1-(oxolan-3-yl)propan-1-one

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

Procedure: To a stirred solution of N-methoxy-N-methyltetrahydrofuran-3-carboxamide (4.1 g) in THF (40 ml) was added ethylmagnesium bromide (3 M in ether, 13.0 ml) at 0° C. The reaction mixture was then slowly warmed to room temperature and stirred for 4 h. The reaction mixture was quenched with saturated 1 M HCl (10 ml), and extracted with EtOAc. The extract was washed with brine, dried over Na2SO4 and concentrated in vacuo. The mixture was purified by silica gel column chromatography (hexane/EtOAc) to give the title compound (3.0 g) as a pale yellow liquid. The reaction mixture was quenched with saturated 1 M HCl (10 ml) extracted with EtOAc The extract was washed with brine dried over Na2SO4 concentrated in vacuo The mixture was purified by silica gel column chromatography (hexane/EtOAc)

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

Procedure: To a stirred solution of N-methoxy-N-methyltetrahydrofuran-3-carboxamide (4.1 g) in THF (40 ml) was added ethylmagnesium bromide (3 M in ether, 13.0 ml) at 0° C. The reaction mixture was then slowly warmed to room temperature and stirred for 4 h. The reaction mixture was quenched with saturated 1 M HCl (10 ml), and extracted with EtOAc. The extract was washed with brine, dried over Na2SO4 and concentrated in vacuo. The mixture was purified by silica gel column chromatography (hexane/EtOAc) to give the title compound (3.0 g) as a pale yellow liquid. The reaction mixture was quenched with saturated 1 M HCl (10 ml) extracted with EtOAc The extract was washed with brine dried over Na2SO4 concentrated in vacuo The mixture was purified by silica gel column chromatography (hexane/EtOAc)

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

Procedure: Operations similar to Production Example 1-(1) were conducted using 1-tetrahydro-3-furanyl-1-propanone in place of 3-methyl-2-butanone, and successively those of Production Example 1-(2) were conducted using 2-amino-5-nitropyridine. The resulting solid was suspended in ethyl acetate, washed with saturated aqueous sodium hydrogencarbonate solution and purified by silica gel column chromatography (hexane/ethyl acetate=2/1) to provide the title compound as yellow crystals. washed with saturated aqueous sodium hydrogencarbonate solution purified by silica gel column chromatography (hexane/ethyl acetate=2/1)

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

Procedure: Into a 100-mL round-bottom flask, was placed 1-(tetrahydrofuran-3-yl)propan-1-one (compound 263.2, 2.5 g, 19.5 mmol), sodium methoxide (1.4 g, 25.9 mmol) and ethyl formate (20 mL). The mixture was stirred overnight at room temperature, then concentrated under reduced pressure. The residue was purified by a silica gel column chromatography with ethyl acetate/petroleum ether (1:20 to 1:5) as eluent to obtain the title compound as a yellow solid (2.0 g, 66%). Into a 100-mL round-bottom flask, was placed concentrated under reduced pressure The residue was purified by a silica gel column chromatography with ethyl acetate/petroleum ether (1:20 to 1:5) as eluent

Conditions: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: Into a 250-mL 3-neck round-bottom flask, was placed a solution of N-methoxy-N-methyltetrahydrofuran-3-carboxamide (compound 263.1, 6.71 g, 42.2 mmol) in tetrahydrofuran (100 mL). The system was purged with nitrogen, then cooled to 0° C. Ethylmagnesium bromide (3M in diethyl ether, 17 mL, 51 mmol) was added drop-wise at 0° C. over 30 min. The resulting solution was stirred overnight at 40° C., then cooled and carefully quenched with aqueous HCl (1M, 10 mL). The resulting mixture was concentrated under reduced pressure and the residue was diluted with water (10 mL). The mixture was extracted with ethyl acetate (3×30 mL) and the combined organic extracts were washed with brine (2×10 mL), dried (Na2SO4), filtered and concentrated under reduced pressure. Obtained the title compound as a light yellow oil (4.5 g, 83%). Into a 250-mL 3-neck round-bottom flask, was placed The system was purged with nitrogen cooled carefully quenched with aqueous HCl (1M, 10 mL) The resulting mixture was concentrated under reduced pressure the residue was diluted with water (10 mL) The mixture was extracted with ethyl acetate (3×30 mL) the combined organic extracts were washed with brine (2×10 mL) dried (Na2SO4) filtered concentrated under reduced pressure