Water → HCID 87209263, compound

Temperature

40 °C

To a solution of 6-chloro-4-methyl-2-vinyl-pyridine (1.24 g, 8.06 mmol) in water (50 mL) and acetone (50 mL), KMnO4 (6.53 g, 41.3 mmol) is added. The dark mixture becomes warm (40° C.) and is stirred at rt for 3 h before it is filtered over a sintered glass filter. The solvent of the colourless filtrate is evaporated to give crude 6-chloro-4-methyl-pyridine-2-carboxylic acid potassium salt (3.2 g) as a colourless solid; LC-MS: tR=67 min, [M+1]+=171.99. This material is suspended in ethanol (150 mL) and H2SO4 (2 mL) is added until a clear solution forms. The mixture is heated to 70° C. for 18 h. The mixture is carefully diluted with sat. aq. NaHCO3 solution until a pH of 9 is reached. The mixture is extracted three times with EA. The combined org. extracts are dried over MgSO4, filtered and concentrated. The crude product is purified by CC on silica gel eluting with heptane:EA 3:2 to give ethyl 6-chloro-4-methyl-pyridine-2-carboxylate (500 mg) as a pale yellow oil; LC-MS: tR=0.87 min; [M+1]+=200.04; 1H NMR (CDCl3): δ 1.45 (t, J=7.3 Hz, 3H), 2.45 (s, 3H), 4.48 (q, J=6.8 Hz, 2H), 7.35 (s, 1H), 7.89 (s, 1H).

1. filtrationis filtered over a sintered glass
2. filtrationfilter
3. customThe solvent of the colourless filtrate is evaporated

ORD record

ord-2c2ff1ae2dfa43b3a3d0590bc89d4fbc

Source dataset

uspto-grants-2013_12

DOI

10.6084/m9.figshare.5104873.v1

Patent number

US08598208B2