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91.
Minoo Dabiri Peyman Salehi Mostafa Baghbanzadeh Ali A. Mohammadi 《Tetrahedron letters》2005,46(36):6123-6126
KAl(SO4)2·12H2O was found to catalyze efficiently a one-pot three-component cyclocondensation of isatoic anhydride and primary amines or ammonia sources such as (NH4)2CO3, NH4OAc and NH4Cl with aromatic aldehydes under mild conditions to afford the corresponding mono- and disubstituted 2,3-dihydroquinazolin-4(1H)-ones in good yields. 相似文献
92.
The composition of the essential oil obtained by hydrodistillation from the leaves of Stachys schtschegleevii Sosn. before the flowering stage was analyzed by GC and GC-MS. Forty-five compounds representing 98.7% of the total oil were identified, of which α-pinene (36.4%), germacrene-D (18.6%), limonene (8.2%), and piperitone (6.2%) were the major constituents. Furthermore, antibacterial activity of the entire oil and its two main monoterpenes was evaluated against six Gram-positive and Gram-negative bacteria. The oil exhibited moderate activity against the tested bacteria.__________Published in Khimiya Prirodnykh Soedinenii, No. 2, pp. 138–140, March–April, 2005. 相似文献
93.
Iran Sheikhshoaie Hojatollah Khabazzadeh Samira Saeid-Nia 《Transition Metal Chemistry》2009,34(5):463-466
[Fe(III)(salen)]Cl (salen = N,N′-ethylenebis(salicylimine)) is an efficient catalyst for the electrophilic substitution of
indole with carbonyl compounds to afford the corresponding bis(indolyl)methanes in good yields in molten tetrabutylammonium
bromide as an ionic liquid. Notable features of this new procedure are shorter reaction times, cleaner reaction profiles,
and simple experimental and work-up procedures. 相似文献
94.
95.
Gary Chartrand Elzbieta B. Jarrett Farrokh Saba Ebrahim Salehi Ping Zhang 《Czechoslovak Mathematical Journal》2001,51(2):351-361
For a nontrivial connected graph F, the F-degree of a vertex in a graph G is the number of copies of F in G containing . A graph G is F-continuous (or F-degree continuous) if the F-degrees of every two adjacent vertices of G differ by at most 1. All P3-continuous graphs are determined. It is observed that if G is a nontrivial connected graph that is F-continuous for all nontrivial connected graphs F, then either G is regular or G is a path. In the case of a 2-connected graph F, however, there always exists a regular graph that is not F-continuous. It is also shown that for every graph H and every 2-connected graph F, there exists an F-continuous graph G containing H as an induced subgraph. 相似文献
96.
Using high resolution capabilities of a time-of-flight instrument and ion trap tandem technique, electron impact mass spectra of 5-acetyl (benzoyl)-4-aryl-3,4-dihydropyrimidin-2 (1H)-ones 1-5 were studied. The molecular ion (M) peaks for 1-3 can be found in the spectra with high abundances, but very weak for 4 and 5,in which strong electron-attracting substituents are attached to the benzene ring. The main fragmentation pathways for 1-5 include the cleavage of (M-Ar) + with high intensity, (M-RCO) + with moderate abundance, (M-H) +with high intensity for the compounds without strong electron-attracting substituent in the aromatic ring, and the pyrimidine ring cleavage (loss of neutral NH=C=X). In addition, a prominent cation (Ph + , m/z 77) can be found in the low mass region of the spectra for all the compounds, which give rise by different pathways between 1- 2 and 3-5. Several additional fragmentations for individual compounds are proposed. 相似文献
97.
Sulfamic acid immobilized on diethylenetriamine functionalized Fe3O4 nanoparticles (SA‐DETA‐Fe3O4) was successfully prepared and characterized by X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FT‐IR), vibrating sample magnetometer (VSM), thermo gravimetric analysis (TGA), X‐Ray diffraction (XRD) and scanning electron microscopy (SEM). The sulfamic acid was found as a magnetically separable and highly active catalyst for the oxidative coupling thiols, oxidation of sulfides. Furthermore, the SA‐DETA‐Fe3O4 showed the high catalytic activity in Knoevenagel condensation of aromatic aldehydes with active methylene compounds (malononitrile and ethyl cynoacetate). The nanosolid catalyst could be easily recovered by a simple magnetic separation and reused for many cycles without deterioration in catalytic activity. 相似文献
98.
99.
F. Hoppensteadt H. Salehi A. Skorokhod 《Journal of Dynamics and Differential Equations》1997,9(3):463-505
Let (X, ) and (Y,C) be two measurable spaces withX being a linear space. A system is determined by two functionsf(X): X X and:X×YX, a (small) positive parameter and a homogeneous Markov chain {y
n
} in (Y,C) which describes random perturbations. States of the system, say {x
n
X, n=0, 1,}, are determined by the iteration relations:x
n+1
=f(x
n
)+(x
n
,Yn+1) forn0, wherex
0
=x
0 is given. Here we study the asymptotic behavior of the solutionx
n
as 0 andn under various assumptions on the data. General results are applied to some problems in epidemics, genetics and demographics.Supported in part by NSF Grant DMS92-06677.Supported in part by NSF Grant DMS93-12255. 相似文献
100.
H. Salehi M. Aryadoust M. Zargar Shoushtari 《Applied Physics A: Materials Science & Processing》2014,116(1):69-77
In this paper, the propagation of acoustic waves in the phononic crystal of 3D with rhombohedral(I) lattice is studied theoretically. The crystal composite constituted of nickel spheres embedded in epoxy. The calculations of the band structure and density of states are performed with the plane wave expansion method in the irreducible part of Brillouin zone. In the present work, we have investigated the effect of lattice angle on the band structure and width of the band gap rhombohedral(I) lattice in the irreducible part of the first Brillouin zone and its planes separately. The results show that more than one complete band gape are formed in the four planes of the irreducible part. The most complete band gaps are formed in the (111) plane and the widest complete band gap in (443) with an angle greater than 80 \(^{\circ }\) . So, if the sound passes through the (111) and (443) planes for the lattice angle close to 90 \(^{\circ }\) , the crystal phononic displays the excellent insulation behavior. Moreover, in the other planes, the lattice angle does not affect on the width and the number of band gaps. Also, for the filling fraction 5 %, the widest complete band gap is formed. These results are consistent with the effect of symmetry on the band gap width, because the (111) plane has the most symmetry. 相似文献