Allosteric modulation of the dopamine receptor by conformationally constrained type VI beta-turn peptidomimetics of Pro-Leu-Gly-NH2.
A peptidomimetic of Pro-Leu-Pro-NH2, 7, possessing an indolizidinone type VI beta-turn mimic was synthesized via improved high-yielding protocols for the preparation and Cbz protection of alpha-allylproline. Bicyclic peptidomimetic 7 and spirobicylic peptidomimetic 8 enhanced the binding of [3H] N-propylnorapomorphine to dopamine receptors indicating that a type VI beta-turn is a possible bioactive conformation of the homochiral Pro-Leu-Pro-NH2 and Pro-Pro-Pro-NH 2 analogues of Pro-Leu-Gly-NH2 at the dopamine receptor allosteric regulatory site. (+info)
Enantioselective synthesis of indolizidines bearing quaternary substituted stereocenters via rhodium-catalyzed [2+2+2] cycloaddition of alkenyl isocyanates and terminal alkynes.