92421-75-5Relevant academic research and scientific papers
Beyond the Diketopiperazine Family with Alternatively Bridged Brevianamide F Analogues
Wauters,Goossens,Delbeke,Muylaert,Roman,Van Hecke,Van Speybroeck,Stevens
, p. 8046 - 8054 (2015)
A method for the preparation of 3,5-bridged piperazin-2-ones from a tryptophan-proline-based diketopiperazine is described using diphosgene to induce the ring closure. Density functional theory calculations were conducted to study the mechanism of this C-C bond formation. Several derivatives of the thus obtained α-chloroamine were synthesized by substitution of the chlorine atom using a range of O-, N-, S-, and C-nucleophiles. This novel class of brevianamide F analogues possess interesting breast cancer resistance protein inhibitory activity.
Origins of Micellar Diastereoselectivity
Moss, Robert A.,Chiang, Yuan-Ching P.,Hui, Yongzheng
, p. 7506 - 7513 (2007/10/02)
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.
