Search results for "composition"
showing 10 items of 2675 documents
Synthesis and thermal decomposition studies of homo- and heteroleptic tin(iv) thiolates and dithiocarbamates: molecular precursors for tin sulfides
2002
The syntheses and X-ray structures of novel heteroleptic thiolate/dithiocarbamate derivatives (Et2NCS2)2(RS)2Sn (R = Cy, CH2CF3) have been examined and their thermal decompositions compared with those of selected tin(II) and tin(IV) dithiocarbamates. The heteroleptic species decompose to SnS by initial elimination of RSSR to afford (Et2NCS2)2Sn and subsequent loss of [Et2NC(S)]2S. In contrast, (Et2NCS2)4Sn decomposes via [(Et2NCS2)2SnS]2, whose structure has been determined, and finally to SnS2 by sequential elimination of [Et2NC(S)]2S. The two families of compounds, (R2NCS2)4Sn and (Et2NCS2)2(RS)2Sn, thus provide single-source materials for bulk SnS2 and SnS, respectively, by virtue of the…
ChemInform Abstract: Addition of Organolithium Reagents to Cinnamic Acids.
2010
Abstract Reaction of tert -butyllithium with p - and m -substituted cinnamic acids at low temperature affords mixtures of 1,4- and 1,3-addition products, whose composition depend on the nature of the substituents. Electron-donating and electron-withdrawing groups favour 1,4- and 1,3-additions, respectively. Linear correlations are obtained with electronic effect and with radical substituent constants.
Evidence for the formation of 1,3- and 1,4-dehydrobenzenes in the thermal decomposition of diaryliodonium-carboxylates
1986
Abstract Abstract: Generation of m- and p-benzynes in decomposition of diaryliodonium- 3- and 4-carboxylates is demonstrated by three-phase method.
Bulk pre-reactional transformations preceding the thermal decomposition of calcium hydroxide into oxide
1990
The present paper is an extended abstract which should be considered as an introduction to the papers already published by us on this new topic. An extended synthesis of these papers was given in the lecture. The original information introduced here is the figure. It is a PH2O vs. T diagram which gives the pre-reactional domain between the stability domains of calcium hydroxide and calcium oxide. Chemical reactions are proposed as an interpretation of the observed pre-reactional transformations.
Versuche zur umsetzung von methylendiphenolen mit glucosederivaten und zur kondensation von O-phenylglucosidderivaten
1981
Attempts to apply known methods of glucosidation to oligo[(hydroxyphenylene)methylene]s were not satisfying. The reaction of 4,4'-dimethyl-2,2'-methylenediphenol (1a) with 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide gave a monoglucoside in 11% yield. A second attempt, the condensation of suitable O-phenylglucoside derivatives was unsuccessful. From a series of O-phenylglucosides (4) only 4-(2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyloxy)benzylbromide could be condensed with O-(4-hydroxymethylphenyl)-2,3,4,6-tetra-O-acetylglucopyranose to the corresponding diglucoside of 4,4'-oxydimethylenediphenol (7). Condensation reactions of the O-phenylglucoside 4k, to obtain an O-glucosidized poly[…
Studies on the synthesis of heterocyclic compounds. Part IV. Further investigation of the pschorr reaction with some pyrazole derivatives
1980
