Sulfuric Acid → 2-(3-Methyl-4-chloro-pyridin-2-yl)-2-cyclopropyl-acetaldehyde

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Reaction Steps

A solution of 2-(1-cyclopropyl-2-methoxy-vinyl)-3-methyl-4-chloro-pyridine (6.41 g, 28.7 mmol) in acetic acid (50 mL) was treated with sulfuric acid (6.52 mL, 143 mmol) at room temperature overnight. The reaction mixture was neutralized with 2N NaOH to pH 8-9 extracted with ethyl acetate (2×100 mL). The organic phases were combined, dried, and concentrated. The residue was purified by flash silica column chromatography (hexane/ethyl acetate=2:1) to afford the title compound as a yellow solid (4.83 g, 80%). ESI-MS m/z: 210 (M+H)+; 1H NMR (CDCl3, 300 MHz) δ ppm: 9.89 (d, J=2.4 Hz, 1H), 8.35 (d, J=5.1 Hz, 1H), 7.26 (d, J=5.4 Hz, 1H), 3.26-3.28 (m, 1H), 2.35 (s, 3H), 1.53-1.59 (m, 1H), 0.55-0.79 (m, 2H), 0.25-0.39 (m, 2H).

Provenance & Evidence