Reacción #1161420

Ecuación de reacción

Methyl 2,4-dibromobutyrate

methylamine

→

N-Methyl-2,4-dibromobutyramide

Disolventes

chloroform

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturacooling in an ice bath
2. 2
   workup.STIRRINGThe reaction mixture was stirred for 16 hours at 5° C.
3. 3
   Lavadothe organic layer washed with water
4. 4
   ExtracciónThe organic extract
5. 5
   Secadowas dried over magnesium sulfate
6. 6
   Filtraciónfiltered
7. 7
   Otrothe solvent removed
8. 8
   OtroThe crude product was purified by column chromatography (silica gel, gradient elution hexane/chloroform to chloroform/ethylacetate)
9. 9
   Otroto yield an off-white solid, (25.4 gm, 51.7%)
10. 10
    OtroThe compound was used in the next step without further purification
11. 11
    OtroA small portion was further purified for elemental analysis

Procedimiento

Methyl 2,4-dibromobutyrate (50 gm, 0.192 mole) was mixed with 40 wt % methylamine in aqueous solution (20.0 ml, 7.22 gm, 0.232 mole) with stirring and cooling in an ice bath. The reaction mixture was stirred for 16 hours at 5° C., chloroform (100 ml) was then added and the organic layer washed with water. The organic extract was dried over magnesium sulfate, filtered and the solvent removed. The crude product was purified by column chromatography (silica gel, gradient elution hexane/chloroform to chloroform/ethylacetate) to yield an off-white solid, (25.4 gm, 51.7%): m.p. 42°-47° C. The compound was used in the next step without further purification. A small portion was further purified for elemental analysis; m.p. 48°-49° C. IR(KBr) 3450, 1660, 1570, 1415, 1240 and 1210 cm-1 ; H-NMR (CDCl3) δ 2.48 (m, 1H, --CH2 -CHBr--), 2.79(m, 1H, --CH2 -CHBy--), (d, 3H, --NH2 -CH3 --), 3.55 (t, 2H, Br--CH2 --CH2), 4.54 (dd, 1H, --CHBr--); 6.39 (s, broad, 1H, --NH--CH3), C--NMR, decoupled (CDCl3) 26.83, 30.27, 37.60, 48.26, 168.65 ppm. Anal. calcd. for C5H9NBr2O (258.949): C, 23.19; H, 3.50; N, 5.41. Found: C, 23.53; H, 3.44; N, 5.29%.

Fuente