856981-00-5Relevant academic research and scientific papers
Acid reactions of the lignin model 1,2-Bis(3,4-dimethoxyphenyl)-1,3-propanediol
Li, Shiming,Karlsson, Olov,Lundquist, Knut,Stomberg, Rolf
, p. 431 - 437 (2007/10/03)
1,2-Bis(3,4-dimethoxyphenyl)-1,3-propanediol on acid treatment [refluxing with 0.1 M (or 0.2 M) acid in dioxane-water (9:1)] undergoes two competing reactions: a reverse Prins reaction leading to (E)-3,3′,4,4′-tetramethoxystilbene (and formaldehyde) and a dehydration with formation of aryl-substituted allyl alcohols [the E and Z forms of 2,3-bis(3,4-dimethoxyphenyl)-2-propen-1-ol, 1,2-bis(3,4-dimethoxyphenyl)-2-propen-1-ol] that are comparatively slowly converted into a series of carbonyl compounds [1,2-bis(3,4-dimethoxyphenyl)-1-propanone, 2,2-bis(3,4-dimethoxyphenyl)propanal, 1,1-bis(3,4-dimethoxyphenyl)-2-propanone, 2,3-bis(3,4-dimethoxyphenyl)propanal] and 2-(3,4-dimethoxyphenyl)-5,6-dimethoxy-1H-indene. HBr (and to a lesser extent HCl) catalyses the formation of allyl alcohols while only traces of these compounds are formed when CH3SO3H is used as the catalyst [(.E)-3,3′,4,4′-tetramethoxystilbene is the predominant reaction product]. HBr promotes the formation of 1,2-bis(3,4-dimethoxyphenyl)-1-propanone from the intermediate (E)-2,3-bis(3,4-dimethoxyphenyl)-2-propen-1-ol. α-Chloromethyl-3,3′,4,4′-tetramethoxystilbene and α-bromomethyl-3,3′,4,4′-tetramethoxystilbene are formed in the reactions catalysed by HCl and HBr, respectively. The preparation and/or isolation of most of the detected acidolysis products is described and their stereochemistry is elucidated. A stereoselective synthesis of threo-1,2-bis(3,4-dimethoxyphenyl)-1,3-propanediol involving hydroboration-oxidation of (E)-2,3-bis(3,4-dimetnoxyphenyl)propenoic acid is reported. Acta Chemica Scandinavica 1997.
