benzyl 1H-pyrrole-2-carboxylate

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:

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

Procedure: Next, To a stirred solution of 1H-pyrrole-2-carboxylic acid benzylester (2.0 g, 9.94 mmol) in 1,2-dichloroethane (15 mL) at 5° C. is sequentially added DMF (1.12 g, 15.31 mmol) and phosphoryl trichloride (2.35 g, 15.31 mmol). After the addition, the mixture is heated to 50° C. and stirred for an hour. Water is added and the mixture is extracted with ethyl acetate (3×). The combined organic layers are washed with water and brine then is dried over magnesium sulfate. The solvent is removed under reduced pressure and the residue is purified by flash chromatography (heptane/ethyl acetate=3:1) to give 5-formyl-1H-pyrrole-2-carboxylic acid benzyl ester; HPLC Retention time 1.64 minutes (condition C): MS 230.3 (M+1). at 5° C. After the addition the mixture is extracted with ethyl acetate (3×) The combined organic layers are washed with water and brine then is dried over magnesium sulfate The solvent is removed under reduced pressure the residue is purified by flash chromatography (heptane/ethyl acetate=3:1)

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

Procedure: Next, To a stirred solution of 1H-pyrrole-2-carboxylic acid benzylester (2.0 g, 9.94 mmol) in 1,2-dichloroethane (15 mL) at 5° C. is sequentially added DMF (1.12 g, 15.31 mmol) and phosphoryl trichloride (2.35 g, 15.31 mmol). After the addition, the mixture is heated to 50° C. and stirred for an hour. Water is added and the mixture is extracted with ethyl acetate (3×). The combined organic layers are washed with water and brine then is dried over magnesium sulfate. The solvent is removed under reduced pressure and the residue is purified by flash chromatography (heptane/ethyl acetate=3:1) to give 5-formyl-1H-pyrrole-2-carboxylic acid benzyl ester; HPLC Retention time 1.64 minutes (condition C): MS 230.3 (M+1). at 5° C. After the addition the mixture is extracted with ethyl acetate (3×) The combined organic layers are washed with water and brine then is dried over magnesium sulfate The solvent is removed under reduced pressure the residue is purified by flash chromatography (heptane/ethyl acetate=3:1)

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

Procedure: Next, To a stirred solution of 1H-pyrrole-2-carboxylic acid benzylester (2.0 g, 9.94 mmol) in 1,2-dichloroethane (15 mL) at 5° C. is sequentially added DMF (1.12 g, 15.31 mmol) and phosphoryl trichloride (2.35 g, 15.31 mmol). After the addition, the mixture is heated to 50° C. and stirred for an hour. Water is added and the mixture is extracted with ethyl acetate (3×). The combined organic layers are washed with water and brine then is dried over magnesium sulfate. The solvent is removed under reduced pressure and the residue is purified by flash chromatography (heptane/ethyl acetate=3:1) to give 5-formyl-1H-pyrrole-2-carboxylic acid benzyl ester; HPLC Retention time 1.64 minutes (condition C): MS 230.3 (M+1). at 5° C. After the addition the mixture is extracted with ethyl acetate (3×) The combined organic layers are washed with water and brine then is dried over magnesium sulfate The solvent is removed under reduced pressure the residue is purified by flash chromatography (heptane/ethyl acetate=3:1)

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

Procedure: To a stirred solution of 1H-pyrrole-2-carboxylic acid (1.11 g, 10 mmol) in DMF (15 mL) is added potassium carbonate (2.07 g, 15 mmol) and (bromomethyl)benzene (1.80 g, 10.50 mmol). After stirring the mixture at room temperature for 18 hours, water is added and the mixture is extracted three times with ethyl acetate. The combined organic layers are washed with water and brine then is dried over magnesium sulfate. The solvent is removed under reduced pressure and the residue is purified by flash chromatography (heptane/ethyl acetate=5:1) to give 1H-pyrrole-2-carboxylic acid benzylester. the mixture is extracted three times with ethyl acetate The combined organic layers are washed with water and brine then is dried over magnesium sulfate The solvent is removed under reduced pressure the residue is purified by flash chromatography (heptane/ethyl acetate=5:1)

