Synthesis of 5-substituted-2,3-dihydro-1,4-benzoxathiins: biological evaluation as melatonin receptors ligands.

The synthesis of benzoxathiins bearing a retroamide function is described from 8-hydroxythiochroman, the key step involving the synthesis of the benzoxathiin ring through a sulfonium salt. These new melatonin analogues were evaluated on human receptors MT1 and MT2 and have a similar affinity to that of melatonin itself.

Substituted oxygenated heterocycles and thio-analogues: synthesis and biological evaluation as melatonin ligands.

A new series of substituted oxygenated heterocycles and thio-analogues were synthesized and evaluated as melatonin receptor ligands. The replacement of the indolic moiety of melatonin by heterocyclic skeleton such as 1,4-benzodioxin, 2,3-dihydro-1,4-benzodioxin, chroman, 2,3-dihydro-1,4-benzoxathiin, thiochroman, carrying the amidic chain on the aromatic ring, leads to compounds showing a weak affinity for melatonin receptors, except for the compounds 1cb and 1hb.