Boron tribromide → 2-cyclopentyl-6-hydroxybenzo[d]isothiazol-3(2H)-one

HRID 404964Notes

Reaction equation

HRID 404964 reaction equation
B(Br)(Br)Br.[CH:5]1([N:10]2[C:14](=[O:15])[C:13]3[CH:16]=[CH:17][C:18]([O:20]C)=[CH:19][C:12]=3[S:11]2)[CH2:9][CH2:8][CH2:7][CH2:6]1>C1C=CC=CC=1>[CH:5]1([N:10]2[C:14](=[O:15])[C:13]3[CH:16]=[CH:17][C:18]([OH:20])=[CH:19][C:12]=3[S:11]2)[CH2:6][CH2:7][CH2:8][CH2:9]1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 250674602-cyclopentyl-6-methoxybenzo[d]isothiazol-3(2H)-one

Product 1

HCID 250674612-cyclopentyl-6-hydroxybenzo[d]isothiazol-3(2H)-oneYield 85%

Reagents, catalysts & solvents 1

HCID 241BenzeneSolvent

Procedure

BBr3 (0.54 g, 2 mmol) was added dropwise to a solution of 2-cyclopentyl-6-methoxybenzo[d]isothiazol-3(2H)-one (0.250 g, 1 mmol) in anhydrous benzene (20 mL) at 0° C. The mixture was gradually warmed to room temperature and then heated at 80° C. for 30 min. The reaction mixture was then cooled to room temperature and carefully quenched with H2O (20 mL). The resulting mixture was then heated to reflux for an hour and filtered; the precipitate was washed with H2O and dried under vacuum to give the crude product. The material was purified by flash chromatography (silica gel, CHCl3: CH3OH, 9:1) to afford (0.200 g, 85%) of 2-cyclopentyl-6-hydroxybenzo[d]isothiazol-3(2H)-one as a colorless solid. 1H NMR (300 MHz, DMSO-d6): δ 10.36 (s, 1H), 7.60 (d, 1H, J=8.5 Hz), 7.20 (s, 1H), 6.80 (d, 1H, J=8.6 Hz), 4.84-4.81 (m, 1H), 2.12-1.98 (m, 2H), 1.75-1.60 (m, 6H). LC-MS (ESI) Calcd for C12H13NO2S [M+H]+: 236.0667. Found: 235.95.

Workup

  1. temperatureheated at 80° C. for 30 min
  2. temperatureThe reaction mixture was then cooled to room temperature
  3. customcarefully quenched with H2O (20 mL)
  4. temperatureThe resulting mixture was then heated
  5. temperatureto reflux for an hour
  6. filtrationfiltered
  7. washthe precipitate was washed with H2O
  8. customdried under vacuum
  9. customto give the crude product
  10. customThe material was purified by flash chromatography (silica gel, CHCl3: CH3OH, 9:1)

Sources & evidence

ORD record
ord-29860f513a0d40d8b0daa7cd8091f343
Source dataset
uspto-grants-2014_06
Patent number
US08748632B2

Reaction notes

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