628-02-4Relevant articles and documents
Conversion of Aliphatic Amides into Amines with benzene. 2. Kinetics and Mechanism
Boutin, Raymond H.,Loudon, G. Marc
, p. 4277 - 4284 (1984)
The reagent benzene (PIFA), used to prepare amines from amides as described in the preceding paper, dissolves in 50:50 (v/v) aqueous acetonitrile to give an acidic solution.This behavior can be explained quantitatively by the dimerization of PIFA in solution under preparatively significant conditions; the dimer, μ-oxo-I,I'-bis(trifluoroacetato-O)-I,I'-diphenyldiiodine(III), 2, can be isolated from the reaction mixture above pH 3.The rate of hexanamide rearrangement by PIFA was studied as a function of PIFA concentration and shown to display asymtotic behavior.The rate is depressed by added trifluoroacetate and accelerated by increasing pH, but not in a simple way.These observations can be accounted for by a mechanism (eq 13-15) in which the dimer 2 complexes with the amide, releasing acid.It is this released acid that accounts for most of the kinetically significant observations.The rearrangement of the amide-dimer complex is the rate-limiting step.Other kinetically indistinguishable mechanism are also possible.The rate of rearrangement promoted by dimer alone is in agreement with that predicted by the proposed mechanism.The imidic acid (enol) form of the amide is considered as a possible kinetically active form of the amide but is rejected on kinetic grounds.
Hydration of Aliphatic Nitriles Catalyzed by an Osmium Polyhydride: Evidence for an Alternative Mechanism
Babón, Juan C.,Esteruelas, Miguel A.,López, Ana M.,O?ate, Enrique
, p. 7284 - 7296 (2021/05/29)
The hexahydride OsH6(PiPr3)2 competently catalyzes the hydration of aliphatic nitriles to amides. The main metal species under the catalytic conditions are the trihydride osmium(IV) amidate derivatives OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2, which have been isolated and fully characterized for R = iPr and tBu. The rate of hydration is proportional to the concentrations of the catalyst precursor, nitrile, and water. When these experimental findings and density functional theory calculations are combined, the mechanism of catalysis has been established. Complexes OsH3{κ2-N,O-[HNC(O)R]}(PiPr3)2 dissociate the carbonyl group of the chelate to afford κ1-N-amidate derivatives, which coordinate the nitrile. The subsequent attack of an external water molecule to both the C(sp) atom of the nitrile and the N atom of the amidate affords the amide and regenerates the κ1-N-amidate catalysts. The attack is concerted and takes place through a cyclic six-membered transition state, which involves Cnitrile···O-H···Namidate interactions. Before the attack, the free carbonyl group of the κ1-N-amidate ligand fixes the water molecule in the vicinity of the C(sp) atom of the nitrile.
Efficient heterogeneous hydroaminocarbonylation of olefins with ammonium chloride as amino source
Sun, Zhao,Yan, Li,Ji, Guangjun,Wang, Guoqing,Ma, Lei,Jiang, Miao,Li, Cunyao,Ding, Yunjie
, (2021/02/26)
An efficient protocol for heterogeneous hydroaminocarbonylation of olefins with ammonium chloride without addition of acid additive has been developed for the first time. We successfully synthesized the Pd@POPs-PPh3 catalyst through a solvothermal synthetic method. Under this heterogeneous catalytic system, C2-C6 olefins displayed good yields and TON, and a yield of 66% of propionamide and TON = 1400 were obtained under mild reaction conditions (403 K, Pethylene = 0.5 MPa, PCO = 2.5 MPa), which is a little higher than those in the homogeneous system. This catalytic system has the advantage of easy separation of product and catalyst, as well as good stability. Uniform dispersion of Pd active sites, strong coordination bond between P and Pd, high surface area, large pore volume and hierarchical porosity of Pd@POPs-PPh3 were confirmed by a series of characterizations, which is believed to be the keys for the good activity and stability of hydroaminocarbonylation reaction.
One-pot reductive amination of carboxylic acids: a sustainable method for primary amine synthesis
Coeck, Robin,De Vos, Dirk E.
supporting information, p. 5105 - 5114 (2020/08/25)
The reductive amination of carboxylic acids is a very green, efficient and sustainable method for the production of (bio-based) amines. However, with current technology, this reaction requires two to three reaction steps. Here, we report the first (heterogeneous) catalytic system for the one-pot reductive amination of carboxylic acids to amines, with solely H2 and NH3 as the reactants. This reaction can be performed with relatively cheap ruthenium-tungsten bimetallic catalysts in the green and benign solvent cyclopentyl methyl ether (CPME). Selectivities of up to 99% for the primary amine could be achieved at high conversions. Additionally, the catalyst is recyclable and tolerant for common impurities such as water and cations (e.g. sodium carboxylate).
