221174-15-8Relevant articles and documents
Stereoelectronic effects on collagen stability: The dichotomy of 4-fluoroproline diastereomers
Hodgest, Jonathan A.,Raines, Ronald T.
, p. 9262 - 9263 (2003)
Collagen is the most abundant protein in animals. Natural collagen consists of a triple helix of (Xaa-Yaa-Gly)n chains, in which the Xaa and Yaa residues are often l-proline. Here, a (2S,4S)-4-fluoroproline (flp) residue is shown to be greatly stabilizing in the Xaa position (but destabilizing in the Yaa position). In contrast, a (2S,4R)-4-fluoroproline (Flp) residue is shown to be greatly destabilizing in the Xaa position (but stabilizing in the Yaa position). The dichotomous effect of the diastereomers appears to arise from a gauche effect, which alters pyrrolidine ring pucker and hence properly (or improperly) preorganizes main-chain dihedral angles. Thus, the rational use of stereoelectronic effects can enhance the conformational stability of a protein. Copyright
HOAt.DCHA as co-coupling agent in the synthesis of peptides employing Fmoc-amino acid chlorides as coupling agents: Application to the synthesis of ss-casomorphin
Sureshbabu, Vommina V.,Chennakrishnareddy, Gundala
body text, p. 981 - 988 (2009/12/28)
A simple, efficient and racemization free method for the synthesis of peptides employing Fmoc-amino acid chlorides mediated by HOAtDCHA as a co-coupling agent has been described. This protocol is successfully employed in the synthesis of the pentapeptide H-Pro-Gly-VaI-GIy-VaI-OH (PGVGV), and ss-casomorphin (H-Tyr-Pro-Phe-Pro-Gly-OH) in 85 and 80% yields, respectively.
Synthesis of β-casomorphin employing Fmoc-amino acid chlorides and t-butyldimethylsilyloxy benzotriazole (TBDMS-OBt)
Tantry, Subramanyam J.,Mathad, Raveendra I.,Suresh Babu, Vommina V.
, p. 2104 - 2108 (2007/10/03)
Coupling of Fmoc-amino acid chlorides can be carried out using t-butyldimethylsilyloxy benzotriazole, the reaction being carried out in organic medium. No addition of base is required. The coupling is fast and racemization free. The workup and isolation of product are easy. Thus, the synthesis of β-casomorphin (Tyr-Pro-Phe-Pro-Gly) is accomplished.
