Selective Synthesis Of Secondary Amines Research Articles

Light-Switchable N-Alkylation Using Amine-Functionalized MOF

Catalytic N-alkylation is a frequently employed method to synthesize secondary amines and imines, yet selectivity control remains as a challenge that normally requires specialized catalysts under harsh reaction conditions. Here we propose a light-switchable N-alkylation of amines with aromatic halides for selective synthesis of secondary amines and imines, using an amine-functionalized metal-organic framework (MIL-125-NH2) under mild conditions. The MIL-125-NH2 catalyst possesses Lewis acidic sites, which catalyze direct dehalogenative condensation of bromides with primary amines to produce secondary amines in the dark. Upon irradiation, the MIL-125-NH2 reduces molecular oxygen to create oxygen radicals, converting bromides into the corresponding aldehydes to yield imines via a dehydrative coupling with amines. With appropriate acidity, rapid oxygen reduction kinetics, and optimized adsorption of aromatic bromides and generated water, the system catalyzes the conversion of a wide range of substrates, thus featuring it a promising method for applications.

Continuous reductive amination of carbonyl compounds with ammonia to synthesize secondary amines with high selectivity

Secondary amines are important compounds in the field of drug development. Applying reductive amination can conveniently synthesize secondary amines from carbonyl compounds. In this work, we propose an economical method for selective synthesis of secondary amines by using ammonia as a nitrogen source. A promising Pt/SiO2 (Pt loading 1 wt%) catalyst was designed for the continuous reductive amination of benzaldehyde (benchmark reaction), and effects of catalyst, solvent, temperature, the molar ratio of ammonia to benzaldehyde, pressure, concentration, liquid flow rate and gas flow rate are investigated. With the optimal reaction conditions, a high yield of dibenzylamine (95.5%) is obtained under very mild reaction temperature (30 ℃) and extremely short reaction times. Furthermore, a kinetic model for the formation of dibenzylamine is established, and corresponding kinetic parameters are obtained. Besides, many substrates, including aromatic aldehydes, biomass derivative furfural and even ketone, can all be smoothly converted into secondary amines.

Platinum Nanoparticles Uniformly Dispersed on Covalent Organic Framework Supports for Selective Synthesis of Secondary Amines

AbstractCovalent organic frameworks (COFs) with pore structures are talented supports for active components. In this report, COF has been rationally fabricated and served as host for growing uniformly dispersed platinum nanoparticles with a narrow size distribution (2 nm). The obtained hybrid Pt/COF exhibits high catalytic activity in the reductive amination of benzaldehyde towards secondary amines with a yield of 96 % and good recyclability. The preferable selectivity towards secondary amines could be attributed to synergistic effects of active platinum nanoparticles and COF, in which metallic Pt nanoparticles were uniformly dispersed with a positively charged surface. This work will open an avenue towards controlling the interaction between active metals and support as well as rational design of catalysts for demanding transformations for fine agrochemicals intermediates.

Selective Synthesis of Secondary Amines from Nitriles by a User‐Friendly Cobalt Catalyst

AbstractSelective hydrogenation/reductive amination of nitriles to secondary amines catalyzed by an inexpensive and user‐friendly cobalt complex, (Xantphos)CoCl2, is reported. The use of (Xantphos)CoCl2 and ammonia borane (NH3−BH3) combination affords the selective reduction of nitriles to symmetrical secondary amines, whereas the employment of (Xantphos)CoCl2 and dimethylamine borane (Me2NH−BH3) along with external amines produce unsymmetrical secondary amines and tertiary amines. The general applicability of this methodology is demonstrated by the synthesis of 43 symmetrical and unsymmetrical secondary and tertiary amines bearing diverse functionalities.magnified image

Oxidation-Reduction Condensation of Diazaphosphites for Carbon-Heteroatom Bond Formation Based on Mitsunobu Mechanism.

An efficient oxidation-reduction condensation reaction of diazaphosphites with various nonacidic pronucleophiles in the presence of DIAD as a weak oxidant has been developed for carbon-heteroatom bond formation. This mild process affords structurally diverse tertiary amines, secondary amines, esters, ethers, and thioethers in moderate to excellent yields. The selective synthesis of secondary amines from primary amines has been achieved. Importantly, a practical application to the synthesis of antiparkinsonian agent piribedil has been demonstrated.

Selective reductive amination of aldehydes from nitro compounds catalyzed by molybdenum sulfide clusters

A one-pot selective synthesis of secondary amines catalyzed by a well-defined Mo3S4 cluster using hydrogen as a benign reductant.

Environmentally friendly synthesis of secondary amines via one-pot reductive amination over a heterogeneous Co–Nx catalyst

The application of earth-abundant transition metal catalysts in the mild and selective synthesis of secondary amines via the reductive amination method is very challenging.

Ruthenium-catalyzed deaminative redistribution of primary and secondary amines.

A ruthenium-hydride complex, [Ru(H)(Cl)(CO)(PCy3)2], was found to be active in the highly selective redistribution of primary and secondary amines bearing an α-hydrogen atom. This new deaminative coupling of amines enables the highly selective synthesis of secondary amines from primary amines and of tertiary amines from secondary amines with the evolution of ammonia. A preliminary mechanistic view of this novel reaction based on catalytic experiments using NMR methods confirms the synthetic observations.

ChemInform Abstract: Selective Synthesis of Secondary Amines from Nitriles Using Pt Nanowires as a Catalyst.

AbstractSymmetrical and unsymmetrical secondary amines are prepared from nitriles in an one‐pot procedure in excellent yields.

Selective synthesis of secondary amines from nitriles using Pt nanowires as a catalyst

A new one-pot method has been developed for the selective synthesis of secondary amines via reductive amination of the corresponding nitriles using Pt nanowires as a catalyst. This method allows for the synthesis of both unsymmetrical and symmetrical secondary amines in excellent yields (up to 95%) in the presence or absence of additional amines, respectively. Furthermore, the reaction proceeds under mild conditions and is environmentally benign.

ChemInform Abstract: Selective Synthesis of Secondary Amines by Pt Nanowire Catalyzed Reductive Amination of Aldehydes and Ketones with Ammonia.

The process of the reductive amination of aldehydes or ketones in the presence of ammonia using unsupported ultra-thin Pt nanowires has been developed. This catalytic system shows high activity and selectivity under mild reaction conditions.

Selective synthesis of secondary amines by Pt nanowire catalyzed reductive amination of aldehydes and ketones with ammonia

The process of the reductive amination of aldehydes or ketones in the presence of ammonia using unsupported ultra-thin Pt nanowires has been developed. This catalytic system shows high activity and selectivity under mild reaction conditions.

ChemInform Abstract: Selective Synthesis of Secondary Amines via N‐Alkylation of Primary Amines and Ammonia with Alcohols by Supported Hydroxide Catalysts.

AbstractAn efficient catalytic system with a reusable heterogeneous catalyst is presented for the title reaction under aerobic conditions.

Selective Synthesis of Secondary Amines with Cu(OH)x/Al2O3

Selective Synthesis of Secondary Amines with Cu(OH)_x/Al₂O₃

Selective Synthesis of Secondary Amines via N-Alkylation of Primary Amines and Ammonia with Alcohols by Supported Copper Hydroxide Catalysts

Abstract The N-alkylation of primary amines and ammonia (in situ generated from urea or aqueous ammonia) with alcohols to secondary amines was efficiently promoted by supported copper hydroxide catalysts, Cu(OH)x/Al2O3 and Cu(OH)x/TiO2. The observed catalysis was truly heterogeneous, and the catalysts could be reused without an appreciable loss of catalytic performance.