Hydrochloric Acid → 6-Bromo-1,2,3,4-tetrahydrocarbazole

Temperature

60 °C

A 250-mL round-bottomed flask was charged with 1-(4-bromophenyl)-2-cyclohexylidenehydrazine (11 g, 41.35 mmol, 1.00 equiv) and conc. HCl (150 mL). The resulting mixture was heated to 60° C. in an oil bath for 4 hours. The reaction progress was monitored by TLC (EtOAc:PE=1:1). Upon completion, the reaction mixture was cooled down to room temperature. The pH was adjusted to 8 with aqueous sodium hydroxide. The resulting mixture was then extracted with ethyl acetate (5×100 mL). The combined organic layers were dried over anhydrous sodium sulfate, filtered off and concentrated on a rotary evaporator. The residue was purified by a silica gel column chromatography eluted with ethyl acetate/petroleum ether (1/10) affording 3-bromo-6,7,8,9-tetrahydro-5H-carbazole as yellow solid (10 g, 97%).

1. temperatureUpon completion, the reaction mixture was cooled down to room temperature
2. extractionThe resulting mixture was then extracted with ethyl acetate (5×100 mL)
3. dry with materialThe combined organic layers were dried over anhydrous sodium sulfate
4. filtrationfiltered off
5. concentrationconcentrated on a rotary evaporator
6. customThe residue was purified by a silica gel column chromatography
7. washeluted with ethyl acetate/petroleum ether (1/10)

ORD record

ord-1d3e449030e847b89aa1ccc591f2293b

Source dataset

uspto-grants-2011_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08080566B1