Ammonium Chloride → HCID 131728960, compound

Participants

Reaction Steps

In a dry flask 2-trimethylsilylethyl (6-fluoro-5-methoxy-2-methyl-1H-indol-3-yl)acetate (4, R1=H=B, R2=CH3, R3=F, R4=CH2CH2Si(CH3)3), (1.0 g, 2.96 mmol) was dissolved in tetrahydrofuran (THF) (10 mL) and hexamethylphosphoramide (HMPA) (1 mL) and cooled to −78° C. Potassium bis(trimethylsilyl)amide 0.5M in toluene (6.52 mL) was added and the reaction was stirred for 30 minutes. 5-Chlorothiophene-2-carbonyl chloride (562 mg, 3.1 mmol) in 3 mL of THF was added and the reaction was stirred for 0.5 hours at −78° C. and 0.5 hours at 0° C., and then treated with saturated ammonium chloride (20 mL) and the reaction extracted with ethyl acetate (3×30 mL), dried over MgSO4 and concentrated to give a thick oil which was purified by chromatography to afford 2-trimethylsilylethyl-{1-[(5chlorothien-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, 42%, >99% pure) as light yellow oil; 1H-NMR (CDCl3/300 MHz) consistent with the assigned structure.

Provenance & Evidence