Syntheses and in Vitro Evaluation of 4-(2-Aminoethyl)-2(3H)-indolones and Related Compounds as Peripheral Prejunctional Dopamine Receptor Agonists

Article abstract of DOI:10.1021/jm00156a010

A series of (β-aminoethyl)indolones and related compounds was synthesized and evaluated in vitro as peripheral prejunctional dopaminergic agonists in the field-stimulated isolated perfused rabbit ear artery. 4-<2-(Di-n-propylamino)ethyl>-7-hydroxy-2(3H)-indolone (26) was the most potent compound (ED₅₀ = 2 +/- 0.3 nM) tested, while the related secondary amine 24 and the des-OH derivatives 28 and 34 were only slightly less potent. 4-Methoxy-benzeneethanamine and 2-methyl-3-nitrophenylacetic acid were employed as starting materials for the synthesis of the 4-(β-aminoethyl)indolones.The ring-opened 3-acylamino analogues 46 and 47 were prepared via nitration of the phenethylamine 43 derived from 4-methoxyphenylacetic acid.The inactive isomeric indolones 38, 39, and 41 were derived from 4-nitrobenzeneethanamine and from indolone-6-acetic acid (13).