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61.
62.
Dawid Maliszewski Agnieszka Wrbel Beata Kolesiska Justyna Frczyk Danuta Drozdowska 《Molecules (Basel, Switzerland)》2021,26(13)
A series of new analogs of nitrogen mustards (4a–4h) containing the 1,3,5-triazine ring substituted with dipeptide residue were synthesized and evaluated for the inhibition of both acetylcholinesterase (AChE) and β-secretase (BACE1) enzymes. The AChE inhibitory activity studies were carried out using Ellman’s colorimetric method, and the BACE1 inhibitory activity studies were carried out using fluorescence resonance energy transfer (FRET). All compounds displayed considerable AChE and BACE1 inhibition. The most active against both AChE and BACE1 enzymes were compounds A and 4a, with an inhibitory concentration of AChE IC50 = 0.051 µM; 0.055 µM and BACE1 IC50 = 9.00 µM; 11.09 µM, respectively. 相似文献
63.
Wawrzyniec Podkocielny Danuta Wdowicka 《Journal of polymer science. Part A, Polymer chemistry》1983,21(10):2961-2972
New polythioesters by interfacial polycondensation of bis/4-mercaptophenyl/ether with oxalyl, succinyl, adipoyl, suberoyl, or sebacoyl chlorides were obtained. To define the optimal conditions of the process, the polythioesters of dithiol and adipoyl or sebacoyl chlorides were chosen as a model system. Yield for all reaction products and reduced viscosity were found. The following factors were studied: organic phase, contribution of catalyst, concentration and molar ratio of reagents, rate of addition of acid chloride, temperature of reaction, contribution of emulsifier, and concentration of hydrochloride acceptor. The structure of all polythioesters was determined by elementary analysis, infrared spectra, and x-ray. Initial decomposition and initial intensive decomposition temperature were defined by the curves of thermogravimetric analysis. Some mechanical and electrical properties of polythioesters from dithiol and adipoyl or sebacoyl chlorides were studied. The molecular weights for these polymers were also determined by gel-chromatography. 相似文献
64.
Zofia Urbańczyk-Lipkowska Kinga Suwińska Danuta Mostowicz Marek Chmielewski 《Journal of chemical crystallography》1995,25(10):693-699
Geometry and molecular conformation of theN-toluenesulfonyl1 andN-acetyl-2 derivatives of peracetylated 2-C:1-N-carbonyl-2-deoxy--d-glucopyranosylamine were investigated with the use of X-ray diffraction methods. Compound1 (C20H23NSO10) crystallizes in the monoclinic P21 space group, withZ=2 anda=8.238(1),b=7.988(1),c=16.928(2)Å, =99.12(1)°. Compound2 (C15H19NO9) crystallizes in orthorhombic P212121 space group withZ=4 anda=8.385(1),b=8.550(1),c=24.000(2) Å. Analysis of differences in bond lengths and angles between compounds1 and2 and other compounds of this class showed that the electronwithdawing effect by the residue located at the nitrogen atom can be manifested by lengthening of the -lactam C-N bonds, with simultaneous shortening of the distance between two carbon atoms at the ring fusion. Semi-empirical calculations suggested that the title compounds displayed two positively charged centers, susceptible for attack of nucleophiles, one at the carbonyl group of -lactam and the second at the anomeric carbon atom. Atomic charges, however, calculated for compounds1 and2 did not explain their different reaction directions during alcoholysis.Part 3. For part 1 and 2, see Refs. 5 and 6. 相似文献
65.
On the basis of the polarized absorption spectra, the guest order parameter as a function of temperature for five dichroic azo dyes dissolved in four members (pentyl to octyl) of the homologous series of n-alkyl-4-(4-isothiocyanatophenyl)bicyclo[2,2,2]octanes has been evaluated. Moreover, the influence of the dichroic dye addition on the nematic-isotropic phase transition temperature has been examined. The relation between the molecular geometry of the guest, its orientation efficiency in the nematic host and the clearing temperature of the azo dye-liquid crystal mixtures has been determined. The experimental results have been compared in some detail with calculations performed on the basis of the mean field theory for binary mixtures. 相似文献
66.
The polarized absorption spectra of eight dichroic dyes, alkyl derivatives of 4-amino-(N-ethylnaphthalimide) dissolved in the nematic liquid crystals 5CB and 6CHBT have been measured as a function of temperature. On the basis of these spectra, the guest order parameter has been evaluated. The influence of the alkyl chain length of the dye molecule on the molecular orientation has been examined. Moreover, the nematic-isotropic transition temperatures for the dye-liquid crystal mixtures have been determined. The experimental results have been compared in some detail with calculations made on the basis of the mean field theory for binary mixtures. 相似文献
67.
The fragmentation behaviour of 18 vicinally substituted aminonitropyridines was studied under electron impact conditions. Tbe decomposition patterns were found to be strongly dependent on the position of substituents. The formation of the aza analogue of carbazole seems to affect considerably the fragmentation of 3-nitro-2-phenylaminopyridine. 相似文献
68.
A number of 2',5'- or 3',5'-diprotected ribonucleosides and 5'-protected 2'- or 3'-deoxy-β-D-erythro-pentofuranosyl nucleosides have been oxidized to the corresponding 3' or 2'-ketonucleoside derivatives using chromium trioxide/pyridine/acetic anhydride or dimethyl sulfoxide/ acetic anhydride. Reduction of the carbonyl functions with sodium borohydride gave the inverted arabino, xylo, or deoxy-threo isomers as predominant products by attack at the less hindered α-face of the sugar ring. Parallel reductions using sodium borodeuteride corroborated the epimeric ratios by demonstrating that complete oxidation of the original hydroxyl groups had occurred. The deuterium labeling also aided in making NMR spectral assignments. 相似文献
69.
It is demonstrated that for Ne-like systems, the zeroth-plus-first-order wavefunctions, obtained within Rayleigh—Schrödinger perturbation theory based on H0 = HHF, are of the same accuracy as variational wavefunctions obtained in CI calculations using very extensive sets of singly and doubly excited configurations. Variational correlation energies for Na+, Mg2+ and Ar8+ are reported for the first time. 相似文献
70.
The orientational order of a liquid crystalline side chain polysiloxane has been investigated by means of polarized light spectroscopy and dielectric relaxation measurements. The order parameters (P2) and (P4) have been determined as a function of the temperature for the smectic and nematic phases. The orienting properties of the polysiloxane investigated have been compared with those of a polysiloxane with the same mesogenic groups, but a shorter spacer. 相似文献