Lossen Rearrangement by Rh(III)-Catalyzed C-H Activation/Annulation of Aryl Hydroxamates with Alkynes: Access to Quinolone-containing Amino Acid Derivatives

A convenient and robust method for the preparation of new CF3-containing 2-quinolones has been developed via Rh(III)-catalyzed C-H activation/Lossen rearrangement/annulation cascade of N-pivaloyloxy-arylamides with internal alkynes bearing α-CF3-α-amino acid moiety...

Synthesis and antimicrobial activity of some novel 1,2-dihydro-[1,2,4]triazolo[1,5-a]pyrimidines bearing amino acid moiety

A new series of [1,2,4]-triazole bearing amino acid derivatives were synthesized under green chemistry conditions and evaluated for their antimicrobial activities.

Self-Assembly of Supramolecular Architectures by the Effect of Amino Acid Residues of Quaternary Ammonium Pillar[5]arenes

Novel water-soluble multifunctional pillar[5]arenes containing amide-ammonium-amino acid moiety were synthesized. The compounds demonstrated a superior ability to bind (1S)-(+)-10-camphorsulfonic acid (S-CSA) and methyl orange dye depending on the nature of the substituent, resulting in the formation one-to-one complexes with both guests. The formation of host-guest complexes was confirmed by ultraviolet (UV), circular dichroism (CD) and 1H NMR spectroscopy. This work demonstrates the first case of using S-CSA as a chiral template for the non-covalent self-assembly of architectures based on pillar[5]arenes. It was shown that pillar[5]arenes with glycine or L-alanine fragments formed aggregates with average hydrodynamic diameters (d) of 165 and 238 nm, respectively. It was established that the addition of S-CSA to the L-alanine-containing derivative led to the formation of micron-sized aggregates with d of 713 nm. This study may advance the design novel stereoselective catalysts and transmembrane amino acid channels.

Enantioselective Synthesis of Chromanones Bearing an α,α-Disubstituted α-Amino Acid Moiety via Decarboxylative Michael Reaction

In this manuscript, a novel, decarboxylative Michael reaction between α-substituted azlactones and chromone-3-carboxylic acids is described. The reaction proceeds in a sequence Michael addition followed by decarboxylative deprotonation, and it results in the formation of chromanones bearing an azlactone structural unit. The possibility of transforming an azlactone moiety into a protected α,α-disubstituted α-amino acid derivative is also demonstrated.

Chiral β3-isocyanopropionates for multicomponent synthesis of peptides and depsipeptides containing a β-amino acid fragment

Chiral β3-isocyanopropionic acids derivatives is a new type of isocyanides for multicomponent reactions. The use of these isocyanides in Ugi and Passerini reactions allows to prepare short peptides and depsipeptides with β-amino acid moiety in the structure.

Syntone chemistry and prebiotic stage in life evolution 1. Aziridinone, a key compound in formation of the first proteinogenic amino acids and polypeptides

In this paper is proposed a new theory concerning the formation of the first proteinogenic amino acids and their corresponding polypeptides starting of three syntones: methylene, nitrene and carbon monoxide. First, at low temperature in nitrogen, these three syntones form aziridinone, an asimetric compound in special conditions. Next, by a series of radical chain, izomerization, cyclization, elimination and polymerization reactions, apparently without a well defined transition states are formed a series of precursor syntones. Finally, these more structured syntones at the contract with the components of primary atmosphere, especially with water, ammonia, hydrogen sulphide, even with carbon dioxide and methane offer the first proteinogenic amino acids and their first corresponding polypeptides. As a very important aspect, the aziridinone cycle furnish the backbone of proteinogenic amino acids. The formation of each proteinogenic amino acid moiety also as its participation to construction of polypeptide structures were estimated by two parameters: (1) the complex structural factor, Fe and (2) the participation coefficient, Cp respectively. Dominantly, the quantitative results given in this paper were acquired by structural, thermodynamical and reactivity studies using DGauss with the B88-LYP GGA energy functional with high integral accuracy. Finally, an experimental assembly for obtention of amino acids and polypeptides is proposed. Brief, the three initial syntones: CH2, NH and CO, in nitrogen form aziridinone. That, in reactions with the same three syntones form, the more structured syntone precursors of proteinogenic amino acids and polypeptides. At the contact with primary atmosphere components are formed the first proteinogenic amino acids and polypeptides. The first polypeptides appear from polypeptide precursors and not from proteinogenic amino acids.