ethyl 5-bromo-4-oxopentanoate

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

Procedure: To a solution of [6-(2-{3-[1,1-bis(Methylethyl)-2-methyl-1-silapropoxy]phenoxy}ethyl)(2-pyridyl)]methylamine (1.60 g, 4.0 mmol) in THF (30 ml) under argon at room temperature, was added tetrabutylammonium fluoride (4.4 ml, 4.4 mmol, 1M in THF). After stirring for 15 minutes, a solution of ethyl 5-bromo-4-oxopentanoate (0.98 g, 4.4 mmol) in THF (5 ml) was added. The mixture was stirred for an additional 3 hours. The solvent was removed under vacuum and the remaining residue was chromatographed over silica gel to yield 860 mg (56%) of Ethyl 5-(3-{2-[6-(methylamino)(2-pyridyl)]ethoxy}phenoxy)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.38 (m, 1H), 7.16 (t, 1H, J=8.2 Hz), 7.08 (t, 1H, J=7.9 Hz), 6.64 (m, 1H), 6.45 (m, 3H), 6.26 (dd, 1H, J=8.2, 2.3 Hz), 4.57 (s, 2H), 4.30 (t, 2H, J=6.8Hz), 4.13 (c, 2H, J=7.2 Hz), 3.07 (m, 2H), 2.91 (m, 5H), 2.63 (t, 2H, J=6.6 Hz), 1.24 (t, 3H, J=7.2 Hz). The mixture was stirred for an additional 3 hours The solvent was removed under vacuum the remaining residue was chromatographed over silica gel

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

Procedure: To a solution of [6-(2-{3-[1,1-bis(Methylethyl)-2-methyl-1-silapropylthio]phenoxy}ethyl)(2-pyridyl)]methylamine (1.34 g, 3.2 mmol) and THF (25 ml) under Argon, was added tetrabutylamonium floride (3.5 ml, 3.5 mmol, 1M in THF) at room temperature. After stirring for 15 minutes, a solution of ethyl 5-bromo-4-oxopentanoate (0.79 g, 3.5 mmol) in THF (5 ml) was added. The mixture was stirred for 3 h. The solvent was removed under vacuum and the remaining residue was chromatographed over silica gel to yield 830 mg (64%) of Ethyl 5-(3-{2-[6-(Methylamino)(2-pyridyl)]ethoxy }phenylthio)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.38 (dd, 1H, J=7.2, 8.0 Hz), 7.17 (t, 1H, J=8.0 Hz), 6.89 (m, 2H), 6.71 (m, 1H), 6.54 (d, 1H, J=8.0 Hz), 6.25 (d, 1H, J=4.0 Hz), 4.30 (t, 2H, J=6.8 Hz), 4.13 (c, 2H, J=7.2 Hz), 3.72 (s, 2H), 3.07 (t, 2H, J=6.8 Hz), 2.91(m, 5H), 2.59 (t, 2H, J=6.8 Hz), 1.24 (t, 3H, J=7.2 Hz). The mixture was stirred for 3 h The solvent was removed under vacuum the remaining residue was chromatographed over silica gel

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

Procedure: Tetrabutylammonium fluoride (7 ml, 7.0 mmol, 1M in THF) was added to a solution of 3-[1,1-bis(Methylethyl)-2-methyl-1-silapropylthio]phenyl acetate (1.53 g, 4.7 mmol) in THF (10 ml) under argon at room temperature. The reaction was stirred for 15 minutes followed by addition of a solution of ethyl 5-bromo-4-oxopentanoate (1.15 g, 5.17 mmol) in THF (5 ml). After stirring for 3 hours, the solvent was removed under vacuum and the crude product was chromatographed over silica gel to yield 920 mg (73%) of ethyl 5-(3-acetyloxyphenylthio)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.29 (t, 1H, J=8.0 Hz), 7.18 (dd, 1H, J=0.8, 7.6 Hz), 7.07 (t, 1H, J=1.6 Hz), 6.94 (dd, 1H, J=1.2, 8.0 Hz), 4.12 (c, 2H, J=7.2 Hz), 3.75 (s, 2H), 2.89 (t, 2H, J=6.8 Hz), 2.60 (t, 2H, J=6.8 Hz), 2.29 (s, 3H), 1.24 (t, 1H, J=7.2 Hz). After stirring for 3 hours the solvent was removed under vacuum the crude product was chromatographed over silica gel

