5- Hydroxy-1,2,3,4-tetrazole, tautomerism

Hydroxy- and 5-mercaptotetrazoles and their mono-N1 -substituted derivatives can be involved into keto-enol and thiol-thione tautomeric equilibria (Equation 7). This is the reason for significant differences in chemical and physical properties of these compounds from other 5R-tetrazoles. 

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