Synthesis and reactions of tetrazolo[1,5-a]pyrimidines [1]

Article abstract of DOI:10.1002/jhet.5570300516

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.