Synthesis of 2(3H)-benzoxazolone derivatives as potential melatonin receptor ligands

This article reports the synthesis of new 2(3H)-benzoxazolone-based ligands for the melatonin receptors in which an acetamidopropyl side-chain was incorporated. Construction of the acetamidopropyl moiety was achieved via a Wadsworth-Emmons approach. Although these compounds can be seen as derivatives of N-[3-(3-methoxyphenyl)propyl]acetamide (MPPA), which is the exact analogue of melatonin in which the 1,2-indole nitrogen atoms are deleted, they exhibit lower affinities for the melatonin receptors probably due to an unfavourable steric bulk and hydrophilic interactions.