Potassium Permanganate → 2-[2-cyclopentyl-1-(4-methanesulfonyl-phenyl)-ethyl]-1H-pyrrolo[2,3-b]pyridine

Participants

Reaction Steps

A solution of the mixture of 2-[2-cyclopentyl-1-(4-methanesulfinyl-phenyl)-ethyl]-1H-pyrrolo[2,3-b]pyridine and 2-[2-cyclopentyl-1-(4-methanesulfinyl-phenyl)-vinyl]-1H-pyrrolo[2,3-b]pyridine (1.7 g) in methanol (50 mL) at 0° C. was treated dropwise with a solution of potassium permanganate (800 mg, 5.09 mmol) in water (15 mL). The resulting mixture was stirred to 1.5 h. The mixture was then partitioned between water (100 mL) and chloroform (100 mL). The aqueous layer was then extracted with ethyl acetate (2×100 mL). The combined organic layers were then dried over magnesium sulfate, filtered and the filterate concentrated in vacuo. Purification using a Biotage flash chromatography system (40 M column, 50% ethyl acetate/hexanes) afforded 2-[2-cyclopentyl-1-(4-methanesulfonyl-phenyl)-ethyl]-1H-pyrrolo[2,3-b]pyridine (420 mg, 23%) as a yellow foam which still contained some impurities. After standing overnight, a white solid had formed and this was then collected by filtration and the solids lightly washed with 10% ethyl acetate/hexanes to afford 2-[2-cyclopentyl-1-(4-methanesulfonyl-phenyl)-ethyl]-1H-pyrrolo[2,3-b]pyridine (300 mg) as a white solid: 1H NMR (300 MHz, CDCl3) δ ppm 9.81 (br s, 1H), 8.18 (dd, J=4.8, 1.5 Hz, 1H), 7.86 (d, J=8.2 Hz, 2H), 7.81-7.90 (m, 1H), 7.48 (d, J=8.2 Hz, 2H), 7.05 (dd, J=7.7, 4.8 Hz, 1H), 6.37 (d, J=1.5 Hz, 1H), 4.25 (t, J=7.9 Hz, 1H), 3.02 (s, 3H), 2.19-2.31 (m, 1H), 2.05-2.17 (m, 1H), 1.61-1.88 (m, 5H), 1.41-1.54 (m, 2H), 1.08-1.24 (m, 2H).

Provenance & Evidence