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141.
From the carbolithiation of 6‐morpholino fulvene ( 3a ) and different ortho‐lithiated heterocycles (furan, thiophene and N‐methylpyrrole), the corresponding lithium cyclopentadienide intermediate ( 4a – c ) was formed. These three lithiated intermediates underwent a transmetallation reaction with TiCl4 resulting in morpholino‐functionalised titanocenes 5a – c . When these titanocenes were tested against LLC‐PK cells, the IC50 values obtained were of 58, 63 and 115 μM for titanocenes 5a – c respectively. The most cytotoxic titanocene 5a with an IC50 value of 58 μM is found to be approximately 20 times less cytotoxic than cis‐platin, which showed an IC50 value of 3.3 μM, when tested on the LLC‐PK cell line, and 10 times less cytotoxic than its dimethylamino‐functionalised analogue (Titanocene C , IC50 = 5.5 μM). 相似文献
142.
Urmas Muinasmaa Clara R fols Elisabeth Bosch Martí Ros s 《Analytica chimica acta》1997,340(1-3):133-141
The dissociation constants of several acids (perchloric, hydrochloric, phosphoric, acetic and benzoic acids) and of some sodium salts (chloride, acetate and benzoate) have been conductometrically determined in tetrahydrofuran/water mixtures up to a 90% of tetrahydrofuran in volume. The results demonstrate that conductometry can be successfully applied to determine the dissociation constants of salts and moderately weak and strong acids in the studied mixtures. The dissociation constants of the acids and some bases taken from the literature have been fitted to solvent composition through a previously derived equation, which is based on a preferential solvation model. The fitting parameters obtained allow calculation of the dissociation constant for any solvent composition inside the applicability solvent composition range. From the pK value, the pH of any buffered solution, such as those used in liquid chromatography, can be calculated for the particular tetrahydrofuran/ water composition of interest. Appreciable ion-pairing for sodium salts and strong acids has been observed for tetrahydrofuran contents higher than 60% in volume. Therefore, the accurate calculation of the pH values of buffers in tetrahydrofuran-rich solutions must take into account the pK values of the acid and salt. 相似文献
143.
A proteomic approach to study protein variation in GM durum wheat in relation to technological properties of semolina 总被引:1,自引:0,他引:1
Di Luccia A Lamacchia C Fares C Padalino L Mamone G La Gatta B Gambacorta G Faccia M Di Fonzo N La Notte E 《Annali di chimica》2005,95(6):405-414
Genetic manipulation of durum wheats by tobacco rab-1 genes influence the trafficking of gluten proteins through the secretory system by up- or down-regulating the transport step from the ER to the Golgi apparatus which may in turn modify functional performance of the grain. Gluten proteins were extracted from two genetically manipulated lines - Svevo B730 1-1 and Ofanto B688 1-2 - and their control lines and were analyzed by two dimensional gel electrophoresis. When the two-dimensional maps were compared by image analysis no significant differences between the GM line with an up-regulated trafficking containing the wild type tobacco rab1 (Svevo B730 1-1) and its control (Svevo control). By contrast, significant differences were found between the GM line with a down-regulated trafficking due to the tobacco rab1 mutant form (Ofanto B688 1-2) and its control (Ofanto control). Of the new protein spots detected in the down-regulated Ofanto B688 1-2 map, only a beta-amylase was identified. The remaining spots were susceptible to chymotripsin action but not to trypsin one, as in the case of the gluten protein. Rheological measurements showed that gluten quality was enhanced in the down-regulated Ofanto B688 1-2 without an increase in the amount of gluten. Proteomics is a useful and powerful tool for investigating protein changes in GMOs and in understanding events in food science and technology. 相似文献
144.
Andrea M. Gasco Clara Cena Antonella Di Stilo Giuseppe Ermondi Claudio Medana Alberto Gasco 《Helvetica chimica acta》1996,79(7):1803-1817
The synthesis, structural characterization, and NO donor properties of a series of terfuroxan (= terfurazan trioxide) derivatives 1a–h and 2a–j are reported (Schemes 1 and 2). Structural assignments were confirmed principally by mass and 13C- and 1H-NMR spectroscopy. The extent and the initial rate of NO release in the presence of thiol cofactor was evaluated for each derivative. Vasodilator effects of all the terfuroxan derivatives were evaluated on endothelium-denuded strips of rat aorta precontracted with noradrenaline. Concentration-response curves were also evaluated in the presence of 10 m?M oxyhemoglobin (HbO2), a well known NO scavenger. The whole series displays high vasodilating potency; the most active terfuroxans ( 1a, b, g and 2i ) are 5–10 times as potent as glyceryl trinitrate taken as reference (see Table 3). The potency decrease observed in the presence of HbO2 agrees with the involvement of NO in the vasorelaxing action. The 4,3′:4′,4″ connection (series 1 ; furoxan numbering) gives rise to the most potent compounds. The conformational factors seem to play important roles in the activity. No clear relationship between physico-chemical properties of the substituents and potencies of derivative emerges. 相似文献
145.
Magalhães Maria Clara F. Silva Maria Celina M. 《Monatshefte für Chemie / Chemical Monthly》2003,134(5):735-743
Monatshefte für Chemie - Chemical Monthly - ?Predictions of lead arsenate solubility and thermodynamic stability have been based on the value of the solubility constant for a precipitate... 相似文献
146.
Planas JG Viñas C Teixidor F Comas-Vives A Ujaque G Lledós A Light ME Hursthouse MB 《Journal of the American Chemical Society》2005,127(45):15976-15982
The existence of a dihydrogen bond (S-H...H-B) and its combination with a C-H...S hydrogen bond in an unusual cooperative effect are demonstrated from a combination of experimental and theoretical methods. This cooperative effect seems to be responsible for self-assembly of mercaptane-metallacarborane complexes such as closo-[3-Ru(eta6-C6H6)-8-HS-1,2-C2B9H10] (1) and closo-[3-Co(eta5-C5H5)-8-HS-1,2-C2B9H10] (3), which present identical supramolecular two-dimensional polymeric networks. The findings, besides documenting structurally the first S-H...(H-B)2 dihydrogen bond and the unconventional cooperative ability of a boron-attached SH group, prove that substituted carboranes have the potential to serve as building blocks for assembling complex structures. 相似文献
147.
148.
149.
Some advantages, disadvantages, and anomalies of various donors in glycosidations are discussed. By studying several two‐component donor/acceptor‐diol reactions, it is shown that regiopreferences are not very sensitive to the type of donor used. However, in competitive glycosidations within a given type of donor and between different types of donor, it is shown that regio‐ and chemoselectivities must be indexed to donor reactivity. 相似文献
150.
Elisabet Fuguet Clara Ràfols Elisabeth Bosch Michael H. Abraham Martí Rosés 《Journal of chromatography. A》2009,1216(40):6877-6879