4-Methoxy-2-aminobenzothiazole → 2-Bromo-4-methoxy-1,3-benzothiazole

HRID 427286Notes

Reaction equation

HRID 427286 reaction equation
N[C:2]1[S:3][C:4]2[CH:10]=[CH:9][CH:8]=[C:7]([O:11][CH3:12])[C:5]=2[N:6]=1.[Br-:13].[K+].N([O-])=O.[Na+]>S(=O)(=O)(O)O>[Br:13][C:2]1[S:3][C:4]2[CH:10]=[CH:9][CH:8]=[C:7]([O:11][CH3:12])[C:5]=2[N:6]=1

Participants

5

Reactant 3

HCID 216224-Methoxy-2-aminobenzothiazoleHCID 253877Potassium BromideHCID 23668193Sodium Nitrite

Product 1

HCID 183569972-Bromo-4-methoxy-1,3-benzothiazoleYield 78.8%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Procedure

To a solution of 2-amino-4-methoxybenzothiazole (1.5 g) and potassium bromide (3.5 g) in sulphuric acid (1.25M, 50 ml) at 0° C. was added sodium nitrite (0.86 g) over a period of 1 hr. The reaction was allowed to warm to room temperature and stirred for 2 hrs, before being extracted with dichloromethane (3×50 ml). The combined organic extracts were dried over magnesium sulphate (5 g), and the solvent removed in vacuo to yield an off white solid. This was purified by flash chromatography (eluent 50% ethyl acetate/hexane) to yield the title compound as a white solid (1.6 g). TLC Ff 0.30 (20% ethyl acetate in hexane)

Workup

  1. extractionbefore being extracted with dichloromethane (3×50 ml)
  2. dry with materialThe combined organic extracts were dried over magnesium sulphate (5 g)
  3. customthe solvent removed in vacuo
  4. customto yield an off white solid
  5. customThis was purified by flash chromatography (eluent 50% ethyl acetate/hexane)

Sources & evidence

ORD record
ord-d1caa672c92a4f6d8821d2f04995a1c3
Source dataset
uspto-grants-2001_11
Patent number
US06313116B1

Reaction notes

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