Amines In Yields Research Articles

Silver Complex Bearing N-Heterocyclic Carbene Bidentate Chelating Ligand as an Efficient Catalyst in Solvent-Free KA2 Coupling.

We report a synthesis of silver complexes bearing chelating bidentate N-heterocyclic carbene, with various substitutions at the terminal positions of the imidazole moiety of the NHC units. The long aliphatic substituents proved to be beneficial in terms of the synthetic efficiency of the complexes, compared to previously reported methyl substitution. The complexes demonstrated excellent suitability for the KA2 coupling reaction, providing quaternary carbon-containing propargylic amines in yields up to 95 %, under solvent-free conditions. The method showed high tolerance for a wide range of substrates, including naturally occurring ketones, underscoring its practicality. To our knowledge, this represents the first use of a well-defined silver species in KA2 coupling, marking an advancement in the field.

Chemoselective Nitro Reduction Using Nitrogen‐Doped Carbon‐Encapsulated Ni Catalyst and Y‐Type Packed Bed Column for Continuous Flow Reaction

AbstractSelective reduction of nitro‐containing arenes and heteroarenes was achieved in 5 minutes at room temperature utilizing inexpensive NaBH4 as a hydrogen source and a newly developed Ni@N−C catalyst, obtained via a simple carbon coating process without the need for an external carbon source. A wide variety of nitro derivatives, including pharmaceutical molecules, was successfully reduced to the corresponding amines in yields ranging from 45% to 99% using the Ni@N−C catalyst under general batch conditions. The reactivity and selectivity of the nitro reduction were further enhanced by a continuous flow reaction system, especially when a newly designed Y‐type column was used, and the Osimertinib intermediate was produced on gram scale after 24 hours without any nickel metal contamination or silica gel chromatography purification.

Mild, Organo-Catalysed Borono-Deamination as a Key to Late-Stage Pharmaceutical Precursors and 18F-Labelled Radiotracers.

A tris(pentafluorophenyl)borane catalysed method for the synthesis of boronic acid esters from aromatic amines in yields of up to 93% was devised. Mild conditions, benign reagents, short reaction times, low temperatures and a wide substrate scope characterize the method. The reaction was found applicable to the synthesis of boronic acid ester derivatives of complex drug molecules in up to 86% isolated yield and high purity suitable for labelling. These boronates were subsequently labelled with [18F]fluoride ion in radiochemical yields of up to 55% with and even without isolation of the boronate-intermediate.

Synthesis and Properties of 1,3-Disubstituted Ureas and Their Isosteric Analogs Containing Polycyclic Fragments: V. 1-(Bicyclo[2.2.1]heptan-2-yl)-3-R- and 1-(1,7,7-Tricyclo[2.2.1]heptan-2-yl)-3-R-ureas

A series of 1,3-disubstituted ureas containing a bicyclic lipophilic group of natural origin were synthesized by the reactions of bicyclo[2.2.1]heptane-2-yl isocyanate with amines in yields of up to 82% and by the reactions of bicyclo[2.2.1]heptan-2-amine and 1,7,7-trimethylbicyclo[2.2.1]heptan-2-amine with 1,1'-carbonyldiimidazole in yields of up to 94%. The synthesized ureas are potent inhibitors of RNA virus replication and soluble epoxide hydrolase.

Enantioselective Rhodium-Catalyzed Allylation of Aliphatic Imines: Synthesis of Chiral C-Aliphatic Homoallylic Amines.

Reported herein is a method for the efficient syntheses of optically active 1-alkyl homoallylic amines in yields up to 95%, 13.5:1 dr, and 98% ee under mild, aqueous reaction conditions, via the Rh-catalyzed asymmetric allylation of aliphatic aldimines. This method provides a streamlined synthetic platform for the preparation of indolizidine and piperidine alkaloids, thus demonstrating its usefulness.

