79416-13-0

Upstream product

• 7432-21-5 N-carbobenzyloxy-L-tryptophane 
• 850232-59-6 benzyl N-[(1S)-2-(1H-1,2,3-benzotriazol-1-yl)-1-(1H-indol-3-ylmethyl)-2-oxoethyl]carbamate 
• 147-85-3 L-proline 
• 55782-87-1 N-carbobenzyloxy-L-tryptophanyl-L-proline methyl ester 
• 64693-64-7 N^α-benzyloxycarbonyl-L-tryptophyl chloride 

Relevant academic research and scientific papers

Efficient peptide coupling involving sterically hindered amino acids

(Chemical Equation Presented) Hindered amino acids have been introduced into peptide chains by coupling N-(Cbz- and Fmoc-α-aminoacyl) benzotriazoles with amino acids, wherein at least one of the components was sterically hindered, to provide compounds 3a-e, (3c +3 c′), 5a-d, (5a + 5a′), 6a-c, (6b + 6b′), 8a-c, 9a-e, 10a-d, and (10a + 10a′) in isolated yields of 41-95% with complete retention of chirality as evidenced by NMR and HPLC analysis. The benzotriazole activation methodology is a new route for the synthesis of sterically hindered peptides. (Note: compound numbers written within brackets represent diastereomeric mixtures or racemates; compound numbers without brackets represent enantiomers.)

Origins of Micellar Diastereoselectivity

Thiol-functionalized surfactant micelles (n-C12H25N+Me2CH2CH2SH,Cl-) were used to cleave Z-Trp-Pro p-nitrophenyl dipeptide esters.Marked kinetic diastereoselectivity was observed in these reactions.For example at pH 8 and concentrations (ca.6-7)x1E-3 M, the micellar thiol cleaved the LL substrate 5-6 times more rapidly than its DL diastereomer.This kinetic diastereoselectivity was shown to develop at surfactant concentrations ca.5x1E-3 M, considerably above the cmc (ca.1x1E-3 M), i.e., at a second "critical concentration".Dynamic light-scattering measurements showed that micelles which had reacted with the LL (but not the DL) substrate underwent a marked increase in apparent hydrodynamic diameter (from ca. 15 to 26 nm) near this second critical concentration.Similar phenomena could be induced upon addition of 2x1E-5 M LL dipeptide surfactant reaction product to the thiol micelles.Micelles of n-C12H25N+Me2CH2CH2OH,Cl- or n-C12H25N+Me3,Cl- were unresponsive to such additions (light scattering).The results are discussed in terms of molecular and supramolecular interactions between surfactant and solubilizate molecules.