rman structural chemistry OH OH R"=OH R"=OH R.OH ewmidin R=R=OH.robinetinidin Anthocvanidins ocyanidi ed by the ech nus are known as procyanidins chin and techin based polymers yield delphinidin.and the rare mono-substituted flavan-3-based polymers An important group of condensed tannins are 5-deoxy-flavan-3-ols polymers.Branching is common in these tannins,because of the reactivity of the 5-deoxy A ring.Profisetinidins andHagerman condensed tannin structural chemistry 4/6 The products of the acid butanol reaction are an unmodified terminal unit, and the colored anthocyanidins produced by the extender units. Catechin- and epicatechin-based polymers produce cyanidin, and thus are known as procyanidins. Gallocatechin and epigallocatechin￾based polymers yield delphinidin, and the rare mono-substituted flavan-3-ol based polymers yield pelargonidin. An important group of condensed tannins are 5-deoxy-flavan-3-ols polymers. Branching is common in these tannins, because of the reactivity of the 5-deoxy A ring. Profisetinidins and 5 HO O OH HO O OH OH OH OH OH OH OH 5 O HO OH HO HO OH 5 HO O OH OH OH 5 O OH HO HO OH HO O OH OH OH OH robinetinidol-(4α−>8)-catechin-(6α->4a)-robinetinidol profisetinidin HO O OH R' OH R'' R HO O OH R' R'' R R'' = OH R = R' = H, apigeninidin R = H, R' = OH, luteolinidin Anthocyanidins + + R'' = OH R = R' = H, pelargonidin R = H, R' = OH, cyanidin R = R' = OH, delphinidin R'' = H R = R' = H, guibourtinidin R = H, R' = OH, fisetinidin R = R' = OH, robinetinidin