Sulfuric Acid → 5-Amino-1-(o-tolyl)-1H-pyrazole-4-carboxamide
Reaction equation
S(=O)(=O)(O)O.[NH2:6][C:7]1[N:11]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=2[CH3:18])[N:10]=[CH:9][C:8]=1[C:19]#[N:20].[OH-:21].[Na+]>>[NH2:6][C:7]1[N:11]([C:12]2[CH:17]=[CH:16][CH:15]=[CH:14][C:13]=2[CH3:18])[N:10]=[CH:9][C:8]=1[C:19]([NH2:20])=[O:21]Participants
4
Conditions
- Temperature
- 40 °C
Procedure
300 ml of 96% strength sulphuric acid are cautiously added to 40.0 g (201.8 mmol) of 5-amino-1-(2-methylphenyl)-1H-pyrazole-4-carbonitrile (Example 9A) while cooling in ice. The mixture is then heated to 40° C. and stirred for 2 hours at this temperature. After cooling, it is poured into 2 l of ice-water and cautiously neutralized with 50% strength sodium hydroxide solution. After extraction with ethyl acetate three times (2 l each time) the combined organic phases are washed with saturated sodium chloride solution and dried over sodium sulphate, and the solvent is distilled off under reduced pressure. 36.0 g (82% of theory) of product (purity >90%) are obtained and are employed without further purification in subsequent reactions.