Organic Lab Reactions 33

Organic Lab Reactions 33 - The phenol is recovered from the...

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28 THE CLAISEN REARRANGEMENT pressure, v. Auwers mb reports b.p. 119.4-119.8°/18 mm., m.p. 37-38°, nf? 1,5811. C-Alhylation. Preparation of 2-Cinnamylphenol. 16 The sodium salt from 18.8 g. of phenol in 100 cc. of benzene is treated with 39.4 g. of cinnamyl bromide dissolved in a small amount of benzene. After reflux- ing for five hours, water is added and the layers' are separated. The benzene is distilled completely (by operating at reduced pressure near the end of the distillation), and-the residue is treated with four times its volume of Claisen's alkali.* The resulting solution is extracted twice with petroleum ether to remove the small amount of neutral material (2-3 g.). This procedure requires fewer extractions than the alternative method of dissolving the reaction product in petroleum ether and extract- ing the solution with Claisen's alkali to remove the phenolic material.
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Unformatted text preview: The phenol is recovered from the alkaline solution by acidification and ether extraction; the ether solution is dried, the solvent is removed, and the residue is distilled. Twenty-five grams (60%), b.p. 207-212/12 mm., of 2-cinnamylphenol is obtained, with a small residue probably consisting of dicinnamylphenol. On redistillation the product has a con-stant b.p. of 208-209/ll mm. and crystallizes to a solid, which, when recrystallized from hot petroleum ether or hot absolute formic acid, melts at 55.5-56.5. The phenylurethan melts at 131.5-132. * Claisen's alkali is prepared by dissolving 350 g. of potassium hydroxide in 250 cc. of water and diluting to 1000 cc. with methanol. lost v . Auwers, Ann., 413. 298 (1917)....
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This note was uploaded on 11/20/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.

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