5-Hydroxytryptamine (5-HT3) receptor antagonists. 3. Ortho-substituted phenylureas.
A novel series of potent 5-HT3 receptor antagonists, ortho-substituted phenylureas 6a-z, is described in which the 5-membered ring of the previously reported indazoles and indolines has been replaced by an intramolecular hydrogen bond. High potency was found both for carbamate 6a and urea 6b. Granatane 6c was less potent than the equivalent tropane. Phenylurea 11c lacking the ortho substituent was inactive. Whereas further substitution could not be tolerated in the aromatic ring, activity was retained with a range of O-alkyl groups, compounds 6k-t. In addition, good activity was found for ortho ester 6u and sulfonamide 6x. The ortho-substituted phenylureas can therefore be regarded as bioisosteres of the 6,5-heterocycles indole, indazole, and indoline.
Bermudez
J
J
Beecham Pharmaceuticals Research Division, Harlow, Essex, England.
Dabbs
S
S
King
F D
FD
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D007202:Indicators and Reagents; D008297:Male; D015394:Molecular Structure; D010671:Phenylurea Compounds / Q000138:chemical synthesis* / Q000494:pharmacology; D051381:Rats; D011985:Receptors, Serotonin / Q000187:drug effects / Q000378:metabolism; D012018:Reflex / Q000187:drug effects; D012701:Serotonin / Q000494:pharmacology; D012702:Serotonin Antagonists / Q000138:chemical synthesis*; D013329:Structure-Activity Relationship
D007202:Indicators and Reagents; D010671:Phenylurea Compounds; D011985:Receptors, Serotonin; D012702:Serotonin Antagonists; D012701:Serotonin