Compound 15

(S)-N-((S)-1-((2-Amino-2-oxoethyl)amino)-4-methyl-1-oxopentan-2-yl)-1-((4S,7S,10S,13S,16S,19R)-19-amino-7-(2-amino-2-oxoethyl)-10-(3-amino-3-oxopropyl)-13-((S)-sec-butyl)-16-(4-hydroxybenzyl)-6,9,12,15,18-pentaoxo-1-thia-5,8,11,14,17-pentaazacycloicosane-4-carbonyl)pyrrolidine-2-carboxamide

From: Selenoether oxytocin analogues have analgesic properties in a mouse model of chronic abdominal pain