Hydrochloric Acid → 3-Piperidinol, 1-methyl-4-phenyl-, trans-

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Reaction Conditions

Reaction Steps

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (21.2 g; 122 mmoles, described in Example 3) and sodium borohydride (7.40 g, 195 mmoles) are dissolved in dried redistilled diglyme (100 ml). The solution is cooled, with stirring, under nitrogen and maintained at 0° C. during dropwise addition of a solution of boron trifluoride etherate (32 ml; 250 mmoles) in diglyme (15 ml). When the addition is complete, the mixture is stirred for 1.5 hours at room temperature. Water (10 ml) is added followed by 6N sodium hydroxide solution (30 ml). The temperature is raised to 50° C. followed by dropwise addition of 30% hydrogen peroxide solution (30 ml, 260 mmoles) over a period of 1 hour. Conc. hydrochloric acid (30 ml) is added, and the solvents are evaporated. The residue is redissolved in water and the evaporation is repeated. The residue is dissolved in water, basified with potassium carbonate solution, and the free base is extracted with ether. The extract is dried (Na2SO4), evaporated, and the residual yellow oil is distilled under reduced pressure. The material distilling at 115°-128° C./0.1 mm is crystallized from hexane to give the title compound, mp 78°-79.5° C. (R. E. Lyle et al, supra, reported mp 82°-84° C.).

Provenance & Evidence