AROMATIC SYSTEMS WITH 10PI ELECTRONS DERIVED FROM 3A-AZAPENTALENE .24. SYNTHESIS OF PYRAZOLO[1,5-D]TETRAZOLES

Unitl now it has not been possible to build stable azolotetrazoles from the corresponding azoles. However, the methylation of some bicyclic anions afforded 3 monomethyl derivatives: 1-methylpyradolo[1,5-d]-tetrazoles (6), 3-methylpyrazolo [1,5-d] tetrazoles (7) and 1-methyl-3-azidopyrazoles (8''). The azides 8'' were characterized by IR spectroscopy, and the structures of the 2 pyrazolo[1,5-d]tetrazole isomers 6 and 7 were assigned on the basis of proton NMR spectroscopy using a relationship indicated by Butler based on increasing the chemical shifts of the N-methyl groups.