A series of 3, 4-dihydro-3-amino-2H-l-benzopyran derivatives were prepared in order to determine the necessary structural requirements for good affinity for~-HT~ A receptors and high selectivity versus other receptors. Modifications of the extracyclic amino substituents, the length of the alkyl side chains, and their substituents were explored. The best compounds (9g, 9k, 15b, 15d) possess imido or sulfonamido functional groups with a ...