4-Isoquinolinol → HCID 12257649, compound

Temperature

-5 °C

6.0 g (41 mmol) of 4-hydroxyisoquinoline are dissolved in 50 ml of 10% strength sodium hydroxide solution, giving a yellowish brown color. The reaction mixture is cooled to -5° C. using an ice/common salt mixture. A mixture comprising 6.6 g (2.1 ml, 41 mmol) of bromine dissolved in 50 ml of 10% strength sodium hydroxide solution is added dropwise to this solution over a period of 1 hour. During this period, the temperature of the reaction solution must never exceed 0° C. After this time, the coolant is removed and the reaction solution is stirred at room temperature for another 3 hours. The reaction solution is then cooled to -10° C. The reaction solution is then brought to a pH of 3 with 2N hydrochloric acid, during which the temperature of the reaction solution never exceeds -5° to 0° C. This gives the crude product as a light yellow solid. The crude product is recrystallized from 180 ml of ethyl acetate.

1. customgiving a yellowish brown color
2. additionis added dropwise to this solution over a period of 1 hour
3. waitDuring this period
4. customnever exceed 0° C
5. customAfter this time, the coolant is removed
6. temperatureThe reaction solution is then cooled to -10° C
7. customthe temperature of the reaction solution never exceeds -5° to 0° C

ORD record

ord-021813666ec043eebbf6b5bcc7eea84b

Source dataset

uspto-grants-1993_11

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US05266700