Synthesis and pharmacological properties of N,N-dialkyl(dialkenyl)amides of 7-methyl-3-phenyl-1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl]-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid.

Synthesis of N,N-dialkyl(dialkenyl)amides of 7-methyl-3-phenyl-2,4-dioxo-1,2,3,4-tetrahydropyrido[2,3-d]pyrimidine-5-carboxylic acid (5-9) and their 1-[2-hydroxy-3-(4-phenyl-1-piperazinyl)propyl] derivatives (10-14) is described. Compounds 10-14 were tested for analgesic and sedative activities as well as for mu-opioid receptors binding affinities. All the amides, being the object of investigation, displayed an interesting analgesic action, which in case of the compounds 10-12 and 14 was superior to that of acetylsalicylic acid in two different tests. Furthermore all the amides (10-14) significantly suppressed the spontaneous locomotor activity, prolonged barbiturate sleep in mice and showed a weak affinity to mu-opioid receptors.