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A rapid and efficient method for the preparation of 3‐(4,6‐dimethyl‐oxazolo[4,5‐c]quinolin‐2‐yl)‐chromen‐2‐ones by the reaction between 3‐amino‐2,8‐dimethyl‐quinolin‐4‐ol and 2‐oxo‐2H‐chromen‐3‐carboxylic acid using sulfamic acid as a acid catalyst and dimethyl formamide as a solvent using the conventional method and microwave irradiation is reported. 相似文献
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Jetti RK Boese R Thakur TS Vangala VR Desiraju GR 《Chemical communications (Cambridge, England)》2004,(22):2526-2527
4-Aminothiophenol exists as 4-ammonio-1-benzenethiolate in the solid and liquid state. The crystal structure is characterised by a tetrahedral beta-As type network which is the driving force for the proton transfer. 相似文献
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Himadri R. Soni Venu Mankad Sanjay D. Gupta Sanjeev K. Gupta Prafulla K. Jha 《Journal of Thermal Analysis and Calorimetry》2012,107(1):39-44
In the present paper, we report an ab initio calculation of the ground state, electronic and thermodynamical properties like
constant volume lattice specific heat, vibrational energy, internal energy, and entropy for GaP and Ga2P is presented. These properties are obtained after calculating the phonon spectrum over the entire Brillouin zone. The calculations
were performed using the ABINIT program package, which is based on density functional theory (DFT) method and the use of pseudopotentials
and plane wave expansion. Difference in the ground state properties such as electronic structure and thermodynamical properties
are discussed. The thermodynamical properties follow the expected trend. There is a good agreement between present theoretical
and limited available experimental data in the case of ground state such as lattice constant and bulk modulus and electronic
properties. With the increase of Ga atoms in the unit cell the semiconducting nature of Ga2P turns to metallic. There is a noticeable difference in the thermodynamical properties in the case of both gallium compounds. 相似文献
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Malcolm B. Polk Venu Kannappan Issifu Harruna Metha Phingbodhipakkiya 《Journal of polymer science. Part A, Polymer chemistry》1986,24(5):931-946
Poly[oxy-2,2′-diphenyleneoxyisophthaloyl-b-oxy(2-methyl-1,3-phenylene)oxyterephthaloyl] I, poly[oxy-2,2′-diphenyleneoxyterephthaloyl-b-oxy(2-methyl-1,3-phenylene)oxyterephthaloyl] II, poly(oxy-2,2′-diphenyleneoxyisophthaloyl-b-oxy-2,2′-diphenyleneoxyterephthaloyl) III, poly[oxy-2,2′-diphenyleneoxyterephthaloyl-b-oxy(2-methyl-1,4-phenylene)oxyterephthaloyl] IV, poly[oxy2,2′-diphenyleneoxyterephthaloyl-b-oxy(2-chloro-1,4-phenylene)oxyterephthaloyl] V, poly[oxy-2,2′-diphenyleneoxyterephthaloyl-co-oxy(2-chloro-1,4-phenylene)oxyterephthaloyl] VI, and poly[oxy-2,2′-diphenyleneoxyterephthaloyl-co-oxy(2-methyl-1,4-phenylene)oxyterephthaloyl] VII have been synthesized and characterized. Random copolyester VI appears to form a birefringent fluid phase above the melting temperature. 相似文献
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Venu MankadHimadri R. Soni Sanjeev K. GuptaPrafulla K. Jha 《Physica B: Condensed Matter》2011,406(19):3599-3604
We present results of first principles total energy calculations of the structure, electronic and lattice dynamics for beryllium semiboride and its three ternary alloys using generalized gradient and local density approximations under the framework of density functional theory. The generalized gradient approximation is used for all compounds except MgBeB using the Perdew-Burke-Ernzehorf exchange correlation functional while local density approximations use the Perdew-Zunger ultrasoft exchange correlation functional. The calculated ground state structural parameters are in good agreement with those of experimental and previous theoretical studies. The electronic band structure calculations show that Be2B may transform to a semiconductor after Al substitution. A linear response approach to density functional theory is used to calculate phonon dispersion curves and vibrational density of states. The phonon dispersion curves of Be2B and AlBeB are positive indicating a dynamical stablility of the structure for these compounds. The phonon dispersion curves of NaBeB and MgBeB show the imaginary phonons throughout the Brillouin zone, which confirms dynamical instability as indicated in band structures for these alloys. We also present the partial phonon density of states for different species of Be2B and AlBeB to bring out the details of the participation of different atoms in the total phonon density of state, particularly the role played by Al atom. The first time calculated phonon properties are clearly able to bring out the significant effect of isoelectronic substitution in Be2B. 相似文献
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A novel synthesis of 2,5-dimethylenetetrahydrofurans, 2-substituted furans and a β,ω-diketophosphonate in good to excellent yields has been achieved by the reaction of allenylphosphine oxides/allenylphosphonate with propargyl alcohol using zinc triflate/triethylamine combination. 相似文献
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The reaction of aryl-substituted propargyl alcohols possessing o-nitro and o-alkylidene groups with (RO)(2)PCl afford novel phosphono(tetrahydro)dibenzazepines, N-hydroxyindolinones or polycyclics (including one with three fused four-membered rings). 相似文献
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The structures of 4-chloro- and 4-bromotribenzoylbenzene, as well as a solid solution prepared from these two components, are isomorphous and dominated by C-X...O=C interactions, whereas type-II I...I interactions are important in the 4-iodo derivative. 相似文献