Organic Syntheses, CV 3, 95
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.
3. Discussion
Appendix
Compounds Referenced (Chemical Abstracts 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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