Ethyl Acetate → 7-Bromo-5-nitrobenzothiazole

HRID 2086054Notes

Reaction equation

HRID 2086054 reaction equation
[N+:1]([C:4]1[C:5](N)=[C:6]([Br:13])[C:7]2[S:11][CH:10]=[N:9][C:8]=2[CH:12]=1)([O-:3])=[O:2].N(OS(=O)(=O)O)=O.O[PH2]=O.CCOC(C)=O>S(=O)(=O)(O)O>[N+:1]([C:4]1[CH:5]=[C:6]([Br:13])[C:7]2[S:11][CH:10]=[N:9][C:8]=2[CH:12]=1)([O-:3])=[O:2]

Participants

6

Reactant 4

HCID 8857Ethyl AcetateHCID 82157Nitrosylsulfuric acidHCID 4124402Phosphinic AcidHCID 227280347-Bromo-5-nitrobenzo[d]thiazol-6-amine

Product 1

HCID 227280317-Bromo-5-nitrobenzothiazoleYield 89%

Reagents, catalysts & solvents 1

HCID 1118Sulfuric AcidSolvent

Conditions

Temperature
25 °C

Procedure

To a solution of 5-nitro-6-amino-7-bromobenzothiazole (1.0 g, 3.7 mmol) in 4 mL of sulfuric acid was added nitrososulfuric acid (1.2 g, 9.5 mmol) in a portion. The resulting reaction mixture was stirred for 12 h at 25° C. The reaction mixture was then cooled to 0° C. and 1 mL of H3PO2 was added into the solution. It was stirred for 12 h at another 25° C. and for 2 h at 50° C. The reaction mixture was then poured into EtOAc and washed with aq. NaHCO3. Organic layer was dried over Na2SO4 and concentrated in vacuo to provide an oil (0.85 g, 3.2 mmol, 89%), which was characterized as the desired product(>95% pure) and subjected to a following reaction without further purification.

Workup

  1. customThe resulting reaction mixture
  2. temperatureThe reaction mixture was then cooled to 0° C.
  3. stirringIt was stirred for 12 h at another 25° C. and for 2 h at 50° C
  4. washwashed with aq. NaHCO3
  5. dry with materialOrganic layer was dried over Na2SO4
  6. concentrationconcentrated in vacuo

Sources & evidence

ORD record
ord-3cb41b38827b408187d73cfc6cf8604c
Source dataset
uspto-grants-2004_04
Patent number
US06723741B2

Reaction notes

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