反应详情

7-Methyl-6-nitrosobenzothiazole was prepared from 6-nitrobenzothiazole according to the general procedure described by Bartoli et al. Synlett 270 (1976). To a solution of 7-methyl-6-nitrosobenzothiazole (889 mg, 5.00 mmol) in AcOH (40 mL) at 70° C. was added iron powder (325 mesh, 559 mg, 10.0 mmol) in a single portion. The resulting dark reaction mixture was stirred for 15 min before it was cooled and concentrated in vacuo to leave a residue which was partitioned between 1N HCl (50 mL) and CH2Cl2 (50 mL). The layers were separated and the organic layer was washed once with 1N HCl (25 mL). The combined aqueous layers were made basic by the addition of solid NaHCO3 and were extracted twice with EtOAc. The organic phases were combined, dried over MgSO4 and concentrated in vacuo to give 534 mg (65%) of compound 497A as a light brown solid. HPLC: 96% at 0.55 min (retention time) (YMC S5 ODS column, 4.6×50 mm Ballistic, 10–90% aqueous methanol over 4 min containing 0.2% H3PO4, 4 mL/min, monitoring at 220 nm). MS (ES): m/z 165.0 [M+H]+.

1. customThe resulting dark reaction mixture
2. temperaturewas cooled
3. concentrationconcentrated in vacuo
4. customto leave a residue which
5. customwas partitioned between 1N HCl (50 mL) and CH2Cl2 (50 mL)
6. customThe layers were separated
7. washthe organic layer was washed once with 1N HCl (25 mL)
8. additionThe combined aqueous layers were made basic by the addition of solid NaHCO3
9. extractionwere extracted twice with EtOAc
10. dry with materialdried over MgSO4
11. concentrationconcentrated in vacuo