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151.
152.
Bioactivity-guided purification of n-BuOH soluble fraction from the ethanol extract of Evolvulus alsinoides resulted in the isolation of two new compounds, 2,3,4-trihydroxy-3-methylbutyl 3-[3-hydroxy-4-(2,3,4-trihydroxy-2-methylbutoxy)-phenyl]-2-propenoate (1) and 1,3-di-O-caffeoyl quinic acid methyl ester (2) along with six known compounds, caffeic acid (3), 6-methoxy-7-O-beta-glucopyranoside coumarin (4), 2-C-methyl erythritol (5), kaempferol-7-O-beta-glucopyranoside (6), kaempferol-3-O-beta-glucopyranoside (7) and quecetine-3-O-beta-glucopyranoside (8). The structure of new compounds 1 and 2 were elucidated by spectroscopic analysis, while known compounds were confirmed by direct comparison of their NMR data with those reported in literature. This is the first report of the presence of phenolic constituents in Evolvulus alsinoides. The isolated compounds 1-5 and 8 were screened for anti-stress activity in acute stress induced biochemical changes in adult male Sprague-Dawley rats. Stress exposure has resulted in significant increase of plasma glucose, adrenal gland weight, plasma creatine kinase (CK), and corticosterone levels. Compound 1 displayed most promising antistress effect by normalizing hyperglycemia, plasma corticosterone, CK and adrenal hypertrophy, while compounds 2 and 3 were also effective in normalizing most of these stress parameters, however compounds 4, 5 and 8 were ineffective in normalizing these parameters.  相似文献   
153.
The reaction of N,N,N′,N′-tetrakis-(1H,benzimidazol-2ylmethyl) propane-1,3-diamine (L) with different inorganic acids affords salts viz., LH4 4+·4ClO4 ?·H2O (1), LH4 4+·4Cl?·2H2O (2), LH4 4+·2H2PO4 ?·H7P3O12 2?·3H3PO4 (3), LH4 4+·4NO3 ? (4), and 2LH+·2CF3COO?·5H2O (5). The X-ray crystallographic studies revealed that the proton transfer occurred from acid to the ligand. It also demonstrated that different type of hydrogen bond between protonated ligand and anions is responsible for the supramolecular framework. The colorimetric test showed color change upon the addition of acids in the solution of the ligand. The photo-physical experiments suggested the fluorescence properties of ligand in the presence of acids.  相似文献   
154.
Molecular modelling studies were performed to identify the essential structural requirements of quinoline-based derivatives for improving their antimalarial activity. The developed CoMFA, CoMSIA and HQSAR models for a training set comprising 37 derivatives showed good statistical significance in terms of internal cross validation (q2) 0.70, 0.69 and 0.80 and non-cross validation (r2) 0.80, 0.79 and 0.80. Also, the predicted r2 values (r2pred) of 0.63, 0.61 and 0.72 for a test set consisting of 12 compounds suggested significant predicting ability of the models. Structural features were correlated in terms of steric, electrostatic, hydrophobic, hydrogen bond donor and hydrogen bond acceptor interactions. Furthermore, the bioactive conformation was explored and explained by docking compounds #28, 32 and 40 into the active binding site of lactate dehydrogenase of Plasmodium falciparum. The QSAR models, contour map and docking binding affinity obtained could be successfully utilized as a guiding tool for the design and discovery of novel quinoline-based derivatives with potent antimalarial activity.  相似文献   
155.
156.
Bakers’ yeast (Saccharomyces cerevisiae) efficiently catalyzes the three-component Biginelli reaction of aldehydes, β-keto esters, and urea/thiourea to form 3,4-dihydropyrimidin-2-(1H)-ones in good to excellent yields.  相似文献   
157.
The CMOS compatible bulk micromachined piezoresistive accelerometer presented in this paper consists of four flexures supporting a proof mass. Four pairs of boron-diffused piezoresistors are located at maximum stress points on the flexures near the proof mass and frame ends. Because of the opposite nature of stress at the two ends, these piezoresistors can be connected to form a Wheatstone bridge such that the off-axis responses are practically cancelled while the on-axis (along perpendicular to proof mass) response is maximized. The device is simulated using CoventorWare. In the fabrication process, dual-doped TMAH solution is used for wet anisotropic etching. The novelty of this etching process is that the bulk micromachining can be performed after aluminum metallization. The etched surface is also smooth. The fabrication is thus CMOS compatible. The accelerometer exhibits good linearity over 0-10 g.  相似文献   
158.
JPC – Journal of Planar Chromatography – Modern TLC - A new, simple, reliable, and validated high-performance thin-layer chromatographic (HPTLC) method has been developed for the...  相似文献   
159.
The modified Toya's expressions for electron-phonon matrix elements have been extended to study the phonon-dispersion relations of anisotropic HCP cadmium crystal. It has been observed that the calculated results are in reasonably good agreement with the experimental results along the symmetry directions.  相似文献   
160.
Summary Novel mixed-ligand nickel(II) complexes having octahedral stereochemistry and general formula [Ni-(acac)2(L)2]/[Ni(meacac)2(L)2]/[Ni(etacac)2(L)2] (where L=3-methyl-1-phenyl-2-pyrazoline-5-one, 2,3-dimethyl-4-methylaminomethanesulphonate sodium monohydrate-1-phenyl-3-pyrazoline-5-one or 4-amino-2,3-dimethyl-1-phenyl-3-pyrazoline-5-one) have been isolated by reacting [Ni(acac)2(H2O)2]/[Ni(meacac)2(H2O)2]/ [Ni(etacac)2(H2O)2] with L in alcohol. The derivatives have been characterized by analytical data, molar conductances, magnetic measurements, electronic and i.r. spectra.  相似文献   
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