2-Chlorothiophene → HCID 11501812, compound

Participants

Reaction Steps

A solution of the product from Step 3, 2-trimethylsilylethyl-{1-[(5-chlorothien-2-yl)carbonyl]-6-fluoro-5-methoxy-2-methyl-1H-indol-3-yl}acetate 5, R1═H═B, R2═CH3, R3═F, R4═CH2CH2Si(CH3)3, A=5-chlorothiophene) (600 mg, 1.24 mmol) dissolved in 8 mL of THF was treated with a solution of tetrabutylammonium fluoride (1M, 3.1 mL, 3.1 mmol) in THF. The solution was stirred at room temperature until the ester had been cleaved (ca. 1 hour), and then the solution was diluted with saturated aqueous ammonium chloride and extracted with ethyl acetate. The combined extracts were washed with brine, dried over MgSO4 and concentrated to give a solid that was purified by chromatography eluting with hexanes and ethyl acetate to provide 280 mg, 59% of pure {1-[(5-chlorothien-2-yl)carbonyl]-6-fluoro-5-methoxy-2-methyl-1H-indol-3-yl}acetic acid (6, R1═H, R2═CH3, R3═F, R4═H, A=5-chlorothiophene), mp 169° C.

Provenance & Evidence