(2,6-dioxo-3H-pyran-4-yl) acetate

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

Procedure: 65.7 g (0.705 mol) of aniline are added to a stirred suspension of 120 g (0.705 mol) of 4-acetyloxy-2H,3H-pyran-2,6-dione in 250 ml of acetic acid. The reaction medium is stirred for 1 h at room temperature and is then diluted by adding 500 ml of water. The solid is drained, washed with water and dried in an oven (50° C.) for 24 h. 150 g (81%) of the expected compound, melting point 125°-126° C., are obtained. is then diluted washed with water dried in an oven (50° C.) for 24 h

Conditions: temp:35.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: 2-bromo-5-methoxyaniline (6 g; 29.7 mmol) was dissolved in acetic acid (33.7 ml) and 2,6-dioxo-3,6-dihydro-2H-pyran-4-yl acetate (4.59 g; 27.0 mmol) was added. The reaction was stirred at 35° C. in a sand bath for 2 h. The reaction was quenched by adding ice-water (250 ml), the precipitate formed was filtered, washed with water and dried over phosphorus pentoxide under reduced pressure to afford 8.98 g (71%) of 1-(2-bromo-5-methoxyphenylamino)-1,5-dioxohex-3-en-3-yl acetate as a grey solid. The reaction was quenched by adding ice-water (250 ml) the precipitate formed was filtered washed with water dried over phosphorus pentoxide under reduced pressure

Conditions: temp:35.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Acetone-1,3-dicarboxylic acid (30 g; 205 mmol) was added in portions to acetic anhydride (55 ml; 582 mmol) and the mixture was stirred at 35° C. for 24 h. The reaction mixture was diluted with toluene (200 ml) and kept at 4° C. for 3 h. A precipitate was isolated by filtration, washed with toluene and dried under reduced pressure to furnish 18.91 g (54%) of 2,6-dioxo-3,6-dihydro-2H-pyran-4-yl acetate as a light brown solid. kept at 4° C. for 3 h A precipitate was isolated by filtration washed with toluene dried under reduced pressure

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

Procedure: 65.7 g (0.705 mol) of aniline are added to a stirred suspension of 120 g (0.705 mol) of 4-acetyloxy-2H,3H-pyran-2,6-dione in 250 ml of acetic acid. The reaction medium is stirred for 1 h at room temperature and is then diluted by adding 500 ml of water. The solid is drained, washed with water and dried in an oven (50° C.) for 24 h. 150 g (81%) of the expected compound, melting point 125°-126° C., are obtained. is then diluted washed with water dried in an oven (50° C.) for 24 h