chlorin

2,3-Dihydroporphin(e); 2,3-dihydroporphyrin; one of the root structures of the chlorophylls (for structure, see porphyrin). Addition of the two-carbon bridge (see structure of chlorophyll) to c. 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.