Toluene → 2,3,5-Trimethylpyridine

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Reaction Steps

To 500 ml of a 5% solution of methyl lithium in ether are added dropwise at room temperature under argon 1200 ml of ether, subsequently 35.6 g of 3,5-lutidine (3,5-dimethylpyridine) and subsequently 400 ml of toluene. The ether is distilled off completely, whereupon the solution is stirred at 100° for 4 hours. Ice is then added portionwise thereto while cooling with methanol/ice until evolution of heat no longer occurs. The toluene phase is separated from precipitated solid and extracted with 66 ml of semi-concentrated hydrochloric acid. The separated aqueous phase is adjusted to a pH of about 10 with 3N sodium hydroxide solution while cooling and extracted twice with 300 ml of ether. The ether extracts are dried over sodium sulphate and evaporated. The residue is distilled in vacuo at 20 mm/72°-74°; there is obtained 2,3,5-collidine (2,3,5-trimethylpyridine) which has a purity of 99.15% according to gas chromatography.

Provenance & Evidence