Acetonylmalonaldehyde (1) was obtained for the first time by hydrolysi
s of -dimethoxy-5-methyltetrahydrofuran-3-carbaldehyde. The interactio
n of 1 with 3-amino-5-methylpyrazole, 3-amino-1,2,4-triazole, 2-aminob
enzimidazole, and 5-aminotetrazole results in the formation of functio
nally substituted azolopyrimidines.