Reacción #465958

Ecuación de reacción

H2O NH4OH

lithium aluminum hydride

methyl 6-bromo-3-chloro-4-nitropyridine-2-carboxylate

→

methyl 4-amino-6-bromo-3-chloropyridine-2-carboxylate

Disolventes

tetrahydrofuran

THF

Condiciones de reacción

Tratamiento posterior

1. 1
   workup.STIRRINGThe solution was stirred 1 hr
2. 2
   Filtraciónfiltering
3. 3
   ExtracciónThe filtrate was extracted with EtOAc (2×75 mL)
4. 4
   SecadoThe organic phase was dried (Na2SO4)
5. 5
   Concentraciónconcentrated
6. 6
   OtroThe red solid was chromatographed over silica in 4:1 EtOAc/hexane

Procedimiento

To a solution of titanium tetrachloride (0.015 mol, 2.8 g) in tetrahydrofuran (50 mL) was added lithium aluminum hydride (0.0175 mol, 0.7 g). The black slurry was stirred 15 min before adding methyl 6-bromo-3-chloro-4-nitropyridine-2-carboxylate, N-oxide (0.007 mol, 2.3 g) in THF (25 mL). The solution was stirred 1 hr before pouring into 1:1 H2O/NH4OH and filtering. The filtrate was extracted with EtOAc (2×75 mL). The organic phase was dried (Na2SO4), and concentrated. The red solid was chromatographed over silica in 4:1 EtOAc/hexane to give methyl 4-amino-6-bromo-3-chloropyridine-2-carboxylate (0.003 mol, 0.8 g); mp 194-5° C. 1H NMR(CDCl3): δ 3.95 (3H, s), 5.3 (2H, bs), 6.9 (1H, s).

Fuente