ORGANIC AZIDES IN HETEROCYCLIC SYNTHESIS .17. SYNTHESIS AND REACTIONS OF TETRAZOLO[1,5-A]PYRIMIDINES

The reaction of ''magic malonates'' (bis-2,4,6-trichlorophenyl malonates, 1) with 5-aminotetrazole (2) in the presence of triethylamine yields the ammonium salts 3. Upon treatment of 3 with strong acids compounds 4a-d were obtained as a mixture of isomeric tetrazolopyrimidines (A) and 2-azidopyrimidines (B). Reaction of 4d with bromine or sulfuryl chloride leads by ring opening and decarboxylation to the halogenated tetrazole derivatives 5 or 7, respectively. The action of acetic anhydride in pyridine on 3d yields the zwitterionic tetramic acid derivative 10.