Six new 5(1H)oxo-2,3-dihydroimidazo[1,2-a]pyrimidine-6-carboxylic ethyl esters bearing an aromatic substituent in position 1 or 2 were obtained. Pharmacological studies on the central action of these derivatives were carried out on mice and rats. The highest activity showed compounds 1 and 2 which produced analgesic effects in mice.