Citric Acid → HCID 58614675, compound

Participants

Reaction Conditions

Reaction Steps

3-Hydroxy-4-methylbenzoic acid (6.86 g, 45.1 mmol) was dissolved in methanol (200 ml). 4N HCl in 1,4-dioxane (34 ml, 0.135 mmol HCl) was added and the solution heated to 55° C. for 18 hours. The solvent was concentrated on a rotary evaporator, and then partitioned between water and ethyl acetate. The aqueous portion was extracted with ethyl acetate once, and the ethyl acetate extracts were combined and washed with water once, brine once, dried with MgSO4, and evaporated to methyl 3-hydroxy-4-methylbenzoate as a crude tan solid (6.66 g) which was used without purification. Methyl 3-hydroxy-4-methylbenzoate (6.66 g, 40.1 mmol) was dissolved in dichloromethane (200 ml), treated with pyridine (4.3 ml, 60.2 mmol), and cooled in an ice water bath. Acetyl chloride (3.6 ml, 50.1 mmol) was added dropwise. The solution was allowed to warm to room temperature, with stirring, over 18 hours. The solution was washed with 1 N aqueous HCl twice, water once, brine once, dried with MgSO4, and evaporated to methyl 3-acetoxy-4-methylbenzoate as a crude tan oil (6.93 g) which was used without purification. Methyl 3-acetoxy-4-methylbenzoate (6.38 g, 30.6 mmol) was dissolved in carbon tetrachloride (130 ml) and treated with benzoic peroxyanhydride (200 mg, 0.83 mmol) and NBS (5.45 g, 30.6 mmol), then heated to 85° C. for 3 hours. After cooling to room temperature, the solution was filtered through Celite 545 and evaporated to a crude yellow solid which was purified by silica gel flash chromatography (5% dichloromethane/hexanes increasing to 35% dichloromethane/hexanes) to yield methyl 3-acetoxy-4-(bromomethyl)benzoate as an off white solid (4.18 g). Methyl 3-acetoxy-4-(bromomethyl)benzoate (2.00 g, 6.97 mmol) was used in procedure O to afford methyl 3-acetoxy-4-(methylsulfonylmethyl)benzoate as a white solid (1.67 g) which was used without purification. Methyl 3-acetoxy-4-(methylsulfonylmethyl)benzoate (1.67 g, 5.83 mmol) was saponified via procedure M to afford 3-hydroxy-4-(methylsulfonylmethyl)benzoic acid as a white solid (1.05 g) which was used without purification. 3-Hydroxy-4-(methylsulfonylmethyl)benzoic acid (860 mg, 3.74 mmol) was dissolved in 1,4-dioxane (25 ml) and treated with thionyl chloride (8 ml) and DMF (5 drops), then heated to 50° C. for 2 hours. The reaction was cooled and evaporated to an oil. The oil residue was dissolved in dichloromethane (40 ml), cooled in an ice water bath, and treated dropwise with a solution of 4-chloro-3-(pyridin-2-yl)aniline (767 mg, 3.74 mmol) in dichloromethane (30 ml). The reaction was stirred 18 hours, allowing to warm to room temperature. The reaction was diluted with dichloromethane (40 ml) and stirred vigorously with water (50 ml) while acidifying to pH 6 with 1 M citric acid. The dichloromethane portion was separated, and enough methanol was added to dissolve precipitating solids. The solution was washed with water once, brine once, dried with MgSO4, and evaporated to a solid which was triturated with dichloromethane, filtered, and air dried to yield 909 mg of crude product. A portion (20 mg) was purified on reverse phase HPLC to yield 16 mg of purified N-(4-chloro-3-(pyridin-2-yl)phenyl)-3-hydroxy-4-(methylsulfonylmethyl)benzamide as a white solid. MS (Q1) 417 (M)+.

Provenance & Evidence