One of the root structures of the chlorophylls (see
porphyrin). Addition of the two-carbon bridge (see
chlorophyll) to chlorin yields phorbin(e); addition of side chains yields the phorbides, distinguished by a number of arbitrary prefixes (those found in the chlorophylls are pheo- and bacteriopheophorbide); esterification of the propionic group by phytyl yields the respective phytins, and the addition of magnesium yields the chlorophylls (magnesium phytinates). See:
porphyrins.