- Some reactions of 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido) acetic acids
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In situ generated 2,4-diaryl substituted münchnones from 2-(4-substitutedphenyl)-2-(N-methyl-N-4-substitutedbenzamido)acetic acids react with acetic anhydride in the presence of 2-nitromethylene thiazolidine, which is most likely acting as a base, and une
- Dürüst, Ya?ar,Karaku?, Hamza,Kariuki, Benson M.,Knight, David W.
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p. 2206 - 2220
(2018/07/15)
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- N-heterocyclic carbene catalyzed oxidative coupling of aldehydes with carbodiimides under aerobic conditions: Efficient synthesis of N-acylureas
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The oxidative coupling reaction of aldehydes with N,N′-disubstituted carbodiimides catalyzed by N-heterocyclic carbenes under aerobic conditions has been achieved. This reaction gives the corresponding N-acylurea derivatives in good to high yields. Various kinds of aldehydes including aliphatic ones and carbodiimides are applicable to this reaction.
- Soeta, Takahiro,Tabatake, Yuhta,Fujinami, Shuhei,Ukaji, Yutaka
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p. 2088 - 2091
(2013/06/05)
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- Synthesis of stable 1H-azirines reinvestigated: A structural corrigendum
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The isoquinoline-catalyzed synthesis of pretended 1H-azirines from phenacyl bromides and N,N-dialkylcarbodiimides was repeated. The products do not possess the structure of antiaromatic 1H-azirines, but simple N-acyl-N,N-dialkylureas were formed instead. This structural corrigendum was confirmed by the independent synthesis of the known ureas and comparison of their 1H NMR and 13C NMR spectroscopic data in the case of six compounds. Thus, 1H-azirines keep their classification as very short-lived intermediates. Georg Thieme Verlag KG · Stuttgart · New York.
- Banert, Klaus,Hagedorn, Manfred,Peisker, Heiko
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supporting information
p. 2943 - 2946
(2013/02/25)
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- 2-thiophenecarbohydrazides: A novel efficient method for the synthesis of 2-thiophenecarbohydrazide
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Hydrazinolysis of carboxylic acid esters in alcoholic solutions is the standard method for preparing carbohydrazides (carboxylic hydrazides). Here we report an efficient process, involving the reaction of activated esters or amides with hydrazine, for the preparation of thiophenecarbohydrazides in yields larger than 90% and high purity. With this new method, a series of heteroaryl-, aryl-, or aralkyl- substituted carbohydrazides were synthesized and characterized. The X-ray crystal structure of 2-thiophenecarbohydrazide (thiophene-2-carboxylic hydrazide, 2-thenoyl-hydrazine) has revealed that it crystallizes in the monoclinic system, space group P21/c, with cell parameters of a = 6.1202(2), b = 8.3907(3), c = 12.5332(5) A, β = 98.6577(11)?, Z = 4, R(F) = 0.0455 and wR(F2) = 0.1805, T = 293 K.
- Elshaarawy, Reda F.M.,Janiakb, Christoph
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experimental part
p. 1202 - 1208
(2012/03/09)
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- Formation of N-acyl-N,N'-dicyclohexylureas from DCC and arenecarboxylic acids in the presence of hydroxybenzotriazole in CH2CI2 at room temperature
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The syntheses of N-acyl-N',N'-dicyclohexylureas from 1,3- dicyclohexylcarbodiimide and arenecarboxylic acids [p-XC6H 4CO2H (X = H or NO2), 2-, 3- or 4-pyridinecarboxylic acid and pyrazinecarboxylic acid] in the
- Kaiser, Carlos R.,Pinheiro, Alessandra C.,De Souza, Marcus V. N.,Wardell, James L.,Wardell, Solange M.S.V.
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experimental part
p. 468 - 472
(2009/08/15)
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- Electrochemical reduction of N-acylureas
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The cathodic reduction of N-acylureas with the structure R-NH-CO-N(COR′)-R in an aprotic medium gives N-alkylamides (R′-CO-NH-R) and amines (R-NH2) in a selective cleavage process. The structure of the R′ group is a significant factor of the el
- Quintanilla, M. Gloria,Montero, Guillermo,Hierro, Angel G.,Diaz, Jose M.,Bassani, Silvina
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p. 928 - 931
(2007/10/03)
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- Substituent effect in reaction of dicyclohexylcarbodiimide with substituted benzoic acids
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A curved Hammett relationship was observed for the reaction of substituted benzoic acids with dicyclohexylcarbodiimide in buffered solution. The reaction is promoted by electron-withdrawing substituents because of larger concentration of the acid anion pr
- Slebioda, Marek
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p. 7829 - 7834
(2007/10/02)
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- Chemoselective alcoholysis of acylureas
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Two methods for the chemoselective alcoholysis of acylureas were developed to generate esters and amides, respectively. In alcoholysis using sodium methoxide in methanol, methoxide attacked the acyl carbonyl to give the corresponding methyl ester. While in alcoholysis using lithium benzyloxide in diethyl ether, benzyloxide attacked the urea carbonyl to give the amide. The chemoselectivity originates in the different chelating abilities of the metals and the polarity of the solvents.
- Kishikawa,Eida,Kohmoto,Yamamoto,Yamada
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p. 173 - 175
(2007/10/02)
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- Mechanism of the reaction of carbodiimides with carboxylic acids
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The kinetic parameters of the reaction of diphenylcarbodiimide with various carboxylic acids have been determined at a temperature interval of 20-160 deg C.The classical scheme for the reaction of carbodiimides with carboxylic acids is extended.It has been found that, at high temperatures, amides and isocyanates are the end products of the reactions.N-Acylureas, initially formed from aromatic carbodiimides and carboxylic acids, dissociate into isocyanates and amides at temperatures above 60 deg C.N-Acylureas formed by the reaction of carboxylic acids with aliphatic carbodiimides prove to be more stable: their dissociation temperature is about 50 deg C higher.Both the formation and dissociation of N-acylureas are much faster when the parent acid is stronger.
- Schotman, A. H. M.
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p. 319 - 324
(2007/10/02)
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