59490-38-9

Upstream product

• 59490-33-4 N-(4-chloro-benzoylamino)-phenylalanine 
• 67-56-1 methanol 
• 22887-55-4 4-benzyl-2-(4-chloro-phenyl)-4H-oxazol-5-one 

Downstream Products

• 59490-33-4 L-4-chlorobenzoylphenylalanine 
• 3005-61-6 methyl (S)-2-(benzoylamino)-3-phenylpropanoate 

Relevant academic research and scientific papers

Rational Design of 2-Substituted DMAP- N-oxides as Acyl Transfer Catalysts: Dynamic Kinetic Resolution of Azlactones

A novel concept that conversion of chiral 2-substituted DMAP into its DMAP-N-oxide could significantly enhance the catalytic activity and still be used as an acyl transfer catalyst is presented. A new type of chiral 2-substituted DMAP-N-oxides, derived from l-prolinamides, has been rationally designed, facilely synthesized, and applied in the dynamic kinetic resolution of azlactones. Using simple MeOH as the nucleophile, various l-amino acid derivatives were produced in high yields (up to 98% yield) and enantioselectivities (up to 96% ee). Furthermore, α-deuterium labeled l-phenylalanine derivative was also obtained. Experiments and DFT calculations revealed that in 2-substituted DMAP-N-oxide, the oxygen atom acted as the nucleophilic site and the N-H bond functioned as the H-bond donor. High enantioselectivity of the reaction was governed by steric factors, and the addition of benzoic acid reduced the activation energy by participating in the construction of a H-bond bridge. The theoretical chemical study indicated that only when attack directions of the chiral catalyst were fully considered could the correct calculation results be obtained. This work paves the way for the utilization of the C2 position of the pyridine ring and the development of chiral 2-substituted DMAP-N-oxides as efficient acyl transfer catalysts.

Enzymatic Asymmetric Synthesis of α-Amino Acids. Enantioselective Cleavage of 4-Substituted Oxazolin-5-ones and Thiazolin-5-ones

A general enzymatic asymmetric synthesis of L-α-amino acids has been developed.This method entails the use of the Pseudomonas cepacia lipase (P-30) to catalyze the enantioselective methanolysis of a variety of 4-substituted 2-phenyloxazolin-5-one derivatives in a nonpolar organic solvent to furnish optically active N-benzoyl-L-α-amino acid methyl esters (ee = 66-98 percent), which in turn is subjected to a protease-catalyzed kinetic resolution yielding enantiomerically pure N-benzoyl-L-α-amino acids.This synergistic coupling of two enzymes allows the ready preparation of L-α-amino acids of high enantiopurity in yields greater than 50 percent, an inherent advantage over conventional resolution procedures.Two proteases were found to catalyze the enantioselective hydrolysis of a variety of 4-substituted 2-phenylthiazolin-5-one derivatives to give N-(thiobenzoyl)-L-α-amino acids of high optical purity.