Sulfuric Acid → (E)-8-chloro-2,3,4,5-tetrahydro-2-methyl-5-(2-(pyridin-4-yl)prop-1-enyl)-1H-pyrido[4,3-b]indole

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Reaction Steps

1-(8-Chloro-1,2,3,4-tetrahydro-2-methylpyrido[4,3-b]indol-5-yl)-2-(pyridin-4-yl)propan-2-ol (1 g, 2.81 mmol, 1 equiv.) was refluxed with 25% sulfuric acid (7 mL) for 2 h. The reaction mixture was cooled to 5° C. in ice-water bath. KOH (15% aqueous solution) was added dropwise to the reaction mixture until pH 9-10 was achieved. The reaction mixture was extracted with EtOAc (3×10 mL). The combined organic layer was washed with water (10 mL) followed by brine, dried over sodium sulfate and evaporated under vacuum. The crude product was purified by silica gel chromatography (100-200 mesh) using a gradient of MeOH-EtOAc (0-10%) followed by HPLC to provide pure product. 1H NMR (DMSO, Oxalate Salt) δ (ppm): 8.60 (d,2H), 7.62 (m,3H), 7.40 (s,1H), 7.30 (d,1H), 7.20 (d,1H), 4.40 (m,2H), 3.10 (m,4H), 2.99 (s,3H), 1.90 (s,3H).

Provenance & Evidence