A series of chiral complexes the form Ir(NHC)2(aa)(H)(X) (NHC = N-heterocyclic carbene, aa chelated amino acid, X halide) was synthesized by oxidative addition α-amino acids to iridium(I) bis-NHC compounds and screened for asymmetric transfer hydrogenation ketones. Following optimization reaction conditions, NHC, acid ligands, high enantioselectivity achieved when employing Ir(IMe)2(l-Pro)(H)(I...

The main goal in developing peptidomimetics is the stabilization of bioactive conformation peptides. Among all secondary structures, turns are paramount importance. This review highlights recent advances design and synthesis cyclic turn mimics. Both amino acids, carbo- hetero-cyclic scaffolds have been considered, focusing on their use preparation ability to induce γ-, β-, α-turns.

Prochymosin is one of the most important aspartic proteinases used as a milk-clotting enzyme in cheese production. In the present investigation we report sequence of cDNA encoding goat ( Capra hircus ) preprochymosin and compare its nucleotide and deduced amino acid sequences with sequences of other ruminants preprochymosin. As bovine prochymosin, the caprine prochymosin cDNA encodes 365 amino ...

prochymosin is one of the most important aspartic proteinases used as a milk-clotting enzyme in cheese production. in the present investigation we report sequence of cdna encoding goat ( capra hircus ) preprochymosin and compare its nucleotide and deduced amino acid sequences with sequences of other ruminants preprochymosin. as bovine prochymosin, the caprine prochymosin cdna encodes 365 amino ...

The reiterative high temperature co-sublimation of an enantiopure or an enantioenriched α-amino acid mixed with racemic α-amino acids leads to deracemization of the latter. A synergistic effect is observed for complex mixtures, and the sense of the handedness is, for all compounds, identical to that of the enantioenriched starting material.

The synthesis of alkyl boronic esters by direct decarboxylative radical addition of carboxylic acids to vinyl boronic esters is described. The reaction proceeds under mild photoredox catalysis and involves an unprecedented single-electron reduction of an α-boryl radical intermediate to the corresponding anion. The reaction is amenable to a diverse range of substrates, including α-amino, α-oxy, ...

Coupling reaction between electron-rich 2-morpholino-4(3H)-pyrimidinone and nucleophilic side chains of several natural α-amino acids promoted by phosphonium salt has been developed to prepare new optically active pyrimidin-4-yl amino acids. The best results were obtained using a two-step method through the easily available benzotriazolyl-1-oxy intermediate. A detailed optimization study of thi...