Alkyl or alkoxyalkyl 5-[3,6-dihydro-1(2H)-pyridyl]-2-oxo-2H-[1,2,4]-oxadiazolo-[2,3-a]primidine -7-carbamates, prepared, inter alia, from the corresponding 6-[3,6-dihydro-1(2H)-pyridyl]-2,4-pyrimidine-dicarbamate-3-oxide, are described. The end products are useful in the treatment of vascular-conditioned hypertension or as vasodilators in the case of peripheral blood supply disorders.