Reaction #417900

Reaction equation

3-chlorobenzoic acid

Water

dibenzo[f,h]quinoxaline

→

Dibenzo[f,h]quinoxaline-1-oxide

Yield 51.0%

Solvents

dichloromethane

Conditions

Workup

1. 1
   Extractionthe organic layer was extracted with dichloromethane
2. 2
   WashThe obtained organic layer was washed with a saturated aqueous sodium hydrogen carbonate solution
3. 3
   Dryingdried over anhydrous magnesium sulfate
4. 4
   FiltrationThen, the resulting solution was filtered
5. 5
   workup.DISTILLATIONThe solvent of this solution was distilled off
6. 6
   OtherThe resulting residue was purified by silica gel column chromatography which
7. 7
   OtherBy recrystallization from dichloromethane
8. 8
   Otherthe object of the synthesis was obtained (as a white powder in a yield of 51%)
9. 9
   OtherThe synthesis scheme of Step 1

Procedure

First, to a solution in which 1.36 g of dibenzo[f,h]quinoxaline was dissolved in 20 mL of dichloromethane was added 2.04 g of 3-chlorobenzoic acid (abbreviation: MCPBA) in a nitrogen atmosphere, followed by stirring at room temperature for 1 week. Water was added to this mixture, and the organic layer was extracted with dichloromethane. The obtained organic layer was washed with a saturated aqueous sodium hydrogen carbonate solution and dried over anhydrous magnesium sulfate. Then, the resulting solution was filtered. The solvent of this solution was distilled off. The resulting residue was purified by silica gel column chromatography which uses a mixed solvent of dichloromethane and ethyl acetate as a developing layer. By recrystallization from dichloromethane, the object of the synthesis was obtained (as a white powder in a yield of 51%). The synthesis scheme of Step 1 is illustrated in the following (a″′-2-1).

Source