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71.
72.
Abstract An efficient, atom-economic, one-pot protocol has been developed for the synthesis of highly functionalized dihydropyridines via four-component reactions of aromatic aldehydes, arylamines, malononitrile, and dimethylacetylenedicarboxylate in the presence of sodium hydroxide in ethanol. This domino reaction proceeded smoothly in good to excellent yields and offered several advantages, including short reaction time, simple experimental procedure, and applicability to a broad range of substrates. Supplemental materials are available for this article. Go to the publisher's online edition of Synthetic Communications® to view the free supplemental file. 相似文献
73.
74.
Nirupama Singh Surbhi Choudhary Sumant Upadhyay Vibha R. Satsangi Sahab Dass Rohit Shrivastav 《Journal of Solid State Electrochemistry》2014,18(2):523-533
Nanocrystalline Zn1???x Ag x O y (x?=?10??3???50?×?10??3) thin films evolved through electrodeposition over ITO substrate have been investigated for photoelectrochemical splitting of water. Samples were characterized by XRD, EDX, SEM, AFM, UV–visible optical absorption, and Mössbauer spectral analysis. Ag incorporation led to a decrease in the band gap energy and alterations in microstructural and semiconductor properties. Raising Ag concentration in samples up to 1 % at. caused a significant reduction in density and electrical resistivity, enhanced absorption along with red shift to the band gap energy, anodic shift in flat band potential, and increased charge carrier density, enabling 1 % at. Ag-incorporated ZnO films most photosensitive by yielding highest short-circuit current, photocurrent density, and applied bias photon to current efficiency. Plausible reasons have been offered. 相似文献
75.
Atta-Ur-Rahman Nasim S Baig I Ara Jahan I Sener B Orhan I Choudhary MI 《Chemical & pharmaceutical bulletin》2002,50(8):1100-1102
Four isoflavone glycosides were isolated from the rhizomes of Iris germanica. Compounds 1 and 2 are new, while compounds 3 and 4 are known isoflavone glycosides. These compounds were identified as iriskashmirianin 4'-O-beta-D-glucoside (1), nigricin 4'-O-beta-D-glucoside (2), irilone 4'-O-beta-D-glucoside (3) and iridin (4). Their structures were determined with the help of spectroscopic methods. 相似文献
76.
77.
A neutron-diffraction study of TlH2PO4 at room temperature (RT) is presented as part of an investigation of the group of monoclinic dihydrogen phosphates: NaDP, deuterated-KDP, CsDP, and TlDP (DP denotes H2PO4). The structure of TlDP, and the nature of its phase transition at 230 K, are discussed and compared with paraelectric CsDP — with which TlDP is nearly isomorphous at RT. 相似文献
78.
The crystal structure of paraelectric CsH2PO4 at room temperature is presented. As suggested by the strong deuteration-dependence of the transition temperature and the distribution of quasielastic scattering, one of the hydrogen bonds is found to be very probably (97.5%) disordered, with H-H=0.48(4)Å. This work is set in the context of the interest now being shown in the group of monoclinic dihydrogen phosphates-deuterated KDP, NaDP, the ferroelectric CsDP and the presumed ferroelectric T1DP (DP denotes H2PO4). Recent work on these other compounds is surveyed briefly. 相似文献
79.
In this paper an attempt has been made to find the solution of the boundary layer equations for two-dimensional laminar steady motion of a viscous incompressible fluid in a convergent channel (sink flow) with suction at the wall. Suction velocity v0 (x) ~ 1/x has been imposed at the wall and an approximate solution has been obtained with the help of similarity transformation. A solution valid at a large distance from the wall and a series solution valid near the wall have been obtained and the two solutions have been joined at a suitable point. It is seen that the boundary layer thickness diminishes as the value of the suction parameter\(\lambda ( = v_0 x/\sqrt {u_1 v} )\) increases. The velocity profile and the boundary layer parameters for solid wall (λ = 0) obtained from this solution are found to be in close agreement with the profile and the parameters calculated from the known exact solution for the solid wall problem. 相似文献
80.
Ahmad VU Hussain J Hussain H Farooq U Farmanullah Lodhi MA Choudhary MI 《Natural product research》2005,19(3):267-274
Two new myrsinol-type diterpene polyesters 3,5,13,17-tetra-O-acetyl-7-O-benzoyl-15-hydroxymyrsinol (1) and 3,5,13,17-tetra-O-acetyl-7-O-butanoyl-13-hydroxymyrsinol (2), with a tricyclic carbon skeleton have been isolated from Euphorbia decipiens Boiss. & Buhse. The structure elucidation of the isolated compounds was based primarily on HREIMS, EIMS, IR, UV, ID-, and 2D-NMR analyses, including COSY, HMQC, HMBC, and NOESY correlations. Compounds 1 and 2 also showed activity against urease enzyme. 相似文献