Synthesis and SAR of 5-amino- and 5-(aminomethyl)benzofuran histamine H3 receptor antagonists with improved potency.
A new series of H3 receptor antagonists was discovered with nanomolar and subnanomolar affinities at human and rat H3 receptors. Starting from an earlier, more structurally limited series of benzofurans, the present series of compounds demonstrated increased structural variety and flexibility with greater in vitro potency. One compound in particular, [2-[2-(2-(R)-methylpyrrolidin-1-yl)ethyl]benzofuran-5-yl](5-nitropyridin-2-yl)amine (7h), gave the best binding potency (human K(i) of 0.05 nM, rat K(i) of 0.11 nM), which represented a 9-fold (in human) and an 11-fold (in rat) improvement over ABT-239 (compound 5), a compound previously reported to have excellent in vitro potency and in vivo efficacy. The synthesis, SAR of the H3 binding affinities, in vitro assay for phospholipidosis, and pharmacokinetic properties of the new compounds are described.
Sun
Minghua
M
Neuroscience Research, Global Pharmaceutical Research Division, Abbott Laboratories, 100 Abbott Park Road, Abbott Park, Illinois 60064-6123, USA.
Zhao
Chen
C
Gfesser
Gregory A
GA
Thiffault
Christine
C
Miller
Thomas R
TR
Marsh
Kennan
K
Wetter
Jill
J
Curtis
Michael
M
Faghih
Ramin
R
Esbenshade
Timothy A
TA
Hancock
Arthur A
AA
Cowart
Marlon
M
D000818:Animals; D001572:Benzofurans / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D002478:Cells, Cultured; D022781:Hepatocytes / Q000187:drug effects / Q000378:metabolism; D006633:Histamine Antagonists / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D006801:Humans; D008297:Male; D010743:Phospholipids / Q000096:biosynthesis; D011759:Pyrrolidines / Q000138:chemical synthesis* / Q000493:pharmacokinetics / Q000494:pharmacology; D011869:Radioligand Assay; D051381:Rats; D017207:Rats, Sprague-Dawley; D018100:Receptors, Histamine H3 / Q000187:drug effects* / Q000378:metabolism; D013329:Structure-Activity Relationship
C505567:(2-(2-(2-methylpyrrolidin-1-yl)ethyl)benzofuran-5-yl)(5-nitropyridin-2-yl)amine; D001572:Benzofurans; D006633:Histamine Antagonists; D010743:Phospholipids; D011759:Pyrrolidines; D018100:Receptors, Histamine H3