Benzimidazole derivatives as novel nonpeptide luteinizing hormone-releasing hormone (LHRH) antagonists. Part 2: Benzimidazole-5-sulfonamides.

The 2-cyclopropyl substituted benzimidazole 2 has been used as a starting point for further optimization of an LHRH antagonist series. SAR studies revealed that a tert-butyl urea fragment connected through a simple carbon chain would improve activity. Further modification of the benzylsulfonamide moiety led to the discovery of 23 (IC(50): 4.2 nM).