Z-Monolignols

Lewis NG, Inciong MaEJ, Dhara KP, Yamamoto E (1989) High performance liquid chromato graphic separation of E and Z monolignols and their glucosides J Chromatogr 979 345-352... 

Although Z-monolignols occur in many plants (e.g., in the bark of Fagus grandifolia), these appear to arise from -monolignols by enzymatic reactions (Davin et al., 1992). 

The (Z)-monolignols (hydroxycinnamyl alcohols) 49 were found along with their predominant ( )-isomers in a number of plants. Still-Gennarri reaction was successful applied to the preparation of (Z)-unsaturated esters 48 from aldehyde 47. The ester 48 was further converted to (Z)-coniferyl alcohol 49 in the synthesis of (Z)-monolignols. ... 

Many studies of plant extracts for monolignol and monolignol glucosides have relied heavily upon TLC comparison with authentic E-standards. Unfortunately, these methods normally only gave partial or no separation of the E and Z isomers. Consequently, development of the aforementioned HPLC methodology (Lewis et al. 1989) now permits the facile analysis of plant extracts, pulping liquors and the like for both E and Z isomers. As previously shown in Fig. 9.2.8, the combined use of a photodiode array detector in such studies can determine whether any other UV-absorbing impurities co-elute with the components of interest. 

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