Discovery and optimization of a series of carbazole ureas as NPY5 antagonists for the treatment of obesity.
The hypothesis that antagonists of the neuropeptide Y5 receptor would provide safe and effective appetite suppressants for the treatment of obesity has prompted vigorous research to identify suitable compounds. We discovered a series of acylated aminocarbazole derivatives (e.g., 3a) that are potent and selective Y5 antagonists, representing interesting starting points but suffering from poor bioavailability and concerns about potential toxicity as a consequence of the embedded aminocarbazole fragment. It proved relatively easy to improve the drug metabolism and pharmacokinetic (DMPK) properties by variation of the side chain (as in 4a) but difficult to eliminate the aminocarbazole fragment. For compounds in this series to have the potential to be drugs, we believed that both the compound itself and the component aniline must be free of mutagenic activity. Parallel structure-activity relationship studies looking at the effects of ring substitution have proved that it is possible by incorporation of a 4-methyl substituent to produce carbazole ureas with potent Y5 activity, comprised of carbazole anilines that in themselves are devoid of mutagenic activity in the Ames test. Compound 4o (also known as NPY5RA-972) is highly selective with respect to Y1, Y2, and Y4 receptors (and also to a diverse range of unrelated receptors and enzymes), with an excellent DMPK profile including central nervous system penetration. NPY5RA-972 (4o) is a highly potent Y5 antagonist in vivo but does not block neuropeptide Y-induced feeding nor does it reduce feeding in rats, suggesting that the Y5 receptor alone has no significant role in feeding in these models.
Block
Michael H
MH
AstraZeneca, Alderley Park, Macclesfield, Cheshire SK10 4TG, United Kingdom. Michael.Block@Astrazeneca.com
Boyer
Scott
S
Brailsford
Wayne
W
Brittain
David R
DR
Carroll
Debra
D
Chapman
Steve
S
Clarke
David S
DS
Donald
Craig S
CS
Foote
Kevin M
KM
Godfrey
Linda
L
Ladner
Anthony
A
Marsham
Peter R
PR
Masters
David J
DJ
Mee
Christine D
CD
O'Donovan
Michael R
MR
Pease
J Elizabeth
JE
Pickup
Adrian G
AG
Rayner
John W
JW
Roberts
Andrew
A
Schofield
Paul
P
Suleman
Abid
A
Turnbull
Andrew V
AV
D000814:Aniline Compounds / Q000138:chemical synthesis / Q000494:pharmacology / Q000633:toxicity; D000818:Animals; D019440:Anti-Obesity Agents / Q000138:chemical synthesis* / Q000494:pharmacology / Q000633:toxicity; D001067:Appetite Depressants / Q000138:chemical synthesis / Q000494:pharmacology / Q000633:toxicity; D002227:Carbazoles / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology / Q000633:toxicity; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D005215:Fasting; D006801:Humans; D009025:Morpholines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology; D009152:Mutagenicity Tests; D051381:Rats; D017208:Rats, Wistar; D017476:Receptors, Neuropeptide Y / Q000037:antagonists & inhibitors*; D013329:Structure-Activity Relationship; D014508:Urea / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000494:pharmacology / Q000633:toxicity
D000814:Aniline Compounds; D019440:Anti-Obesity Agents; D001067:Appetite Depressants; D002227:Carbazoles; D009025:Morpholines; C463522:NPY5RA 972; D017476:Receptors, Neuropeptide Y; C100568:neuropeptide Y5 receptor; D014508:Urea