ethyl 2-(2,3-dihydrofuran-4-yl)-2-oxoacetate

Conditions: temp:7.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (100 g) was dissolved in dichloromethane (500 ml). Ethanol (150 ml) was added to reaction mass and then reaction mass was cooled to 5 to 10° C. N-bromosuccinimide (115 g) was added lot wise by maintaining temp below 10° C. Reaction mass was then stirred at 20-30° C. till completion of reaction. Reaction mass was washed with sodium bicarbonate solution (8%, 3×400 ml). Sodium sulphite solution (15%, 1700 ml) was charged to dichloromethane layer. Reaction mass was stirred for 8 hrs at 25-35° C. Organic and aqueous layer separated. Dichloromethane layer was washed with water (2×340 ml). Dichloromethane layer was then concentrated to residue to get Ethyl-2-(2-ethoxytetrahydrofuran-3-yl)-2-oxoacetate (Yield 114 g) reaction mass by maintaining temp below 10° C Reaction mass Reaction mass was washed with sodium bicarbonate solution (8%, 3×400 ml) Sodium sulphite solution (15%, 1700 ml) was charged to dichloromethane layer Reaction mass was stirred for 8 hrs at 25-35° C Organic and aqueous layer separated Dichloromethane layer was washed with water (2×340 ml) Dichloromethane layer was then concentrated to residue

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (10 g) was dissolved in Ethanol (50 ml) and Methane sulphoic acid (0.1 ml) was added to it. The reaction mass was stirred at 40-50° C. for 12 hrs. Reaction mass was concentrated to residue under vacuum. Residue was dissolved in dichloromethane (50 ml) and washed with water (50 ml). Reaction mass was concentrated to residue to get ethyl-2-(2-ethoxytetrahydrofuran-3-yl)-2-oxoacetate (Yield 9.2 g). Reaction mass was concentrated to residue under vacuum Residue was dissolved in dichloromethane (50 ml) washed with water (50 ml) Reaction mass was concentrated to residue

Conditions: temp:45.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (10 g) was dissolved in Ethanol (50 ml) and Dichloromethane (50 ml). The reaction mass was stirred at 40-50° C. for 12 hrs. Reaction mass was concentrated to residue under vacuum at 40° C. Residue was dissolved in dichloromethane (50 ml) and washed with water (50 ml). Reaction mass was concentrated to residue to get ethyl-2-(2-ethoxytetrahydrofuran-3-yl)-2-oxoacetate (Yield 9.9 g). Reaction mass was concentrated to residue under vacuum at 40° C Residue was dissolved in dichloromethane (50 ml) washed with water (50 ml) Reaction mass was concentrated to residue

Conditions: temp:7.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (100 g) was dissolved in dichloromethane (500 ml) and Ethanol (150 ml) was added to reaction mass and then reaction mass was cooled to 5 to 10° C. N-bromosuccinimide (115 g) was added lot wise by maintaining temp below 10° C. Reaction mass was then stirred at 20-30° C. till completion of reaction. Reaction mass was washed with sodium bicarbonate solution (8%, 3×400 ml). Reaction mass was then concentrated to residue to get Ethyl-2-(3-bromo-2-ethoxytetrahydrofuran-3-yl)-2-oxoacetate (Yield 170 g). reaction mass by maintaining temp below 10° C Reaction mass Reaction mass was washed with sodium bicarbonate solution (8%, 3×400 ml) Reaction mass was then concentrated to residue

Conditions: temp:-2.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (45 g) was dissolved in tetrahydrofuran (225 ml) and Methanol (45 ml). The reaction mass was cooled to −5 to 0° C. N-bromosuccinimide (47 g) was added lot wise by maintaining temp below 0° C. Reaction mass was then stirred at 20-25° C. for 12 hrs. Reaction mass was concentrated to residue under vacuum at 40° C. Residue was dissolved in Ethyl acetate (450 ml) and washed with sodium sulphite solution (10%, 2×135 ml). Reaction mass was then concentrated to residue to get ethyl-2-(3-bromo-2-methoxytetrahydrofuran-3-yl)-2-oxoacetate (Yield 63 g). by maintaining temp below 0° C Reaction mass Reaction mass was concentrated to residue under vacuum at 40° C Residue was dissolved in Ethyl acetate (450 ml) washed with sodium sulphite solution (10%, 2×135 ml) Reaction mass was then concentrated to residue

Conditions: temp:7.51; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Ethyl-2-(4,5-dihydrofuran-3-yl)-2-oxoacetate (VI, 100 g) was dissolved in dichloromethane (500 ml) and Ethanol (150 mL) was added. The reaction mass was cooled to 5 to 10° C. N-bromosuccinimide (115 g) was added lot wise by maintaining temp below 10° C. Reaction mass was then stirred at 20-30° C. till completion of reaction. Reaction mass was washed with sodium bicarbonate solution (2%, 3×400 mL) and the organic layer was used for the next step. by maintaining temp below 10° C Reaction mass Reaction mass was washed with sodium bicarbonate solution (2%, 3×400 mL)