Sustainable synthesis of amines using molecularly defined and nanoparticles-based catalysts

This dissertation describes the sustainable synthesis and functionalization of amines by catalytic reductive amination of carbonyl compounds and ammonia or amines in presence of molecular hydrogen or formic acid.Diese Dissertation befasst sich mit der nachhaltigen Synthese und Funktionalisierung von Aminen mittels katalytischer, reduktiver Aminierung von Carbonylverbindungen zusammen mit Ammoniak oder Aminen in der Gegenwart von Wasserstoff oder Ameisensäuren

Simple ruthenium-catalyzed reductive amination enables the synthesis of a broad range of primary amines

The production of primary benzylic and aliphatic amines, which represent essential feedstocks and key intermediates for valuable chemicals, life science molecules and materials, is of central importance. Here, we report the synthesis of this class of amines starting from carbonyl compounds and ammonia by Ru-catalyzed reductive amination using H2. Key to success for this synthesis is the use of a simple RuCl2(PPh3)3 catalyst that empowers the synthesis of >90 various linear and branched benzylic, heterocyclic, and aliphatic amines under industrially viable and scalable conditions. Applying this catalyst, −NH2 moiety has been introduced in functionalized and structurally diverse compounds, steroid derivatives and pharmaceuticals. Noteworthy, the synthetic utility of this Ru-catalyzed amination protocol has been demonstrated by upscaling the reactions up to 10 gram-scale syntheses. Furthermore, in situ NMR studies were performed for the identification of active catalytic species. Based on these studies a mechanism for Ru-catalyzed reductive amination is proposed

Cu‐Oxide Nanoparticles Catalyzed Synthesis of Nitriles and Amides from Alcohols and Ammonia in Presence of Air

The synthesis and functionalization of nitrogen-containing compounds continue to be important due to their wide applications. In particular, the preparation of nitriles and amides applying cost-effective and green methodologies is of central importance because these products represent valuable fine and bulk chemicals and serve as key precursors and central intermediates in organic synthesis and drug discovery as well as materials. Here, the preparation of nitriles and primary amides from alcohols and ammonia by a heterogeneous Cu-catalyzed aerobic oxidation process is reported. The optimal catalyst for this synthesis is based on supported copper oxide-nanoparticles, which are prepared by the impregnation and pyrolysis of simple copper nitrate on carbon. Applying these reusable nanoparticles, various simple, substituted, and functionalized aromatic, heterocyclic, and aliphatic nitriles are synthesized starting from inexpensive and easily accessible alcohols and ammonia in the presence of air. In addition, the synthesis of selected primary amides in a water medium is also performed using these Cu nanoparticles. © 2022 The Authors. Advanced Sustainable Systems published by Wiley-VCH GmbH

Silica-supported Fe/Fe–O nanoparticles for the catalytic hydrogenation of nitriles to amines in the presence of aluminium additives

The hydrogenation of nitriles to amines represents an important and frequently used industrial process due to the broad applicability of the resulting products in chemistry and life sciences. Despite the existing portfolio of catalysts reported for the hydrogenation of nitriles, the development of iron-based heterogeneous catalysts for this process is still a challenge. Here, we show that the impregnation and pyrolysis of iron(II) acetate on commercial silica produces a reusable Fe/Fe-O@SiO2 catalyst with a well-defined structure comprising the fayalite phase at the Si-Fe interface and alpha-Fe nanoparticles, covered by an ultrathin amorphous iron(III) oxide layer, growing from the silica matrix. These Fe/Fe-O core-shell nanoparticles, in the presence of catalytic amounts of aluminium additives, promote the hydrogenation of all kinds of nitriles, including structurally challenging and functionally diverse aromatic, heterocyclic, aliphatic and fatty nitriles, to produce primary amines under scalable and industrially viable conditions.Web of Science51292

Cobalt-based nanoparticles prepared from MOF-carbon templates as efficient hydrogenation catalysts

The development of efficient and selective nanostructured catalysts for industrially relevant hydrogenation reactions continues to be an actual goal of chemical research. In particular, the hydrogenation of nitriles and nitroarenes is of importance for the production of primary amines, which constitute essential feedstocks and key intermediates for advanced chemicals, life science molecules and materials. Herein, we report the preparation of graphene shell encapsulated Co3O4- and Co-nanoparticles supported on carbon by the template synthesis of cobalt-terephthalic acid MOF on carbon and subsequent pyrolysis. The resulting nanoparticles create stable and reusable catalysts for selective hydrogenation of functionalized and structurally diverse aromatic, heterocyclic and aliphatic nitriles, and as well as nitro compounds to primary amines (>65 examples). The synthetic and practical utility of this novel non-noble metal-based hydrogenation protocol is demonstrated by upscaling several reactions to multigram-scale and recycling of the catalyst

Ultra-small cobalt nanoparticles from molecularly-defined Co-salen complexes for catalytic synthesis of amines

We report the synthesis of in situ generated cobalt nanoparticles from molecularly defined complexes as efficient and selective catalysts for reductive amination reactions. In the presence of ammonia and hydrogen, cobalt-salen complexes such as cobalt(ii)-N,N′-bis(salicylidene)-1,2-phenylenediamine produce ultra-small (2-4 nm) cobalt-nanoparticles embedded in a carbon-nitrogen framework. The resulting materials constitute stable, reusable and magnetically separable catalysts, which enable the synthesis of linear and branched benzylic, heterocyclic and aliphatic primary amines from carbonyl compounds and ammonia. The isolated nanoparticles also represent excellent catalysts for the synthesis of primary, secondary as well as tertiary amines including biologically relevant N-methyl amines. This journal is © The Royal Society of Chemistry

Simple ruthenium-catalyzed reductive amination enables the synthesis of a broad range of primary amines

Synthesis of primary amines via operationally simple, inexpensive and environmentally friendly methodologies has high impact in industrial settings. Here, the authors show a reductive amination process involving a ruthenium catalyst, aldehydes/ketones, ammonia, and hydrogen that displays a remarkable scope of primary amine products