In attempts to obtain intramolecular N-alkylated bioyclo compounds from 5- haloalkylbarbituric acids, only 0-alkylated compounds could be obtained. The resulting pyranopyrimidine, 7, and furanopyrimidine, 9, could be opened with alcohols to give the corresponding ether in the side chain of the barbituric acid. With water the side chain alcohol wm obtained.