tert-butyl N-(2-amino-5-fluorophenyl)carbamate

Conditions: temp:63.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: tert-Butyl 2-amino-5-fluorophenylcarbamate (30.5 g), toluene (300 mL), triethylamine (34.1 g) and ethyl 3,3,3-trifluoro-2-oxopropanoate (69.5 g) were charged into a reactor and warmed to 63° C. for 14 h, then cooled to ambient temperature. A 5% aq. NaOH solution (390 mL) was added, stirred, settled, and then the lower layer was separated. The organic layer extracted with another charge of 5% aq. NaOH solution (130 mL). To the combined aq. NaOH layers was charged 2-methyl-THF (390 mL) and concentrated HCl (77.9 g), keeping the temperature below 25° C. The layers were mixed, settled and separated. The acidic aq. layer was separated, and the organic layer was extracted with water (260 mL). The layers were separated and the organic layer was filtered to remove insoluble material. The product was isolated by switching the solvent to toluene by distillation (a total of 1.1 L toluene used). The final slurry was briefly warmed to 80° C. and then cooled −10° C. and filtered. The cake was washed with toluene (128 mL), then dried under vacuum at 60° C. To the crude solid was added ethanol (350 mL) and warmed to reflux to dissolve the solids. The solution was cooled to room temperature and concentrated to approximately 270 mL total volume by distillation. Water (250 g) was then added over 30 min. The slurry was filtered and washed with cold (1:1) ethanol: water (2×60 mL). The solid was dried under vacuum at 60° C. (26.1 g, 83% yield). cooled to ambient temperature the lower layer was separated The organic layer extracted with another charge of 5% aq. NaOH solution (130 mL) To the combined aq. NaOH layers was charged 2-methyl-THF (390 mL) and concentrated HCl (77.9 g) the temperature below 25° C The layers were mixed separated The acidic aq. layer was separated the organic layer was extracted with water (260 mL) The layers were separated the organic layer was filtered to remove insoluble material The product was isolated by distillation (a total of 1.1 L toluene The final slurry was briefly warmed to 80° C. cooled −10° C. filtered The cake was washed with toluene (128 mL) dried under vacuum at 60° C To the crude solid was added ethanol (350 mL) warmed to reflux to dissolve the solids The solution was cooled to room temperature concentrated to approximately 270 mL total volume by distillation Water (250 g) was then added over 30 min The slurry was filtered washed with cold (1:1) ethanol The solid was dried under vacuum at 60° C. (26.1 g, 83% yield)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A slurry of Raney nickel (W.R. Grace 2800, 30.6 g calc. dry weight) was added to a 2-gallon Parr stirred pressure reactor containing THF (3 L). tert-Butyl 5-fluoro-2-nitrophenylcarbamate (102 g) was added. The vessel was sealed, purged, and pressurized to about 30 psig with hydrogen. The mixture was vigorously stirred at ambient temperature (20° C.) while hydrogen was supplied on-demand at 30 psig. After stirring for 16 h, the vessel was vented and purged with nitrogen. The product mixture was filtered to remove the catalyst using THF (1 L) to rinse the reactor and catalyst cake. The solvent was removed under vacuum. Heptane (510 mL) was added and the mixture was heated to 50° C. for 1 h, then cooled slowly to 0° C. The solids were filtered and washed with cold heptanes (100 mL) and dried under vacuum at 50° C. (76.7 g of product isolated, 87% pure, 73% yield). The vessel was sealed purged The mixture was vigorously stirred at ambient temperature (20° C.) while hydrogen After stirring for 16 h purged with nitrogen The product mixture was filtered to remove the catalyst to rinse the reactor and catalyst cake The solvent was removed under vacuum Heptane (510 mL) was added cooled slowly to 0° C The solids were filtered washed with cold heptanes (100 mL) dried under vacuum at 50° C.

