Advances toward new antidepressants with dual serotonin transporter and 5-HT1A receptor affinity within a class of 3-aminochroman derivatives. Part 2.

Novel compounds combining a 5-HT1A moiety (3-aminochroman scaffold) and a 5-HT transporter (indole analogues) linked through,a common basic nitrogen via an alkyl chain attached at the 1- or 3-position of the indole were evaluated for dual affinity at both the 5-HT reuptake site and the 5-HT1A receptor. Compounds of most interest were found to have a 5-carbamoyl-8-fluoro-3-amino-3,4-dihydro-2H-1-benzopyran linked to a 3-alkylindole (straight chain), more specifically substituted with a 5-fluoro ((R)-(-)-35c), 5-cyano ((-)-52a), or 5,7-difluoro ((-)-52g). Several factors contributed to 5-HT1A affinity, serotonin rat transporter affinity, and functional antagonism in vitro. Although most of our analogues showed good to excellent affinities at both targets, specific features such as cyclobutyl substitution on the basic nitrogen and stereochemistry at the 3-position of the chroman moiety seemed necessary for antagonism at the 5-HT1A receptor. Branched linkers seemed to impart antagonism even as racemates, however, potency of these analogues in the functional assay was not desirable enough to further pursue these compounds.