Chemiluminescence in the reaction of the RuII trisbipyridyl complex with dimethyldioxirane

The reaction of dimethyldioxirane (1) with the Ru^II trisbipyridyl complex accompanied by chemiluminescence (CL) was studied. It is established that the intensity of CL and the rate of its decay increase proportionally with the concentration of Ru^II. The bimolecular rate constant (k ₂) of the reaction of1 with Ru^II was determined. The activation parameters (E _a and logA) for this reaction were calculated from the temperature dependence ofk ₂. The excitation yield of Ru^II* (η _Ru ^* ) was estimated. The quenching of Ru^II* by dioxirane was studied, and the bimolecular quenching constant and the coefficient of excitation regeneration were determined. It was suggested that the catalysis of the decomposition of1 and the excitation of Ru^II occurvia a mechanism of chemically initiated electron exchange. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1138–1142, June, 1997.     

Reaktionen vonN-Sulfinylverbindungen mit dem 1,2,4-Trithia-3,5-diborolan-Ringsystem und Substitutionsreaktionen am 1,2,4-Trithia-3,5-diborolan und 1,2-Dithia-4-aza-3,5-diborolidin

The reaction of trimethylsilyl- and pentafluorophenyl-N-sulfinylamine respectively with 3,5-dihalogeno-1,2,4-trithia-3,5-diborolanes yields the 1,2-dithia-4-aza-3,5-diborolidines1-3.Tert-butyl-N-sulfinylamine and 3,5-dimethyl-1,2,4-trithia-3,5-diborolane react analogous. OtherN-sulfinylamines however split the disulfane bridge in 3,5-dimethyl-1,2,4-trithia-3,5-diborolane and the 1,4-dithia-2-aza-3,5-diborolidines5A-7(A) are formed. Besides of boroxines, cyclo-2,4,6-trimethyl-1,3-dioxa-5-aza-2,4,6-triboranes and cyclo-2,4,6-trimethyl-1-oxa-3,5-diaza-2,4,6-triboranes are formed as byproducts,8–10 have been isolated. In 1,2,4-trithia-3,5-diborolanes and 1,2-dithia-4-aza-3,5-diborolidines the bromo-atoms can be substituted by alkyl (13, 14), by amino (15–20) and by isothiocyanato groups. The compounds were characterised analytically and spectroscopically (MS; NMR:¹H,¹¹B,¹⁹F,²⁹Si; IR).

     

Die Veresterungsgeschwindigkeiten der Monoaminobenzoesäuren und der 1- und 2-Pyridinkarbonsäuren in Glykol und Glyzerin

Zusammenfassung Es werden die Veresterungsgeschwindigkeiten der Monoaminobenzoesäuren und der 1- und 2-Pyridinkarbonsäuren bei 25° mit Chlorwasserstoff als Katalysator sowohl in wasserfreiem als auch in wasserhaltigem Glykol und in wasserfreiem Glyzerin gemessen, die derm- und derp-Aminobenzoesäure und der 2-Pyridinkarbonsäure (Nikotinsäure) auch in wasserhaltigem Glyzerin. Die Abhängigkeit der monomolekularen Geschwindigkeitskonstanten vom Wassergehalt (w) des Mediums und dem Überschuß der Konzentration der Salzsäure über die der organischen Säure, bzw. ihres Esters (C) wird für die drei zuletzt genannten Säuren durch Formeln dargestellt. Diese Geschwindigkeitskonstanten nehmen durchwegs sowohl in wasserfreiem als auch in wasserhaltigem Glykol und Glyzerin nicht nur rascher als die Konzentration der gesamten Salzsäure, sondern auch als die des obigen Überschusses, d. h. der freien Salzsäure, zu.FürC=1/3 sind beiw=0.03 die Geschwindigkeitskonstanten derm- und derp-Aminobenzoesäure und der Nikotinsäure in Äthylalkohol um 20–30 %, die der Anthranilsäure um 70%, die der Pikolinsäure um 130% größer als in Glykol, beiw=0.7 dagegen die der drei ersteren Säuren um 35–50% kleiner.In Glykol sind die Konstanten bei der Anthranilsäure und den Pyridinkarbonsäuren kleiner als in Glyzerin, bei den übrigen wie bei den früher untersuchten Säuren aber größer.Die sterische Wirkung der Aminogruppe in Orthostellung ist in Glykol größer, in Glyzerin kleiner als in Äthylalkohol.Unter gleichen Bedingungen Bind die Konstanten der Veresterungsgeschwindigkeit der Nikotinsäure in Glykol und Glyzerin etwa viermal, in Äthylalkohol nur etwa zweimal größer als die der Pikolinsäure.     

Enaminone‐Based Synthesis of Dipodazine Derivatives

A series of racemic dipodazine analogues 9 were prepared in 22–80% yield from (3Z,6RS)‐3‐[(dimethylamino)methylidene]‐6‐methyl‐1‐(phenylmethyl)piperazine‐2,5‐dione ( 7 ) (Scheme 1), which was prepared in four steps from (RS)‐alanine methyl ester hydrochloride. The preparation of nonracemic 7 from (S)‐alanine methyl ester hydrochloride failed, since the introduction of the enamino functionality at position 3 of the precursor 6 was accompanied by almost complete racemization.     

