24788-07-6Relevant academic research and scientific papers
Enzymatic synthesis of C-terminal arylamides of amino acids and peptides
Nuijens, Timo,Cusan, Claudia,Kruijtzer, John A. W.,Rijkers, Dirk T. S.,Liskamp, Rob M. J.,Quaedflieg, Peter J. L. M.
supporting information; experimental part, p. 5145 - 5150 (2009/12/06)
(Chemical Equation Presented) A mild and cost-efficient chemo-enzymatic method for the synthesis of C-terminal arylamides of amino acid and peptides is described. Using the industrial serine protease Alcalase under near-anhydrous conditions, C-terminal arylamides of N-Cbz-protected amino acids and peptides could be obtained from the corresponding C-terminal carboxylic acids, methyl (Me) or benzyl (Bn) esters, in high chemical and enantio- and diastereomeric purities. Yields ranged between 50% and 95% depending on the size of the aryl substituents and the presence of electron-withdrawing substituents. Complete α-C-terminal selectivity could be obtained even in the presence of various unprotected side-chain functionalities such as β/γ-carboxyl, hydroxyl, and guanidino groups. In addition, the use of the cysteine protease papain and the lipase Cal-B gave anilides in high yields. The chemo-enzymatic synthesis of arylamides proved to be completely free of racemization, in contrast to the state-of-the-art chemical methods.
Enantioselective nickel-catalyzed conjugate addition of dialkylzinc to chalcones using chiral α-amino amides
Escorihuela, Jorge,Burguete, M. Isabel,Luis, Santiago V.
scheme or table, p. 6885 - 6888 (2009/04/07)
A series of α-amino amides derived from natural amino acids (alanine, valine, phenylalanine, isoleucine, and phenylglycine) have been synthesized and fully characterized. Their Ni(II) complexes prepared from Ni(acac)2 catalyze the enantioselective conjugate addition of diethylzinc to chalcones in high yields and in good enantioselectivities (up to 84%). The side chain of the amino acid and the substituents in the amide nitrogen govern the enantioselectivity of the catalytic process.
