A pyridine side-chain terminus has been incorporated into the indole-5-carb
oxamide and indole-5-acetamide series of GnRH antagonists. Potent activity
was observed in binding and functional assays. Certain branched or cyclic t
ertiary amides were identified as preferred in each series. Alkylation of t
he side-chain secondary amine had generally unfavorable effects. Variations
of the gem-dialkyl substituents in the indole-5-acetamide series were also
investigated. (C) 2001 Elsevier Science Ltd. All rights reserved.