N,N'-Dimethylethylenediamine → 6-chloro-1-(1-ethyl-1H-pyrazol-4-yl)-7-fluoro-1H-indole

Participants

Reaction Conditions

Reaction Steps

To a stirred solution of 6-chloro-7-fluoro-1H-indole 8 (400 mg, 2.36 mmol) in toluene (10 mL) were added 4-bromo-1-ethyl-1H-pyrazole 4 (Step 3 above; 414 mg, 2.36 mmol), potassium phosphate (1.25 g, 5.91 mmol), N,N′-dimethylethylenediamine (84 mg, 0.95 mmol) and Cu(I)I (45 mg, 0.24 mmol) at RT under inert atmosphere. The resulted solution was purged with argon and sealed the tube. The reaction mixture was then heated to 140° C. for 16 h. After completion of the reaction (monitored by TLC), the reaction mixture was cooled to RT, diluted with hexane (10 mL) and filtered through a short pad of celite. The filtrate was washed with water (2×10 mL), dried over Na2SO4, filtered and concentrated under reduced pressure to obtain the crude. The crude was purified (silica gel chromatography; 8-10% EtOAc/Hexanes) to afford compound 9 (224 mg, 36%) as a light brown thick liquid. 1H NMR (500 MHz, CDCl3): δ 7.64 (s, 1H), 7.61 (s, 1H), 7.31 (d, J=8.0 Hz, 1H), 7.12-7.07 (m, 2H), 6.60-6.59 (m, 1H), 4.22 (q, J=7.5 Hz, 2H), 1.55 (t, J=7.5 Hz, 3H); LC-MS (ESI): 94.7%; m/z 264.1 (M+H+); (column: X Select C-18, 50×3.0 mm, 3.5 μm); RT 3.87 min; 5 mM NH4OAc: ACN; 0.8 mL/min).

Provenance & Evidence