Dimethylformamide → 2-(4-Hexyloxyphenyl)-5-ethoxycarbonylbenzoxazole

Participants

Reaction Steps

To a suspension of 4-hexyloxybenzoic acid in oxalyl chloride (10 ml) and dichloromethane (10 ml) was added N,N-dimethylformamide (0.1 ml). The mixture was stirred at room temperature for 2 hours. The solvent was removed under reduced pressure to give crude 4-hexyloxybenzoate chloride. To a suspension of Ethyl 3-amino-4-hydroxybenzoate (733 mg) and triethylamine (1.38 ml) and 4-dimethylaminopyridine (DMAP, 10 mg) in methylene chloride (10 ml) was added the solution of 4-hexyloxybenzoyl chloride obtained above in dichloromethane (5 ml) dropwise at 10° C. The reaction mixture was stirred at 10° C. for 1.5 hours and diluted with dichloromethane (20 ml). the solution was washed with H2O (20 ml), 1N HCl aq. (20 ml×2), H2O (20 ml) and brine (20 ml) successively. The organic layer was dried over MgSO4 and the solvent was removed under reduced pressure. To the residue was added toluene (15 ml) and p-toluenesulfonic acid (10 mg). The mixture was refluxed for 6 hours and the solvent was removed under reduced pressure. The residue was triturated with acetonitrile, and precipitate was collected with filtration and dried over PO5 to give 2-(4-Hexyloxyphenyl)-5-ethoxycarbonylbenzoxazole (0.60 g).

Provenance & Evidence