4-phenyl-1,2,4-triazole-3,5-dione
4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) is an azodicarbonyl compound. PTAD is one of the strongest dienophiles and reacts rapidly with dienes in Diels-Alder reactions. The most prominent use of PTAD was the first synthesis of prismane in 1973.
Chemical data
- Formula
- C8H5N3O2
- Molecular weight
- 175.14 g/mol
- IUPAC name
- 4-phenyl-1,2,4-triazole-3,5-dione
via PubChem
Drug data · ChEMBL
- Molecule type
- Small molecule
via ChEMBL · EBI
Wikidata facts
- Mass
- 175.038176
Show 3 more facts
- chemical formula
- C₈H₅N₃O₂
- canonical SMILES
- C1=CC=C(C=C1)N2C(=O)N=NC2=O
- Commons category
- 4-Phenyl-1,2,4-triazole-3,5-dione
Sources (2)
~1 min read
Article
2 sectionsContents
- Synthesis
- References
4-Phenyl-1,2,4-triazoline-3,5-dione (PTAD) is an azodicarbonyl compound. PTAD is one of the strongest dienophiles and reacts rapidly with dienes in Diels-Alder reactions. The most prominent use of PTAD was the first synthesis of prismane in 1973.
==Synthesis== The compound was first synthesized in 1894 by Johannes Thiele and . The oxidation of 4-Phenylurazole with lead tetroxide in sulfuric acid yielded small quantities of the substance. It took until 1971 until a practical synthesis was published. The synthesis starts by combining hydrazine and diethyl carbonate. The product of this step is reacted with phenyl isocyanate to form 4-Phenyl-1-carbethoxysemicarbazide (4), which is cyclized with base to form 4-Phenylurazole (5). Oxidation with tert-Butyl hypochlorite then yields PTAD (6).