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41.
A number of novel N-protected β-amino nitriles were prepared as substrates for two nitrile-converting microorganisms, Rhodococcus sp. R312 and Rhodococcus erythropolis NCIMB 11540. The respective biotransformation products, β-amino acids, are known to be pharmacological very potent compounds. 相似文献
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43.
A model system for the synthesis of phloroglucinol containing natural products was synthesized. Key steps include a manganic acetate-mediated cyclization and the facile conversion of an alkene into a β-bromoenone. 相似文献
44.
Alessandra LattanziLiliana R. Orelli Patrizia BaroneAntonio Massa Patrizia IanneceArrigo Scettri 《Tetrahedron letters》2003,44(7):1333-1337
A mild and practical procedure of Horner-Wadsworth-Emmons olefination promoted by lithium hydroxide and α-cyano phosphonates has been set up for the synthesis of α,β-unsaturated nitriles. The reaction conditions are tolerated by functionalized ketones and the exclusive formation of E-γ-hydroxy α,β-unsaturated nitriles has been observed. 相似文献
45.
46.
药物分子与β—环糊精络合的光谱研究 总被引:4,自引:0,他引:4
环糊精能在水溶液中包络尺寸合宜的分子至其疏水性的环状腔体中,包络过程被用于增大有机分子的水溶性,用作酶的模拟,用于色谱学、荧光光度法和室温磷光法等。β-环糊精(β-CD)是最通用的一种,其内腔直径为0.7nm。 相似文献
47.
We have reported recently that high-speed normal-phase (NP) HPLC separations of a broad range of organic compounds can be performed on cyano columns using gradients of methanol in hexane-like solvent-ethoxynonafluorobutane (ENFB), available commercially. In this communication, we demonstrate that atmospheric pressure chemical ionization (APCI) in combination with mass spectrometry (MS) can be effectively used for detection in such separations. The efficiency of APCI under conditions studied has also been compared to the efficiency of traditional electrospray ionization (ESI) in combination with MS for reversed-phase (RP) HPLC of the same compounds. The compounds included in this study were steroids, benzodiazepines, and other central nervous system-active substances, nonsteroidal anti-inflammatory drugs, tricyclic antidepressants, and beta-adrenergic blocking agents. Non-polar compounds were found to respond stronger when APCI-MS technique was used, whereas APCI and ESI ionization efficiencies were comparable when polar substances were studied. The combination of normal-phase HPLC separation conditions with mass spectral detection may expand the range of LC-MS applications traditionally associated with reversed-phase HPLC and ESI-MS detection. 相似文献
48.
The halohydrin reaction of chiral N-enoyl-2-oxazolidinones 1 by halogen (Br2/I2) and water were efficiently carried out in aqueous organic solvent promoted by silver(I) with high anti- and regioselectivity and moderate to good diastereoselectivities. The alkenoyl, cinnamoyl and electron-deficient cinnamoyl substrates smoothly underwent bromohydrin reaction in aqueous acetone but no iodohydrin reaction, where as electron-rich cinnamoyl substrates preferred to undergo iodohydrin reaction in aqueous acetone with moderate diastereoselectivity and enhanced diastereoselectivity was observed in aqueous THF. 相似文献
49.
《Tetrahedron》2004,60(3):693-701
The hydrolytic and transglycosylation capabilities of 35 fungal β-N-acetylhexosaminidases with p-nitrophenyl 2-amino-2-deoxy-β-d-glucopyranoside and its four N-acyl derivatives (CHO, COCH2OH, COCH2CH3, COCF3) as substrates were tested. The preparation of four novel p-nitrophenyl disaccharides from these unnatural substrates catalysed by enzymes from Aspergillus oryzae, Penicillium oxalicum and Talaromyces flavus represents a considerable extension of the synthetic potential of glycosidases. 相似文献
50.
A highly functionalized cyclopentanone building block 13 was prepared by a facile Rh-catalyzed intramolecular CH insertion reaction of an enantiopure α-diazo-γ-hydroxy-β-ketosulfone 12, in turn derived from an α-hydroxy acid 2. A cyclic γ-hydroxy vinyl sulfone 16 was also prepared from 13. 相似文献