Dihydroconiferyl alcohol

Savidge, R. A. Forster, H. Coniferyl alcohol metabolism in conifers—II. Coniferyl alcohol and dihydroconiferyl alcohol biosynthesis. Phytochemistry 2001, 57, 1095-1103. 

Savidge, R. A. Dihydroconiferyl alcohol in developing xylem of Pinus contorta. Phytochemistry 1987, 26, 93-94. 

The ether-soluble fraction from hydrol lignin A was analyzed by NMR spectra and by gas chromatography. The NMR spectra is nearly identical with that of dihydroconiferyl alcohol and dihydrosinapyl alcohol, which were shown to be present in large amounts by gas chromatography. 

The similar spectrum of products isolated under similar conditions of reaction from hard and softwoods indicates a basic similarity in the structural features of the releasable fragment of each species. The liberation, as the major product, of either dihydroconiferyl alcohol or dihydro-coniferyl alcohol plus dihydrosinapyl alcohol (depending on the wood species) indicates that a fairly accessible portion of the lignin substance is of a polyphenylpropanoid structure. The other, more highly fragmented products are most likely secondary reaction products derived from the initially liberated phenylpropanoid compounds. As such they should not be considered as unique units of lignin structure. 

Pepper and Supathna (1978) studies the effect on product yields of Rh-C applications ranging in amount from 1 to 30% of the original wood in the hydrogenolysis of spruce wood meal The yield of dihydroconiferyl alcohol, (9), was found to increase while the yield of 4-n-propylguaiacol, (8), decreased When the catalyst application exceeded 10%, traces of cyclohexyl derivatives were detected The maximum total yield of (8) and (9) was obtained with a 10-20% catalyst application... 

In summary, a previously unidentified unit present in small quantities in normal lignins was identified by NMR as a major component of the hydroxyphenylpropanoid polymeric component of a pine mutant deficient in CAD. The guaiacylpropane-l,3-diol units arise from conversion of dihydroconiferyl alcohol monomers by radical reactions and also incorporate into lignins as monomers. Like DHCA, however, GPD does not possess an unsaturated side-chain and is, thus, limited to coupling on the ring 4-0-, 5-,... 

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