反应详情

To a solution of MeONa (0.4 M) in methanol (30 mL), freshly prepared from sodium (273 mg, 11.88 mmol) and dry methanol (30 mL), was added methyl 2-(2-(2-bromo-5-fluorobenzylcarbamothioyl)hydrazono)propanoate (15, 1.434 g, 3.96 mmol). The mixture was heated at reflux for 22 h. Most of the solvent was evaporated. The residue was diluted with water (100 mL), acidified with 2 N HCl to pH=1˜2, and then extracted with EtOAc (50 mL×2). The extracts were washed with brine, dried over MgSO4, and concentrated to give a mixture which was separated by silica gel column, and eluted with 20-30% ethyl acetate in petroleum ether to give 4-(2-bromo-5-fluorobenzyl)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (16). MS: m/z, 330 (65%, M+1), 332 (60%, M+23).

1. temperatureThe mixture was heated
2. temperatureat reflux for 22 h
3. customMost of the solvent was evaporated
4. additionThe residue was diluted with water (100 mL)
5. extractionextracted with EtOAc (50 mL×2)
6. washThe extracts were washed with brine
7. dry with materialdried over MgSO4
8. concentrationconcentrated
9. customto give a mixture which
10. customwas separated by silica gel column
11. washeluted with 20-30% ethyl acetate in petroleum ether