benzyl 4-fluorobenzoate

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: To a stirring solution of ethyl-N-hydroxyacetimidate (3.79 g, 36.8 mmol) in anhydrous DMF (150 mL) under Ar was added tBuOK (4.09 g, 36.4 mmol) all at once. After 40 min benzyl-4-fluorobenzoate 17 (7.63 g, 17.9 mmol) was added and the reaction was stirred at room temperature. After 4 h the reaction was diluted with H2O (500 mL), extracted with EtOAc (4×100 mL), and the combined organics were washed with H2O (2×100 mL), dried over Na2SO4, filtered, and concentrated. Flash chromatographic purification over silica (5-10% gradient EtOAc in hexanes) afforded 19 as a clear syrup (6.02 g, 58%). 1H-NMR (500 MHz, CDCl3) δ 1.36 (t, J=7.0 Hz, 3H), 2.12 (s, 3H), 4.20 (q, J=7.0 Hz, 2H), 5.34 (s, 2H), 7.15-7.19 (m, 2H), 7.31-7.35 (m, 2H), 7.36-7.41 (m, 2H), 7.42-7.36 (m, 2H), 8.00-8.14 (m, 2H); 13C-NMR (125 MHz, CDCl3) δ 14.3, 14.4, 63.1, 66.4, 113.4, 122.9, 128.1, 128.1, 128.6, 131.5, 136.3, 163.5, 166.3, 166.4; GC-MS 228 m/z [M-85]+, benzyl-4-hydroxybenzoate C14H12O3 requires 228. extracted with EtOAc (4×100 mL) the combined organics were washed with H2O (2×100 mL) dried over Na2SO4 filtered concentrated Flash chromatographic purification over silica (5-10% gradient EtOAc in hexanes)

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

Procedure: Benzyl alcohol (4.05 mL, 39.1 mmol) was added slowly to a stirring solution of 4-fluorobenzoic acid (5.00 g, 35.7 mmol), 4-(dimethylamino)pyridine (432 mg, 3.53 mmol), and 1,3-dicyclohexylcarbodiimide (8.15 g, 39.5 mmol) in anhydrous CH2Cl2 at room temperature under an argon atmosphere. After 18 h the reaction was worked up according to procedures as outlined for the synthesis of 16. Flash chromatographic purification over silica (10% EtOAc in hexanes) afforded 17 as a clear, colorless liquid (7.75 g, 94%). 1H-NMR (500 MHz, CDCl3) δ 5.35 (s, 2H), 7.06-14 (m, 2H), 7.32-7.41 (m, 3H), 7.41-7.47 (m, 2H), 8.06-8.12 (m, 2H); 13C-NMR (125 MHz, CDCl3) δ 66.84, 115.5 (d, JC-F=22.0 Hz), 126.4 (d, JC-F=2.9 Hz), 128.2, 128.3, 128.6, 132.3 (d, JC-F=9.6 Hz), 135.9, 165.5, 165.8 (d, JC-F=253 Hz); GC-MS 230 m/z [M]+, C14H11OF2 requires 230. Flash chromatographic purification over silica (10% EtOAc in hexanes)

Conditions: temp:0.00; pressure:0.00; stir:

Conditions: temp:0.00; pressure:0.00; stir:

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

Procedure: A mixture of 4-fluorobenzoic acid (4.9 g, 35.3 mmol), benzyl bromide (3.8 mL, 31.7 mmol), and cesium carbonate (17.2 g, 53 mmol) in DMF (50 mL) at room temperature was stirred for 24 hours, diluted with water, and extracted with diethyl ether. The combined extracts were washed with brine, dried (MgSO4), filtered, and concentrated to provide the desired product. MS (DCI) m/e 248 (M+H)+. extracted with diethyl ether The combined extracts were washed with brine dried (MgSO4) filtered concentrated

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

Procedure: A mixture of 4-fluorobenzoic acid (4.9 g, 35.3 mmol), benzyl bromide (3.8 mL, 31.7 mmol), and cesium carbonate (17.2 g, 53 mmol) in DMF (50 mL) at room temperature was stirred for 24 hours, diluted with water, and extracted with diethyl ether. The combined extracts were washed with brine, dried (MgSO4), filtered, and concentrated to provide the desired product. MS (DCI) m/e 248 (M+H)+. extracted with diethyl ether The combined extracts were washed with brine dried (MgSO4) filtered concentrated

