ONE-POT SYNTHESIS OF 5-(4-PYRAZOLE-1-YL)TETRAZOLEDERIVATIVES FROM 5-AMINOTETRAZOLE

Condensation reactions of 5-hydrazinotetrazole with malonic dialdehyde and acetylacetone are considered. 12 new derivatives of 5-(pyrazole-1-yl)tetrazoles were synthesized and characterized. Commercially available 5-aminotetrazole was oxidized by potassium permanganate in aqueous alkaline solution yielding 5,5'-azotetrazolate pentahydrate which was decomposed in acidic media to 5-hydrazinotetrazole. One-pot procedure is suggested to prepare the 5(pyrazole-1-yl)tetrazole derivatives from 5-aminotetrazole. According to introduced method after carrying out condensation with β-carbonyl compounds reaction mixture was treated by an equivalent amount of bromine. Target products were separated from the reaction mixture as corresponding 4-bromoderivatives of 5-(pyrazole-1-yl)tetrazoles. The presence of a bromine atom in structure of synthesized compounds greatly facilitates processes of their isolation, purification and further alkylation of tetrazole ring. Debromination was realized by hydrogenation over palladium catalyst by hydrogen at moderate pressure. For synthesis of 4-nitroderivatives of 5-(pyrazole-1-yl)tetrazoles nitration in system HNO 3 /H 2 SO 4 was used. 5-(4-amino-3,5-dimethylpyrazole-1-yl)tetrazole was prepared by the reduction of 5-(4-nitro-3,5-dimethylpyrazole-1-yl)tetrazole.