Reaktion #327473

Reaktionsgleichung

MeONa

sodium

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

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

→

4-(2-chloro-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 36 h
3. 3
   SonstigeMost of the solvent was evaporated
4. 4
   workup.ADDITIONThe resulting residue was diluted with water (300 mL)
5. 5
   Extraktionextracted with EtOAc (250 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 (0.82 M) in methanol (200 mL), freshly prepared from sodium (3.80 g, 165 mmol) and dry methanol (200 mL), was added methyl 2-(2-(2-chloro-5-fluorobenzylcarbamothioyl)hydrazono)propanoate (28, 10.00 g, 31.5 mmol). The mixture was heated at reflux for 36 h. Most of the solvent was evaporated. The resulting residue was diluted with water (300 mL), acidified with 2 N HCl to pH=1˜2, and then extracted with EtOAc (250 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-chloro-5-fluorobenzyl)-6-methyl-3-thioxo-3,4-dihydro-1,2,4-triazin-5(2H)-one (29).

Quelle