Structure Lignin is highly heterogeneous polymer derived from a handful of precursor lignols that crosslink in diverse ways. The lignols that crosslink are of three main types, all derived from phenylpropane: coniferyl alcohol (4-hydroxy-3-methoxyphenylpropane) (  its radical is sometimes called guaiacyl), sinapyl alcohol (3,5-dimethoxy-4-hydroxyphenylpropane) (  its radical is sometimes called syringyl), and paracoumaryl alcohol (4-hydroxyphenylpropane) (  its radical is sometimes called 4-hydroxyphenyl).
Structure Lignin is highly heterogeneous polymer derived from a handful of precursor lignols that crosslink in diverse ways. The lignols that crosslink are of three main types, all derived from phenylpropane: coniferyl alcohol (4-hydroxy-3-methoxyphenylpropane) ( G, its radical is sometimes called guaiacyl), sinapyl alcohol (3,5-dimethoxy-4-hydroxyphenylpropane) ( S, its radical is sometimes called syringyl), and paracoumaryl alcohol (4-hydroxyphenylpropane) ( H, its radical is sometimes called 4-hydroxyphenyl).
A
G,
A
S,
A
H,