117402-81-0

Upstream product

• 4132-86-9 N-benzyloxycarbonylalanine 
• 71-36-3 butan-1-ol 
• 1142-20-7 N-Cbz-Ala 
• 60625-90-3 Cbz-alanine ethyl ester 
• 72604-33-2 (RS)-Z-Ala-OEt 
• 28819-05-8 (S)-2-benzyloxycarbonylamino-propionic acid methyl ester 

Downstream Products

• 1142-20-7 N-Cbz-Ala 
• 18323-56-3 Z-(S)-Ala-(S)-Leu-NH₂ 
• 2885-02-1 (S)-butyl 2-aminopropanoate 
• 1353757-51-3 (S,E)-n-butyl 2-methyl-2-(pyrrolidin-1-yl)-4-(p-toluenesulfonyl)but-3-enoate 

Relevant academic research and scientific papers

Transesterification of α-amino esters catalyzed by a tetranuclear zinc cluster: Zn4(OCOCF3)6O

Transesterification of amino acid ester derivatives was developed using a tetranuclear zinc cluster, Zn4(OCOCF3)6O, as the catalyst. Because the reaction conditions were very mild, a variety of N-protective groups and functional groups on side chains were tolerated. Georg Thieme Verlag Stuttgart. New York.

Asymmetric α-2-tosylethenylation of N,N-dialkyl-l-amino acid esters via the formation of non-racemic ammonium enolates

Asymmetric α-2-tosylethenylation of (S)-2-(pyrrolidin-1-yl)propanoic acid esters was shown to produce good yields with high enantioselectivities. The reaction proceeds via the formation of a non-racemic ammonium enolate without an external source of chirality.

Zinc-catalyzed amide cleavage and esterification of β- hydroxyethylamides

Snipping tool: Zn(OTf)2 is an efficient catalyst for selective cleavage of amides bearing a β-hydroxyethyl group on the nitrogen atom. The mechanism involves an N,O-acyl rearrangement and transesterification. This new catalytic system can be applied to sequence-specific peptide bond scission at the amine side of a serine residue. Tf=trifluoromethanesulfonyl. Copyright

The role of conformational flexibility of enzymes in the discrimination between amino acid and ester substrates for the subtilisin-catalyzed reaction in organic solvents

To investigate how the conformational flexibility of subtilisin affects its ability to discriminate between enantiomeric amino acid and ester substrates for the subtilisin-catalyzed reaction in an organic solvent, the flexibility around the active site and the surface of subtilisin was estimated from the mobility of a spin label bound to subtilisin by ESR spectroscopy. Many studies on enzyme flexibility focus on the active site. Both the surface and active site flexibility play an important role in the enantioselectivity enhancement of the enzyme-catalyzed reaction. It was found, however, that the different behavior observed for the enantioselectivity between the amino acid and ester substrates could be correlated with the flexibility around the surface rather than the flexibility at the active site of subtilisin. In other words, for the ester substrates, the greater flexibility around the surface of subtilisin induced by a conformational change resulting from the presence of an additive such as DMSO is essential for the enantioselectivity enhancement. This model is also supported by the Michaelis-Menten kinetic parameters for each enantiomeric substrate. Our findings provide insight into the enantioselectivity enhancement for the resolution of enantiomers for enzyme-catalyzed reactions in organic solvents.

Broadening of the substrate tolerance of α-chymotrypsin by using the carbamoylmethyl ester as an acyl donor in kinetically controlled peptide synthesis

In the kinetically controlled approach of peptide synthesis mediated by α-chymotrypsin, the broadening of the protease's substrate tolerance is achieved by switching the acyl donor from the conventional methyl ester to the carbamoylmethyl ester. Thus, as a typical example, the extremely low coupling efficiency obtained by employing the methyl ester of an inherently poor amino acid substrate, Ala, is significantly improved by the use of this particular ester. Its ameliorating effect is observed also in the couplings of other amino acid residues such as Gly and Ser as carboxy components.

PAPAIN-ASSISTED RESOLUTION OF NATURAL AND XENOBIOTIC α-AMINO ACIDS

A new and convenient method for the preparation of pure enantiomers of α-amino acids is described.Industrial papain, catalyzes the synthesis of L-Z-amino acid ethyl esters in ethanolic medium, with good yields.These esters are obtained from DL-Z-amino acids with 100percent optical purity.Unreactive D-Z-amino acids are readily isolated from reaction medium.Physical constants of natural and xenobiotic L-Z-amino acid esters and D-Z-amino acids are described.