Hagerman condensed tannin structural chemistry The flavan-3,4-diols,or luecoanthocyanidins,are sometimes confused with proanthocyanidins. The flavan-3,4-diols are monomeric flavonoids that yield the anthocyanidins upon treatment with heat and acid.They thus have reactive chemistry similar to that of the condensed tannins,but they do not interact with protein to form precipitable complexes. OH Flavan-3,4-diols R"=H(stable) R=H,R'=OH,leucofisetinidin R"=OH able) R=R opelargonidin R=H,R' OH,leucocyanidin R=R'=OH,leucodelphinidin The flavan-4-ols are also luecoanthoc anidins,but are unique in their lability.They yield the anthocyan din tr upo at山 with alcoholic acid ar HO OH Flavan-4-ols R=H,apiferol(leucoapigeninidin) R=OH,luteoferol(leucoluteolinidin)Hagerman condensed tannin structural chemistry 6/6 The flavan-3,4-diols, or luecoanthocyanidins, are sometimes confused with proanthocyanidins. The flavan-3,4-diols are monomeric flavonoids that yield the anthocyanidins upon treatment with heat and acid. They thus have reactive chemistry similar to that of the condensed tannins, but they do not interact with protein to form precipitable complexes. The flavan-4-ols are also luecoanthocyanidins, but are unique in their lability. They yield the anthocyanidins upon treatment with alcoholic acid at room temperature. O R'' R' R HO OH OH OH R" = H (stable) R = H, R' = OH, leucofisetinidin R'' = OH (unstable) R = R' = H, leucopelargonidin R = H, R' = OH, leucocyanidin R = R' = OH, leucodelphinidin Flavan-3,4-diols HO O OH OH R OH R = H, apiferol (leucoapigeninidin) R = OH, luteoferol (leucoluteolinidin) Flavan-4-ols