M-Bromobenzyl alcohol

Tw-Bromobenzaldehyde is added slowly to an excess (5-7 moles) of 50% aqueous potassium hydroxide, the mixture wanmng sli tly. After all the aldehyde has been added the mixture is warmed on the water bath until the aldehyde odor has disappeared (one hour). With certain halobenzaldehydes the addition of a small amount of ethanol hastens the reaction. After dilution of the reaction mixture with water the m-bromobenzyl alcohol is extracted with ether. Removal of the ether and distillation of the product yields 89% of the alcohol, b.p. 128°/10 mm. The alkaline solution is acidified and the i-bromobenzoic add cdlected. The yield of acid (m.p. 155°) is 96%. 

The substituted benzyl alcohols listed below are prepared in a similar manner from the corresponding aldehydes in the yield indicated vanillyl alcohol, m.p. 113-114°, recrystallized from benzene, 95% anisyl alcohol, b.p. 127-130°/8 mm., 92% piperonyl alcohol, m.p. 52-53°, recrystallized from a mixture of ether and petroleum ether, 91% p-chlorobenzyl alcohol, m.p. 71-72.5°, recrystallized from ben-zene-ligroin mixture, 92% o-chlorobenzyl alcohol, m.p. 64 -65°, 96% p-bromobenzyl alcohol, m.p. 76-76.5°, 96%. 

Needles. M.p. 63°. Sol. E O, AcOH, CSj, CgH, hot EtOH Spar < sol. H O. Sublimes VolatUe in steam. CrOi, — p.bromobenzoic acid. Ale. KOH —> p-bromobenzoic acid -f p-bromobenzyl alcohol... 

A soln. of p-bromobenzaldehyde and pyridine borane in isopropyl ether refluxed 45 min. p-bromobenzyl alcohol. Y 94%.—The reducing power of pyridine borane is considerably less than that of those hydrides heretofore used for the reduction of carbonyl compounds to the alcohol stage. Acids and acid chlorides gave lower yields and esters could not be reduced. F. e. and reductions s. R. P. Barnes, J. H. Graham, and M. D. Taylor, J. Org. Ghem. 23, 1561 (1958). 

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