The chemiluminescence of dispiro(1,2-dioxetane-diadamantane) sorbed on silipore activated by a phenanthroline complex of Eu(iii)

The thermal decomposition of dispiro(1,2-dioxetane-diadamantane) (1) sorbed on silipore containing EuCl₃ ando-phenanthroline was investigated. The observed chemiluminescence is caused by radiative deactivation of EU^*(iii) formed according to an energy transfer mechanism. Chemiluminescence decay in the course of the decomposition of1 is exponential with the rate constantk. The activation parameters of the decomposition of1 sorbed on silipore were determined from the temperature dependence ofk. These parameters are independent of the Eu(iii) content. A kinetic compensating effect was found: the dependence of logA onE _a as a function of the content of1. The mechanism of the compensating effect is discussed.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 3, pp. 447–451, March, 1995.     

Analytical quality control by solid sampling GFAAS in the production of animal tissue reference materials: lead and cadmium in bovine liver reference materials

Summary The function of solid sampling graphite furnace atomic absorption spectrometry (SS-GFAAS) in the laboratory-internal preparation, production and standardization of bovine liver reference material is described. Analytical quality assurance was achieved by using a wet digestion decomposition procedure and GFAAS (WD-GFAAS) as well as three different methods of SS-GFAAS. It will be shown, that SS-GFAAS is an adequate and efficacious method of analytical quality control in the production of reference materials. Details are given about the preliminary steps of sample selection and preparation, applying SS-GFAAS both as a screening method and for the detection of contamination during the production of the reference materials. The element contents of the four bovine liver materials measured after decomposition with nitric acid in the open system by GFAAS and also by Flame-AAS, using the slotted tube atom trap, are compared statistically with the results obtained by SS-GFAAS. In solid sampling analyses three different systems were applied: a solid sampling ZAA-spectrometer with platform-boat, a D₂AA-spectrometer with solid sampling graphite tube and platform-drawer and an autoprobe-D₂AA-spectrometer with solid sampling autoprobe and graphite tube.     

Umsetzung von Metall- und Metalloidverbindungen mit mehrfunktionellen Molekülen, 31. Mitteilung

The reaction of galliumtrichloride and galliumtribomide resp. with 2,6-dimethyl- and 2,4,6-trimethyl-N-trimethylsilyl-trifluoroacetanilide leads to the trifluoracetanilidodihalogenogallanes1–3. The 2,6,9-trioxa-4,8-diaza-1,5-digalla-bicyclo-[3.3.1]-nonadiene derivatives1 a–3 a are formed probably as by products.N-Trimethylsilyltrifluoroacetamide reacts with galliumtrichloride to yield the trifluoroacetamido-dichlorogallane4.N-Trimethylsilyl-N,N,N-triorganyl-thioureas react with galliumtrichloride under elimination of chlorotrimethylsilane to give the thio-ureido-gallanes5 and6. IfN,N-diorganylureas andN,N-diorganyl-thio-ureas resp. are reacted with galliumtrichloride and methyl-gallium-dichloride resp., the thio-ureido- and ureido-gallanes7–9 are obtained by elimination of hydrogenchloride. The compounds are characterized by analysis and spectral data (NMR:¹H,¹⁹F; MS; IR). The substances are monomeric in the gas phase, obviously due to internal coordination.

30. Mitt.:W. Maringgele undA. Meller, J. Organomet. Chem., im Druck.     

Zur Reaktion von Hydrazinen mit Fluorsilanen und lithiierten Aminen

Lithium salts of hydrazines react with fluorosilanes under formation of fluorosilylhydrazines and LiF. Five membered rings are obtained in the reaction of bis(fluorosilyl)-hydrazines with lithiated amines. The mass,¹H-and¹⁹F-nmr spectra of the compounds are reported.

     

Synthesis and Transformation of Methyl 2‐(6‐Hydroxy‐2‐phenylpyrimidin‐4‐yl)acetate: Simple Preparation of Pyrimidines with Heterocyclic Substituents

A simple and efficient synthesis of four new substituted pyrimidines, compounds 9a – d , from the title compound 3 is described. Conversion of 3 to methyl (E)‐3‐(dimethylamino)‐2‐(6‐methoxy‐2‐phenylpyrimidin‐4‐yl)prop‐2‐enoate ( 4 ), followed by condensation with various dinucleophiles according to the ‘enaminone methodology’, afforded the target compounds 9 in medium‐to‐good yields.     

Reactions of substituted furo[3,2-<Emphasis Type="Italic">b</Emphasis>]pyrrole-5-carboxhydrazides and their biological activity

The reactions of substituted furo[3,2-b]pyrrole-5-carboxhydrazides 1 with 5-arylfuran-2-carboxaldehydes 2, 4,5-disubstituted furan-2-carboxaldehydes 3 and thiophene-2-carboxaldehyde 4 has been studied. The advantage of microwave irradiation on some of these reactions was reflected in the reduced reaction time and increased yields. Reactions of 1 with 4-substituted 1,3-oxazol-5(4H)-ones 11 led to diacylhydrazines 13 or to imidazole derivatives 14 depending on the temperature. 1,2,4-Triazole-3-thione 17 was synthesized by two-step reaction of 1 with phenylisothiocyanate and subsequent base-catalyzed cyclization of thiosemicarbazide 16. The effects of hydrazones 5–10 on inhibition of photosynthetic electron transport in spinach chloroplasts and chlorophyll content in the antialgal suspensions of Chlorella vulgaris were investigated.