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1.
The effect of the replacement of MnO2 by Fe2O3 on the oxidation states of iron in some lithium borosilicate glasses were studied using Mössbauer spectroscopy. DTA and infrared measurements showed the presence of two glassy phases, one of them containing iron and the other manganese. The Mössbauer spectra were measured at room temperature for all the glass samples. The spectra revealed the presence of Fe ions only in ferric state in both tetrahedral and octahedral coordination. Also, it was observed that the ratio between the number of iron ions in both coordination states has not changed with the increase of MnO2 content.  相似文献   
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This work deals with the theoretical study of Diels-Alder inverse and normal electron demand reactions. Based on various calculation methods such as SCF/6-31G and DFT/B3LYP with the standard basis set 6-31G, we discuss the possibility of reactions between cyclopentadiene with a series of 2-aryl-4,6-dinitrobenzotriazole 1-oxides from a thermodynamic perspective.  相似文献   
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Although 125I-hydroxypindolol (125I-HYP) has been an excellent probe of adenoceptor function in certain tissues, but 125I-pindolol (125I-PIN) was found more specific for -adrenoceptor labeling. This study describes a fast and efficient method for radiolabeling of pindolol with iodine-125, where both chloramine-T and iodogen were used as oxidizing agents. The use of iodogen coated glass frit has a great advantage in increasing the radiochemical yield of 125I-pindolol and this was attributed to the increase of the interphaces boundary between the solid and liquid. This technique reduces the quantity of iodogen required to produce high radiochemical yield by its half. The radiochemical yield was determined by TLC system using chloroform: acetic acid: water (15:4:1) as developing solvent and by HPLC using reversed phase RP-18 column and acetonitrile: 0.1M ammonium bicarbonate pH 7.5 (1:1) as a mobile phase at flow rate (1ml/min). The radiochemical yield was found to be 48.6 and 62.9% respectively.  相似文献   
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Abstract

In the present study, evaluation of the antiproliferative activity of Pachypodium lamerei Drake leaves (family Apocyaceae) against human breast cancer cell lines MDA-MB-231 was done for the total methanolic extract, crude alkaloidal mixture and ursolic acid using the MTT colorimetric assay. The methanolic extract showed the strongest antiproliferative activity followed by ursolic acid and crude alkaloidal fraction with an IC50 equal to 6.2, 14.55 and 56.3?µg/ml respectively compared to oleocanthal. It is the first record for the LC/ESI-MS/MS alkaloidal profiling of the leaves of P. lamerei. Seven alkaloids were tentatively identified according to their fragmentation patterns. Four alkaloids were related to the parent indole class and two alkaloids belong to the quinoline class in addition to one steroidal alkaloid with a pregnan nucleus. Phytochemical investigation of the methanolic extract led to the isolation of three triterpenoidal compounds including ursolic acid, 11,12-didehydroursolic acid lactone and ursolic acid lactone.  相似文献   
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3-Substituted quinazoline-2,4(1H,3H)-dione and 2,3-di-substituted quinazolineone derivatives attract considerable interest due to their pharmacological properties. In this paper, we report the synthesis of N-substituted-3-nitrophthalimide derivatives II?CIII, the reactions of phthalimide III with amines, hydrazines, and amino acid derivatives to synthesise a small library of 3-substituted-5-nitroquinazoline-2,4(1H,3H)-diones IV?CXIV and 2,3-di-substituted-6-nitro-quinazolineones XVIII?CXIX.  相似文献   
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8-Chloro-7-formyl-4-oxo-2-phenyl-4H-pyrimido[1,2-a]pyrimidine-3-carbonitrile ( 3 ) is constructed using N-(5-cyano-6-oxo-4-phenyl-1,6-dihydropyrimidin-2-yl) acetamide ( 2 ) via Vilsmeier-Haack formylation reaction. Compound 3 reacted with 3-(triethoxysilyl)propan-1-amine under different conditions. Condensation of pyrimidopyrimidine 3 with thiosemicarbazone derivative gave Schiff base 8 , which upon treating with Vilsmeier-Haack reagent afforded pyrazole carbothioamide 9 . Cyclocondensation of compound 3 with some binucleophiles namely thiocarbohyrazide, hydrazine carbodithioic acid, benzyl hydrazinecarbodithioate and/or 2-thioxopyrimidinone was investigated. Structures of the new synthesized compounds were confirmed by their analytical and spectral data.  相似文献   
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