SYNTHESIS OF ERYTHRO AND THREO FORMS OF LIGNIN MODELS OF THE ARYLGLYCEROL BETA-GUAIACYL ETHER TYPE

Lignin-related arylglycerol beta-guaiacyl ethers [2-(2-methoxyphenoxy)-1-(3,4,5-trimethoxyphenyl)-1,3-propanediol,2-(2-methoxyphenoxy)-1-(4-methoxyphenyl)-1,3-propanediol, 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol and 1-(3,4-dimethoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol] have been prepared by reacting alpha-lithiated (2-methoxyphenoxy)acetic acid with aromatic aldehydes and subsequent reduction of the 3-hydroxypropionic acids formed with borane-dimethyl sulfide complex. Isolation of the erythro and threo forms from the product mixtures was accomplished by ion-exchange chromatography. The tetrabutylammonium salt of vanillin was used as a reactant in the synthesis of 1-(4-hydroxy-3-methoxyphenyl)-2-(2-methoxyphenoxy)-1,3-propanediol.