Thermal decomposition of the diazonium sulfate derived from N-methyl-(1-phenyl-3-methylpyrazol-5-yl)-2-aminobenzamide afforded products formulated as 1-phenyl-3-methyl[2]benzopyrano[4,3-c]pyrazol-5-one (yield 10%), 1,4-dimethyl-3-phenylpyrazolo[3,4-c]isoquinolin-5-one (yield 10%), N-methyl-(1-phenyl-3-methylpyrazol-5-yl)-2-hydroxybenzamide (yield 8%) and 4′-hydroxy-2,3′-dimethyl-1′-phenylspiro[isoindoline-1,5′-[2]-pyrazolin]-3-one (yield 20%). Decomposition of the diazonium sulfate derived from N-methyl-(1,3-diphenylpyrazol-5-yl)-2-aminobenzamide gave products formulated as 7,9-dimethyldibenzo[e,g]pyrazolo[1,5-a][1,3]-diazocin-10-(9H)one (yield 8%), 4-methyl-1,3-diphenylpyrazolo[3,4-c]isoqu…
Optische aktivität bei copolymeren aus (—)-acrylsäure-menthylester und styrol
1965
Die Copolymerisation von (–)-Acrylsaure-menthylester mit Styrol wurde untersucht. Die Copolymerisationsparameter betragen: r1 = 0,28 (Acrylsaurementhylester), r2 = 0,84 (Styrol); hieraus folgt fur Q = 0,45 und e = 0,40. Die spezifische Drehung der Copolymeren erwies sich bei 5 Wellenlangen als lineare Funktion des Acrylsaurementhylestergehaltes. Aus den Drehwerten kann daher die Zusammensetzung bestimmt werden; Ruckschlusse auf die Sequenzlangenverteilung sind aber nicht moglich. The copolymerization of (—)-menthyl acrylate with styrene was investigated. The reactivity ratios and the Q- and e-values were found to be: r1 = 0.28 (menthylacrylate), r2 = 0.84 (styrene); Q = 0.45, e = 0.40. The …
ChemInform Abstract: Nb4Te17I4, a New Pseudo One-Dimensional Solid-State Polytelluride.
2010
The new ternary compound Nb4Te17I4 has been prepared and structurally characterized. It crystallizes in the monoclinic system, space group C2/c with unit-cell parameters a = 16.199(4), b = 8.128(2), c = 27.355(6) A, β = 110.84(2)°, Z = 4. The structure consists of infinite one-dimensional niobium/tellurium chains running parallel to the crystallographic c direction. The chains are separated by iodine atoms. Short and long metal–metal distances alternate in the sequence of three consecutive short bonds ([d ≈ 3.1 – 3.2 A) and one long (d = 4.268 A) metal–metal separation. Each Nb atom is eight-coordinate. The composition of the chain is ∞11[(Nb5+)2(Nb4+)2(Te22−)4(Te32−)3(I−)4].
Über die zersetzung von hydroperoxyden durch katalase und durch lebereiweißfraktionen
1959
Es werden Herstellung und Eigenschaften einer Eiweisfraktion aus Rinderleber beschrieben, die auf Wasserstoffperoxyd, athyl-, Isopropyl- und tert.-Butylhydroperoxyd zersetzende Wirkung ausubt. Der fur das Zustandekommen der Zersetzungsreaktion der drei letzgenannten Peroxyde notwendige Acceptor wird als athanol identifiziert. Die Eiweisfraktion wird bezuglich ihrer Eigenschaften mit einer kristallisierten Katalase verglichen und aus dem Ergebnis der Schlus gezogen, das sie mit Katalase identisch ist. Als Reaktionsprodukt der enzymatisch katalysierten Reaktion zwischen tert.-Butylhydroperoxyd und athanol wurde Acetaldehyd nachgewiesen. The preparation and properties of an albumen fraction fr…
Polycondensed nitrogen heterocycles. Part25. Aminopyrrolo[1,2-f]-phenanthridines by decomposition of 2-(3-azidophenyl)-1-arylpyrroles
1994
Acid catalyzed decomposition of the azido derivatives 4a-c gave rise to amino-hydroxy-phenylpyrroles of type 7 and 8 upon hydrolysis of the intermediate aryl nitrenium ions, together with the hydrogen abstraction compounds of type 3. The aminopyrrolo[1,2-f]phenanthridines 10, 11, and 12 were obtained by treatment with TFMSA of the azide 4d in which the ring being attacked was made more nucleophilic by the introduction of the methoxy group.