Sulfuric Acid → 2-Chloro-4-hydroxybenzonitrile
Reaction equation
[Cl:1][C:2]1[CH:9]=[C:8](N)[CH:7]=[CH:6][C:3]=1[C:4]#[N:5].S(=O)(=O)(O)[OH:12].N([O-])=O.[Na+].NC(N)=O>O>[Cl:1][C:2]1[CH:9]=[C:8]([OH:12])[CH:7]=[CH:6][C:3]=1[C:4]#[N:5]Participants
Reactant 4
Product 1
Reagents, catalysts & solvents 1
Conditions
- Temperature
- 0 °C
Procedure
A mixture of 2-chloro-4-aminobenzonitrile (25 g, 0.187 m) in stirred concentrated sulfuric acid (58 g) and water (570 ml) was heated at between 49° and 61° C. for approximately thirty minutes. The suspension was cooled to approximately 0° C. and a cold solution of sodium nitrite (13.2 g, 0.187 m) in water (125 ml) was added dropwise at a solution temperature of between 0° and 6° C. Stirring continued thereafter for approximately three hours and then urea (1.5 g) was added to the mixture. The resulting insoluble impurity was filtered off. An aqueous solution of 50% sulfuric acid (600 ml) was added while the reaction mixture was heated at a temperature between 74° and 81° C. and stirred until the evolution of nitrogen gas ceased. The reaction product was separated by filtration and then recrystallized from water to yield 2-chloro-4-hydroxybenzonitrile (17.9 g, 62.5%, mp 160° C.).
Workup
- temperaturewas heated at between 49° and 61° C. for approximately thirty minutes
- filtrationThe resulting insoluble impurity was filtered off
- additionAn aqueous solution of 50% sulfuric acid (600 ml) was added while the reaction mixture
- temperaturewas heated at a temperature between 74° and 81° C.
- stirringstirred until the evolution of nitrogen gas
- customThe reaction product was separated by filtration
- customrecrystallized from water
Sources & evidence
- ORD record
- ord-f3ff8b032ae0427aa665278fe2da4603
- Source dataset
- uspto-grants-1984_01
- Patent number
- US04424371
Reaction notes
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