Phenylpropanol cinnamyl alcohol

Hydrogenation of cinnamaldehyde has been studied extensively since selectivity has often been an issue. Under mild conditions the carbonyl group is reduced giving cinnamyl alcohol, whereas at elevated temperatures complete reduction to 3-phenylpropanol [122-97 ] results. It is possible to saturate the double bond without concomitant reduction of the carbonyl group through selective hydrogenation with a ferrous chloride-activated palladium catalyst (30), thereby producing 3-phenylpropanol [104-53-0]. 

Storax resin is extracted from Liquidambar orientalis (Hammamelidiaceae) and Altingia and its major components are cinnamyl cinnamate and 3-phenylpropanyl cinnamate, with significant amounts of benzoic and cinnamic acids, and 3-phenylpropanol and cinnamyl alcohols [130,131]. The volatile content is very low and triterpenes (oleanonic and 3-epioleanolic acids and liquid ambronovic acid) have also been observed [130,132]. 

It is convenient to investigate the selectivity provided by a given catalyst in the hydrogenation of / rans-cinnamaldehyde (3-phenyl-2-propenal, A) which can yield three products cinnamyl alcohol (3-phenyl-2-propenol, B), dihydrocinnamaldehyde (3-phenylpropanal, Q and 3-phenylpropanol (D) (Scheme 3.18). Data of a few catalytie systems are eollected into Table 3.8. 

The product of a lithium aluminum hydride reduction of a cinnamic acid or ester 1 is highly dependent on the solvent. The product of exclusive carbonyl reduction, cinnamyl alcohol 2, was obtained in hydrocarbon solvents (pentane, hexane or benzene) even under prolonged reflux. 3-Phenylpropanol 3, resulting from carbonyl and C-C double bond reduction was produced in diethyl ether. However, phenylcyclopropane 4 was obtained in tetrahy-drofuran or 1,2-dimethoxyethane, notably after prolonged reflux. 

Cinnamaldehyde Cinnamyl alcohol p-Methylacetophenone Propiophenone Beniyl acetate Ethyl beneoate Methyl toluate Ethyl salicylate Cumene Mesitylene Propyl bensene Bensyl ethyl ether 3-Phenylpropanol... 

Phenetidine Ethyl fumarate Ethyl maleate Ethyl succinate Octyl alcohol sec-Octyl alcohol Butyl sulfide Quinoline Cinnamyl alcohol p-Methylacetophenone Benzyl acetate Ethyl benzoate 3-Phenylpropanol Phorone Naphthalene... 

Fuganti. C.. Ghiringhelli. D.. and Grasselli. P. (1975) Stereochemical coiuse of the reduction of cinnamaldehyde and cinnamyl alcohol to 3-phenylpropanol by fermenting baker s yeast. J, Chem, Soc, Chem. Commun., 846-847. 

Cinnamic alcohol can be dehydrogenated to give cinnamaldehyde and oxidized to give cinnamic acid. Hydrogenation yields 3-phenylpropanol and/or 3-cyclo-hexylpropanol. Reaction with carboxylic acids or carboxylic acid derivatives results in the formation of cinnamyl esters, some of which are used as fragrance materials. 

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