Boron tribromide → 4-Hydroxybenzothiazole

HRID 2220337Notes

Reaction equation

HRID 2220337 reaction equation
B(Br)(Br)Br.C[O:6][C:7]1[C:12]2[N:13]=[CH:14][S:15][C:11]=2[CH:10]=[CH:9][CH:8]=1>C(Cl)Cl>[OH:6][C:7]1[C:12]2[N:13]=[CH:14][S:15][C:11]=2[CH:10]=[CH:9][CH:8]=1

Participants

4

Reactant 2

HCID 25134Boron tribromideHCID 126318584-Methoxy-1,3-benzothiazole

Product 1

HCID 819014-HydroxybenzothiazoleYield 156.3%

Reagents, catalysts & solvents 1

HCID 6344DichloromethaneSolvent

Conditions

Temperature
40 °C

Procedure

Boron tribromide (3.09 ml, 1M solution in DCM, 3.09 mmol) was added dropwise at 0° C. to a stirred solution of 4-methoxy-benzothiazole (510 mg, 3.09 mmol) in dry DCM (30ml). The resulting solution was warmed to 40° C. and allowed to stir overnight. The resulting solution was concentrated in vacuo and diluted with water and HCl (2N). The aqueous phase was neutralised to pH˜7 with NaHCO3 and the solution extracted with EtOAc (3×100 ml) and the combined organic extracts dried (MgSO4) and the solvent removed in vacuo. The resulting oil was purified by flash chromatography eluting silica gel with hexane:EtOAc [4:1] to hexane:EtOAc [7:3] to give the title compound as a tan solid (730 mg, 80%); δH (300 MHz, CDCl3) 7.59 (1H, s, CH), 7.46 (1H, dd, Ar), 7.36 (1H, t, Ar), 7.02 (1H, dd, Ar).

Workup

  1. concentrationThe resulting solution was concentrated in vacuo
  2. additiondiluted with water and HCl (2N)
  3. extractionthe solution extracted with EtOAc (3×100 ml)
  4. dry with materialthe combined organic extracts dried (MgSO4)
  5. customthe solvent removed in vacuo
  6. customThe resulting oil was purified by flash chromatography
  7. washeluting silica gel with hexane

Sources & evidence

ORD record
ord-a6f910b2831040b380d7ef2b23800210
Source dataset
uspto-grants-2008_08
Patent number
US07417064B2

Reaction notes

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