1. New non-peptide endothelin-A receptor antagonists: synthesis, biological properties, and structure-activity relationships of 5-(dimethylamino)-N-pyridyl-,-N-pyrimidinyl-,-N-pyridazinyl-, and -N-pyrazinyl-1-naphthalenesulfonamides.
- Author
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Bradbury RH, Bath C, Butlin RJ, Dennis M, Heys C, Hunt SJ, James R, Mortlock AA, Sumner NF, Tang EK, Telford B, Whiting E, and Wilson C
- Subjects
- Animals, Antihypertensive Agents chemistry, Antihypertensive Agents metabolism, Antihypertensive Agents pharmacology, Blood Pressure drug effects, Dansyl Compounds chemistry, Dansyl Compounds metabolism, Endothelin-1, Endothelins antagonists & inhibitors, Endothelins metabolism, Guinea Pigs, Magnetic Resonance Spectroscopy, Male, Molecular Structure, Protein Binding, Protein Precursors antagonists & inhibitors, Protein Precursors metabolism, Rats, Rats, Wistar, Receptor, Endothelin A, Receptors, Endothelin metabolism, Structure-Activity Relationship, Antihypertensive Agents chemical synthesis, Dansyl Compounds chemical synthesis, Dansyl Compounds pharmacology, Endothelin Receptor Antagonists
- Abstract
Use of automated synthesis led to the discovery of several 6-membered nitrogen heterocycles as replacements for the N-isoxazolyl substituent present in the 1-naphthalenesulfonamides endothelin-A (ETA) antagonist 5-(dimethylamino)-N-(3,4-dimethyl-5-isoxazolyl)-1-naphthalenesu lfo namides (BMS 182874). In each of these heterocycles, a small substituent such as halogen para to the position of attachment to the sulfonamide nitrogen atom was found to be advantageous for ETA receptor affinity. Of these heterocycles, 2-pyrazines offered the greatest scope for improving receptor affinity. Optimization of the substituents at the 3- and 5-positions in the pyrazine ring led to potent, ETA-selective compounds such as 5-(dimethylamino)-N-(5-chloro-3-methoxy-2-pyrazinyl)-1- naphthalenesulfonamides (7m, ETA pIC50 8.1). When dosed orally at 10 mg/kg to conscious, normotensive rats infused with big ET-1, compounds such as 7m showed significant inhibition of the pressor response with a duration of effect lasting for the 5-h course of the experiment.
- Published
- 1997
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