反应详情

温度

50 °C

A mixture of 1,2-diethyl 4-cyanotetrahydro-1,2-pyridazinedicarboxylate (i.e the product of Step E) (5.5 g, 0.024 mol) and thioacetamide (5.5 g, 0.073 mol) in trifluoroacetic acid (about 10 mL) was heated at 50° C. for 20 h. The reaction mixture was cooled, and then partitioned between water and diethyl ether (about 30 mL). The layers were separated and the aqueous layer was extracted with diethyl ether (2×). The combined organic extracts were washed with water (about 30 mL), dried magnesium sulfate, filtered and concentrated under reduce pressure to an orange oil. The oil was adsorbed onto Celite® (diatomaceous filter aid), and then purified by silica gel column chromatography (25% to 60% gradient of ethyl acetate in petroleum ether as eluant) to provide the title compound as a yellow solid (3.97 g).

1. temperatureThe reaction mixture was cooled
2. custompartitioned between water and diethyl ether (about 30 mL)
3. customThe layers were separated
4. extractionthe aqueous layer was extracted with diethyl ether (2×)
5. washThe combined organic extracts were washed with water (about 30 mL), dried magnesium sulfate
6. filtrationfiltered
7. concentrationconcentrated
8. custompurified by silica gel column chromatography (25% to 60% gradient of ethyl acetate in petroleum ether as eluant)