The early studies of the structural changes necessary to convert the hormone serotonin (I) into a specific antimetabolite of it had shown that one good way was to move the amino group from its position in the side chain of the hormone to position 5 in the indole nucleu~.~~~ The 5-amino-indoles, with alkyl groups in positions 3 (or 2 and 3) were active antiserotonins. However, they possessed the disadvantage that they were destroyed ...
