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941.
The mass spectra of 1,1′-diacetylferrocene, 1,1′-dipropionyl ferrocene and their deuterium and Fe57 isotope labeled analogs are herein reported and discussed. Fragmentation pathways are established and evidence is presented that in the process of fragmentation there is extensive interaction between substituents on the two ferrocene rings. This process apparently has little precedent in the mass spectrometry of ferrocene derivatives. Specifically, the experimental results suggest the simultaneous elimination of two molecules of carbon monoxide, or in another case, of carbon monoxide and ethylene from ions produced in the mass spectrometry of the above compounds. 相似文献
942.
The acid-catalyzed and water-catalyzed solvolysis ofbenzoylphenyldiazomethane (1) have been studied in water and in t-butanol-water mixtures, the mole fraction of water (nH2O) being varied from 0·75-1·00. Increasing t-butanol concentrations produce a pronounced decrease in both kH⊕ and kH2O. In the “water reaction” mutually compensatory changes of AH and AS are associated with the rate variations, with minima in AH and AS at about nH2O = 0·95. In addition it was found that the magnitude of the salt effect of (n-Bu)4NCl on the rate of hydrolysis of 1 in water at 25° is much larger than that of LiCl, NaCl and NaBr. Assuming that the rate of the “water reaction” is largely determined by water acidity, the data are suggestive for the existence of a relation between water acidity and solvent structural integrity in highly aqueous t-butanol-water solutions. 相似文献
943.
The hydrolysis reaction of
,
and
,
-dipalmitoylphosphatidylcholine (DPPC) catalized by bee venom phospholipase A2 was studied in spreading monolayer at the water/air interface. DPPC and the hydrolysis products, palmitic acid and
-lysophosphatidylcholine, palmitoyl were characterized at the interface by means of surface pressure, surface potential and ellipsometric measurements. Furthermore, mixed monolayers of reagents and products were investigated to ascertain their miscibility. The results show that the hydrolysis reaction can be followed by the decrease of surface pressure with time on subphases containing β-cyclodextrin, a well-known complexing agent of many amphiphilic compounds. The order of the reaction, the kinetic constant and other kinetic parameters are deduced. 相似文献
944.
Thomas F.O. Lim Jerry K. Myers Greg. T. Rogers Paul Ronald Jones 《Journal of organometallic chemistry》1977,135(2):249-259
The regioselectivity of the hydroboration of the methylchlorovinylsilanes, ClnMe3?nSiCHCH2 (n= 0 ? 3), has been investigated using BH3←THF, 9-BBN, disiamyl- and dicyclohexylborane. Methylation of the adducts with methylmagnesium bromide is complicated by formation of tetraalkylboronates. Alkaline hydrogen peroxide oxidation of the boronates gives reasonable yields of the corresponding α- and β-trimethylsilylethanols forn= 0 and 1. Forn= 2 and 3, conversion of the adducts to the corresponding α- and β- deuteroethylsilanes by treatment with excess sodium methoxide in methanol-0-d provides a more effective means of derivatization. Addition of the alkenes,n= 2 or 3, to excess BH3←THF givesca. 90% of the α-boro-organo-chlorosilanes. For all of the alkenes, the dialkylboranes giveca. 80% of the β-boron adducts. 相似文献
945.
A.Lahmam Bennani H.F. Wellenstein A. Duguet B. Nguyen A.D. Barlas 《Chemical physics letters》1976,41(3):470-473
We present a new experimental determination of the Compton profiles of CH4 and C2H4 molecules using high energy electron impact. The observable q range has been extended up to 10 au (6 au for C2H4). Good agreement is found with an earlier X-ray scattering experiment and with new theoretical calculations. 相似文献
946.
T. L. Wetzel R. Shorrosh R. F. Borkman 《International journal of quantum chemistry》1994,50(2):151-160
Ab initio Hartree–Fock, Møller–Plesset perturbation theory (MP 2), and quadratic configuration interaction, using single and double substitutions (QCISD ), calculations were carried out for the NF3+ ion. Optimized structures were examined at the various levels of theory. Calculation of the inversion barrier height shows the importance of optimizing the geometry at the post-Hartree–Fock level and the inclusion of polarization functions. The best calculated inversion barrier was 13.3 kcal/mol, compared to an experimental value of 17.3 kcal/mol. The dissociation transition state was computed to determine the well depth of the NF3+ ion and its stability toward dissociation. The computed well depth was 28 and 48 kcal/mol at the SCF and MP 2 levels, respectively. © 1994 John Wiley & Sons, Inc. 相似文献
947.
B. G. Kovalev K. Loftstedt S. F. Nedopekina A. M. Sorochinskaya K. S. Artokhin E. A. Nesterov É. Viik 《Chemistry of Natural Compounds》1991,27(4):503-506
Four components have been isolated from an extract of the sex pheromone of the mothHeliothis maritima and have been identified: hexadecanal, hexadec-cis-11-enal, hexadec-cis-9-enal, and hexadec-cis-11-en-1-ol.
All-Union Scientific-Research Institute for Biological Methods of Plant Protection, Kishinev. Don Zonal Scientific-Research
Institute of Agriculture. Don Scientific-Production Combine. Ecology Division of Lund University, Lund, Sweden. Translated
from Khimiya Priorodnykh Soedinenii, No. 4, pp. 574–577, July–August, 1991. 相似文献
948.
B. S. Shasha D. Trimnell F. H. Otey 《Journal of polymer science. Part A, Polymer chemistry》1981,19(8):1891-1899
A simple method of encapsulating water-insoluble pesticides in a starch matrix is described. The method consists of mixing the pesticide with alkali starch followed by precipitation with a calcium chloride solution. A starch–calcium adduct that entraps the pesticide in small cells within granular particles is formed. Liquid and solid pesticides were successfully encapsulated by the new method. By use of the herbicide trifluralin [2,6-dinitro-N,N-dipropyl-4-(trifluoromethyl) benzenamine] as core material more than 90% recovery and encapsulation was achieved. Use of acid-modified starches and flours resulted in a lower percentage of encapsulation. Effective encapsulation was also achieved by replacing calcium chloride with strontium chloride or barium chloride. 相似文献
949.
E. S. Levitina E. D. Lubuzh L. F. Godunova E. I. Karpeiskaya E. I. Klabunovskii 《Russian Chemical Bulletin》1989,38(5):1011-1014
1. | It has been shown that when 2-methyl- and 2-phenyl-4-benzylideneoxazolin-5-ones react with a-phenylethylamine in dimethoxyethane the rate of opening of the oxazoline ring is dependent on the nature of the substituents at the para-position of the aromatic ring of the benzylidene group. Electron-donating substituents retard the process and electron-withdrawing substituents accelerate it. |
2. | It has been shown that replacement of Me by Ph on C2 of the oxazolone ring results in an increase in rate of aminolysis. |
950.
V. A. Mamedov I. A. Nuretdinov Yu. Ya. Efremov F. G. Sibgatullina 《Russian Chemical Bulletin》1989,38(4):867-869
1. | The reaction of esters of 3-phenyl-3-chloro-2-ketopropionic acid with sodium alcoholates in alcohol (methanol or ethanol) at reflux leads to the formation of an ester of 2,5-diketo-3,4-diphenyl-3-methoxyhexanedioic or 2,5-diketo-3,4-diphenyl-3-ethoxyhexanedioic acid. |
2. | The reactions of esters of 3-phenyl-3-chloro-2-ketopropionic acid with the corresponding sodium alcoholates in dilute solution at 0C give the product of the substitution of chlorine by an alkoxy group in quantitative yield. |