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

Procedure: To DMF (5.93 g) was added POCl3 (12.45 g) dropwise at 0° C. The mixture was warmed to RT, diluted with DCM (40 mL) and cooled again to 0° C. A solution of 1H-pyrrole-2-carboxylic acid benzyl ester (15.00 g, prepared by adopting a procedure from J. Barry, G. Bram and A. Petit, Heterocycles 1985, 23, 875-880) in DCM (40 mL) was added dropwise at such a rate that the temperature of the reaction mixture did not rise above 0° C. The reaction was the heated to reflux for 30 min whereupon it was cooled to 10° C. A solution of sodium acetate (28g) in water (90 mL) was added carefully. After stirring for 15 min the two resulting phases were separated and the aqueous phase was washed with DCM (3×75 mL). The combined organic phases were washed with saturated Na2CO3 solution and brine, dried over MgSO4 and concentrated. The residue was purified by flash column chromatography on silica (ethyl acetate/heptanes 1:2) to provide 5-formyl-1H-pyrrole-2-carboxylic acid benzyl ester (8.0 g) and 4-formyl-1H-pyrrole-2-carboxylic acid benzyl ester (4.0 g). cooled again to 0° C did not rise above 0° C heated to reflux for 30 min whereupon it was cooled to 10° C were separated the aqueous phase was washed with DCM (3×75 mL) The combined organic phases were washed with saturated Na2CO3 solution and brine dried over MgSO4 concentrated The residue was purified by flash column chromatography on silica (ethyl acetate/heptanes 1:2)

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

Procedure: To DMF (5.93 g) was added POCl3 (12.45 g) dropwise at 0° C. The mixture was warmed to RT, diluted with DCM (40 mL) and cooled again to 0° C. A solution of 1H-pyrrole-2-carboxylic acid benzyl ester (15.00 g, prepared by adopting a procedure from J. Barry, G. Bram and A. Petit, Heterocycles 1985, 23, 875-880) in DCM (40 mL) was added dropwise at such a rate that the temperature of the reaction mixture did not rise above 0° C. The reaction was the heated to reflux for 30 min whereupon it was cooled to 10° C. A solution of sodium acetate (28g) in water (90 mL) was added carefully. After stirring for 15 min the two resulting phases were separated and the aqueous phase was washed with DCM (3×75 mL). The combined organic phases were washed with saturated Na2CO3 solution and brine, dried over MgSO4 and concentrated. The residue was purified by flash column chromatography on silica (ethyl acetate/heptanes 1:2) to provide 5-formyl-1H-pyrrole-2-carboxylic acid benzyl ester (8.0 g) and 4-formyl-1H-pyrrole-2-carboxylic acid benzyl ester (4.0 g). cooled again to 0° C did not rise above 0° C heated to reflux for 30 min whereupon it was cooled to 10° C were separated the aqueous phase was washed with DCM (3×75 mL) The combined organic phases were washed with saturated Na2CO3 solution and brine dried over MgSO4 concentrated The residue was purified by flash column chromatography on silica (ethyl acetate/heptanes 1:2)

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

Procedure: Lit. J. Org. Chem., 44:975 (1979). To a stirred solution of 5.0 g (45.0 mmol) pyrrole-2-carboxylic acid and 31.3 ml (225 mmol) triethylamine in 100 ml DMF was added dropwise 26 ml (225 mmol) benzyl bromide and stirring continued for 72 h at room temperature. The reaction mixture was then concentrated in vacuo and the residue resuspended in dichloromethane and washed twice with saturated sodium bicarbonate solution and twice with water, and the aqueous phases back-extracted with dichloromethane. The combined organic extracts were dried over sodium sulphate and concentrated in vacuo. Flash chromatography (25% EtOAc in hexane) afforded 8.23 g (90%) of the title compound as a yellow oil. The reaction mixture was then concentrated in vacuo washed twice with saturated sodium bicarbonate solution and twice with water the aqueous phases back-extracted with dichloromethane The combined organic extracts were dried over sodium sulphate concentrated in vacuo

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

Procedure: Lit. J. Org. Chem., 44:975 (1979). To a stirred solution of 5.0 g (45.0 mmol) pyrrole-2-carboxylic acid and 31.3 ml (225 mmol) triethylamine in 100 ml DMF was added dropwise 26 ml (225 mmol) benzyl bromide and stirring continued for 72 h at room temperature. The reaction mixture was then concentrated in vacuo and the residue resuspended in dichloromethane and washed twice with saturated sodium bicarbonate solution and twice with water, and the aqueous phases back-extracted with dichloromethane. The combined organic extracts were dried over sodium sulphate and concentrated in vacuo. Flash chromatography (25% EtOAc in hexane) afforded 8.23 g (90%) of the title compound as a yellow oil. MS m/e (%): 201 (M+, 33), 94 ([M−OBn]+, 22), 91 (Bn+, 100). The reaction mixture was then concentrated in vacuo washed twice with saturated sodium bicarbonate solution and twice with water the aqueous phases back-extracted with dichloromethane The combined organic extracts were dried over sodium sulphate concentrated in vacuo