N-bromobutanimide → ethyl 3-((2-bromo-6-chloro-1-(1-propyl-1H-pyrazol-4-yl)-1H-indol-3-yl)thio)benzoate

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Reaction Steps

To a stirred solution of compound 3 (100 mg, 0.22 mmol) in CCl4 (10 mL) was added NBS (44.85 mg, 0.25 mmol) at RT under inert atmosphere and stirred for 12 h. The reaction was monitored by TLC; after completion of the reaction, the reaction mixture was diluted with water (20 mL) and extracted with CH2Cl2 (3×20 mL). The combined organic extracts were dried over sodium sulphate, filtered and concentrated under reduced pressure to obtain the crude. This was purified by silica gel column chromatography using 10-15% EtOAc/Hexanes to afford compound 4 (55 mg, 47%) as an off-white solid. 1H NMR (500 MHz, CDCl3): δ 7.90 (s, 1H), 7.78-7.77 (m, 1H), 7.68 (s, 1H), 7.66 (s, 1H), 7.49 (d, J=8.5 Hz, 1H), 7.25-7.24 (m, 2H), 7.20 (s, 1H), 7.14 (d, J=8.5 Hz, 1H), 4.35 (q, J=7.0 Hz, 2H), 4.20 (t, J=7.5 Hz, 2H), 2.03-1.98 (m, 2H), 1.35 (t, J=7.0 Hz, 3H), 1.01 (t, J=7.5 Hz, 3H); LC-MS (ESI): 93.3%; m/z 520.8 (M++2); (column: X Select CSH C-18, 50×3.0 mm, 3.5 μm); RT 5.02 min; 5 mM NH4OAc: ACN; 0.8 mL/min).

Provenance & Evidence