Syntheses of depsipeptide analogues of the insect neuropeptide proctolin

Abstract

Four depsipeptide analogues of the insect neuropeptide proctolin (H-Arg-Tyr-Leu-Pro-Thr-OH) have been prepared, containing a single ester linkage between Arg 1 and Tyr 2, Tyr 2 and Leu 3, and between Pro 4 and Thr 5, respectively. A didepsipentapeptide containing an ester linkage between Tyr 2 and Leu 3 and between Pro 4 and Thr 5, has also been prepared. The depsipeptide 4 is the first example of a backbone-modified proctolin analogue which shows full myotropic activity.