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71.
Han JH Yoo SK Seo JS Hong SJ Kim SK Kim C 《Dalton transactions (Cambridge, England : 2003)》2005,(2):402-406
The systematic oxidation reactions of a wide range of alcohols have been carried out by using an iron porphyrin complex in order to understand their relation to cytochrome P-450 enzymes and to have a practical application to organic synthesis. The iron porphyrin complex catalyzed efficiently alcohol oxidation to the respective carbonyl compound via a high-valent iron-oxo porphyrin intermediate ((Porp)Fe=O+). Several mechanistic studies such as isotope 18O labeling, deuterium isotope effect, linear free energy relationship, and ring-opening of radical clock substrate, have suggested that the alcohol is oxidized by a sequence of reactions involving an alpha-hydroxyalkyl radical intermediate and oxygen rebound to form the gem-diol, dehydration of which yields the carbonyl compounds. Moreover, it has been proposed that a two-state reactivity mechanism can also be adopted for alcohol oxidation reactions in iron porphyrin model systems as exhibited by P-450 enzymes. 相似文献
72.
Yong‐Min Lee Yoon‐Bo Shim Seung Jae Lee Sung Kwon Kang Sung‐Nak Choi 《Acta Crystallographica. Section C, Structural Chemistry》2002,58(12):o733-o734
The structure of the title compound, C15H27N2+·ClO4?, consists of a monoprotonated sparteinium cation and a perchlorate anion. The two tertiary N atoms of the cation, one perchlorate O atom and a H atom form a bifurcated hydrogen bond, the four hydrogen‐bonding atoms being nearly in the same plane. 相似文献
73.
A new calix[4]crown chemosensor based on dual sensing probes reveals Pb2+ ion selectivity over other metal ions, which arises from a hypsochromic shift of azo units in UV spectrum as well as a fluorescence enhancement of pyrenyl parts in fluorescence spectrum via a suppressed FRET. 相似文献
74.
Spherical molecularly imprinted polymer particles: a promising tool for molecular recognition in capillary electrokinetic separations 总被引:2,自引:0,他引:2
De Boer T Mol R De Zeeuw RA De Jong GJ Sherrington DC Cormack PA Ensing K 《Electrophoresis》2002,23(9):1296-1300
Spherical molecularly imprinted polymer particles obtained via precipitation polymerization, were introduced as a pseudostationary phase in capillary electrophoresis (CE) to study molecular recognition. Analyses were performed via a partial filling technique using (+)-ephedrine-imprinted microspheres (100-200 nm) which were polymerized from methacrylic acid and 1,1,1-Tris(hydroxymethyl)propanetrimethacrylate using acetonitrile as the solvent. The influence of pH and the modifier content on the separation was investigated. A 0.1% w/v suspension in an aqueous 10 mM phosphate buffer (pH 2.5 with 40% acetonitrile) was hydrodynamically injected into the CE system (80% of the effective capillary length) and led to full baseline separation of racemic ephedrine within 10 min. 相似文献
75.
Silver ions dissolved in a polymer matrix are additionally coordinated by carbonyl oxygens of asparagines and their counter anions interact with cationic sites, resulting in the enhanced activity of the silver ion as an olefin carrier for facilitated olefin transport. 相似文献
76.
A new trihydroxy briarane-related diterpenoid, junceellolide I (1), along with a known metabolite, (1R,2R,5Z,7R,8S,9R,10R,12R,14R,17S)-2,14-diacetoxy-8,17-epoxy-9,12-dihydroxybriara-5,11(20)-dien-19-one (2), have been isolated from the gorgonian coral Junceella fragilis, collected off the southern Taiwan coast. The structure, including the relative configuration of the new compound 1, was elucidated by the combination of spectral data, particularly in high-resolution 1H- and 13C-NMR spectroscopy utilizing COSY, HMBC, HMQC, and NOESY experiments. 相似文献
77.
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79.
Hwang JY Choi HS Seo JS La HJ Kim DS Jeon HS Jeon MK Lee DH Gong YD 《The Journal of organic chemistry》2005,70(24):10151-10154
[reaction: see text] A library containing 1200 analogues of 2,6-difunctionalized 2-methyl-2H-1-benzopyran was constructed by using a solid-phase synthesis protocol. Polymer-bound 6-amido-, 6-sulfonamido-, and 6-uredo-functionalized 2-hydroxymethyl-2-methylbenzopyrans 10 were prepared as part of a first-generation diversification step by employing reactions of respective acid halides, sulfonyl chlorides, and isocyanates with the amine precursor 7. Transformations of the resin-bound intermediates 10 by reactions with alkyl and acid halides were then used to produce a diverse series of 2,6-difunctionalized 2-methyl-2H-1-benzopyran analogues 12 and 14. 相似文献
80.
Reaction of trienes with α,β-unsaturated aldehydes produces bicyclic products via a tandem Diels-Alder/ene reaction. The adduct from tiglic aldehyde was converted into isoligularone by conversion to a furan followed by benzylic oxidation. 相似文献