Oxalyl chloride → HCID 58541902, compound

Participants

Reaction Steps

To a mixture of crude 4-methoxy-phthalic acid 2-methyl ester (850 mg) in CH2Cl2 (25 mL) is added oxalyl chloride (3.0 mL) and DMF (1 drop). The reaction mixture is stirred at room temperature for 1 hour, and is concentrated under reduced pressure. To the freshly formed 5-chloro-2-chlorocarbonyl-benzoic acid methyl ester in pyridine (5.0 mL) is added N-hydroxy-acetamidine (350 mg, 4.72 mmol). The reaction mixture is heated at 100° C. for 16 hours. The reaction mixture is allowed to cool to room temperature, diluted with EtOAc (100 mL), and washed with H2O (75 mL×2). The organic layer is dried with Na2SO4 and is filtered. The filtrate is concentrated under reduced pressure and the residue is purified by silica gel flash column chromatography with 35% EtOAc in heptanes as the eluent to afford 5-methoxy-2-(3-methyl-1,2,4-oxadiazol-5-yl)-benzoic acid methyl ester (600 mg, 60%).

Provenance & Evidence