzofurazan fluorescent reagent, 4-N-(4-N'-aminoethyl)piperazino-7-nitro-2,1,3-benzoxadiazole and then were run on capillary electrophoresis in a NH4Ac-HAc buffer of pH 3.1 containing 2.4 mM beta-cyclodextrin. At room temperature, the derivatization reaction was catalyzed by triphenyl phosphine and diphenyl disulfide in acetonitrile medium, and the derivatives fluoresce around 530 nm when excited at 488 nm. With the CE running on a 50 cm x 50 microm I.D. length fused-silica capillary of by using Ar+ laser induced-fluorescence detection, the detection limits attained were in the range of 0.16 to 0.3 fmol. 相似文献
144.
O-Permethylated cyclodextrins (MeCDs) were found to be polymerizable with the initiator-activator system of HI-I2 or HI-ZnX2, undergoing ring-cleavage to give linear 1-->4-glucan. Among several conditions investigated, HI-ZnCl2 in CH2Cl2 at 0 degree C proved most effective to control this cationic ring-opening polymerization (CROP). The MALDI-TOF-MS spectrum revealed that the molecular weight distribution of the glucan obtained from gamma-MeCD uniquely consisted of large, regular intervals, each of which were identical to the molecular weight of gamma-MeCD (1634). 相似文献
145.
A novel fluorescent reagent for hydroperoxides, 4-(2-diphenylphosphinoethylamino)-7-nitro-2,1,3-benzoxadiazole (1), was developed on the basis of the method for designing photoinduced electron transfer (PET) reagents having a benzofurazan skeleton. Compound 1 was quantitatively reacted with hydroperoxides to give its fluorescent derivative, 2. In acetonitrile, the Phi value (0.44) of 2 was 31 times greater than that of 1. The long excitation (458 nm) and emission (520 nm) wavelengths of 2 are suitable for the determination of hydroperoxides, especially in biosamples. [structure: see text] 相似文献
146.
Santa T Al-Dirbashi OY Ichibangase T Fukushima T Rashed MS Funatsu T Imai K 《Biomedical chromatography : BMC》2007,21(11):1207-1213
The applicability of benzofurazan derivatization regents to carboxylic acids analysis in LC/ESI-MS/MS (high-performance liquid chromatography/electrospray ionization tandem mass spectrometry) was examined. The product ion spectra of DAABD-AE {4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(2-aminoethylamino)-2,1,3-benzoxadiazole}, DAABD-PZ {4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-N-piperazino-2,1,3-benzoxadiazole}, DAABD-PiCZ {4-[4-carbazoylpiperidin-1-yl]-7-[2-(N,N-dimethylamino)ethylaminosulfonyl]-2,1,3-benzoxadiazole}, DAABD-ProCZ {4-[2-carbazoylpyrrolidin-1-yl]-7-[2-(N,N-dimethylamino) ethylaminosulfonyl]-2,1,3-benzoxadiazole} and DAABD-Apy {4-[2-(N,N-dimethylamino)ethylaminosulfonyl]-7-(3-aminopyrrolidin-1-yl)-2,1,3-benzoxadiazole}, and their acetylated compounds were obtained. An intense fragment ion at m/z 151 corresponding to (dimethylamino)ethylaminosulfonyl moiety was observed in each spectra, suggesting that these reagents were suitable for ESI-MS/MS analysis. DAABD-AE, DAABD-APy and DAABD-PZ were applied to the analysis of octanoic acid and it was found that DAABD-AE and DAABD-APy gave high signal intensity suitable for LC/ESI-MS/MS. 相似文献