- Organosilyl isocyanates. Reactions with hydrazine, 1,1-dimethylhydrazine, and 1-methyl-1-[2-(1-methylhydrazino)ethyl]hydrazine and structural and electronic characteristics
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Reactions of organosilyl isocyanates with hydrazine, 1,1-dimethylhydrazine, and 1-methyl-1-[2-(1-methylhydrazino)ethyl]hydrazine provide a facile synthetic route to urea and previously unknown semicarbazides. Quantum chemistry was used to study the structure and electronic properties of (chloromethyl)- dimethylsilyl isocyanate and (chlorodimethylsilyl)methyl isocyanate and to obtain the thermodynamic parameters of their isomerization.
- Kirilin,Belova,Knyazev,Lega,Petrov,Chernyshev
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- Azo bond hydrogenation with hydrazine, R-NHNH2, and hydrazobenzene
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Hydrogenation of azo bonds with hydrazine, mono-substituted hydrazine, and hydrazobenzene was studied with selected diazene compounds under oxygen-free conditions. The reactions proceed rapidly and in high yield in several solvents, utilizing all N-H protons. While the reduction process is accompanied by the evolution of nitrogen gas in the case of N2H4, the intermediacy of diimide could not be confirmed by standard trapping experiments.
- Koppes, William M.,Moran, Jesse S.,Oxley, Jimmie C.,Smith, James L.
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- The three-component biginelli reaction: A combined experimental and theoretical mechanistic investigation
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Biginelli reactions have been monitored by direct infusion electrospray ionization mass spectrometry (ESI-MS) and key cationic intermediates involved in this three-component reaction have been intercepted and further characterized by tandem MS experiments
- De Souza, Rodrigo O.M.A.,Da Penha, Eduardo T.,Milagre, Humberto M.S.,Garden, Simon J.,Esteves, Pierre M.,Eberlin, Marcos N.,Antunes, Octavio A.C.
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supporting information; body text
p. 9799 - 9804
(2010/05/19)
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- Method and apparatus for preparing hydrazo-dicarbonamide using urea as starting material
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The present invention relates to a method and apparatus for preparing hydrazodicarbonamide using urea as starting material economically and environmentally desirably. The apparatus includes a pyrolysis furnace to obtain biuret and ammonia by pyrolyzing urea; a recrystallization reactor to purify the biuret obtained from the pyrolysis furnace; a first reactor to obtain an metal monohalobiuret salt by reacting the biuret with metal hypohalogen compound or with halogen and base; a second reactor to synthesize the hydrazodicarbonamide by reacting the monohalobiuret metal salt with ammonia; and an ammonia evaporator to separate the excess ammonia from hydrazodicarbonamide and to supply the separated ammonia to an ammonia concentrator.
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- Method for synthesizing hydrazodicarbonamide
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A method for synthesizing hydrazodicarbonamide (HDCA) by a reaction of monohalobiuret metal salt having the formula 1 or 2, which is derived from biuret, and ammonia, wherein M is a metal and X is a halogen. The monohalobiuret metal salt is inexpensive and easy to synthesize and thus a great yield of HDCA can be obtained from the monohalobiuret metal salt at low cost.
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(2008/06/13)
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- Synthesis of bishydrazones (aldazines)
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Bishydrazones have been prepared by thermolysis of aldehyde hydrazone under reduced pressure in a sealed tube at 120-30°C. The possible mass spectral fragementation mode of bishydrazones have also been discussed.
- Linganna,Rai, K. M. Lokanatha,Shashikanth
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p. 1126 - 1128
(2007/10/03)
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- Kinetics and mechanism of the thermal decomposition of azodicarbonamide, I
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The study on the kinetics of the thermal decomposition of azodicarbonamide, H2NCON = NCONH2 suggested a mechanism according to the scheme H2NCON=NCONH2->N2+2H2NCO', followed by the formation of a complex, H2NCON=NCONH2 + H2NCO->[H2NCON'-NHCONH2-NHCO] which decomposes rapidly to hydrazodicarbonamide (H2NCONH-NHCONH2) CO and N' or reacts with H2NCO' to form hydrazodicarbonamide and cyanic acid. This mechanism was confirmed by the computerized simulation of the measured kinetic curves of CO, N2, and cyanic acid, determined by gravimetric, volumetric, gas Chromatographie methods. Simulation of DSC curves confirmed also this mechanism by the fact that the sum of the reaction heats of the endo- and exothermic steps (calculated by the rate equations derived from the mechanism) resulted the measured reaction heat.
