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91.
Formal total synthesis of magellanine is described. Key features in the synthesis were stereoselective Ireland-Claisen rearrangement and intramolecular Pauson-Khand reaction of exo-cyclic enynes. 相似文献
92.
Miyuki Hagiwara Tôru Tagawa Eishun Tsuchida Isao Shinohara Tsutomu Kagiya 《高分子科学杂志,A辑:纯化学与应用化学》2013,50(8):1591-1609
A study was made on the radiation-induced cross-linking reaction of polyethylene by exposing film samples to [ddot]Co γ-rays in vacuum or in the presence of various acetylenic compounds such as acetylene, its C3 to C5 higher derivatives, and their mixture with tetrafluoroethylene (TFE). The samples (0.2 mm thick) were found to decrease in weight when irradiated in vacuum, but to increase in the presence of the additives. The IR spectrum measurements of the resultant showed that the trans-vinylene unsaturation increased by the irradiation, especially in the presence of the C3 to C5 derivatives, and terminal vinyl increased markedly in acetylene. However, the formation of these unsaturations were depressed when the film was irradiated in the mixed gas with TFE. The rate of the cross-linking reaction was accelerated by the addition of acetylene-TFE, acetylene, trifluoromethyl-acetylene, perfluorobutyne-2, perfluorobutyne-2-TFE, and methylacetylene-TFE [G(cross-linking) = 4.4-1.2]. It was reduced with methylacetylene, butyne-1, butyne-1-TFE, pentyne-1, pentyne-1-TFE, pentyne-2, pentyne-2-TFE, [G(cross-linking) = 0.6-0.1]. On the basis of these experimental results a chain reaction scheme of the cross-linking is proposed, and it is discussed on the basis of the activation energy of the elementary reactions. 相似文献
93.
Mitsuji Yamashita Akihiro Yabui Kazumitsu Suzuki Yukihiro Kato Miyuki Uchimura Akihito Iida 《Journal of carbohydrate chemistry》2013,32(4-5):499-519
Abstract Some phosphanyl sugar derivatives, which are analogs of sugars having a phosphorus atom in place of the ring oxygen, were synthesized from 2- and 3-phospholenes as starting materials. Catalytic cis-dihydroxylation of 2-phospholene or 3-phospholene 1-oxide derivatives with osmium(VIII) oxide in the presence of a cooxidant afforded 3-deoxy- or 1-deoxy-tetrofuranose-type phosphanyl sugar derivatives, respectively. cis- Dihydroxylation of 4-acyloxy-2-phospholene 1-oxide derivatives gave tetrofuranose type phosphanyl sugar derivatives. Some of these derivatives of phosphanyl sugars were subjected to structural analyses using 1H NMR and X-ray crystallography. 相似文献
94.
95.
Ohyama Kaname Oyamada Kana Kishikawa Naoya Arakawa Miyuki Ohba Yoshihito Kamino Masahiro Wada Mitsuhiro Nakashima Kenichiro Kuroda Naotaka 《Chromatographia》2009,70(9-10):1501-1504
A new class of chiral stationary phases (CSP) with peptide chiral selectors was prepared by solid-phase synthesis with a tert-butoxycarbonyl-L-amino acid on silica. The type of amino acid that is favorable for this class of CSP is discussed. Using the CSP with the phenylalanine peptide selector, the effect of peptide length on the enantioselectivity was investigated in normal-phase mode. The applicability of the CSP with a phenylalanine peptide to chiral ligand-exchange chromatography was also examined.
相似文献96.
We investigated simultaneous determination of haloperidol (HAL), its three metabolites [reduced HAL (R-HAL), 3-(4-fluorobenzoyl)propionic acid (FBPA) and 4-(4-chlorophenyl)-4-hydroxypiperidine (CPHP)] and two related compounds [spiperone (SPI) and droperidol (DRO)] in phosphate-buffered saline using high-performance liquid chromatography (HPLC) coupled with dual ultraviolet detection (220 and 250 nm). Retention times of HAL, R-HAL, FBPA, CPHP, SPI and DRO were 16.8, 11.8, 10.2, 4.1, 12.6 and 8.3 min, respectively. Their lower limits of detection were 7.5, 14, 4.5, 12, 10 and 20 ng/mL in the same order. The coefficients of variation for their intra- and inter-day assays were less than 7.8 and 9.4%, respectively. Of the other centrally acting drugs, only amoxapine interfered with the peak of DRO. Using our procedure, the binding study of tested compounds to synthetic melanin, human serum albumin and alpha1-acid glycoprotein was performed by determining the unbound concentration to total concentration ratio. These results indicated that simultaneous assay of HAL, R-HAL, FBPA, CPHP, SPI and DRO in phosphate-buffered saline by HPLC equipped with dual ultraviolet detection is simple, sensitive and reproducible. Also, our assay system can be applied to the binding study of these compounds to synthetic melanin, human serum albumin and alpha1-acid glycoprotein. 相似文献
97.
98.
Insecticidal compounds against Drosophila melanogaster from Cornus officinalis Sieb. et Zucc 总被引:3,自引:0,他引:3
Dimethyl malate (1) and 5-hydroxymethyl furfural (2) were isolated as insecticidal compounds by bioassay-guided fractionation from MeOH extract of the fruits of Cornus officinalis Sieb. et Zucc. Insecticidal activity against larvae of D. melanogaster was demonstrated: 1 and 2 gave the LC50 value of 6.15 and 11.8 micromol/mL of diet concentration, respectively. Acute toxicity against adults of D. melanogaster, 1 and 2 had the insecticidal activity, with the LD50 value of 21.5 and 34.0 microg/adult. 相似文献
99.
100.
Nishikawa T Koide Y Kajii S Wada K Ishikawa M Isobe M 《Organic & biomolecular chemistry》2005,3(4):687-700
The total synthesis of alpha-C-mannosyltryptophan (C-Man-Trp), a naturally occurring C-glycosylamino acid, was achieved from a commercially available alpha-methyl-D-mannoside in 10 steps including the following key steps: the C-glycosidation of a mannose derivative with a stannylacetylene, Castro indole synthesis, and Sc(ClO4)3-promoted coupling with L-serine-derived aziridine carboxylate. The glucose- and galactose-analogues of C-Man-Trp were also synthesized in a similar manner. Conformational analyses of the synthesized C-glycosyltryptophan and its synthetic intermediate are briefly discussed. 相似文献