Reaction #42464

Reaction equation

Methyl 8-iodo-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

potassium carbonate

bromobutane

→

title compound

Yield 72.6%

Methyl 4-butyl-8-iodo-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate

Yield 72.6%

Solvents

—

ethyl acetate hexanes

water

DMSO

Conditions

Workup

1. 1
   TemperatureThe mixture was cooled to room temperature
2. 2
   Otherseparated
3. 3
   WashThe organic layer was washed with water, and brine
4. 4
   Dryingdried (magnesium sulfate)
5. 5
   Filtrationfiltered
6. 6
   Concentrationconcentrated under reduced pressure
7. 7
   OtherPurification by flash column chromatography (silica, 1:10 ethyl acetate/hexanes)

Procedure

To a solution of Methyl 8-iodo-3-oxo-3,4-dihydro-2H-1,4-benzoxazine-6-carboxylate (2.64 g) and potassium carbonate (5 g) in DMSO (20 mL) was added bromobutane (5 g), and the reaction mixture was stirred for 1 h at 80° C. The mixture was cooled to room temperature, diluted with 1:1 ethyl acetate/hexanes (100 mL) and water (160 mL), and separated. The organic layer was washed with water, and brine, dried (magnesium sulfate), filtered, and concentrated under reduced pressure. Purification by flash column chromatography (silica, 1:10 ethyl acetate/hexanes) afforded 2.24 g of the title compound: 1H NMR (300 MHz, CDCl3) δ 8.13, 7.63, 4.74, 3.96, 3.92, 1.64, 1.42, 0.97.

Source