Probes for narcotic receptor mediated phenomena. 23. Synthesis, opioid receptor binding, and bioassay of the highly selective delta agonist (+)-4-[(alpha R)-alpha-((2S,5R)-4-Allyl-2,5-dimethyl-1-piperazinyl)-3-methoxybenzyl]- N,N-diethylbenzamide (SNC 80) and related novel nonpeptide delta opioid receptor ligands Calderon, S.N.; Rice, K.C.; Rothman, R.B.; Porreca, F.; Flippen-Anderson, J.L.; Kayakiri, H.; Xu, H.; Becketts, K.; Smith, L.E.; Bilsky, E.J.; Davis, P.; Horvath, R. Journal of Medicinal Chemistry 40(5): 695-704 1997 https://eurekamag.com/research/047/079/047079526.php