Nitric Acid → 3-methyl-4-phenyl-4H-1,2,4-triazole

Participants

Reaction Steps

2.5 mol of phenyl isothiocyanate (Formula XXI of Chart B) is added to 0.5 mol of acethydrazide (Formula IV of Chart B) in 500 ml of absolute ethanol and refluxed for one hour, cooled and filtered. This is then dissolved in a solution of 28.0 gm sodium hydroxide in 400 ml of water and the mixture is refluxed for two hours. The reaction mixture is cooled in an ice bath and treated with 100 ml of concentrated hydrochloric acid. The resulting solid is filtered and recrystallized. 66.7 mmol of the solid is added to 53 ml of 20% nitric acid and heated on a steam bath. When the vigorous exothermic reaction is complete, an additional 53 ml of 20% nitric acid is added, and an additional 66.7 mmol of previous solid. Portions of the solid are reacted with nitric acid until all of the previous solid is reacted. After the final addition the reaction mixture is heated twenty minutes on a steam bath, cooled to ambient temperature and poured into cold 15% aqueous ammonium hydroxide solution. The subtitled product is extracted with chloroform, dried and concentrated to yield 3-methyl-4-phenyl-4H-1,2,4-triazole, (Formula XXIV, Chart B) mp 109°-111° C.

Provenance & Evidence