Reacción #65639

Ecuación de reacción

compound

t-Butyl-2,3-dioxobutyrate

5,6-diamino-2,2-dimethyl-1,3-benzodioxole

dihydrochloride

NaOH

→

2,2,7-Trimethyl-1,3-dioxolo-[4,5-g]-quinoxaline-6-carboxylic acid, 1,1-dimethylethyl ester

Disolventes

water

tetrahydrofuran

Condiciones de reacción

Tratamiento posterior

1. 1
   Temperaturawas refluxed for 2 hours
2. 2
   Concentraciónconcentrated in vacuo
3. 3
   Otroto remove the organic solvent tetrahydrofuran
4. 4
   Extracciónextracted with ethyl acetate
5. 5
   LavadoThe combined organic phases were washed with brine
6. 6
   Secadodried (Na2SO4)
7. 7
   Otroevaporated in vacuo
8. 8
   Otroto leave an oil which
9. 9
   Otrocrystallized by the addition of petroleum ether

Procedimiento

[5,6-diamino-2,2-dimethyl-1,3-benzodioxole; dihydrochloride salt] (U.S. Pat. No. 4,904,775, Example 3D) (6.8 g, 0.02 mmol) was dissolved in a mixture of 25 ml water and 10 ml tetrahydrofuran and the pH of the solution was adjusted to 5.5 by the addition of 2N NaOH. After addition of the compound from Example 1 (3.8 g; 0.02 mol) the mixture was refluxed for 2 hours, concentrated in vacuo to remove the organic solvent tetrahydrofuran and then extracted with ethyl acetate. The combined organic phases were washed with brine, dried (Na2SO4) and then evaporated in vacuo to leave an oil which crystallized by the addition of petroleum ether.

Fuente