Formations of 5-aminotetrazole rings using azide anion include the following: (i) addition of NaN 3 to carbodiimides 9c,10a or cyanamides; 11 and (ii) nucleophilic substitution by N 3 - of (a) chlorine in α-chloroformamidines, 12a which can be obtained from nitriles and alkyl halides, 12b - d (b) the sulfite anion in aminoiminomethanesulfonic acids, 12e and (c) sulfur from thioureas in the presence of mercury 12f or lead salts 9a (Scheme 1).
![(1H-benzo[d][1,2,3]triazol-1-yl)(piperidin-1-yl)methanimine Structure](https://image.chemsrc.com/caspic/154/656835-57-3.png)
