Stereoretentive N-Arylation of Amino Acid Esters with Cyclohexanones Utilizing a Continuous-Flow System
The N-arylation of chiral amino acid esters with minimal racemization is a challenging transformation because of the sensitivity of the α-stereocenter. A versatile synthetic method was developed to prepare N-arylated amino acid esters using cyclohexanones as aryl sources under continuous-flow conditions. The designed flow system, which consists of a coil reactor and a packed-bed reactor containing a Pd(OH)2/C catalyst, efficiently afforded the desired N-arylated amino acids without significant racemization, accompanied by only small amounts of easily removable co-products (i. e., H2O and alkanes). The efficiency and robustness of this method allowed for the continuous synthesis of the desired product in very high yield and enantiopurity with high space-time yield (74.1 g L?1 h?1) and turnover frequency (5.9 h?1) for at least 3 days.
Peptides bearing an acryloyl residue at their N-terminus were coupled with various C-glycosides in an equimolar ratio via cross-metathesis. The newly formed olefin was obtained with high E/Z selectivity in satisfying to high yields with low homodimerizati
L-Selective dipeptide synthesis using novel thermophilic enzyme from Clostridium sp.
A novel, inexpensive, thermophilic protease-type enzyme isolated from Clostridium thermohydrosulfuricum was used for dipeptide synthesis. The enzyme showed broad substrate selectivity and enantioselectivity towards L-amino acids in peptide bond formation.
Preparation process of α-L-aspartyl-L-phenylalanine methyl ester
This invention relates to an improved process for preparing α-L-aspartyl-L-phenylalanine methyl ester. More specifically, it relates to a process for preparing α-L-aspartyl-L-phenylalanine methyl ester which comprises treating, as a raw material, N-formyl
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(2008/06/13)
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