Early precursors in the biosynthesis of cularine-type benzylisoquinoline alkaloids

Cularine-type benzylisoquinoline alkaloids containing 7,8-substitution in the A-ring (crassifoline, cularine) are biosynthetically formed by an atypical and enzymatically catalysed Pictet–Spengler analogous (ortho) condensation of dopamine and an appropriate aldehyde.