Toluene → Benzyl 5,6-dihydropyridine-1(2H)-carboxylate

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Reaction Steps

83.1 g (1 mol) of 1,2,5,6-tetrahydropyridine are dissolved in 300 ml of benzene. 83 g of sodium bicarbonate are introduced into this solution and the mixture is cooled to 0° under a nitrogen atmosphere and, at this temperature, treated dropwise in the course of one hour with 332 ml of a 50% strength solution of benzyl chloroformate in toluene (1 mol). The reaction mixture is stirred at 0° for a further 21/2 hours and then poured into 1.5 liters of ice-water. The benzene phase is separated off and the aqueous phase is extracted by shaking 3 times with 250 ml of methylene chloride; subsequently the combined organic phases are washed with 1 N hydrochloric acid and then with a saturated solution of sodium chloride, dried over sodium sulphate and evaporated under a water pump vacuum. The oily residue is distilled under a high vacuum and gives 1-carbobenzyloxy-1,2,5,6-tetrahydropyridine with a boiling point of 102°-113°/0.01 mm Hg.

Provenance & Evidence