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The facile synthesis of valuable primary and secondary amines is reported using a sequential procedure of hydroaminomethylation and Pd-catalyzed hydrogenolysis. The hydroaminomethylation reaction was catalyzed by a cationic Rh(I) iminopyridyl complex and the N-alkylated benzylamines were produced with high chemoselectivity, albeit as mixtures of linear and branched products. Performing the hydrogenolysis reaction using 10% Pd/C, provided access to valuable primary and secondary amines which have applications in the surfactant, pharmaceutical and polymer industries.

Herein we report the selective transfer hydrogenation (TH) of nitriles to secondary (2°) amines with simple Ni(II)-catalysts using ammonia borane (AB) as a source of hydrogen (H2). A bis(pyrazolylmethyl)pyridine (L1) or ethylenediamine (L4) ligated Ni(II) pre-catalyst, created in situ, could hydrogenate several aromatic- and aliphatic nitriles in full conversions and isolated yields of up to 88% under ambient temperature and in very short reaction times. Deuterium labelling experiments illustrated the incorporation of a proton on the nitrogen and hydride on the α-carbon of dibenzylamine. Using α-picoline borane, containing no dissociable protons, assisted with the postulation of a two-step TH mechanism of benzonitrile. AB was subjected to dehydrogenation and it was observed that a maximum of 2.96 equivalents of H2 gas could be generated from NiCl2?6H2O/L1.

Symmetric secondary amines were synthesized by the self-condensation of primary amines over a palladium-loaded titanium dioxide (Pd/TiO2) photocatalyst. The reactions afforded a series of secondary amines in moderate to excellent isolated yields at ambient temperature (30 °C, in cyclopentyl methyl ether). Applicability for one-pot pharmaceutical synthesis was demonstrated by a photocatalytic reaction sequence of self-condensation of an amine followed by N-alkylation of the resulting secondary amine with an alcohol.

The water-soluble rhodium complex generated in situ from [Rh (COD)Cl]2 in aqueous ammonia has been revealed as a highly efficient catalyst for the hydrogenation of aromatic nitriles, to primary amines with excellent yields. The catalyst is also highly selective towards primary amines in the case of sterically hindered aliphatic nitriles. The catalytic system can also be recycled and re-used with no significant loss of activity.

Symmetrical tertiary amines have been efficiently realized from amine and secondary amines via deaminated homocoupling with heterogeneous bimetallic Co2Rh2/C as catalyst (molar ratio Co:Rh=2:2). Unsymmetric secondary anilines were produced from the reaction of anilines with symmetric tertiary amines. The Co2Rh2/C catalyst exhibited very high catalytic activity towards a wide range of amines and could be conveniently recycled ten times without considerable leaching. (Figure presented.).

Abstract: A new one-pot method has been introduced in this work for the synthesis of symmetrical primary, secondary, and tertiary alkyl amines from alkyl halides and 5-methyl-1,3,4-thiadiazole-2-amine as a nitrogen-transfer reagent. In this method, all three types of amines have been successfully prepared after changing the ratio of substrates and base control. In addition to the introduction of a new nitrogen-transfer reagent, other important features of this work include normal atmospheric conditions and excellent yields under mild reaction conditions.

Hydrogenation of carbonitriles catalyzed by nickel nanoparticles in the presence of primary amines led to the predominant formation of unsymmetrical secondary amines. In the presence of secondary amines hydrogenation of nitrites provided enamines as main products. Hydrogenation of nitriles in the presence of formamide or acetamide afforded formyl or acetyl derivatives of primary amines.

Hydrogenation of carbonitriles catalyzed by nickel nanoparticles in isopropanol proceeds under atmospheric pressure of hydrogen within 6-15 h to yield mainly secondary amines. Hydrogenation of α-aminonitriles results in reductive decyanation. β-Aminonitriles undergo hydrogenolysis at the nitrogen-carbon bond.

The liquid-phase hydrogenation of cinnamonitrile to selectively obtain the unsaturated primary amine (cinnamylamine) was studied at 383 K and 13 bar on Ni, Co, Ru and Cu metals supported on a commercial silica. Ni/SiO2 and Co/SiO2 were the most active catalysts for cinnamonitrile conversion but formed only small amounts of cinnamylamine. In contrast, Cu/SiO2 and Ru/SiO2 presented low activity for cinnamonitrile hydrogenation but formed selectively cinnamylamine in the liquid phase; nevertheless, on both samples the carbon balance was only about 40%. In an attempt of promoting the rate and yield to cinnamylamine, additional catalytic runs were carried out at higher temperatures and H2 pressures on a highly dispersed Cu(11%)/SiO2 catalyst prepared by the chemisorption-hydrolysis method. Results showed that when cinnamonitrile hydrogenation was performed at 403 K and 40 bar on Cu(11%)/SiO2, the yield to cinnamylamine was 74% giving as by-product only the unsaturated secondary amine (dicinnamylamine).

