2-Chlorothiophene → HCID 11501812, compound

Participants

Reaction Steps

A solution of the product from Step 3, 2trimethylsilylethyl-{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 elating 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. 1H NMR (CDCl3/300 MHz) 7.35 (d, 1H, J=4.0 Hz), 7.09 (d, 1H, J=11.7 Hz), 7.00 (d, 1H, J=7.2 Hz), 6.98 (d, 1H, J=4.0 Hz), 3.93 (s, 3H), 3.70 (s, 2H), 2.42 (s, 3H).

Provenance & Evidence