p-Toluenesulfonic acid → 7-Bromo-1,2-benzothiazole

HRID 389438Notes

Reaction equation

HRID 389438 reaction equation
[Br:1][C:2]1[C:3]([S:11]C(C)(C)C)=[C:4]([CH:8]=[N:9]O)[CH:5]=[CH:6][CH:7]=1.C1(C)C=CC(S(O)(=O)=O)=CC=1>C(O)CCC>[Br:1][C:2]1[C:3]2[S:11][N:9]=[CH:8][C:4]=2[CH:5]=[CH:6][CH:7]=1

Participants

4

Reactant 2

HCID 6101p-Toluenesulfonic acidHCID 866623981-[3-bromo-2-(tert-butylsulfanyl)phenyl]-N-hydroxymethanimine

Product 1

HCID 193873027-Bromo-1,2-benzothiazoleYield 17.3%

Reagents, catalysts & solvents 1

HCID 2631-ButanolSolvent2×

Procedure

A mixture of crude 1-[3-bromo-2-(tert-butylsulfanyl)phenyl]-N-hydroxymethanimine (7 g) and p-toluenesulfonic acid (730 mg, 3.88 mmol) in n-butanol (100 mL) was heated to reflux for 16 h. n-Butanol was evaporated, water (100 mL) and saturated aqueous sodium bicarbonate (50 mL) were added and the mixture was extracted with DCM (3×80 mL). The combined organic fractions were dried over anhydrous sodium sulfate, filtered and concentrated to afford 900 mg (17%) of the crude title compound as a brown solid. 1H NMR (300 MHz, CDCl3): δ 7.26-7.40 (t, J=8.1 Hz, 1H), 7.62 (d, J=6.9 Hz, 1H), 8.02 (d, J=8.4 Hz, 1H), 9.04 (s, 1H).

Workup

  1. temperaturewas heated
  2. customwas evaporated
  3. additionwater (100 mL) and saturated aqueous sodium bicarbonate (50 mL) were added
  4. extractionthe mixture was extracted with DCM (3×80 mL)
  5. dry with materialThe combined organic fractions were dried over anhydrous sodium sulfate
  6. filtrationfiltered
  7. concentrationconcentrated

Sources & evidence

ORD record
ord-e35f8bdb73214b87b3837235f29810de
Source dataset
uspto-grants-2013_02
Patent number
US08378104B2

Reaction notes

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