159551-91-4

Upstream product

• 501-53-1 benzyl chloroformate 
• 13504-85-3 (2S,4R)-1-(benzyloxycarbonyl)-4-hydroxypyrrolidine-2-carboxylic acid 
• 51-35-4 4R-4-hydroxyproline 
• 13500-53-3 N-benzyloxycarbonyl-(2S,4R)-4-hydroxyproline benzyl ester 
• 159551-89-0 (S)-2,5-dihydro-pyrrole-1,2-dicarboxylic acid dibenzyl ester 
• 159551-87-8 (2S,4R)-N^α-Cbz-4-[(p-toluenesulfonyl)oxy]proline benzyl ester 
• 159551-88-9 dibenzyl (2S,4S)-4-(phenylselanyl)pyrrolidine-1,2-dicarboxylate 
• 100-39-0 benzyl bromide 

Downstream Products

• 159551-90-3 (1R,2S,5S)-6-oxa-3-aza-bicyclo[3.1.0]hexane-2,3-dicarboxylic acid dibenzyl ester 
• 95341-64-3 (2S,3R,4S)-3,4-dihydroxypyrrolidine-2-carboxylic acid 

Relevant academic research and scientific papers

Scaling the Amphiphilic Character and Antimicrobial Activity of Gramicidin S by Dihydroxylation or Ketal Formation

The acid lability of aliphatic ketals, which often serve as protection groups for 1,2-diols, is influenced by their local structural environment. The acetonide of the protected amino acid cis-dihydroxyproline (Dyp) is a typical protecting group cleavable by traces of TFA. The tricyclic acetonide of the dipeptide d-Hot-Tap is resistant to TFA and thus can serve as a bioorthogonal modification of bioactive peptides. With the aim of improving antimicrobial activity and hemolytic properties, we use these reactivity differences to scale the membrane affinity of the decapeptide Gramicidin S cyclo(d-Phe-Pro-Val-Orn-Leu-)2 (GS). The cis-dihydroxylated amino acids are used to increase the polarity of GS or obversely decrease the polarity by stereoselective ketal formation with an aliphatic ketone. While Dyp (GS mimetic 15) has only minimal influence on the biological properties of GS, d-Hot-Tap at the position of d-Phe1-Pro2 eradicates the biological activity (GS mimetic 16). The acid-stable ketals 17-19 are bioorthogonal modifications which reconstitute the biological activity of GS. We describe an improved synthesis of orthogonally protected Fmoc-Dyp-acetonide (9) and of several Fmoc-d-Hot-Tap-ketals for solid-phase peptide synthesis.

Substrate specificity of proline 4-hydroxylase: Chemical and enzymatic synthesis of 2S,3R,4S-epoxyproline

The substrate specificity of L-proline 4-hydroxylase, a 2-oxoglutarate dependent dioxygenase from Streptomyces griseoviridus P8648, was investigated. Preliminary assays measuring turnover of 2-oxyglutarate indicated 3,4-dehydro-L-proline was an efficient