Design and synthesis of 1-(2-alkanamidoethyl)-6-methoxy-7-azaindole derivatives as potent melatonin agonists.

A series of 7-azaindolic ligands bearing a methoxy group and a N-acetyl chain as melatoninergic pharmacophores were synthesized and their binding affinities towards MT(1) and MT(2) receptors were evaluated. Compounds 7a-c and 12 (cyclohexyl ring connected at C-2 and C-3 position) appears as important melatonin MT(2) and MT(1) receptors agonists. On the other hand, the presence of basic groups (amines) at position C-3 was detrimental to the melatoninergic affinities.