Reaction #42724

Reaction equation

bromine

product

5-Acetyl-8-benzyloxy-1H-quinolin-2-one

Boron trifluoride diethyl etherate

→

title compound

Yield 134.3%

8-Benzyloxy-5-(2-bromoacetyl)-1H-quinolin-2-one

Yield 134.3%

Solvents

dichloromethane

dichloromethane

Conditions

Workup

1. 1
   Temperaturethe mixture was warmed to room temperature
2. 2
   Otherto give a thick suspension
3. 3
   TemperatureThe suspension was heated at 45° C. (oil bath)
4. 4
   Temperaturecooled to room temperature
5. 5
   ConcentrationThe mixture was concentrated under reduced pressure
6. 6
   Othertriturated with 10% aqueous sodium carbonate (200 mL) for 1 hour
7. 7
   OtherThe solids were collected on a Buchner funnel
8. 8
   Washwashed with water (4×100 mL)
9. 9
   Otherdried under reduced pressure
10. 10
    OtherThe product of two runs was combined for purification
11. 11
    OtherThe crude product (52 g) was triturated with 50% methanol in chloroform (500 mL) for 1 hour
12. 12
    OtherThe product was collected on a Buchner funnel
13. 13
    Washwashed with 50% methanol in chloroform (2×50 mL) and methanol (2×50 mL)
14. 14
    OtherThe solid was dried under reduced pressure

Procedure

The product from step (c) (20.0 g, 68.2 mmol) was dissolved in dichloromethane (200 mL) and cooled to 0° C. Boron trifluoride diethyl etherate (10.4 mL, 82.0 mmol) was added via syringe and the mixture was warmed to room temperature to give a thick suspension. The suspension was heated at 45° C. (oil bath) and a solution of bromine (11.5 g, 72.0 mmol) in dichloromethane (100 mL) was added over 40 min. The mixture was kept at 45° C. for an additional 15 min and then cooled to room temperature. The mixture was concentrated under reduced pressure and then triturated with 10% aqueous sodium carbonate (200 mL) for 1 hour. The solids were collected on a Buchner funnel, washed with water (4×100 mL) and dried under reduced pressure. The product of two runs was combined for purification. The crude product (52 g) was triturated with 50% methanol in chloroform (500 mL) for 1 hour. The product was collected on a Buchner funnel and washed with 50% methanol in chloroform (2×50 mL) and methanol (2×50 mL). The solid was dried under reduced pressure to give the title compound (34.1 g) as a powder.

Source