Reaction #90009

Reaction equation

water

8-Hydroxy-6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazole-3-carbonitrile

Compound A6

8-Hydroxy-6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazole-3-carbonitrile

trifluoromethanesulfonic acid

→

Trifluoro-methanesulfonic acid 3-cyano-6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazol-8-yl ester

Solvents

pyridine

Conditions

Workup

1. 1
   Extractionextracted with dichloromethane
2. 2
   DryingThe organic layer was dried over magnesium sulfate
3. 3
   OtherThe drying agent was removed by filtration
4. 4
   Otherthe residues obtained
5. 5
   Concentrationafter concentration under reduced pressure
6. 6
   Otherwere purified by silica gel column chromatography (ethyl acetate/hexane)
7. 7
   Otherto obtain the target compound (white powder, 641 mg, 81%)

Procedure

8-Hydroxy-6,6-dimethyl-11-oxo-6,11-dihydro-5H-benzo[b]carbazole-3-carbonitrile (Compound A6, 550 mg, 0.189 mmol) was dissolved in pyridine (18 mL), added with anhydrous trifluoromethanesulfonic acid (0.758 ml, 3 eq.), and stirred at room temperature for 30 min. The reaction solution was added to water and then extracted with dichloromethane. The organic layer was dried over magnesium sulfate. The drying agent was removed by filtration and the residues obtained after concentration under reduced pressure were purified by silica gel column chromatography (ethyl acetate/hexane) to obtain the target compound (white powder, 641 mg, 81%).

Source