... 1 Cloning of several melatonin receptor genes has revealed at least three melatonin receptor proteins. ... Scheme 1. Reagents and conditions: (a) formic acid 95 °C, ∼50% yield; (b) R 6 (C O)Cl, Et 3 N, CH 2 Cl 2 or R 6 (C O)Cl, poly(4-vinylpyridine), dichloroethane, Wa21J (Supelco) polyamine scavenging resin, rt (42–88% yield). ... 181–190. [5]; RJ Mattson, JD Catt, D. Keavy, CP Sloan, J. Epperson, Q. Gao, DB Hodges, L. Iben, CD Mahle, E. Ryan, FD Yocca; ...