4-Phenyl-1,2,4-triazole-3,5-dione
Encyclopedia
4-Phenyl-1,2,4-triazole-3,5-dione (PTAD) is an azodicarbonyl compound. PTAD is one of the strongest dienophiles and reacts rapidly with diene
s in Diels-Alder reactions. The most prominent use of PTAD was the first successful synthesis of prismane
in 1973.
and O. Stange. The oxidation of 4-Phenylurazol with lead tetroxide in sulfuric acid
yielded small quantities of the substance. It took til 1971 when a practical synthesis was published. The synthesis starts from hydrazine
and diethyl carbonate
. The product of this step is reacted with phenyl isocyanate and subsequently transformed to the 4-Phenylurazol. Cyclization and subsequent oxidation yields PTAD (6) gebildet wird.
Diene
In organic chemistry a diene or diolefin is a hydrocarbon that contains two carbon double bonds.Conjugated dienes are functional groups, with a general formula of CnH2n-2. Dienes and alkynes are functional isomers...
s in Diels-Alder reactions. The most prominent use of PTAD was the first successful synthesis of prismane
Prismane
Prismane is a polycyclic hydrocarbon with the formula C6H6. It is an isomer of benzene, more specific: a valence isomer. Prismane is far less stable than benzene. The carbon atoms of the prismane molecule are arranged in the shape of a six-atom triangular prism. Albert Ladenburg proposed this...
in 1973.
Synthesis
The compound was first synthesized in 1894 by Johannes ThieleJohannes Thiele (chemist)
Friedrich Karl Johannes Thiele was a German chemist and a prominent professor at several universities, including those in Munich and Strasbourg. He developed many laboratory techniques related to isolation of organic compounds...
and O. Stange. The oxidation of 4-Phenylurazol with lead tetroxide in sulfuric acid
Sulfuric acid
Sulfuric acid is a strong mineral acid with the molecular formula . Its historical name is oil of vitriol. Pure sulfuric acid is a highly corrosive, colorless, viscous liquid. The salts of sulfuric acid are called sulfates...
yielded small quantities of the substance. It took til 1971 when a practical synthesis was published. The synthesis starts from hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
and diethyl carbonate
Diethyl carbonate
Diethyl carbonate is a carbonate ester of carbonic acid and ethanol. At room temperature diethyl carbonate is a clear liquid with a low flash point....
. The product of this step is reacted with phenyl isocyanate and subsequently transformed to the 4-Phenylurazol. Cyclization and subsequent oxidation yields PTAD (6) gebildet wird.