- Levai, Gyula,Nyitrai, Zs,Meszlenyi, Gabor
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p. 885 - 900
(2007/10/03)
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- ORGANIC REACTIONS IN THE AQUEOUS MEDIUM Part VI. Synthesis of Substituted Pyrazoles and Pyrazolones
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The reactions of semicarbazide hydrochloride and hydrazine monohydrate with ethyl acetoacetate, acetylacetone, benzoylacetone and dibenzoylmethane leading to the formation of pyrazole and pyrazolone derivatives have been intensively studied in the aqueous as well as in the nonaqueous medium under various sets of conditions. This has resulted in the development of simple and convenient methods for the synthesis of pure ethyl acetoacetate semicarbazone (I), 3-methylpyrazol-5-one-1-carboxamide (II), 3-methylpyrazol-5-one (III), 3,5-dimethylpyrazol-1-carboxamide (V), 3,5-dimethylpyrazole (VI), 3-phenyl-5-methylpyrazole-1-carboxamide (VII), 3-phenyl-5-methylpyrazole (VIII) and 3,5-diphenylpyrazole (IX). It has been suggested that the reaction of semicarbazide hydrochloride with β-diketo compounds proceeds through four stages. A reaction scheme has been proposed to explain the formation of different products. Key words.Synthesis, Pyrazole and Pyrazolone derivatives.
- Ali, Sh. Shaukat,Ashraf, C. M.,Younas, M.,Ehsan, A.
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p. 502 - 510
(2007/10/02)
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- Metal complexed acetylenic compounds useful as environmental indicating materials
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Acetylenic complexes are disclosed that are useful as environmental indicating materials whereby exposure thereof to environmental stimuli induces a color change. These complexes contain at least one effective complexing metal and at least one acetylenic compound of the general formula: Wherein a is 1 or 2, b is about 0-5; c is 0 or 1; with the proviso that when a is 1, b and c are 0, when a is 2, b is about 0-5 and c is 0 or 1; and R is --(CH2)n -NHC(O)NHR'; wherein n is an integer of about 1 to 10; and R' is selected from the group consisting of: (a) hydrogen; (b) cycloalkyl; (c) alkenyl; (d) cycloalkenyl; (e) alkyl; (f) phenyl; (g) alkoxy; (h) alkoxy alkyl; and (i) alkoxycarbonylalkyl.
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- Synthesis of Pyranopyrazol-4(1H)-ones and -4(2H)-ones from Dehydroacetic Acid. Homo- and Heteronuclear Selective NOE Measurements for Unambiguous Structure Assignment
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Cyclization of dehydroacetic acid N-substituted hydrazones furnished 1-substituted 3,6-dimethylpyranopyrazol-4(1H)-ones, together with varying amounts of N,N'-disubstituted 5-hydroxy-3-methyl-4-(3-methyl-1H-pyrazol-5-yl)-1H-pyrazoles.The same pyranopyrazolones were obtained regioselectively without side reactions from N-alkylhydrazines and 4-chloro-3-(1-chlorovinyl)-6-methyl-2H-pyran-2-one, ("Dehydroacetchlorid"), while N-arylhydrazines gave the 2-aryl-3,6-dimethylpyranopyrazol-4(2H)-ones.NMR NOE methods, including long-range selective heteronuclear 13C NOE enhancement measurements, allowed unambiguous between -4(1H)-ones and -4(2H)-ones.
- Cantos, Albert,March, Pedro de,Moreno-Manas, Marcial,Pla, Anna,Sanchez-Ferrando, Francisco,Virgili, Albert
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p. 4425 - 4432
(2007/10/02)
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- Some macrocyclic compounds and their preparation
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The present invention relates to novel macrocyclic carbonyl compounds of the macrocyclic carbamate and lactone type, to chiral macrocyclic structures, to macrocyclic urea compounds and to macrocyclic thiolactones and to a process for the preparation of same. The process of the invention comprises reacting a stannoxane, silazane or silathiane compound with an activated carbonyl compound in an organic solvent at moderate temperature.
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- Process for preparing hydrazodicarbonamide
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Hydrazodicarbonamide is prepared by reacting a compound represented by STR1 with urea while the former is being continuously or intermittently introduced into the reaction system and while the carbonyl compound and ammonia produced as by-products are being withdrawn from the system.
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- Process for the production of azodicarbonamide
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A process for the preparation of azodicarbonamide by oxidation of hydrazodicarbonamide in an aqueous suspension containing hydrogen peroxide wherein the reaction is carried out in the presence of iodine at a temperature between 50° and 95° C. while the reaction mixture has a pH ranging from 1.0 to 5.0.
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- Preparation of carbodiimides from ureas by dehydration
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Biscarbodiimides which are known to be effective as a surface application for polyethylene terephthalate fibers in lowering carboxyl end group concentration of the fibers and increasing hydrolytic stability, are prepared by the dehydration of ureas with triphenylphosphine and carbon tetrachloride.
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- Preparation of hydrazodicarbonamide
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A process for preparing hydrazodicarbonamide directly from a ketazine and urea in water without any acid catalyst according to the following reaction is disclosed. EQU1 wherein the R groups may be the same or different.
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