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

Procedure: Tetrabutylammonium fluoride (7 ml, 7.0 mmol, 1M in THF) was added to a solution of 3-[1,1-bis(Methylethyl)-2-methyl-1-silapropylthio]phenyl acetate (1.53 g, 4.7 mmol) in THF (10 ml) under argon at room temperature. The reaction was stirred for 15 minutes followed by addition of a solution of ethyl 5-bromo-4-oxopentanoate (1.15 g, 5.17 mmol) in THF (5 ml). After stirring for 3 hours, the solvent was removed under vacuum and the crude product was chromatographed over silica gel to yield 920 mg (73%) of ethyl 5-(3-acetyloxyphenylthio)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.29 (t, 1H, J=8.0 Hz), 7.18 (dd, 1H, J=0.8, 7.6 Hz), 7.07 (t, 1H, J=1.6 Hz), 6.94 (dd, 1H, J=1.2, 8.0 Hz), 4.12 (c, 2H, J=7.2 Hz), 3.75 (s, 2H), 2.89 (t, 2H, J=6.8 Hz), 2.60 (t, 2H, J=6.8 Hz), 2.29 (s, 3H), 1.24 (t, 1H, J=7.2 Hz). After stirring for 3 hours the solvent was removed under vacuum the crude product was chromatographed over silica gel

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

Procedure: Bromine (22 g, 7.2 mL, 138.8 mmol) was added to a solution of ethyllevulinate (20 g, 138.8 mmol) in 250 mL EtOH at room temperature under a flow of N2 for a period of 0.5 h. After the addition was complete, the reaction mixture was stirred at room temperature for another 0.5 h, and then refluxed for 1.5 h. The reaction mixture was cooled to room temperature and concentrated in vacuo. The residue was taken into ether, washed with saturated aqueous NaHCO3 (3×50 mL), water, brine, dried (MgSO4) and concentrated to give 20.3 g of K-13 as a dark brown oil. This was used without purification for next step. 1H NMR. After the addition refluxed for 1.5 h The reaction mixture was cooled to room temperature concentrated in vacuo washed with saturated aqueous NaHCO3 (3×50 mL), water, brine dried (MgSO4) concentrated to give 20.3 g of K-13 as a dark brown oil This was used without purification for next step

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

Procedure: Bromine (22 g, 7.2 mL, 138.8 mmol) was added to a solution of ethyllevulinate (20 g, 138.8 mmol) in 250 mL EtOH at room temperature under a flow of N2 for a period of 0.5 h. After the addition was complete, the reaction mixture was stirred at room temperature for another 0.5 h, and then refluxed for 1.5 h. The reaction mixture was cooled to room temperature and concentrated in vacuo. The residue was taken into ether, washed with saturated aqueous NaHCO3 (3×50 mL), water, brine, dried (MgSO4) and concentrated to give 20.3 g of K-13 as a dark brown oil. This was used without purification for next step. 1H NMR. After the addition refluxed for 1.5 h The reaction mixture was cooled to room temperature concentrated in vacuo washed with saturated aqueous NaHCO3 (3×50 mL), water, brine dried (MgSO4) concentrated to give 20.3 g of K-13 as a dark brown oil This was used without purification for next step

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

Procedure: Bromine (22 g, 7.2 mL, 138.8 mmol) was added to a solution of ethyllevulinate (20 g, 138.8 mmol) in 250 mL EtOH at room temperature under a flow of N2 for a period of 0.5 h. After the addition was complete, the reaction mixture was stirred at room temperature for another 0.5 h, and then refluxed for 1.5 h. The reaction mixture was cooled to room temperature and concentrated in vacuo. The residue was taken into ether, washed with saturated aqueous NaHCO3 (3×50 mL), water, brine, dried (MgSO4) and concentrated to give 20.3 g of K-13 as a dark brown oil. This was used without purification for next step. 1H NMR. After the addition refluxed for 1.5 h The reaction mixture was cooled to room temperature concentrated in vacuo washed with saturated aqueous NaHCO3 (3×50 mL), water, brine dried (MgSO4) concentrated to give 20.3 g of K-13 as a dark brown oil This was used without purification for next step

