- Reaction of Ethyl Chlorosodiocarbamate with Organic Azides
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Ethyl chlorosodiocarbamate (3) is reactive as a nucleophile toward ethyl azidoformate (4) and tosyl azide but not toward alkyl or aryl azides.Diethyl iminodiformate (5), nitrogen gas, and sodium chloride are the principal products from the reaction of 3 with 4.Mechanistic studies support a reaction scheme involving attack of 3 at the carbonyl group of azide 4, instead of attack at the terminal azido nitrogen.The results of this study are correlated with hard and soft acid and base theory.
- Gibson, Harry H.,Macha, Matthew R.,Farrow, Sherry J.,Ketchersid, Terry L.
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- Unexpectedly Stable (Chlorocarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, and Related Compounds That Model the Zumach-Weiss-Kühle (ZWK) Reaction for Synthesis of 1,2,4-Dithiazolidine-3,5-diones
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The Zumach-Weiss-Kühle (ZWK) reaction provides 1,2,4-dithiazolidine-3,5-diones [dithiasuccinoyl (Dts)-amines] by the rapid reaction of O-ethyl thiocarbamates plus (chlorocarbonyl)sulfenyl chloride, with ethyl chloride and hydrogen chloride being formed as coproducts, and carbamoyl chlorides or isocyanates generated as yield-diminishing byproducts. However, when the ZWK reaction is applied with (N-ethoxythiocarbonyl)urethane as the starting material, heterocyclization to the putative "Dts-urethane"? does not occur. Instead, the reaction directly provides (chlorocarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, a reasonably stable crystalline compound; modified conditions stop at the (chlorocarbonyl)[1-ethoxy-(N-ethoxycarbonyl)formimidoyl]disulfane intermediate. The title (chlorocarbonyl)(carbamoyl)disulfane cannot be converted to the elusive Dts derivative, but rather gives (N-ethoxycarbonyl)carbamoyl chloride upon thermolysis, or (N-ethoxycarbonyl)isocyanate upon treatment with tertiary amines. Additional transformations of these compounds have been discovered, providing entries to both known and novel species. X-ray crystallographic structures are reported for the title (chlorocarbonyl)(carbamoyl)disulfane; for (methoxycarbonyl)(N-ethoxycarbonylcarbamoyl)disulfane, which is the corresponding adduct after quenching in methanol; for [1-ethoxy-(N-ethoxycarbonyl)formimidoyl](N′-methyl-N′-phenylcarbamoyl)disulfane, which is obtained by trapping the title intermediate with N-methylaniline; and for (N-ethoxycarbonylcarbamoyl)(N′-methyl-N′-phenylcarbamoyl)disulfane, which is a short-lived intermediate in the reaction of the title (chlorocarbonyl)(carbamoyl)disulfane with excess N-methylaniline. The new chemistry and structural information reported herein is expected to contribute to accurate modeling of the ZWK reaction trajectory.
- Barany, George,Britton, Doyle,Chen, Lin,Hammer, Robert P.,Henley, Matthew J.,Schrader, Alex M.,Young, Victor G.
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p. 11313 - 11321
(2015/12/01)
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- Dibutyltin oxide catalyzed aminolysis of oxalate to carbamate, oxamate and derivatives of imidazolidine trione
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Catalytic aminolysis of oxalates by simple and substituted ureas has been shown to give carbamates, oxamates and derivatives of imidazolidine trione. Various substituted ureas and oxalates were screened to verify the applicability of the protocol. The rol
- Kunde, Lalita B.,Kalyani, Vishwanath S.,Gupte, Sunil P.
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experimental part
p. 402 - 407
(2010/08/06)
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- Synthesis of 1-Oxo-1H-pyrazolotriazol-4-ium-3-olates. - A Ring-Chain Tautomerism in the Series of Bicyclic Dipolar Heterocycles
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1-(Trimethylsilyl)pyrazole (12) reacts with chlorocarbonyl isocyanate to give a compound, which - dependent on the state of aggregation - may exist both as a bicyclic dipolar heterocycle (7) and as monocyclic 1-pyrazolyl carbonyl isocyanate (8).Methyl-substituted derivatives (19a, b) show a similar behaviour.MNDO calculations for the parent systems (7, 8) are in accord with these experimental observations.The structure of 5,6,7-trimethyl-1-oxo-1H-pyrazolotriazol-4-ium-3-olate (19b) has been clarified by X-ray analysis.