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (4.0 g, 17.68 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Talde, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (50 mL) was added cyclohexanecarbaldehyde (1.98 g, 2.13 mL, 17.68 mmol, 1.0 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (R)-methoxy-phenyl-acetic acid (2.94 g, 17.68 mmol, 1.0 equiv; [CAS RN 3966-32-3]) and isocyanomethyl-benzene (2.07 g, 2.15 mL, 17.68 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (18 mL) was added and the reaction mixture stirred at rt overnight. The solution was concentrated by evaporation under reduced pressure, the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 and the aqueous layer extracted with dichloromethane. The combined organic phases were dried over MgSO4 and concentrated by evaporation under reduced pressure. The crude material was purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate to give 5.9 g (69%) of the title compound. 1H NMR (300 MHz, CDCl3): δ 1.25 (t, J=7.5 Hz, 3H), 1.41 (t, J=7.5 Hz, 3H), 3.43 (s, 3H), 4.01 (q, J=7.5 Hz, 2H), 4.26 (q, J=7.5 Hz, 2H), 5.05 (s, 1H), 6.43-6.48 (m, 2H). MS (ISP): 486.4 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight The solution was concentrated by evaporation under reduced pressure the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 the aqueous layer extracted with dichloromethane The combined organic phases were dried over MgSO4 concentrated by evaporation under reduced pressure The crude material was purified by silica column chromatography eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (4.0 g, 17.68 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Talde, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (50 mL) was added cyclohexanecarbaldehyde (1.98 g, 2.13 mL, 17.68 mmol, 1.0 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (R)-methoxy-phenyl-acetic acid (2.94 g, 17.68 mmol, 1.0 equiv; [CAS RN 3966-32-3]) and isocyanomethyl-benzene (2.07 g, 2.15 mL, 17.68 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (18 mL) was added and the reaction mixture stirred at rt overnight. The solution was concentrated by evaporation under reduced pressure, the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 and the aqueous layer extracted with dichloromethane. The combined organic phases were dried over MgSO4 and concentrated by evaporation under reduced pressure. The crude material was purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate to give 5.9 g (69%) of the title compound. 1H NMR (300 MHz, CDCl3): δ 1.25 (t, J=7.5 Hz, 3H), 1.41 (t, J=7.5 Hz, 3H), 3.43 (s, 3H), 4.01 (q, J=7.5 Hz, 2H), 4.26 (q, J=7.5 Hz, 2H), 5.05 (s, 1H), 6.43-6.48 (m, 2H). MS (ISP): 486.4 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight The solution was concentrated by evaporation under reduced pressure the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 the aqueous layer extracted with dichloromethane The combined organic phases were dried over MgSO4 concentrated by evaporation under reduced pressure The crude material was purified by silica column chromatography eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate

Conditions: temp:63.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: tert-Butyl 2-amino-5-fluorophenylcarbamate (30.5 g), toluene (300 mL), triethylamine (34.1 g) and ethyl 3,3,3-trifluoro-2-oxopropanoate (69.5 g) were charged into a reactor and warmed to 63° C. for 14 h, then cooled to ambient temperature. A 5% aq. NaOH solution (390 mL) was added, stirred, settled, and then the lower layer was separated. The organic layer extracted with another charge of 5% aq. NaOH solution (130 mL). To the combined aq. NaOH layers was charged 2-methyl-THF (390 mL) and concentrated HCl (77.9 g), keeping the temperature below 25° C. The layers were mixed, settled and separated. The acidic aq. layer was separated, and the organic layer was extracted with water (260 mL). The layers were separated and the organic layer was filtered to remove insoluble material. The product was isolated by switching the solvent to toluene by distillation (a total of 1.1 L toluene used). The final slurry was briefly warmed to 80° C. and then cooled −10° C. and filtered. The cake was washed with toluene (128 mL), then dried under vacuum at 60° C. To the crude solid was added ethanol (350 mL) and warmed to reflux to dissolve the solids. The solution was cooled to room temperature and concentrated to approximately 270 mL total volume by distillation. Water (250 g) was then added over 30 min. The slurry was filtered and washed with cold (1:1) ethanol: water (2×60 mL). The solid was dried under vacuum at 60° C. (26.1 g, 83% yield). cooled to ambient temperature the lower layer was separated The organic layer extracted with another charge of 5% aq. NaOH solution (130 mL) To the combined aq. NaOH layers was charged 2-methyl-THF (390 mL) and concentrated HCl (77.9 g) the temperature below 25° C The layers were mixed separated The acidic aq. layer was separated the organic layer was extracted with water (260 mL) The layers were separated the organic layer was filtered to remove insoluble material The product was isolated by distillation (a total of 1.1 L toluene The final slurry was briefly warmed to 80° C. cooled −10° C. filtered The cake was washed with toluene (128 mL) dried under vacuum at 60° C To the crude solid was added ethanol (350 mL) warmed to reflux to dissolve the solids The solution was cooled to room temperature concentrated to approximately 270 mL total volume by distillation Water (250 g) was then added over 30 min The slurry was filtered washed with cold (1:1) ethanol The solid was dried under vacuum at 60° C. (26.1 g, 83% yield)

