356531-67-4Relevant academic research and scientific papers
H2 Activation by Non-Transition-Metal Systems: Hydrogenation of Aldimines and Ketimines with LiN(SiMe3)2
Elliott, Daniel C.,Marti, Alex,Mauleón, Pablo,Pfaltz, Andreas
supporting information, p. 1918 - 1922 (2019/01/16)
In recent years, H2 activation at non-transition-metal centers has met with increasing attention. Here, a system in which H2 is activated and transferred to aldimines and ketimines using substoichiometric amounts of lithium bis(trimethylsilyl)amide is reported. Notably, the reaction tolerates the presence of acidic protons in the α-position. Mechanistic investigations indicated that the reaction proceeds via a lithium hydride intermediate as the actual reductant.
Synthesis of Symmetric and Unsymmetric Secondary Amines from the Ligand-Promoted Ruthenium-Catalyzed Deaminative Coupling Reaction of Primary Amines
Arachchige, Pandula T. Kirinde,Lee, Hanbin,Yi, Chae S.
, p. 4932 - 4947 (2018/05/08)
The catalytic system generated in situ from the tetranuclear Ru-H complex with a catechol ligand (1/L1) was found to be effective for the direct deaminative coupling of two primary amines to form secondary amines. The catalyst 1/L1 was highly chemoselective for promoting the coupling of two different primary amines to afford unsymmetric secondary amines. The analogous coupling of aniline with primary amines formed aryl-substituted secondary amines. The treatment of aniline-d7 with 4-methoxybenzylamine led to the coupling product with significant deuterium incorporation on CH2 (18% D). The most pronounced carbon isotope effect was observed on the α-carbon of the product isolated from the coupling reaction of 4-methoxybenzylamine (C(1) = 1.015(2)). A Hammett plot was constructed from measuring the rates of the coupling reaction of 4-methoxyaniline with a series of para-substituted benzylamines 4-X-C6H4CH2NH2 (X = OMe, Me, H, F, CF3) (ρ = -0.79 ± 0.1). A plausible mechanistic scheme has been proposed for the coupling reaction on the basis of these results. The catalytic coupling method provides an operationally simple and chemoselective synthesis of secondary amine products without using any reactive reagents or forming wasteful byproducts.
An efficient palladium-catalyzed N-alkylation of amines using primary and secondary alcohols
Dang, Tuan Thanh,Ramalingam, Balamurugan,Shan, Siah Pei,Seayad, Abdul Majeed
, p. 2536 - 2540 (2013/11/19)
PdCl2 in the presence of dppe or Xantphos(t-Bu) as the ligand is found to be an efficient catalyst for the N-alkylation of various primary and cyclic secondary amines using primary alcohols at 90-130 C under neat conditions. Interestingly, good to excellent yields were achieved when more challenging secondary alcohols were used as alkylating agents at 130-150 C. The reaction could be easily scaled up, as demonstrated for a 10 mmol scale achieving yields up to 90% with a TON of 900.
Structure-activity relationships of small molecule inhibitors of RAGE-Aβ binding
Ross, Nathan T.,Deane, Rashid,Perry, Sheldon,Miller, Benjamin L.
, p. 7653 - 7658 (2013/08/23)
The Receptor for Advanced Glycation Endproducts ('RAGE') mediates transport of amyloid-β peptide (Aβ) into the brain, and is therefore an important target for the development of therapeutic agents for Alzheimer's disease. We describe structure-activity relationships for inhibition of RAGE-Aβ binding, derived from the analysis of a library of tertiary amides.
Optimization of Triazine Nitriles as Rhodesain Inhibitors: Structure-Activity Relationships, Bioisosteric Imidazopyridine Nitriles, and X-ray Crystal Structure Analysis with Human CathepsinL
Ehmke, Veronika,Winkler, Edwin,Banner, David W.,Haap, Wolfgang,Schweizer, W. Bernd,Rottmann, Matthias,Kaiser, Marcel,Freymond, Celine,Schirmeister, Tanja,Diederich, Francois
supporting information, p. 967 - 975 (2013/07/27)
The cysteine protease rhodesain of Trypanosoma brucei parasites causing African sleeping sickness has emerged as a target for the development of new drug candidates. Based on a triazine nitrile moiety as electrophilic headgroup, optimization studies on the substituents for the S1, S2, and S3 pockets of the enzyme were performed using structure-based design and resulted in inhibitors with inhibition constants in the single-digit nanomolar range. Comprehensive structure-activity relationships clarified the binding preferences of the individual pockets of the active site. The S1 pocket tolerates various substituents with a preference for flexible and basic side chains. Variation of the S2 substituent led to high-affinity ligands with inhibition constants down to 2nM for compounds bearing cyclohexyl substituents. Systematic investigations on the S3 pocket revealed its potential to achieve high activities with aromatic vectors that undergo stacking interactions with the planar peptide backbone forming part of the pocket. X-ray crystal structure analysis with the structurally related enzyme human cathepsinL confirmed the binding mode of the triazine ligand series as proposed by molecular modeling. Sub-micromolar inhibition of the proliferation of cultured parasites was achieved for ligands decorated with the best substituents identified through the optimization cycles. In cell-based assays, the introduction of a basic side chain on the inhibitors resulted in a 35-fold increase in antitrypanosomal activity. Finally, bioisosteric imidazopyridine nitriles were studied in order to prevent off-target effects with unselective nucleophiles by decreasing the inherent electrophilicity of the triazine nitrile headgroup. Using this ligand, the stabilization by intramolecular hydrogen bonding of the thioimidate intermediate, formed upon attack of the catalytic cysteine residue, compensates for the lower reactivity of the headgroup. The imidazopyridine nitrile ligand showed excellent stability toward the thiol nucleophile glutathione in a quantitative invitro assay and fourfold lower cytotoxicity than the parent triazine nitrile.
Rapid and efficient access to secondary arylmethylamines
Fleury-Brégeot, Nicolas,Raushel, Jessica,Sandrock, Deidre L.,Dreher, Spencer D.,Molander, Gary A.
, p. 9564 - 9570 (2012/08/28)
Ammoniomethyl trifluoroborates are very powerful reagents that can be used to access biologically relevant aryl- and heteroaryl-methylamine motifs via Suzuki-Miyaura cross-couplings. Until now, this method was limited to the production of tertiary and primary amines. The synthesis of a large array of secondary ammoniomethyltrifluoroborates has been achieved through a one step nucleophilic substitution reaction on the potassium bromomethyltrifluoroborate. Smooth cross-coupling conditions have been designed, based on the use of an aminobiphenyl palladium precatalyst, to couple these trifluoroborates efficiently with aryl bromides. This strategy offers a new way to access biologically relevant motifs and allows, with the previously developed methods, access to all three classes of aminomethylarenes. Secondary ammoniomethyltrifluoroborates can be easily synthesized by nucleophilic substitution on potassium bromomethyltrifluoroborate. These reagents have then been used in Suzuki-Miyaura cross-couplings with aryl bromides, offering an effective access to the aminomethylarene structural motif. This new method provides an interesting alternative to the reductive amination procedure (see scheme). Copyright