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

Procedure: A mixture of 4-fluorobenzoic acid (5.0 g, 36 mmol) in CH2Cl2 was treated with oxallyl chloride (6.2 mL, 72 mmol) and a catalytic amount of DMF. The mixture was stirred until the evolution of gas stopped and then concentrated under reduced pressure. The residue was re-dissolved in CH2Cl2 and the solution was added in a drop wise manner to a mixture of benzyl alcohol (3.9 g, 36 mmol), diisopropyl ethyl amine (12.6 mL, 72 mmol) and a catalytic amount of DMAP in CH2Cl2. After stirring overnight the reaction mixture was concentrated and the residue was passed through a silica gel plug with 10% Et2O in hexanes. The intermediate 4-fluoro benzoic acid benzyl ester obtained from the above procedure was dissolved in DMSO (25 mL). Followed addition of piperazine (14 g, and the mixture was heated in a sealed tube at 120° C. overnight. Next morning the reaction mixture was partitioned between EtOAc and water. The water layer was basified to pH 12 with solid NaOH, extracted once again with EtOAc and the combined EtOAc layer was dried over Na2SO4, filtered and concentrated to afford the product (8.5 g, Yield: 80%). HRMS m/z calcd for C18H20N2O2 [M+H]: 297.1598. Found: 297.1597. concentrated under reduced pressure The residue was re-dissolved in CH2Cl2 After stirring overnight the reaction mixture was concentrated

Conditions: temp:120.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A solution of 4-fluoro-benzoic acid benzyl ester (720 mg, 3.13 mmol) in dioxane (10 mL) was treated with diisopropyl ethyl amine (1.64 mL, 9.39 mmol), ethyl isonipecotate (1.54 g, 9.39 mmol), a catalytic amount of DMAP and heated in a sealed tube at 120° C. for approximately 18 h. The mixture was then cooled, followed addition of another portion of ethyl isonipecotate (1.54 g, 9.39 mmol) and the mixture was reheated at 120° C. After stirring for one more day the mixture was cooled, another portion of ethyl isonipecotate (1.54 g, 9.39 mmol) was added and the mixture was heated again at 120° C. and stirred for an additional 3 day period. The mixture was then cooled and partitioned between EtOAc and water. The EtOAc layer was collected, dried over Na2SO4, filtered and concentrated and the residue was chromatographed with a silica gel column and 0-50% Et2O in hexanes gradient. The intermediate isolated from this operation was dissolved in EtOH (15 mL). Followed addition of 10% Pd/C (15 mg) and the mixture was hydrogenated under one atmosphere of hydrogen for 3.5 h. Followed filtration, the solids were washed with EtOH and the combined organic layer was evaporated to afford the product (200 mg, Yield 10%). HRMS m/z calcd for C15H19NO4 [M+H]+: 278.1387. Found: 278.1387. The mixture was then cooled was reheated at 120° C was cooled stirred for an additional 3 day period The mixture was then cooled partitioned between EtOAc and water The EtOAc layer was collected dried over Na2SO4 filtered concentrated the residue was chromatographed with a silica gel column and 0-50% Et2O in hexanes gradient The intermediate isolated from this operation Followed filtration the solids were washed with EtOH the combined organic layer was evaporated

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

Procedure: A mixture of 4-fluorobenzoic acid (1.0 g, 7.13 mmol) in Et2O was treated with oxallyl chloride (760 mL, 8.55 mmol) and a catalytic amount of DMF. The mixture was then stirred until the evolution of gas stopped. The mixture was then filtered and concentrated under reduced pressure. The residue was dissolved in a small volume of CH2Cl2 and the solution was added in a drop wise manner to a mixture of benzyl alcohol (770 mg, 7.13 mmol), diisopropyl ethyl amine (2.49 mL, 14.3 mmol) and a catalytic amount of DMAP in CH2Cl2 (20 mL). After stirring overnight the reaction mixture was concentrated and the residue was passed through a silica gel plug with 10% Et2O in hexanes to afford the product (991 mg, Yield: 60%). FIRMS m/z calcd for C14H11O2F [M+H]+: 230.0743. Found: 230.0742. The mixture was then filtered concentrated under reduced pressure The residue was dissolved in a small volume of CH2Cl2 After stirring overnight the reaction mixture was concentrated