3-METHYL-3,4-DIHYDRO-2(1H)-QUINOXALINONE

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-Methyl-3,4-dihydroquinoxalin-2(1H)-one (0.5 g, 3.1 mmol) together with 0.35 ml (4.3 mmol) of methyl vinyl ketone and a catalytic amount of triethylamine were stirred for 20 hours at room temperature in 20 ml of anhydrous ethanol. Silica gel chromatography with methyl tert.-butyl ether/heptane=2:1 gave 620 mg (87%) of the desired product, melting point 108-109° C. (methyl tert.-butyl ether/heptane).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (3RS)-3-Methyl-3,4-dihydroquinoxalin-2(1H)-one (4.86 g, 0.03 mol) dissolved in 50 ml of N,N-dimethylformamide, was alkylated with 4.2 ml (0.033 mol) of 3-methyl-2-buten-1-yl bromide (90%) in the presence of 4.60 g (0.033 mol) of pulverulent potassium carbonate. The reaction mixture was stirred at room temperature until reaction of the educt was complete. The solvent was then stripped off in vacuo, the residue was taken up in ethyl acetate and water, the phases were separated, the aqueous phase was extracted twice with ethyl acetate, and the combined organic extracts were washed twice with water. Drying over sodium sulfate, concentration in vacuo and crystallization from pentane gave 5.80 g (84%) of white crystalline product of melting point 92-93° C. water, the phases were separated the aqueous phase was extracted twice with ethyl acetate the combined organic extracts were washed twice with water Drying over sodium sulfate, concentration in vacuo and crystallization from pentane

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 3-Methyl-3,4-dihydroquinoxalin-2(1H)-one (0.5 g, 3.1 mmol) together with 0.35 ml (4.3 mmol) of methyl vinyl ketone and a catalytic amount of triethylamine were stirred for 20 hours at room temperature in 20 ml of anhydrous ethanol. Silica gel chromatography with methyl tert.-butyl ether/heptane=2:1 gave 620 mg (87%) of the desired product, melting point 108-109° C. (methyl tert.-butyl ether/heptane).

Conditions: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: (3RS)-3-Methyl-3,4-dihydroquinoxalin-2(1H)-one (4.86 g, 0.03 mol) dissolved in 50 ml of N,N-dimethylformamide, was alkylated with 4.2 ml (0.033 mol) of 3-methyl-2-buten-1-yl bromide (90%) in the presence of 4.60 g (0.033 mol) of pulverulent potassium carbonate. The reaction mixture was stirred at room temperature until reaction of the educt was complete. The solvent was then stripped off in vacuo, the residue was taken up in ethyl acetate and water, the phases were separated, the aqueous phase was extracted twice with ethyl acetate, and the combined organic extracts were washed twice with water. Drying over sodium sulfate, concentration in vacuo and crystallization from pentane gave 5.80 g (84%) of white crystalline product of melting point 92-93° C. water, the phases were separated the aqueous phase was extracted twice with ethyl acetate the combined organic extracts were washed twice with water Drying over sodium sulfate, concentration in vacuo and crystallization from pentane