5-Aminotetrazole Explained

5-Aminotetrazole is an organic compound with the formula HN4CNH2. It is a white solid that can be obtained both in anhydrous and hydrated forms.

The molecule is planar.[1] The hydrogen bonding pattern in the hydrate supports the assignment of NH being adjacent to carbon in the ring.[2]

Preparation

A synthesis of 5-aminotetrazole through the action of nitrous acid on aminoguanidine was reported by Johannes Thiele in 1892.[3]

The exact structure of the compound was not known at the time, although it was known to crystallize as a monohydrate. The correct structural formula was published in 1901 by Arthur Hantzsch, who obtained it from the reaction between cyanamide and hydrazoic acid.[4]

To avoid direct handling of the problematic hydrazoic acid, a mixture of sodium azide and hydrochloric acid has been used to give the monohydrate at 73% yield.[5]

In a more efficient and controllable one-pot synthesis, cyanamide is treated with hydrazine hydrochloride to give aminoguanidine hydrochloride, which is then diazotized as in Thiele's original process. Addition of ammonia or sodium hydroxide followed by heat-induced cyclization gives the anhydrous product in 74% yield.[6] [7]

Structure

The structure of 5-aminotetrazole has been determined several times by X-ray crystallography, both as the anhydrous[8] and monohydrated forms.[9] The structures are very similar, consisting of a planar molecule, including the amino group.

Uses

5-Aminotetrazole has found applications in heterocyclic chemistry, particularly as a synthon for some multicomponent reactions.[10]

The N-4 is basic as indicated by its binding to metal halides, such as the coordination complex .[11]

The compound has a particularly high nitrogen content of 80%. Partly for this reason, the compound is prone to decomposition to nitrogen gas (N2). It has been widely investigated for gas-generating systems, such as airbags and blowing agents.[12]

Notes and References

  1. Hiroshi Fujihisa, Kazumasa Honda, Shigeaki Obata, Hiroshi Yamawaki, Satoshi Takeya, Yoshito Gotoha, Takehiro Matsunaga "Crystal structure of anhydrous 5-aminotetrazole and its high-pressure behavior" CrystEngComm, 2011, volume 13, pp. 99-102.
  2. D. D. Bray and J. G. White "Refinement of the structure of 5-aminotetrazole monohydrate" Acta Crystallogr. (1979). B35, pp. 3089-3091.
  3. Thiele. Johannes. 1892-01-01. Ueber Nitro- und Amidoguanidin. Justus Liebigs Annalen der Chemie. 270. 1–2. 1–63. 10.1002/jlac.18922700102. 0075-4617.
  4. Hantzsch. A.. Vagt. A.. 1901-01-01. Ueber das sogenannte Diazoguanidin. Justus Liebigs Annalen der Chemie. 314. 3. 339–369. 10.1002/jlac.19013140307. 0075-4617.
  5. MIHINA. JOSEPH S.. HERBST. ROBERT M.. The Reaction of Nitriles with Hydrazoic Acid: Synthesis of Monosubstituted Tetrazoles. 1950-09-01. The Journal of Organic Chemistry. 15. 5. 1082–1092. 10.1021/jo01151a027. 0022-3263.
  6. US. 5424449. Process for the preparation of 5-aminotetrazole. 1995-06-13. 1995-06-13. Rothgery. Knollmueller. Eugene F.. Karl O..
  7. US. 5594146. Process for producing 5-aminotetrazole. 1997-01-14. 1997-01-14. Murotani. Mura. Takeda. Shibafuchi. Masahiro. Hajime. Makoto. Hiroshi.
  8. 10.1039/c0ce00278j. Crystal structure of anhydrous 5-aminotetrazole and its high-pressure behavior . 2011 . Fujihisa . Hiroshi . Honda . Kazumasa . Obata . Shigeaki . Yamawaki . Hiroshi . Takeya . Satoshi . Gotoh . Yoshito . Matsunaga . Takehiro . CrystEngComm . 13 . 99–102 .
  9. 10.1107/S0567740879011493. Refinement of the structure of 5-aminotetrazole monohydrate . 1979 . Bray . D. D. . White . J. G. . Acta Crystallographica Section B Structural Crystallography and Crystal Chemistry . 35 . 12 . 3089–3091 .
  10. Dolzhenko. A. V.. 2017. 5-Aminotetrazole as a Building Block for Multicomponent Reactions (Review). Heterocycles. en. 94. 10. 1819–1846. 10.3987/rev-17-867. 31 January 2024 . free.
  11. 10.1021/ic300394c. Two Acentric Mononuclear Molecular Complexes with Unusual Magnetic and Ferroelectric Properties . 2012 . Zhao . Fang-Hua . Che . Yun-Xia . Zheng . Ji-Min . Grandjean . Fernande . Long . Gary J. . Inorganic Chemistry . 51 . 8 . 4862–4868 . 22480292 .
  12. Lesnikovich, A. I.; Ivashkevich, O. A.; Levchik, S. V.; Balabanovich, A. I.; Gaponik, P. N.; Kulak, A. A. "Thermal decomposition of aminotetrazoles" Thermochimica Acta 2002, vol. 388, pp. 233-251.

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