Reaction #84032

Reaction equation

6-bromo-N-methoxy-N-methyl-2-naphthamide

methyl magnesium bromide

hydrochloric acid

→

1-(6-bromonaphthalen-2-yl)-ethanone

Yield 99.0%

Solvents

tetrahydrofurane

Conditions

Workup

1. 1
   TemperatureThe reaction mixture was cooled in an ice bath
2. 2
   Temperaturecarefully added drop wise while cooling on an ice bath
3. 3
   OtherThe organic solvent was evaporated
4. 4
   Extractionthe precipitated product extracted with dichloromethane (500 mL)
5. 5
   DryingThe solution was dried over sodium sulphate
6. 6
   Filtrationfiltered
7. 7
   Concentrationconcentrated
8. 8
   OtherThe solid residue was dried in vacuum at 40° C.

Procedure

6-bromo-N-methoxy-N-methyl-2-naphthamide (82.9 g, 282 mmol, 1 equiv.) was dissolved in tetrahydrofurane (600 mL) in a 4-neck flask under nitrogen. The reaction mixture was cooled in an ice bath and methyl magnesium bromide (3.2 M in methyl-tetrahydrofurane, 197 mL, 2.2 equiv.) was added drop wise during 1 hour, while maintaining the temperature of the reaction mixture between 10-15° C. The reaction mixture was stirred 30 minutes further in an ice bath. Aqueous hydrochloric acid (2 M, 100 mL) was then carefully added drop wise while cooling on an ice bath. The organic solvent was evaporated and the precipitated product extracted with dichloromethane (500 mL). The solution was dried over sodium sulphate, filtered and concentrated. The solid residue was dried in vacuum at 40° C. yielding 1-(6-bromonaphthalen-2-yl)-ethanone (70.6 g, 99%).

Source