Synthesis and pharmacological evaluation of new 1-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines as norepinephrine potentiators.

4-Hydroxy-2-methyl-4-phenyl-1,2,3,4-tetrahydroisoquinoline (PI-OH) (1a) and its derivatives form a new class of compounds which possess norepinephrine (NE) potentiating activity. As a new series of compounds, 1-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepines (2a--f) were synthesized by the intramolecular Barbier reaction of N-[2-(2-iodophenyl)ethyl]phenacylamines (6a--f) with n-BuLi as a key reaction step. The potentiating activities of the benzazepines 2a--f on the contraction of rat anococcygeus muscle induced by NE were tested. Among the compounds tested in this study, compound 2a showed moderate potentiating activity (the activity ratio was 7.3-fold at 3 x 10(-5) M).