- Novel syntheses of oxamides, oxamates and oxalates from diisopropenyl oxalate
-
Diisopropenyl oxalate, obtained by catalytic addition of oxalic acid to propyne, is a useful reagent for the access to a variety of α-dicarbonyl compounds such as oxamides, oxamates and oxalates, under very mild conditions.
- Neveux, Muriel,Bruneau, Christian,Lecolier, Serge,Dixneuf, Pierre H.
-
-
Read Online
- Reactions of dehydroascorbic acid with primary aliphatic amines including Nα-acetyllysine
-
The reaction of L-dehydroascorbic acid (DHA) with primary aliphatic amines including Nα-acetyllysine was examined by HPLC. A new aminoreductone, 2-deoxy-2-(propylamino)ascorbic acid (1) was isolated and the structure elucidated by spectroscopic data. Furthermore oxalic acid mono-(2) and diamides (3) were identified as important degradation products of DHA under Maillard conditions. 3-Deoxy-3-(alkylamino)ascorbic acids (4), typical condensation products of L-ascorbic acid and amines, were also detected in the reaction mixtures of DHA. All products are formed under oxidative and nonoxidative conditions from DHA.
- Larisch, Bernd,Pischetsrieder, Monika,Severin, Theodor
-
-
Read Online
- Visible-Light-Induced Palladium-Catalyzed Dehydrogenative Carbonylation of Amines to Oxalamides
-
The palladium-catalyzed oxidative carbonylation of amines toward the synthesis of oxalamides has been established around 30 years ago and it usually needs the presence of (over)stoichiometric amounts of oxidant. In this work, the first transformation of this type in which the oxidant was replaced by visible light is described. The new approach uses a simple robust Pd complex, which can even be partially recycled. A mechanistic reason is provided and supported by control experiments and EPR studies, showing that PdI was formed and Pd0 was the active species. Both nitrogen- and the intermediate acyl radical can be detected. Moreover, the formation of hydrogen was confirmed by gas GC.
- Meyer, Tim,Rabeah, Jabor,Brückner, Angelika,Wu, Xiao-Feng
-
supporting information
p. 5642 - 5647
(2021/03/09)
-
- Environmentally friendly transesterification and transacylation reactions under libr catalysis
-
A room-temperature, convenient transesterification of various esters, induced by catalytic amounts of lithium bromide and diethylamine in a solvent-free environment, is described. Products are obtained in good purity by simple filtration to remove the catalyst and evaporation of the volatile portion. The procedure has also been successfully applied to transacetylation and aminolysis of esters. Springer-Verlag 2010.
- Abaee, M. Saeed,Akbarzadeh, Elahe,Sharifi, Roholah,Mojtahedi, Mohammad M.
-
experimental part
p. 757 - 761
(2011/07/08)
-
- Selective oxidative carbonylation of amines to oxamides and ureas catalyzed by palladium complexes
-
A new process for converting secondary amines into N,N,N′,N′- tetraalkyloxamides under CO pressure, catalyzed by homogeneous palladium complexes in the presence of 1,4-dichloro-2-butene (DCB) as an oxidant, has been developed. The mechanism of the oxidative double-carbonylation process, consisting of the oxidation of Pd(0) to Pd(11) with DCB through a β-chloride elimination of the η3-(chloromethyl) allylpalladiuni(11) intermediate, the formation of mono- and bis(carbamoyl)palladium species, and a reductive elimination of the two carbamoyl ligands, is proposed based on studies of the behavior of carbamoylpalladium complexes. When primary amines are employed with DCB as the oxidant, N,N′-dialkyloxamide is catalytically produced, whereas urea is exclusively produced when iodine is used as the oxidant. The reaction of an N-monopropylcarbamoylpalladium complex with propylamine under CO gave N,N′-dipropylurea, whereas a treatment with diethylamine yielded unsymmetrical N,N-diethyl-N′-propylurea, implying the intermediate formation of propyl isocyanate that is converted into the urea upon a reaction with the added amine. A kinetic study on the reaction of chloro-N- propylcarbamoylpalladium with triethylamine suggested a process proceeding through a base-promoted dcprolonalion of the N-monoalkylcarbamoyl ligand to form propyl isocyanate.
- Hiwatari, Kozo,Kayaki, Yoshihito,Okita, Koshi,Ukai, Tomohiro,Shimizu, Isao,Yamamoto, Akio
-
p. 2237 - 2250
(2007/10/03)
-
- Reactivity of Carbamoyl Radicals. A New, General, Convenient Free-Radical Synthesis of Isocyanates from Monoamides of Oxalic Acid
-
A new, general, simple synthesis of isocyanates was developed by oxidation of monoamides of oxalix acid with peroxydisulfate catalyzed by Ag and Cu salts.The reaction was carried out in a two-phase system (water and an organic solvent), and it is suitable also for practical applications, due to the simple experimental conditions and the inexpensive as well as nontoxic reagents.The first example of homolytic intramolecular aromatic carbamoylation is also reported.
- Minisci, Francesco,Fontana, Francesca,Coppa, Fausta,Yan, Yong Ming
-
p. 5430 - 5433
(2007/10/02)
-
- SmI2 Promoted Coupling Reaction of Isocyanates to Oxamides
-
Oxamides were obtained in moderate to good yields by the reaction of isocyanates with the SmI2/HMPA/THF system under mild conditions.The system also caused desulfurization of isothiocyanates to give isocyanides in good yields.
- Liu, Yun-Shan,Bei, Mei-Zhi,Zhou, Zhi-Hua,Takaki, Ken,Fujiwara, Yuzo
-
p. 1143 - 1144
(2007/10/02)
-
- Oxidative coupling of amines and carbon monoxide catalyzed by palladium complexes. Mono- and double carbonylation reactions promoted by iodine compounds.
-
Iodine is an effective promoter for the carbonylation of primary and secondary amines to ureas using palladium acetate as the catalyst and a base (e.g.K2CO3) in acetonitrile (3 h at 95 deg C and 2.7 atm).Oxamides are formed in excellent yields when secondary amines are carbonylated in the presence of iodide ion and oxygen, while primary amines give ureas as the principal product at 95 deg C, and oxamide at room temperature.
- Pri-Bar, Ilan,Alper, Howard
-
p. 1544 - 1547
(2007/10/02)
-