2-Amino-4-chlorophenol → (5-Chloro-2-hydroxy-phenyl)-urea

A solution of potassium cyanate (6.14 g, 75.6 mmol) in water (50 mL) was added dropwise to a stirred suspension of 2-amino-4-chlorophenol (5.00 g, 34.8 mmol) in a mixture of acetic acid (350 mL) and water (250 mL) and the resulting solution was stirred at room temperature for 3 hours. The reaction mixture was extracted three times with ethyl ether. The ether extracts were combined and concentrated to a thick oil. A 10% solution of sodium hydrogen carbonate (250 mL) was added to the above oil. The solid product was filtered and washed several times with water and recrystallized (toluene containing a little methanol) to afford the subtitle compound (3.27 g, 50.4%)

1. extractionThe reaction mixture was extracted three times with ethyl ether
2. concentrationconcentrated to a thick oil
3. additionA 10% solution of sodium hydrogen carbonate (250 mL) was added to the above oil
4. filtrationThe solid product was filtered
5. washwashed several times with water
6. customrecrystallized (toluene containing a little methanol)

ORD record

ord-0d004d5f862547c98c736a8d1037b861

Source dataset

uspto-grants-2005_09

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US06943188B2