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

Procedure: To a solution of [6-(2-{3-[1,1-bis(Methylethyl)-2-methyl-1-silapropoxy]phenoxy}ethyl)(2-pyridyl)]methylamine (1.60 g, 4.0 mmol) in THF (30 ml) under argon at room temperature, was added tetrabutylammonium fluoride (4.4 ml, 4.4 mmol, 1M in THF). After stirring for 15 minutes, a solution of ethyl 5-bromo-4-oxopentanoate (0.98 g, 4.4 mmol) in THF (5 ml) was added. The mixture was stirred for an additional 3 hours. The solvent was removed under vacuum and the remaining residue was chromatographed over silica gel to yield 860 mg (56%) of Ethyl 5-(3-{2-[6-(methylamino)(2-pyridyl)]ethoxy}phenoxy)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.38 (m, 1H), 7.16 (t, 1H, J=8.2 Hz), 7.08 (t, 1H, J=7.9 Hz), 6.64 (m, 1H), 6.45 (m, 3H), 6.26 (dd, 1H, J=8.2, 2.3 Hz), 4.57 (s, 2H), 4.30 (t, 2H, J=6.8Hz), 4.13 (c, 2H, J=7.2 Hz), 3.07 (m, 2H), 2.91 (m, 5H), 2.63 (t, 2H, J=6.6 Hz), 1.24 (t, 3H, J=7.2 Hz). The mixture was stirred for an additional 3 hours The solvent was removed under vacuum the remaining residue was chromatographed over silica gel

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

Procedure: To a solution of [6-(2-{3-[1,1-bis(Methylethyl)-2-methyl-1-silapropylthio]phenoxy}ethyl)(2-pyridyl)]methylamine (1.34 g, 3.2 mmol) and THF (25 ml) under Argon, was added tetrabutylamonium floride (3.5 ml, 3.5 mmol, 1M in THF) at room temperature. After stirring for 15 minutes, a solution of ethyl 5-bromo-4-oxopentanoate (0.79 g, 3.5 mmol) in THF (5 ml) was added. The mixture was stirred for 3 h. The solvent was removed under vacuum and the remaining residue was chromatographed over silica gel to yield 830 mg (64%) of Ethyl 5-(3-{2-[6-(Methylamino)(2-pyridyl)]ethoxy }phenylthio)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.38 (dd, 1H, J=7.2, 8.0 Hz), 7.17 (t, 1H, J=8.0 Hz), 6.89 (m, 2H), 6.71 (m, 1H), 6.54 (d, 1H, J=8.0 Hz), 6.25 (d, 1H, J=4.0 Hz), 4.30 (t, 2H, J=6.8 Hz), 4.13 (c, 2H, J=7.2 Hz), 3.72 (s, 2H), 3.07 (t, 2H, J=6.8 Hz), 2.91(m, 5H), 2.59 (t, 2H, J=6.8 Hz), 1.24 (t, 3H, J=7.2 Hz). The mixture was stirred for 3 h The solvent was removed under vacuum the remaining residue was chromatographed over silica gel

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

Procedure: Tetrabutylammonium fluoride (7 ml, 7.0 mmol, 1M in THF) was added to a solution of 3-[1,1-bis(Methylethyl)-2-methyl-1-silapropylthio]phenyl acetate (1.53 g, 4.7 mmol) in THF (10 ml) under argon at room temperature. The reaction was stirred for 15 minutes followed by addition of a solution of ethyl 5-bromo-4-oxopentanoate (1.15 g, 5.17 mmol) in THF (5 ml). After stirring for 3 hours, the solvent was removed under vacuum and the crude product was chromatographed over silica gel to yield 920 mg (73%) of ethyl 5-(3-acetyloxyphenylthio)-4-oxopentanoate. NMR 1H Cl3CD δ: 7.29 (t, 1H, J=8.0 Hz), 7.18 (dd, 1H, J=0.8, 7.6 Hz), 7.07 (t, 1H, J=1.6 Hz), 6.94 (dd, 1H, J=1.2, 8.0 Hz), 4.12 (c, 2H, J=7.2 Hz), 3.75 (s, 2H), 2.89 (t, 2H, J=6.8 Hz), 2.60 (t, 2H, J=6.8 Hz), 2.29 (s, 3H), 1.24 (t, 1H, J=7.2 Hz). After stirring for 3 hours the solvent was removed under vacuum the crude product was chromatographed over silica gel