Synthesis of novel 5-substituted 3-amino-3,4-dihydro-2H-1-benzopyran derivatives and their interactions with the 5-HT1A receptor.

A series of new enantiomerically pure 3-amino-3,4-dihydro-2H-1-benzopyrans (3-aminochromans) has been synthesized from (R)- and (S)-5-methoxy-3-amino-3,4-dihydro-2H-1-benzopyran. The absolute configuration of the respective (R)- and (S)-enantiomers was deduced from X-ray crystallography of (R)-3-(N-isopropylamino)-5-methoxy-3,4-dihydro-2H-1-benzopyran, (R)-9a. Various 5-substituents were introduced via palladium-catalyzed carbonylation of N-substituted 3-amino-5-trifluoromethanesulfonyloxy-3,4-dihydro-2H-1-benzopyran. The effect of N- and 5-substitution on affinity for the 5-HT1A receptor was evaluated in competition experiments using rat hippocampal membranes and [3H]8-OH-DPAT as radioligand. Selected compounds were also tested for their affinity to the D1 (rat striatum), D2 (rat striatum), D2A (human cloned), and 5-HT2A (rat cortex) receptors. The intrinsic activity of the compounds was evaluated by measuring their effect on VIP-stimulated cAMP production in GH4ZD10 cells stably transfected with the 5-H...