Conditions: temp:50.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A slurry of Raney nickel (W.R. Grace 2800, 30.6 g calc. dry weight) was added to a 2-gallon Parr stirred pressure reactor containing THF (3 L). tert-Butyl 5-fluoro-2-nitrophenylcarbamate (102 g) was added. The vessel was sealed, purged, and pressurized to about 30 psig with hydrogen. The mixture was vigorously stirred at ambient temperature (20° C.) while hydrogen was supplied on-demand at 30 psig. After stirring for 16 h, the vessel was vented and purged with nitrogen. The product mixture was filtered to remove the catalyst using THF (1 L) to rinse the reactor and catalyst cake. The solvent was removed under vacuum. Heptane (510 mL) was added and the mixture was heated to 50° C. for 1 h, then cooled slowly to 0° C. The solids were filtered and washed with cold heptanes (100 mL) and dried under vacuum at 50° C. (76.7 g of product isolated, 87% pure, 73% yield). The vessel was sealed purged The mixture was vigorously stirred at ambient temperature (20° C.) while hydrogen After stirring for 16 h purged with nitrogen The product mixture was filtered to remove the catalyst to rinse the reactor and catalyst cake The solvent was removed under vacuum Heptane (510 mL) was added cooled slowly to 0° C The solids were filtered washed with cold heptanes (100 mL) dried under vacuum at 50° C.

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (22.63 mg, 0.10 mmol, 1.0 equiv, Intermediate B) in MeOH (1.0 mL) was added cyclohexanecarbaldehyde (16.83 mg, 18.05 μl 0.15 mmol, 1.5 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (2-chloro-phenoxy)-acetic acid (18.66 mg, 0.10 mmol, 1.0 equiv; [CAS RN 614-61-9]) and cyclohexyl isocyanide (10.92 mg, 12.27 μl, 0.10 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (0.2 mL) was added and the reaction mixture stirred at rt overnight. Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water provided 6.3 mg (13%) of the title compound. MS (ISP): 498.1 [M+H]+. stirring continued at rt for 2 h the reaction mixture stirred at rt overnight Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (4.0 g, 17.68 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Takle, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (50 mL) was added cyclohexanecarbaldehyde (1.98 g, 2.13 mL, 17.68 mmol, 1.0 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (R)-methoxy-phenyl-acetic acid (2.94 g, 17.68 mmol, 1.0 equiv; [CAS RN 3966-32-3]) and isocyanomethyl-benzene (2.07 g, 2.15 mL, 17.68 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (18 mL) was added and the reaction mixture stirred at rt overnight. The solution was concentrated by evaporation under reduced pressure, the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 and the aqueous layer extracted with dichloromethane. The combined organic phases were dried over MgSO4 and concentrated by evaporation under reduced pressure. The crude material was purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate to give 5.9 g (69%) of the title compound. 1H NMR (300 MHz, CDCl3): 1.25 (t, J=7.5 Hz, 3H), 1.41 (t, J=7.5 Hz, 3H), 3.43 (s, 3H), 4.01 (q, J=7.5 Hz, 2H), 4.26 (q, J=7.5 Hz, 2H), 5.05 (s, 1H), 6.43-6.48 (m, 2H). MS (ISP): 486.4 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight The solution was concentrated by evaporation under reduced pressure the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 the aqueous layer extracted with dichloromethane The combined organic phases were dried over MgSO4 concentrated by evaporation under reduced pressure The crude material was purified by silica column chromatography eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (33.94 mg, 0.15 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Takle, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (2.0 mL) was added cyclohexanecarbaldehyde (25.80 mg, 27.08 μL, 0.23 mmol, 1.5 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (3-chloro-phenyl)-acetic acid (34.12 mg, 0.20 mmol, 1.33 equiv; [CAS RN 1878-65-5]) and cyclohexyl isocyanide (16.38 mg, 18.41 μL, 0.15 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (0.2 mL) was added and the reaction mixture stirred at rt overnight. Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water provided 2.1 mg (3%) of the title compound. MS (ISP): 482.3 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (4.0 g, 17.68 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Takle, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (50 mL) was added cyclohexanecarbaldehyde (1.98 g, 2.13 mL, 17.68 mmol, 1.0 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (R)-methoxy-phenyl-acetic acid (2.94 g, 17.68 mmol, 1.0 equiv; [CAS RN 3966-32-3]) and isocyanomethyl-benzene (2.07 g, 2.15 mL, 17.68 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (18 mL) was added and the reaction mixture stirred at rt overnight. The solution was concentrated by evaporation under reduced pressure, the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 and the aqueous layer extracted with dichloromethane. The combined organic phases were dried over MgSO4 and concentrated by evaporation under reduced pressure. The crude material was purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate to give 5.9 g (69%) of the title compound. 1H NMR (300 MHz, CDCl3): δ1.25 (t, J=7.5 Hz, 3H), 1.41 (t, J=7.5 Hz, 3H), 3.43 (s, 3H), 4.01 (q, J=7.5 Hz, 2H), 4.26 (q, J=7.5 Hz, 2H), 5.05 (s, 1H), 6.43-6.48 (m, 2H). MS (ISP): 486.4 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight The solution was concentrated by evaporation under reduced pressure the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 the aqueous layer extracted with dichloromethane The combined organic phases were dried over MgSO4 concentrated by evaporation under reduced pressure The crude material was purified by silica column chromatography eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (33.94 mg, 0.15 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Takle, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (2.0 mL) was added cyclohexanecarbaldehyde (25.80 mg, 27.08 μL, 0.23 mmol, 1.5 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (3-chloro-phenyl)-acetic acid (34.12 mg, 0.20 mmol, 1.33 equiv; [CAS RN 1878-65-5]) and cyclohexyl isocyanide (16.38 mg, 18.41 μL, 0.15 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (0.2 mL) was added and the reaction mixture stirred at rt overnight. Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water provided 2.1 mg (3%) of the title compound. MS (ISP): 482.3 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight Removal of the solvent mixture under reduced pressure and purification by preparative HPLC on reversed phase eluting with a gradient of acetonitrile/water

