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41.
Total synthesis of (-)-lentiginosine was achieved from D-mannitol using highly stereoselective reactions. Similarly, (+)-lentiginosine was synthesized from L-tartaric acid. 相似文献
42.
An efficient and mild method for the reduction of aromatic nitro and azido groups on solid support using Al/NiCl2·6H2O and Al/NH4Cl is described. This solid phase reduction technique has been applied towards the synthesis of DNA binding pyrrolo[2,1-c][1,4]benzodiazepine antitumour antibiotics. 相似文献
43.
Ghosh SK Hossain SU Bhattacharya S Bhattacharya SC 《Journal of photochemistry and photobiology. B, Biology》2005,81(2):121-128
The compound 2-(2-selenocyanic acid ethyl ester)-1H-benz[de] isoquinoline-1,3-(2H)-dione (SEBID), a ubiquitous, bioactive naphthalimide derivative is expected to possess an anticancer, anti-tumor and other important therapeutic activities of significant potency with low systematic toxicity. In this paper, the synthesis of the compound, photophysics of the newly prepared naphthalimide derivative and its interaction with model transport protein Bovine serum albumin (BSA) have been reported using the absorption and steady state fluorescence spectroscopic techniques exploiting the intrinsic fluorescence emission properties of BSA as a probe. Interaction of this organoselenium compound in different dioxane-water mixtures with increase in the polarity of the medium has been studied spectroscopically. Interaction of SEBID with BSA leads to a dramatic decrease in the fluorescence intensity of BSA, which suggests the binding of SEBID with the tryptophan residue of BSA. Furthermore, different thermodynamic parameters for SEBID-BSA interaction have been calculated. Rationalization of the data has been attempted, particularly in relation to prospective applications in the biomedical research. 相似文献
44.
[Chemical reaction: see text] A radical based Wagner-Meerwein-type rearrangement has been observed in camphoric systems. The radical was generated from the epoxide using Cp2TiCl as the radical source. The radical initiator Cp2TiCl was prepared in situ from commercially available Cp2TiCl2 and Zn dust in THF under argon. 相似文献
45.
2-Diethylaminoethanethiol hydrochloride is proposed for spectrophotometric determination of palladium(II). The sensitivity of the reaction is 0.0085 smg/cm2 and the yellow colored complex shows absorption maxima at 258 mμ and 303 mμ. Color development is slow in the cold but complete after heating for 10–15 min. The optimum pH range is 3.5 to 5.5 and the system adheres to Beer's law between 0.2 and 16.8 p.p.m. of palladium. The average and maximum relative standard deviations were 0.60% and 1.40% respectively. Interferences due to other platinum metals were studied and a procedure is suggested for the simultaneous determination of rhodium and palladium. 相似文献
46.
A method is described to impart flexibility and mechanical strength to conducting polyaniline by polymerizing aniline on fabrics and on cellulose papers. The study indicates that these conducting fabrics offer 16–18 dB of shielding effectiveness for the control of electromagnetic interference (EMI) up to a frequency of 103 MHz. 相似文献
47.
Chandra S Gupta LK 《Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy》2005,62(4-5):1089-1094
Nickel(II) complexes, having the general composition Ni(L)2X2, have been synthesized [where L: isopropyl methyl ketone semicarbazone (LLA), isopropyl methyl ketone thiosemicarbazone (LLB), 4-aminoacetophenone semicarbazone (LLC) and 4-aminoacetophenone thiosemicarbazone (LLD) and X=Cl-, 1/2SO(4)2-]. All the Ni(II) complexes reported here have been characterized by elemental analyses, magnetic moments, IR, electronic and mass spectral studies. All the complexes were found to have magnetic moments corresponding to two unpaired electrons. The possible geometries of the complexes were assigned on the basis of electronic and infrared spectral studies. Newly synthesized ligand and its nickel(II) complexes have been screened against different bacterial and fungal growth. 相似文献
48.
A kinetic model has been developed for the bulk polymerization of vinyl chloride using Talamini's hypothesis of two-phase polymerization and a new concept of kinetic solubility which assumes that rapidly growing polymer chains have considerably greater solubility than the thermodynamic solubility of preformed polymer molecules of the same size and so can remain in solution even under thermodynamically unfavourable conditions. It is further assumed that this kinetic solubility is a function of chain length. The model yields a rate expression consistent with the experimental data for vinyl chloride bulk polymerization and moreover is able to explain several characteristic kinetic features of this system. Application of the model rate expression to the available rate data has yielded 2.36 × 108l mol?1 sec?1 for the termination rate constant in the polymer-rich phase; as expected, this value is smaller than that reported for homogenous polymerization by a factor of 10–30. 相似文献
49.
A new series of N-substituted bis-(tetrahydropapaverine) ring systems have been synthesised in expectation of better antispasmodic activity in comparison with papaverine. The synthesis of the targeted heterocycles is described along with a discussion of their structure activity relationship. The general synthetic methods of bis-(tetrahydropapaverine) analogues involve tetrahydropapaverine, various piperazines, diisocyanates and diisothiocyanates as starting materials. Pharmacological evaluation involves the in vitro antispasmodic activity on a freshly removed guinea pig ileum using a force displacement transducer amplifier connected to a physiograph. Among the analogues synthesized in the present study, N,N'-bis-[2-carbamoyl-1-(3,4-dimethoxybenzyl)-6,7-dimethoxy-1,2,3,4-tetrahydroisoquinolinyl]piperazine (22), was found to be the most potent muscle relaxant (IC(50): 0.31 microM). 相似文献
50.
Israel Cabasso Suresh K. Sahni David Vofsi 《Journal of polymer science. Part A, Polymer chemistry》1988,26(11):2997-3014
Phosphonic acid ester derivatives of glycerol, D -mannitol, D -sorbitol, pentaerythritol, and dipentaerythritol have been synthesized by transacetalation reactions with diethyl 2,2-diethoxyethylphosphonate. These phosphonated derivatives of polyols and carbohydrates have been esterified to from the corresponding methacrylates. All these compounds have been characterized on the basis of their elemental analysis and spectroscopic (infrared including FT–IR, 1H-, 13C-, 31P-NMR, and mass) methods. Transacetalation reactions with dialkyl 2,2-dialkoxyethylphosphonate lead to the synthesis of 1,3-dioxane derivatives in the case of D -mannitol, pentaerythritol, and dipentaerythritol, whereas a mixture of both 1,3-dioxane and 1,3-dioxolane derivatives is obtained with D -sorbitol and glycerol. The methacrylates of phosphonylated polyol derivatives show the capacity to dissolve and interact with metal salts such as bismuth bromide and uranyl nitrate. Some of the polymers obtained from these monomers have been characterized on the basis of their spectral and thermal (differential scanning calorimetry) properties. 相似文献