Amine-constrained pyridazinone histamine H3 receptor antagonists

Pyridazinone 1 was recently reported as a potent H3R antagonist with good drug-like properties and in vivo activity. A series of constrained amine analogs of 1 was synthesized to identify compounds with improved pharmacokinetic profiles. From these efforts, a new class of (S)-2-pyrrolidin-1-ylmethyl-1-pyrrolidinyl amides was identified.