A comprehensive comparative molecular field analysis (CoMFA) model for the binding of ligands to the neuronal voltage-gated sodium channel was generated based on 67 diverse compounds. Earlier published CoMFA models for this target provided μM ligands, but the improved model described here provided structurally novel compounds with low nM IC50. For example, new compounds 94 and 95 had IC50 values of 129 and 119 nM, respectively.

A range of alternative, more environmentally conservative solvents have been evaluated for use within the direct reductive amination reactions of aldehydes using borane-based reductants. The data generated has been used to develop a guide to facilitate replacement of less desirable chlorinated solvents, such as DCE, from these widely used synthetic processes.

Aliphatic and aromatic secondary amines were synthesised selectively by one pot reductive amination of nitriles with primary amines using Pt/C (3% by weight) catalyst in a continuous flow multichannel microreactor. Molecular hydrogen was used as a clean reducing agent at moderate reaction conditions. The Royal Society of Chemistry 2013.

The use of supercritical carbon dioxide (scCO2) on the hydrogenation of benzonitrile was investigated over Pd and other metal catalysts. Without any additive, benzonitrile was hydrogenated to benzylamine with high conversion (90.2%) and selectivity (90.9%) using the Pd/MCM-41 catalyst. A strong influence of CO2 pressure on the conversion and selectivity were observed. As the CO2 pressure increases, the conversion was increased, and after reaching the maximum at around 8-10 MPa, it decreased. Moreover, simply by tuning the CO2 pressure, it is possible to obtain benzylamine or dibenzylamine. For instance, at lower pressure CO2 acts as a protecting agent, leading to the formation of the primary amine, but at higher pressure, the yield of primary amine as well as the solubility of the imine intermediate in CO2 increases, which results high selectivity for dibenzylamine. A plausible mechanism has been proposed to show the role of CO2 on the selectivity toward primary and secondary amines. The results confirm that the presence of CO2 is mandatory for the formation of benzylamine with high selectivity. Furthermore, the other reaction parameters, such as reaction time, H2 pressure, temperature etc., also affect the conversion as well as selectivity of benzylamine. This process has been extended to the hydrogenation of a series of different nitrile compounds.

(Chemical Equation Presented) The efficient selective synthesis of secondary and tertiary amines has been achieved by means of Cp*Ir- catalyzed multialkylation of ammonium salts with alcohols without solvent: the reactions of ammonium acetate with alcohols gave tertiary amines exclusively, while those of ammonium tetrafluoroborate afforded secondary amines selectively. Using this method, secondary 5- and 6-membered cyclic amines were synthesized from ammonium tetrafluoroborate and diols in one pot.

An efficient, general procedure for highly chemoselective reductive mono-alkylation of ammonia with ketones is reported. Treatment of ketones with ammonia in ethanol and titanium(IV) isopropoxide, followed by in situ sodium borohydride reduction, and a straightforward workup afforded primary amines in good to excellent yields. Reductive alkylation of ammonia with aldehydes, on the other hand, afforded the corresponding symmetrical secondary amines selectively.

Disulfenamides, synthesized by reactions between primary amines and arenesulfenyl chlorides and between alkyl bromides and lithium N,N-bis(arylsulfenyl)amides , yield aminyl radical intermediates on reduction with tributyltin hydride.

Aminomethylation of styrene with formaldehyde and dimethylamine leads to N-methylbenzenepropanamine (1), N-(3-phenylpropyl)benzenepropanamine (3), and α-methylenebenzenepropanal (4) as major products.The ratio of 1, 3 and 4 is considerably influenced by the ratio of the reactants.The best yield of 1 is obtained by using dimethylamine in excess.Styrene in excess favors the formation of 3, and equivalent amounts of reactants afford the best yield of 4.Using formaldehyde in excess leads to the complete N-methylation of 1 and 3.When styrene reacts with formaldehyde and diethylamine or diisopropylamine the most important aminomethylation products are N-ethylbenzenepropanamine (11) or N-isopropylbenzenepropanamine (12), respectively, and 3 and 4 in both cases.The formation of the major products in the aminomethylation of styrene can be explained by the hydride transfer mechanism represented earlier as one competing mechanism for the aminomethylation of certain bicyclic alkenes.The N-methylation of amine 1 and 3, when formaldehyde is used in excess, is due to Eschweiler methylation under aminomethylation conditions.