Eighty-one (acylamino)pyridines (I, R = H, 3-, 5-, or 6-Me, or 4-Ph; R1 = Et, H, Me, Pr, Ph, or cyclohexyl, Z = CH2CH2, CHEtCH2, CHMeCH2, CMe2CH2, CHMeCHMe, CH2CHMe, or CH2CMe2; NR2R3 = e.g. NMe2, NEt2, NMeCH2Ph, piperidino, 1-pyrrolidinyl, 1-azepinyl, or morpholino) were prepared by acylation of II.II were obtained either by reaction of 2-bromopyridines with H2NZR2R3 or of 2-aminopyridines with XZNR2R3 (X = Cl or Br).I were tested for morphine antagonistic and morphine agonistic properties.The most active compound was the fumarate of propiram (I, R = H, R1 = Et, Z = CHMeCH2, NR2R3 = piperidino).Also I with NR2R3 = azabicyclos had high analgesic potency with a favorable therapeutic index.Some I showed distinct morphine agonistic but no morphine antagonistic effects.