19764-31-9Relevant articles and documents
Structures and properties of a diastereoisomeric molecular compound of (2S,3S)- and (2R,3S)-N-acetyl-2-amino-3-methylpentanoic acids
Yajima, Tatsuo,Kimura, Makiko,Nakakoji, Mami,Horikawa, Takao,Tokuyama, Yurie,Shiraiwa, Tadashi
, p. 2293 - 2298 (2009)
An X-ray crystal structural analysis revealed that (2S,3S)-N-acetyl-2- amino-3-methylpentanoic acid (N- acetyl-l-isoleucine; Ac-l-I1e) and (2R,3S)-N-acetyl-2- amino-3-methylpentanoic acid (N-acetyl-d-alloisoleucine; Ac-d-aIle) formed a molecular compound containing one Ac-l-Ile molecule and one Ac-d-aIle molecule as an unsymmetrical unit. This molecular compound is packed with strong hydrogen bonds forming homogeneous chains consisting of Ac-l-Ile molecules or Ac-d- aIle molecules and weak hydrogen bonds connecting these homogeneous chains in a fashion similar to that observed for Ac-l-Ile and Ac-d-aIle. Recrystallization of an approximately 1:1 mixture of Ac-l-Ile and Ac-d-aIle from water gave an equimolar molecular compound due to its lower solubility than that of Ac-d-aIle or especially Ac-l-Ile. The results suggest that the equimolar mixture of Ac-l-Ile and Ac-d-aIle could be obtained from an Ac-l-Ile-excess mixture by recystallization from water.
Bio- And Medicinally Compatible α-Amino-Acid Modification via Merging Photoredox and N-Heterocyclic Carbene Catalysis
Chen, Lei,Du, Ding,Feng, Jie,Gao, Jian,Lu, Tao,Ma, Rui,Shi, Zhihao,Zhang, Kuili
supporting information, (2020/09/02)
An N-heterocyclic carbene and photoredox cocatalyzed α-amino-acid decarboxylative carbonylation reaction is presented. This method displays good scope generality, providing a direct pathway to access various downstream α-amino ketones under bio- and medicinally compatible conditions. Moreover, this strategy is appealing to chemical biology because it has great potential for the chemical modification of peptides or the late-stage synthesis of keto-peptides.
Oxidative Damage in Aliphatic Amino Acids and Di- and Tripeptides by the Environmental Free Radical Oxidant NO3?: the Role of the Amide Bond Revealed by Kinetic and Computational Studies
Nathanael, Joses G.,Wille, Uta
, p. 3405 - 3418 (2019/03/11)
Kinetic and computational data reveal a complex behavior of the important environmental free radical oxidant NO3? in its reactions with aliphatic amino acids and di- and tripeptides, suggesting that attack at the amide N-H bond in the peptide backbone is a highly viable pathway, which proceeds through a proton-coupled electron transfer (PCET) mechanism with a rate coefficient of about 1 × 106 M-1 s-1 in acetonitrile. Similar rate coefficients were determined for hydrogen abstraction from the α-carbon and from tertiary C-H bonds in the side chain. The obtained rate coefficients for the reaction of NO3? with aliphatic di- and tripeptides suggest that attack occurs at all of these sites in each individual amino acid residue, which makes aliphatic peptide sequences highly vulnerable to NO3?-induced oxidative damage. No evidence for amide neighboring group effects, which have previously been found to facilitate radical-induced side-chain damage in phenylalanine, was found for the reaction of NO3? with side chains in aliphatic peptides.
