Oxazole → 1-butyl-4-(1,3-oxazol-2-yl)-1H-indole-6-carboxylic acid

Participants

Reaction Conditions

Reaction Steps

To a −72° C. solution of oxazole (0.069 g) in dry THF (20 mL) was added dropwise 1.6 M N-butyl lithium (0.68 mL). The mixture was stirred at −72° C. for 30 minutes at which time 1.0 M zinc chloride (3.3 mL) was added. The mixture was allowed to warm to 0° C. at which time methyl 1-butyl-4-iodo-1H-indole-6-carboxylate (0.37 g) and tetrakis triphenylphosphine palladium(0) (0.07 g) were added and the mixture heated to 85° C. The mixture was heated at 85° C. for 20 h then cooled to room temperature and partitioned between water and ethyl acetate. The layers were separated and the organic layer washed with water, dried over anhydrous sodium sulfate and concentrated under reduced pressure. Column chromatography was performed on silica gel (100 mL) using 20% ethyl acetate in hexanes as eluent. The residue was dissolved in methanol (10 mL) and 1N NaOH (3 mL) and heated at 60° C. for 2 h. The mixture was acidified to pH 4 with 1N HCl and extracted with ethyl acetate. The ethyl acetate extracts were dried over anhydrous sodium sulfate and concentrated to dryness under reduced pressure to give 0.2 g of the title compound: MS (ESI+) for C16H16N2O3 m/a 283.16 (M+H)+.

Provenance & Evidence