反应详情

A mixture of 4-mercapto-3-nitrobenzoic acid (1 eq.) and zinc dust (0.35 eq) in formic acid was refluxed for 6 h. The mixture was allowed to cool to room temperature, filtered and concentrated under reduced pressure. The residue was diluted with water, adjusted to pH=6.5 with aqueous NaOH (2N) and extracted three times with EtOAc. The organic layers were combined, dried over MgSO4, filtered and concentrated under reduced pressure. The crude was purified by chromatography on silica gel (elution with DCM/MeOH: 1/0 to 95/5) to afford benzothiazole-5-carboxylic acid.

1. temperaturewas refluxed for 6 h
2. filtrationfiltered
3. concentrationconcentrated under reduced pressure
4. additionThe residue was diluted with water
5. extractionextracted three times with EtOAc
6. dry with materialdried over MgSO4
7. filtrationfiltered
8. concentrationconcentrated under reduced pressure
9. customThe crude was purified by chromatography on silica gel (elution with DCM/MeOH: 1/0 to 95/5)