Synthesis of C-Ribosyl-1,2,3-triazolyl Carboxamides

Because of the emergence of new viruses, the need for new antiviral broad-spectrum compounds remains important. In this context, herein the synthesis of C-nucleosides, structurally close to ribavirin, a nucleoside presenting various biological activities and used until now particularly for its broad-spectrum antiviral properties, is reported. The compounds were designed in order to increase their stability and the number of hydrogen bond donor or acceptor in comparison to ribavirin, and to investigate the role of the carboxamide group on the biological activity. The efficient synthesis of 11 C-nucleosides is based on an indium-mediated alkynylglycosylation as the key step, followed by the construction of the triazole heterocycle. Amidation was performed with primary and secondary amines in yields up to 85%. An analogue nucleoside with a triazole without carboxamide group was also prepared in order to compare its activity. Finally, the carboxamide group was moved to the N-1 triazole position to mimic ribavirin.

Cs2CO3‐Promoted Direct N‐Alkylation: Highly Chemoselective Synthesis of N‐Alkylated Benzylamines and Anilines

Herein is described an efficient and chemoselective method for the synthesis of diversely substituted secondary amines in yields up to 98 %. Direct mono‐N‐alkylation of primary benzylamines and anilines with a wide range of alkyl halides is promoted by a cesium base in the absence of any additive or catalyst. The basicity and solubility of cesium carbonate in anhydrous N,N‐dimethylformamide not only enables mono‐N‐alkylation of primary amines but also suppresses undesired dialkylation of the desired amines.

Reactivity of cyclic sulfamidates towards lithium acetylides: synthesis of alkynylated amines

A synthetically useful level of reactivity of cyclic sulfamidates toward acetylides is described. Ring-opening reactions of a structurally diverse set of 1,2- and 1,3-cyclic sulfamidates with a range of lithium acetylides from aliphatic, cyclic, aromatic, heteroaromatic, and functionalized alkynes proceed smoothly in a regioselective manner to give the corresponding N-sulfate intermediates. Hydrolysis of these intermediates under acidic conditions furnishes the alkynylated amines in yields ranging from 29% to 98%. The scope of the acetylenic substitution reaction with the structural variations in both the cyclic sulfamidates and alkynes is briefly examined.

Ruthenium-catalyzed direct amination of alcohols with tertiary amines

A highly selective phosphine-based ruthenium catalyst system efficiently catalyzes the direct amination of alcohols with aliphatic tertiary amines, yielding unsymmetric tertiary amines in yields up to 87%. Ligand and solvent both affect the reaction yields significantly. The reaction can be performed with a wide variety of functionalities.

Synthesis of new diverse macrocycles from diol precursors

The formation of a library of diverse macrocycles with different ring sizes from two easily accessible building blocks is presented. Reacting diol precursors with electrophilic reagents lead to 17-membered sulfites and 19-membered malonates in 34-79% yield. Double-reductive amination of dialdehyde analogs of the diol precursors leads to 15-membered amines in yields ranging from 9 to 60%, reflecting large differences in reactivity based on steric environment

Synthesis and X-ray crystallographic study of 6,12-epiiminodibenzo[ b, f][1,5]diazocines

Seven 6,12-epiiminodibenzo[b,f][1,5]diazocines 2 with different substituents at position 13 have been prepared from o-(triphenylphosphoranylideneamino)benzaldehyde 1 and the corresponding aliphatic and aromatic primary amines in yields ranging from 40 to 80%. The molecular and crystal structures of componds 2d (R = 4 H 3C-C 6H 4) and 2e (R = 4 H 3CO-C 6H 4) have been determined by X-Ray analysis. Compound 2d crystallizes as a racemate while compound 2e crystallizes as a unique enantiomer (absolute configuration R,R).

Synthesis of asymmetric secondary and tertiary amines from a primary amine and alcohol over the methanol synthesis industrial catalyst SNM-1

Vapor-phase reactions ofn-pentan-1-ol with 2-ethylhexyiamine and ofn-heptan-1-ol with cyclohexylamine occurring in the presence of an industrial oxide copper-zinc-aluminum catalyst SNM-1 at 175–185°C have been found to afford the corresponding asymmetric secondary and tertiary amines in yields of 59–99 % and 5–49 %, respectively.