Dimethyl Sulfate → 4-(3-Methoxycarbonylpropyl)-1-methoxypyridinium methyl sulfate salt

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Reaction Steps

Peracetic acid (40%, 2.9 ml) is added to 4-(3-methoxycarbonylpropyl)pyridine (3.20 g) at room temperature. The mixture is heated at 80° for 1 hour and the acetic acid is evaporated after a test for peroxide is negative. The residue is taken up in methylene chloride (50 ml), filtered, and the solvent evaporated. The resulting 4-(3-methoxycarbonylpropyl)pyridine-N-oxide is treated with dimethylsulfate (2.8 g, 22.2 mmol) in 12 ml of toluene at 80° C. for 1 hour. The solvent is evaporated to yield 5.45 g of the 4-(3-methoxycarbonylpropyl)-1-methoxypyridinium methyl sulfate salt which is added at 0° to a solution of 89.75 g potassium cyanide in 20 ml of water. The reaction is stirred at 0° for l hour and 25° for 3 hours and then extracted with methylene chloride (1×30 ml). The aqueous phase is reextracted, after standing for 24 hours, with methylene chloride (1×30 ml), and the combined extracts are dried over sodium sulfate and evaporated to yield a red oil. Chromatography on 70 g of silica gel with ether as the eluent yields 2-cyano-4-(3-methoxycarbonylpropyl)pyridine as an oil; NMR (CDCl3) 3.67 (s, 3 H), 7.42 (d, 1 H), 7.60 (s, 1 H), 8.60 (d, 1 H); IR (CH2Cl2) 1725 cm-1.

Provenance & Evidence