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11.
The question of possible neutral intermediates which may lie on the reaction pathway in going from longifolene to isolongifolene has been investigated using BF3·Et2O-AcOD and D3PO4-dioxane, as reagents. It has been found that longicyclene is not an obligatory intermediate. The mode of cleavage of cyclopropane ring in longicyclene has been investigated. 相似文献
12.
Organic sulfonyl fluorides are of interest owing to their insecticidal, germicidal and enzyme inhibitory properties. In the current work, synthesis of p-toluenesufonyl fluoride was accomplished by reacting p-toluenesulfonyl chloride with solid potassium fluoride using PEG-400 as a catalyst under solid-liquid phase transfer catalysis (S-L PTC) at 30 °C. p-Toluenesulfonyl fluoride is used as peroxygen bleach activator. It also finds use in the treatment of Alzheimer's disease. The mechanism is based on homogeneous solubilization of solid. PEG forms a complex with metal cation which associates with the nucleophile and it participates in SN2 type reactions. The reaction is intrinsically kinetically controlled. A complete theoretical analysis is done to determine both the rate constant and equilibrium constant from the same set of data. The activation energy and Gibbs free energy are also calculated. 相似文献
13.
Ab initio MO and experimental pi-selectivities of hydride additions to 4-oxatricyclo[5.2.1.0(2,6)]decan-10-one and 4-oxatricyclo[5.2.1.0(2,6)]dec-8-en-10-one are described. The interactions of sigma(C1-C2) and sigma(C6-C7) with pi(C=O), on one hand, and those of sigma(C1-C9) and sigma(C7-C8) with pi(C=O), on the other hand, support anti-selectivities for both. This is in full accordance with the experiments. The arguments that are based on electrostatic interactions and electron donation from the ring oxygen do not apply. 相似文献
14.
The use of fenugreek mucilage, a natural polysaccharide and a direct food additive, as a flocculating agent for removal of suspended and dissolved solids from sewage effluent has been reported. A flocculation study has been done by the standard jar test method. The percent removal of suspended solid (SS) and dissolved solid (TDS) was determined by varying the polymer dose, pH and contact time. X-ray diffraction patterns of the solid waste material of mucilage and flocs (so obtained after treatment) were used to suggest the incorporation of the crystalline waste material in the mucilage. The optimal mucilage concentration was found to be 0.16 mg/l. The suitable pH range for maximum solid removal (SS and TDS) was alkaline and the time required for treatment was 1-3 h. 相似文献
15.
Zulys A Panda TK Gamer MT Roesky PW 《Chemical communications (Cambridge, England)》2004,(22):2584-2585
The cyclooctatetraene-bis(phosphinimino)methanide complex [[CH(PPh2NSiMe3)2]Sm(eta8-C8H8)] has been prepared; although this compound has no alkyl or amide ligand it shows moderate activity as a catalyst for the hydroamination/cyclisation reaction. 相似文献
16.
Tarun Ghosh 《Tetrahedron letters》2004,45(32):6169-6172
C-(4-Oxo-4H-1-benzopyran-3-yl)-N-alkyl-/aryl-nitrones derived from 4-oxo-4H-1-benzopyran-3-carboxaldehyde, rearrange to 2-alkyl-/aryl-amino-3-formylchromone and/or 3-(alkyl-/aryl-aminomethylene)chroman-2,4-dione depending upon the reaction medium. 3-(Alkylaminomethylene)chroman-2,4-dione has been utilized in the synthesis of 1-benzopyrano[3,4-d]isoxazole-4-one. 相似文献
17.
Y. Sesha Sayi K. L. Ramakumar Rajendra Prasad C. S. Yadav P. S. Shankaran G. C. Chhapru H. C. Jain 《Journal of Radioanalytical and Nuclear Chemistry》1998,230(1-2):5-9
A hot vacuum extraction technique for the determination of hydrogen in metal and alloy samples has been standardised. After measuring the total pressure of the evolved gases, individual hydrogen and deuterium intensities are measured using an on-line quadrupole mass spectrometer. Synthetic mixtures of H2 and D2, in known concentrations, have been analysed by QMS and an analytical expression correlating the measured [D2]/[HD] intensity ratio with the mole fraction of deuterium in the synthetic mixture has been arrived at. The precision and accuracy in the measurement of hydrogen is about 10% at 50 ppmw level. 相似文献
18.
Synthesis of Pharmaceutical Intermediates by Toluene Benzylation over Heteropoly Acids on Different Support 下载免费PDF全文
V. V. Bokade G.D. Yadav 《天然气化学杂志》2007,16(2):186-192
Selective formation of pharmaceutical intermediates like diphenylmethane, dimethyl- diphenylmethane, benzyl toluene and benzoic acid by liquid phase, toluene benzylation with benzyl chloride as a benzylating agent, was systematically studied over plane clay (K-10, montmorillonite), plane H-Beta, plane MFI structured titanosilicate (TS-1) and heteropoly acids [HPA, namely dodeca-tungstophosphoric acid [H3PO4.12WO3.xH2O] (TPA), dodeca-molybdo phosphoric acid ammonium salt hydrate [H12Mo12N3O40P aq] (DMAA), sodium tungstate hydrated purified [Na12WO4.2H2O] (STH)] supported on clay, H-beta and TS-1. The 20%TPA/Clay, 30%TPA/H-Beta and 30%TPA/TS-l, were observed to be the best catalyst samples over plane clay, plane H-Beta and plane TS-1. The catalyst samples are compared with respect to benzyl chloride conversion and selectivities for diphenylmethane, dimethyl-diphenylmethane, benzyl toluene and benzoic acid. The reaction follows the pseudo-first order rate power law model. The apparent rate constants are calculated and compared with the reported ones. 相似文献
19.
Acid catalysed dehydration of the diols 5 , derived from the cyclohexenone 3 affords mixtures of 8 and 11 . The product ratio 8/11 , although strongly dependent on both the reaction conditions and the substituent R, is independent of the diol configuration; this indicates a cationic intermediate 6 . Conditions were found, which allow the sequence A → B → C → D (Scheme 2) to be applied to the syntheses of the enones 8, 21 and 25 in fair to good yields from the corresponding cyclohexenones 3, 18 and 22 . 相似文献
20.
JPC – Journal of Planar Chromatography – Modern TLC - A high-performance thin-layer chromatographic method has been developed for determination of a new antiamoebic drug, satranidazole,... 相似文献