Reacción #927744

Ecuación de reacción

methyl 2-chloropropionate

triethylamine

4,5-Dimethoxy-1,2-dinitrobenzene

hydrogen

hydrogen

→

6,7-Dimethoxy-3-methyl-3,4-dihydroquinoxalin-2(1H)-one

Disolventes

ethanol

methanol

ethyl acetate

Condiciones de reacción

Tratamiento posterior

1. 1
   Otrothe catalyst was removed by filtration with suction
2. 2
   OtroTo remove the water completely
3. 3
   Concentraciónwas concentrated
4. 4
   Lavadothe mixture was washed twice with water
5. 5
   Secadodried (sodium sulfate)
6. 6
   OtroThe crude product was crystallized
7. 7
   OtroA analytically pure sample of melting point 151° C. was obtained by silica gel chromatography

Procedimiento

4,5-Dimethoxy-1,2-dinitrobenzene (34.2 g, 0.15 mol) was hydrogenated in 500 ml of methanol with Raney nickel catalysis using 1 atm hydrogen. After the calculated amount of hydrogen had been taken up, the process was stopped, the catalyst was removed by filtration with suction, and the solvent was stripped off in vacuo. To remove the water completely, the mixture was taken up twice in methanol and reconcentrated. 4,5-Dimethoxy-1,2-phenylenediamine (24.0 g), which remained as a brown oil, was refluxed for 48 hours in 200 ml of ethanol (96%) together with 17.1 ml (0.15 mol) of methyl 2-chloropropionate, with an addition of 21.0 ml (0.15 mol) of triethylamine. The solution, which was very dark, was concentrated, the concentrate was taken up in ethyl acetate, the mixture was washed twice with water and dried (sodium sulfate), and the solvent was stripped off in vacuo. The crude product was crystallized by stirring with diethyl ether (6.2 g, 19%). A analytically pure sample of melting point 151° C. was obtained by silica gel chromatography using ethyl acetate as the eluent.

Fuente