Halotetrazoles

Halogen atoms at the tetrazole-5-position are readily displaced by better nucleophiles because of the electron-depleted character of the ring. The nucleophilic displacement was much more rapid with l-substituted-5-bromotetrazoles than with the 2-substituted isomers <84CHEC-I(5)791>. These reactions are often best carried out by warming the halotetrazole in the neat amine or hydrazine when these are liquid. Synthetic uses of the reaction are shown in Schemes 6 and 10. New routes to 5-halotetrazole derivatives have been found <95J06468>... 

Halotetrazole Salts. The hazards heretofore encountered in the prepn of halotetrazoies have been eliminated, and a safe method for diazoti-zing 5-aminotetrazole has been devised. Several salts of halotetrazoies were prepd, and aside from results of practical importance such as the production of compds of interest as initiator materials, this work may give rise to some important theoretical consideration as to the fundamental chemistry of initiators... 

Halotetrazoles react with nucleophiles leading to substitution, e.g. with phenols and K2CO3 in acetone ... 

Substitution of the halogen in 5-halotetrazoles occurs with nitrogen nucleophiles. 

The other metallic salts of 5-halotetrazoles can be prepared via the sodium salt, which is obtained by reaction of the cupric salt of 5-halotetrazole with sodium hydroxide to give the sodium salts [42, 53]. The sodium salt can be also obtained directly from 5-ATZ [75]. 

Out of the whole range of 5-halotetrazole salts, only the cupric salt of 5-chlorotetrazole has found a use—e.g., in primers for space applications [1]. Many other metallic salts of 5-chlorotetrazole (e.g., silver salt) have been disqualified from application mainly due to their high mechanical sensitivity [76]. 

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