5-Benzofurancarboxylic acid

white to light yellow crystal powde

A stirred mixture of methyl benzofuran-5-carboxylate (1.3 g, 7.38 mmol) in MeOH (51 mL) and sodium hydroxide (41 mL of a 5percent aqueous solution) is heated to 65° C. for 4 h. The mixture is cooled to rt, and MeOH is removed in vacuo. The remaining aqueous layer is extracted with CH2Cl2. The CH2Cl2 layer is discarded, and the aqueous layer is acidified to pH=1 with concentrated hydrochloric acid. The aqueous layer is extracted with CHCl3. The organic layer is washed with water, dried (MgSO4), filtered and concentrated in vacuo to afford 1.2 g (98percent) of benzofuran-5-carboxylic acid as a white solid. 1H NMR (400 MHz, DMSO-d6) δ12.9, 8.30, 8.11, 7.92, 7.69, 7.09.A stirred mixture OF 4 (1. 3 G, 7. 38 MMOL) in methanol (51 mL) and sodium hydroxide (41 mL of a 5 percent aqueous solution) is heated to 65 C for 4 h. The mixture is cooled to room temperature, and the methanol is removed in vacuo. The remaining aqueous layer is extracted with methylene chloride. The methylene chloride layer is discarded, and the aqueous layer is acidified to PH=L with concentrated hydrochloric acid. The aqueous layer is extracted with chloroform. The organic layer is washed with water, dried over anhydrous magnesium sulfate, filtered and concentrated in vacuo to afford 1.2 g (98percent) of BENZOFURAN-5-CARBOXYLIC acid 5 as a white solid: H NMR (400 MHz, DMSO-D6) 8 12.9, 8.30, 8.11, 7.92, 7.69, 7.09.A solution of LiOH (1.13 g, 47.2 mmol) in water (20 mL) was added to a solution of 123 (2.77 g, 15.7 mmol) in THF (40 mL) and MeOH (40 mL) and the solution was stirred at r.t. for 18 h and then evaporated. The residue was dissolved in water (50 mL) and acidified with cone. HCl to pH 2. The precipitate was dissolved in EtOAc, the organic fraction was dried and evaporated to give 124 (2.49 g, 98percent). 1H NMR (DMSO-dA solution of LiOH (1.13 g, 47.2 mmol) in water (20 mL) wasadded to a solution of the above ester (2.77 g, 15.7 mmol) in THF(40 mL) and MeOH (40 mL) and the solution was stirred at 20 Cfor 18 h and then evaporated. The residue was dissolved in water(50 mL) and acidified with conc. HCl to pH 2. The precipitate wasdissolved in EtOAc, the organic fraction was dried and evaporatedto give benzofuran-5-carboxylic acid (2.49 g, 98percent). 1H NMR(DMSO d6) d 12.86 (s, 1H), 8.30 (d, J = 1.4 Hz, 1H), 8.10 (d, J = 2.2Hz, 1H), 7.92 (dd, J = 8.6, 1.8 Hz, 1H), 7.68 (dt, J = 8.6, 0.7 Hz, 1H), 7.08 (dd, J = 2.2, 0.9 Hz, 1H).To a mixture of methyl benzofuran-5-carboxylate (1.0 g, 5.7 mmol) in methanol (10 mL) and water (1 mL) was added sodium hydroxide (0.45 g, 11 mmol). The mixture was stirred at room temperature for 16 hours. On completion, the mixture was adjusted to pH = 5-6 with 4 M hydrochloric acid, resulting in formation of a solid. The solid was collected by filtration and dried in vacuo to give compound B-139 (0.61 g, 65percent yield) as a white solid.Methyl 4-hydroxy-3-[(trimethylsilyl)ethynyl]benzoate (11 g, 44.5 mmol) is combined with CuI (423 mg, 2.2 mmol) and DIA (7.1 ml, 50 mmol) in MeOH (110 mL) in a flask under nitrogen. The reaction is warmed to 60° C. for 6 h, the volatiles are removed in vacuo, and the brown-green residue is chromatographed over 500 g silica gel (230-400 mesh) eluting with 20percent EtOAc/hexane. Two pools are isolated to provide 3.43 g (31percent) of the early eluting methyl 2-trimethylsilylbenzofuran-5-carboxylate and 2.63 g (33percent) of the later eluting methyl benzofuran-5-carboxylate. The pools are combined in MeOH (130 mL). The solution is treated with 2N NaOH (46.8 ml, 93.6 mmol), is warmed to 50° C., and is stirred for 2 h. The mixture is cooled, the volatiles are removed in vacuo, and the residue is dissolved in water (50 mL). The pH of the mixture is adjusted to 2 with 12N HCl, is diluted with water (40 mL), and the mixture is cooled to 0° C. The off-white solid is collected, washed with water, and is dried to give 6.0 g. The solid is dried in vacuo over P2O5 for 18 h to give 4.6 g (99percent) of benzofuran-5-carboxylic acid as an off-white solid. MS for C9H6O3, (EI) m/z: 162 (M)+.Methyl 4-hydroxy-3-[(trimethylsilyl)ethynyl]benzoate (11 g, 44.5 mmol) is combined with cuprous iodide (423 mg, 2.2 mmol)and diisopropylamine (7.1 ml, 50 mmol) in 110 ml CH

Molecular Weight:162.14
XLogP3:1.9
Hydrogen Bond Donor Count:1
Hydrogen Bond Acceptor Count:3
Rotatable Bond Count:1
Exact Mass:162.031694049
Monoisotopic Mass:162.031694049
Topological Polar Surface Area:50.4
Heavy Atom Count:12
Complexity:190
Covalently-Bonded Unit Count:1
Compound Is Canonicalized:Yes