Ethyl Acetate → 7-Bromo-5-nitrobenzothiazole
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
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
- customThe resulting reaction mixture
- temperatureThe reaction mixture was then cooled to 0° C.
- stirringIt was stirred for 12 h at another 25° C. and for 2 h at 50° C
- washwashed with aq. NaHCO3
- dry with materialOrganic layer was dried over Na2SO4
- concentrationconcentrated in vacuo
Sources & evidence
- ORD record
- ord-c3011ab581014581b8ca55f3bfe37049
- Source dataset
- uspto-grants-2001_10
- Patent number
- US06303643B1
Reaction notes
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