4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole

4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole is an organic compound with the formula SC2N3H(NH2)(N2H3). The compound consists of a 1,2,4-triazole heterocycle with three functional groups: amine, thioamide and hydrazyl. X-ray crystallography shows that this molecule is polar but with a C=S double bond. It is prepared by the reaction of hydrazine with thiourea:[1]

4-Amino-3-hydrazino-5-mercapto-1,2,4-triazole
Names
Preferred IUPAC name
4-Amino-5-hydrazinyl-2,4-dihydro-3H-1,2,4-triazole-3-thione
Other names
Purpald; AHMT; 1,2,4-Triazolidin-3-one, 4-amino-5-thioxo-, hydrazone (9CI); 4H-1,2,4-Triazole-3-thiol, 4-amino-5-hydrazino- (6CI,7CI)
Identifiers
3D model (JSmol)
ChemSpider
ECHA InfoCard 100.015.578 Edit this at Wikidata
UNII
  • InChI=1S/C2H6N6S/c3-5-1-6-7-2(9)8(1)4/h3-4H2,(H,5,6)(H,7,9)
    Key: RDIMQHBOTMWMJA-UHFFFAOYSA-N
  • c1(=S)[nH]nc(n1N)NN
Properties
C2H6N6S
Molar mass 146.17
Appearance white solid
Density 1.69 g/cm3
Melting point 228 °C (442 °F; 501 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
2 SC(NH2)2 + 3 N2H4 → SC2N3H(NH2)(N2H3) + 4 NH3 + H2S

The compound has been used as a reagent for the colorimetric detection of aldehydes.[2]

References

edit
  1. ^ N. W. Isaacs and C. H. L. Kennard "Crystal structure of 4-amino-3-hydrazino-5-mercapto-1,2,4-triazole" J. Chem. Soc. B, 1971, 1270-1273. doi:10.1039/J29710001270
  2. ^ Hopps, Harvey B. "Purpald: a Reagent that Turns Aldehydes Purple!" Aldrichimica Acta 2000, volume 33, pp. 28-30.