tert-Butanol → HCID 86673332, compound

Participants

Reaction Steps

5-Formyl-2-thiophenecarboxylic acid (25 g, 160 mmol) was dissolved in tert-butyl alcohol (400 ml) and dichloromethane (100 ml), di-tert-butyl bicarbonate (42.0 g, 192 mmol), and 4-dimethylaminopyridine (2.0 g, 16 mmol) were added, and the mixture was stirred at room temperature for 3 days. The solvent was evaporated under reduced pressure, ethyl acetate was added, and the mixture was washed successively with water, 0.5N aqueous sodium hydroxide solution and saturated brine. The ethyl acetate layer was dried over anhydrous sodium sulfate. The desiccant was filtered off, and the filtrate was concentrated under reduced pressure. 5 g of the obtained residue was dissolved in tetrahydrofuran (50 ml) and methanol (5 mL), sodium borohydride (0.50 g, 13 mmol) was added at 0° C., and the mixture was stirred for 2 hours. The reaction mixture was diluted with ethyl acetate, washed successively with 0.5N hydrochloric acid and saturated brine, and dried over anhydrous sodium sulfate. The desiccant was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was dissolved in dichloromethane (100 ml), and methanesulfonyl chloride (1.9 mL, 24 mmol) and N,N-diisopropylethylamine (5.7 mL, 33 mmol) were added at 0° C., and the mixture was stirred overnight. The solvent was concentrated under reduced pressure, ethyl acetate was added, and the mixture was washed successively with water and saturated brine. The ethyl acetate layer was dried over anhydrous sodium sulfate. The desiccant was filtered off, and the filtrate was concentrated under reduced pressure. The obtained residue was purified by silica gel column chromatography (hexane/ethyl acetate) to give the title compound (5.3 g, 23 mmol).

Provenance & Evidence