反应详情

温度

120 °C

To 7-oxo-4,5,6,7-tetrahydro-benzothiazole-2-carboxylic acid ethyl ester (0.1128 g, 0.50 mmol) was added DMF/DMA solution (3 mL) and the mixture was refluxed under nitrogen for 1 hour. The reaction mixture was concentrated in vacuo and the resulting crude product (6-dimethylaminomethylene-7-oxo-4,5,6,7-tetrahydro-benzothiazole-2-carboxylic acid ethyl ester) was taken through to the next step without further purification. The above was dissolved in anhydrous DMA (3 mL) and treated with 3-guanidino-benzenesulfonamide hydrogen chloride (128 mg, 0.51 mmol) and powdered potassium carbonate (35 mg, 0.26 mmol). The mixture was heated to 120° C. with vigorous stirring for 12 hours. The mixture was cooled down to room temperature, and diluted with water. The resulting solid was filtered, rinsed with more water, a little bit of iPrOH and Et2O. The crude solid was purified by silica gel to give the title compound as a brown solid in 24% yield (52mg). MS (ES+) 432, (ES−) 430. δH (d6 DMSO) 1.36 (3H, t), 3.05 (2H, t), 3.17 (2H, t), 4.42 (2H, q), 7.33 (2H, s), 7.41 (1H, d), 7.50 (1H, t), 7.89 (1H, d), 8.43 (1H, t), 8.52 (1H, s), 10.04 (1H, s).

1. temperaturethe mixture was refluxed under nitrogen for 1 hour
2. concentrationThe reaction mixture was concentrated in vacuo
3. customthe resulting crude product (6-dimethylaminomethylene-7-oxo-4,5,6,7-tetrahydro-benzothiazole-2-carboxylic acid ethyl ester) was taken through to the next step without further purification
4. dissolutionThe above was dissolved in anhydrous DMA (3 mL)
5. temperatureThe mixture was cooled down to room temperature
6. filtrationThe resulting solid was filtered
7. washrinsed with more water
8. customThe crude solid was purified by silica gel