Hydrogen Bromide → 2-Methyl-1,3-benzothiazol-6-ol

HRID 706223Notes

Reaction equation

HRID 706223 reaction equation
C[O:2][C:3]1[CH:12]=[CH:11][C:6]2[N:7]=[C:8]([CH3:10])[S:9][C:5]=2[CH:4]=1.Br>[Br-].C([P+](CCCC)(CCCC)CCCC)CCC.[OH-].[Na+]>[CH3:10][C:8]1[S:9][C:5]2[CH:4]=[C:3]([OH:2])[CH:12]=[CH:11][C:6]=2[N:7]=1

Participants

5

Reactant 2

HCID 260Hydrogen BromideHCID 762546-Methoxy-2-methylbenzothiazole

Product 1

HCID 7593042-Methyl-1,3-benzothiazol-6-olYield 81.5%

Reagents, catalysts & solvents 2

HCID 76564Tetrabutylphosphonium bromideCatalystHCID 14798Sodium HydroxideSolvent2×

Conditions

Temperature
105 °C

Procedure

A mixture of 6-methoxy-2-methyl-benzothiazole (19.71 g, 0.11 mol), tetrabutylphosphonium bromide (3.73 g, 0.01 mol), and 48% HBr (120 mL) was stirred at 105° C. for twenty-eight hours before it was cooled to room temperature, neutralized with 10N NaOH (90 mL) and 1N NaOH (45 mL) to pH=4. The resulting precipitate was filtered, washed with water (3×100 mL), dried in vacuo to give the title compound as a pale brown solid (14.81 g): 1H NMR (CDCl3, 200 MHz): δ=7.77 (m, 1H), 7.24 (m, 1H), 6.94 (m, 1H), 5.28 (s, 1H), 2.79 (s, 3H).

Workup

  1. temperaturewas cooled to room temperature
  2. filtrationThe resulting precipitate was filtered
  3. washwashed with water (3×100 mL)
  4. customdried in vacuo

Sources & evidence

ORD record
ord-290c4b452c5846fdbd01dabb2c22e23d
Source dataset
uspto-grants-2015_11
Patent number
US09174976B2

Reaction notes

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