4-溴-5-乙氧基-2(5H)-呋喃酮

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents are removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents are removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.00; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: A mixture of 4-bromo-5-ethoxy-5H-furan-2-one (2.07 g, 10.0 mmol) and sodium azide (0.66 g, 10.2 mmol) in dimethylformamide (10 mL) was stirred at room temperature under nitrogen for 24 h. The reaction was diluted with ethyl acetate, was washed with 0° C. water and with brine, was dried over sodium sulfate, and was evaporated. Purification by flash chromatography (SiO2) eluted with 1:9 ethyl acetate:hexanes afforded 4-azido-5-ethoxy-5H-furan-2-one (1.04 g, 62% yield) as a pale yellow oil. 1H-NMR (500 MHz, CDCl3) δ 5.83 (s, 1H), 5.63 (s, 1H), 3.99 (m, 1H), 3.88 (m, 1H), 1.35 (t, J=7.1 Hz, 3H) ppm. was washed with 0° C. water with brine, was dried over sodium sulfate was evaporated Purification by flash chromatography (SiO2) eluted with 1:9 ethyl acetate

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure was carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. was added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction was stirred 1 h at 0° C., then 2 h at room temperature. The solvents were removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents were removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure was carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. was added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction was stirred 1 h at 0° C., then 2 h at room temperature. The solvents were removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents were removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure was carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. was added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction was stirred 1 h at 0° C., then 2 h at room temperature. The solvents were removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents were removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents are removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents are removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.

反应条件: temp:0.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

实验步骤: This procedure may be carried out in a manner similar to that described by C. Escobar, et al., Ann. Quim. (1971), 67, 43-57.). To a solution of 5-ethoxy-5H-furan-2-one (II, R1=Et) (10.0 g, 78.0 mmol) in carbon tetrachloride (50 mL) at 0° C. is added over 0.5 h a solution of bromine (4.05 mL, 78.2 mmol) in carbon tetrachloride (25 mL). The reaction is stirred 1 h at 0° C., then 2 h at room temperature. The solvents are removed under reduced pressure and the residue was short-path distilled at pump vacuum (about 0.5 mm). The fraction collected at 100° C.-120° C. provided 4-bromo-5-ethoxy-5H-furan-2-one (13.2 g, 82% yield) as a yellow oil. 1H-NMR (500 MHz, CDCl3) δ 6.24 (s, 1H), 5.63 (s, 1H), 3.71 (m, 1H), 3.63 (m, 1H), 1.14 (t, J=7.1 Hz, 3H) ppm. 2 h at room temperature The solvents are removed under reduced pressure the residue was short-path distilled at pump vacuum (about 0.5 mm) The fraction collected at 100° C.-120° C.