28184-70-5Relevant articles and documents
Solid phase decarbamoylation of monoalkylureas and N-carbamoylpeptides using gaseous NO(x): A new easy deprotection reaction with minimum waste
Collet, Helene,Boiteau, Laurent,Taillades, Jacques,Commeyras, Auguste
, p. 3355 - 3358 (1999)
Treating solid monoalkylureas (including N-carbamoylpeptides) when hydrated by ca. 1 eq. water, by gaseous NOx (nitrogen peroxide or a mixture of nitric oxide and oxygen) in stoichiometric excess, deprotects quantitatively the amino function at room tempe
A systematic entropy relationship for the general-base catalysis of the deprotonation of a carbon acid. A quantitative probe of transition-state solvation
Bunting, John W.,Stefanidis, Dimitrios
, p. 779 - 786 (2007/10/02)
The general-base-catalyzed deprotonation of a carbon acid, the l-methyl-4-(phenylacetyl)pyridinium cation (pKa = 9.02 at 25 °C), has been investigated for 32 general-base catalysts (25 amines and seven phenoxide ions) in aqueous solution. Amines give a generally scattered Bronsted plot; ring-substituted benzylamines have ?= 0.52, and ring-substituted phenoxides have ?= 0.60, with the phenoxides being more reactive than amines of similar basicity. The temperature dependences of the general-base-catalyzed deprotonation of this carbon acid have been measured over the range 15-45 °C for 12 base catalysts (eight primary, secondary, and tertiary amines; 4-(dimethylamino)pyridine; two phenoxide ions; hydroxide ion). The entropies of activation for these deprotonations show a clean curvilinear dependence upon the entropies of protonation of these base species, with the hydroxide ion being the only significant deviant from this relationship. This observation quantitatively establishes the importance of solvation effects as the major source of deviations that are commonly observed in Bronsted relationships for general-base-catalyzed processes.
THE INTERACTION OF ALIPHATIC AMINES WITH TRANSITION-METAL COMPLEXES OF AROMATIC DI-IMINES. PART 1. KINETICS AND THERMODYNAMICS OF REACTION OF THE TRIS(5-NITRO-1,10-PHENANTHROLINE)NICKEL(II) CATION WITH ALIPHATIC AMINES IN DIMETHYLFORMAMIDE
Bartolotta, Antonio,Cusumano, Matteo,Giannetto, Antonino,Ricevuto, Vittorio
, p. 1105 - 1110 (2007/10/02)
Addition of aliphatic amines to the complex 2 (nphen = 5-nitro-1,10-phenanthroline) in dipolar aprotic solvents gives deep red solutions.A spectrophotometric investigation of these processes leading to the formation of 1:2 adducts of complex:amine, most likely 'Meisenheimer' complexes, has been carried out in dimethylformamide.Both equilibrium and rate constants for adduct formation between 2 and piperidine, n-propylamine, or benzylamine have benn calculated by low-temperature stopped-flow techniques.The reactions are exothermic; the equilibrium data at - 50 deg C show that co-ordination of the ligand to nickel(II) largely increases the stability of the adduct between nphen and piperidine.Kinetic data are in agreement with a stepwise mechanism in which nucleophilic attack of the amine at the ligand is followed by proton transfer from the species formed to a second amine molecule.Proton transfer is either fast or rate determining depending on the nature of the amine.
