Bradykinin B1 antagonists: SAR studies in the 2,3-diaminopyridine series.

SAR study of the biphenyl region of 2,3-diaminopyridine bradykinin B 1 antagonists was investigated with non-aromatic carbo- and heterocyclic rings. A piperidine ring was found to be a good replacement for the proximal phenyl ring while replacement of the distal phenyl was optimal with a cyclohexyl group leading to a dramatic improvement in affinity for the B 1 receptor.