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

Procedure: To a solution of (2-amino-5-fluoro-phenyl)-carbamic acid tert-butyl ester (4.0 g, 17.68 mmol, 1.0 equiv; prepared as described in M. J. Bamford, M. J. Alberti, N. Bailey, S. Davies, D. K. Dean, A. Gaiba, S. Garland, J. D. Harling, D. K. Jung, T. A. Panchal, C. A. Parr, J. G. Steadman, A. K. Talde, J. T. Townsend, D. M. Wilson, J. Witherington Bioorg. Med. Chem. Lett. 2005, 15, 3402-3406) in methanol (50 mL) was added cyclohexanecarbaldehyde (1.98 g, 2.13 mL, 17.68 mmol, 1.0 equiv; [2043-61-0]) and the mixture stirred at rt. After 30 min, (R)-methoxy-phenyl-acetic acid (2.94 g, 17.68 mmol, 1.0 equiv; [CAS RN 3966-32-3]) and isocyanomethyl-benzene (2.07 g, 2.15 mL, 17.68 mmol, 1.0 equiv; [931-53-3]) were added and stirring continued at rt for 2 h. A solution of 4 M HCl in dioxane (18 mL) was added and the reaction mixture stirred at rt overnight. The solution was concentrated by evaporation under reduced pressure, the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 and the aqueous layer extracted with dichloromethane. The combined organic phases were dried over MgSO4 and concentrated by evaporation under reduced pressure. The crude material was purified by silica column chromatography using a MPLC system (CombiFlash Companion, Isco Inc.) eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate to give 5.9 g (69%) of the title compound. 1H NMR (300 MHz, CDCl3): δ 1.25 (t, J=7.5 Hz, 3H), 1.41 (t, J=7.5 Hz, 3H), 3.43 (s, 3H), 4.01 (q, J=7.5 Hz, 2H), 4.26 (q, J=7.5 Hz, 2H), 5.05 (s, 1H), 6.43-6.48 (m, 2H). MS (ISP): 486.4 [M+H]+. prepared stirring continued at rt for 2 h the reaction mixture stirred at rt overnight The solution was concentrated by evaporation under reduced pressure the pH adjusted to 9 by addition of a solution of 1 M NaHCO3 the aqueous layer extracted with dichloromethane The combined organic phases were dried over MgSO4 concentrated by evaporation under reduced pressure The crude material was purified by silica column chromatography eluting with a gradient of heptane (+1% triethylamine)/ethyl acetate