(±)-Cryptamides A-D, Four Pairs of Novel Dopamine Enantiomer Trimers from the Periostracum Cicadae.

Four pairs of novel dopamine enantiomer trimers, (±)-cryptamides A-D (-), and 10 pairs of previously described dopamine enantiomer dimers (-) were isolated from the Periostracum cicadae, the cast-off shell of the insect . Aside from being pairs of enantiomers, the eight trimers were also elucidated to be regioisomers, most likely resulting from their mechanism of formation, [4 + 2] cycloaddition. The discovery of dopamine trimers is rarely reported when it comes to natural products derived from insects.