Org. Synth. 1946, 26, 11
DOI: 10.15227/orgsyn.026.0011
3-AMINO-1H-1,2,4-TRIAZOLE
[1H-1,2,4-Triazole, 3-amino-]
Submitted by Georg Sjostedt and Leopold Gringas.
Checked by E. C. Horning, H. Lloyd, and L. Matternas.
1. Procedure
To 136 g. (1 mole) of finely powdered aminoguanidine bicarbonate in a 500-ml. two-necked round-bottomed flask fitted with a thermometer is added 48 g. (40 ml., 1.05 moles) of 98–100% formic acid (Note 1). The foaming mixture is heated cautiously, with gentle rotation of the flask to avoid local overheating, until gas evolution ceases and the whole mass is dissolved. The solution of aminoguanidine formate is held at a temperature of 120° for 5 hours (Note 2). After the solution is cooled, 500 ml. of 95% ethanol is added, the product is dissolved by heating, and the solution is filtered while hot. The product, obtained by evaporating the ethanol solution to dryness on the steam bath, and oven-drying at 100°, is 80–81.6 g. (95–97%) of colorless crystalline 3-amino-1,2,4-triazole melting at 152–156° (Note 3). The 3-amino-1,2,4-triazole can be recrystallized from ethanol (Note 4).
2. Notes
1.
The submitters report that
aminoguanidine bicarbonate of practical grade is satisfactory. The checkers used Eastman Kodak white label quality.
2.
The submitters and checkers used an infrared heater.
3.
The main part of the
ethanol can be removed by distillation. From the remaining ethanolic solution yellow crystals precipitate, which are collected on a
Büchner funnel. When melted and dried they lose water and give
3-amino-1,2,4-triazole in its pure form.
4.
The
3-amino-1,2,4-triazole may be crystallized from
ethanol or
ethanol-
ether.
1 The checkers preferred
ethanol (200 ml. for 40 g.). The recovery is
70–73%, m.p.
152–153°.
3. Discussion
3-Amino-1,2,4-triazole has been prepared by evaporating
formylguanidine nitrate with
sodium carbonate,
2 and from
5(3)-amino-1,2,4-triazolecarboxylic acid-3(5) by heating above its melting point,
3,4,5 or by a long digestion with
acetic acid.
2 It has been prepared from the sulfate in essentially the same yield and purity.
1
Appendix
Chemical Abstracts Nomenclature (Collective Index Number);
(Registry Number)
5(3)-amino-1,2,4-triazolecarboxylic acid-3(5)
ethanol (64-17-5)
acetic acid (64-19-7)
ether (60-29-7)
sodium carbonate (497-19-8)
formic acid (64-18-6)
Aminoguanidine bicarbonate (2582-30-1)
3-Amino-1H-1,2,4-triazole,
1H-1,2,4-Triazole, 3-amino-,
3-amino-1,2,4-triazole (61-82-5)
aminoguanidine formate
formylguanidine nitrate
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