Reaktion #327461

Reaktionsgleichung

MeONa

sodium

methyl 2-(2-(2-bromo-5-fluorobenzylcarbamothioyl)hydrazono)propanoate

Methyl 2-(2-(2-bromo-5-fluorobenzylcarbamothioyl)hydrazono)propanoate

→

4-(2-bromo-5-fluorobenzyl)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one

Lösungsmittel

methanol

methanol

Reaktionsbedingungen

Aufarbeitung

1. 1
   TemperaturThe mixture was heated
2. 2
   Temperaturat reflux for 22 h
3. 3
   SonstigeMost of the solvent was evaporated
4. 4
   workup.ADDITIONThe residue was diluted with water (100 mL)
5. 5
   Extraktionextracted with EtOAc (50 mL×2)
6. 6
   WaschenThe extracts were washed with brine
7. 7
   Trocknendried over MgSO4
8. 8
   Einengenconcentrated
9. 9
   Sonstigeto give a mixture which
10. 10
    Sonstigewas separated by silica gel column
11. 11
    Wascheneluted with 20-30% ethyl acetate in petroleum ether

Vorschrift

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).

Quelle