2-CHLORO-4-HYDROXYBENZONITRILE synthesis

Yield: 62.5%

Reaction Conditions:

with urea;sodium nitrite in sulfuric acid;water

Steps:

1.5 Step 5
Step 5 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°

References:

Timex Corporation US4424371, 1984, A