- Boettcher, Andreas,Debaerdemaeker, Tony,Radziszewski, Juliusz G.,Friedrichsen, Willy
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p. 895 - 908
(2007/10/02)
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- Synthesis, Structure, and Properties of N-(Dialkoxymethylene)carbamic Esters
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The title compounds 1 can be synthesized from the imidocarbonates 4 and the chloroformates 5 in the presence of amine bases in 35-68percent yield. - Hydrolysis of 1 under mild conditions yields the imidocarbonates 6. - In the solid state (1bb, X-ray analy
- Kupfer, Rainer,Wuerthwein, Ernst-Ulrich,Krestel, Magda,Allmann, Rudolf
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p. 3236 - 3246
(2007/10/02)
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- The photochemical addition of N-haloamides to olefins: a comparison of cyclic and acyclic N-halo-N-alkylamides and N-halo-N-acylamides (N-haloimides)
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Upon photochemical decomposition in the presence of cyclohexene and 1-octene, an N-halo-N-acylamide (N-haloimide) leads to better yields of addition than its N-halo-N-alkyl analogue, and cyclic N-halo-N-alkyl and N-halo-N-acylamides add more efficiently than their acyclic analogues.The yields of addition were higher with N-chlorosuccinimide which has been added also to 1-methylcyclohexene than with N-bromosuccinimide which did not add to 1-methylcyclohexene.
- Lessard, Jean,Couture, Yvon,Mondon, Martine,Touchard, Daniel
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p. 105 - 112
(2007/10/02)
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- THE ELECTROCHEMICAL REDUCTION OF N-FLUOROETHANS IN ACETONITRILE. THE GENERATION OF CARBETHOXYNITRENE
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The electrochemical reduction of N-fluoro-N-methylurethan (1a) and N-fluorourethan (2a) in acetonitrile generates the amide anion and fluoride ion.Both the fluoride and the amide react with the starting N-fluoroamide either as bases or as nucleophiles.Many products are formed and the coulometric results are low (0.5 to 0.7 F/mol).In the case of NFU (2a), abstraction of the proton on nitrogen both by the urethan anion and the fluoride anion generates the conjugate base EtOCOF (7) which immediately undergoes α-elimination of the fluoride ion to give carbethoxynitrene (11).This nitrene was generated also by treating NFU (2a) with a base such as triethylamine of lithium hydride.The α-elimination of F1- from EtOCOF is much easier than α-elimination of Cl1- from EtOCOCl.
- Lessard, Jean,Berube, Denis
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p. 768 - 777
(2007/10/02)
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- Deamination via Nitrogen Derivatives of Sulfonic Acids: N-Alkyl-N-nitroso-4-toluenesulfonamides, N-Alkyl-N-nitro-4-toluenesulfonamides, and N-Alkyl-N'-(4-toluenesulfonyloxy)diimide N-Oxides
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The thermal decomposition of several N-alkyl-N-nitroso-4-toluenesulfonamides, N-alkyl-N-nitro-4-toluenesulfonamides, and N-alkyl-N'-(4-toluenesulfonyloxy)diimide N-oxides was undertaken to determine whether the basicity of the negatively charged counterion in deamination reactions was a reaction variable.The nitrososulfonamides decompose following first-order kinetics to give the corresponding esters with retention of configuration.The reaction characteristics are very similar to those of the N-nitrosocarboxamides, and the reaction mechanisms are presumably very similar also.The N-nitrosulfonamides required high temperatures for decomposition, and they gave an anomalous set of products: amide (by denitration) and olefins, but no nitrous oxide or toluenesulfonate esters.The N'-toluenesulfonoxydiimide N-oxides, isomeric to the nitrosulfonamides, proved to be surprisingly stable compounds; they decompose by first-order kinetics to yield the corresponding esters and nitrous oxide.
- White, Emil H.,Lewis, Charles P.,Ribi, Max A.,Ryan, Thomas J.
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p. 552 - 558
(2007/10/02)
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