ethyl 7-fluoro-1-benzofuran-4-carboxylate

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 7-fluoro-benzofuran-4-carboxylic acid ethyl ester (1.54 mmol) and NaOH (2.31 mmol) in MeOH (1.7 mL) and water (1.7 mL) is heated to 55° C. for 90 min. The mixture is concentrated vacuo and made acidic by addition of aq. HCl (1.0 M). The obtained precipitate is filtered off and dried in vacuo to give the desired product. 1H NMR (DMSO-d6): δ=13.19 (bs, 1H); 8.25 (s, 1H); 7.89-7.94 (m, 1H); 7.41 (s, 1H); 7.36 (t, J=9.5 Hz, 1H). The mixture is concentrated vacuo made acidic by addition of aq. HCl (1.0 M) The obtained precipitate is filtered off dried in vacuo

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

Procedure: A mixture of 7-fluoro-2-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester and 7-fluoro-2-methoxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester (1.15 g, see above) in toluene (6.0 mL) is added dropwise to a solution of PTSA (0.25 mmol) in toluene (5.0 mL) which is heated to reflux. Heating is continued for 5 h, an additional portion of PTSA (0.25 mmol) is added and the mixture is again heated to reflux for 7 h. The solvents are removed in vacuo and the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5) to give the desired product. is heated to reflux Heating the mixture is again heated to reflux for 7 h The solvents are removed in vacuo the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5)

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

Procedure: A mixture of 7-fluoro-2-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester and 7-fluoro-2-methoxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester (1.15 g, see above) in toluene (6.0 mL) is added dropwise to a solution of PTSA (0.25 mmol) in toluene (5.0 mL) which is heated to reflux. Heating is continued for 5 h, an additional portion of PTSA (0.25 mmol) is added and the mixture is again heated to reflux for 7 h. The solvents are removed in vacuo and the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5) to give the desired product. is heated to reflux Heating the mixture is again heated to reflux for 7 h The solvents are removed in vacuo the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5)

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 7-fluoro-benzofuran-4-carboxylic acid ethyl ester (1.54 mmol) and sodium hydroxide (2.31 mmol) in MeOH (1.7 mL) and water (1.7 mL) is heated to 55° C. for 90 min. The mixture is concentrated in vacuo and made acidic by addition of hydrochloric acid (1.0 M). The obtained precipitate is filtered off and dried in vacuo to give the desired product. 1H-NMR (DMSO-d6): δ=13.19 (bs, 1H); 8.25 (s, 1H); 7.89-7.94 (m, 1H); 7.41 (s, 1H); 7.36 (t, J=9.5 Hz, 1H). The mixture is concentrated in vacuo made acidic by addition of hydrochloric acid (1.0 M) The obtained precipitate is filtered off dried in vacuo

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

Procedure: A mixture of 7-fluoro-2-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester and 7-fluoro-2-methoxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester (1.15 g, see above) in toluene (6.0 mL) is added dropwise to a solution of PTSA (0.25 mmol) in toluene (5.0 mL) which is heated to reflux. Heating is continued for 5 h, an additional portion of PTSA (0.25 mmol) is added and the mixture is again heated to reflux for 7 h. The solvents are removed in vacuo and the residue is purified by flash chromatography (gradient: heptane to heptane/EtOAc 95/5) to give the desired product. 1H-NMR (CDCl3): δ=7.99 (dd, J=8.3 Hz, J=4.3 Hz, 1H); 7.78 (s, 1H); 7.44 (bs, 1H); 7.10 (t, J=9.3 Hz, 1H); 4.46 (q, J=7.0 Hz, 2H); 1.47 (t, J=7.0 Hz, 3H). is heated to reflux Heating the mixture is again heated to reflux for 7 h The solvents are removed in vacuo the residue is purified by flash chromatography (gradient: heptane to heptane/EtOAc 95/5)

Conditions: temp:55.01; pressure:0.00; stir:; See reaction.notes.procedure_details.

Procedure: A mixture of 7-fluoro-benzofuran-4-carboxylic acid ethyl ester (1.54 mmol) and NaOH (2.31 mmol) in MeOH (1.7 mL) and water (1.7 mL) is heated to 55° C. for 90 min. The mixture is concentrated vacuo and made acidic by addition of aq. HCl (1.0 M). The obtained precipitate is filtered off and dried in vacuo to give the desired product. 1H NMR (DMSO-d6): δ=13.19 (bs, 1H); 8.25 (s, 1H); 7.89-7.94 (m, 1H); 7.41 (s, 1H); 7.36 (t, J=9.5 Hz, 1H). The mixture is concentrated vacuo made acidic by addition of aq. HCl (1.0 M) The obtained precipitate is filtered off dried in vacuo

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

Procedure: A mixture of 7-fluoro-2-hydroxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester and 7-fluoro-2-methoxy-2,3-dihydro-benzofuran-4-carboxylic acid ethyl ester (1.15 g, see above) in toluene (6.0 mL) is added dropwise to a solution of PTSA (0.25 mmol) in toluene (5.0 mL) which is heated to reflux. Heating is continued for 5 h, an additional portion of PTSA (0.25 mmol) is added and the mixture is again heated to reflux for 7 h. The solvents are removed in vacuo and the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5) to give the desired product. is heated to reflux Heating the mixture is again heated to reflux for 7 h The solvents are removed in vacuo the residue is purified by FC (gradient: heptane to heptane/EtOAc 95/5)