Purpurin-18 methyl ester, as a starting material, was converted into purpurin-18 imide linked substituted structures bearing hydroxyl or acyl group at nitrogen atom in the imide by aminolysis for exocyclic ring. The hydroxyl, acyl or substituted groups with relevant functional structures were introdued by oxidation, allomerization, radical substitution and nucleophilic substitution reaction making use of active reactive regions on the periphery. The synthesis of 12 unreported chlorophyllous chlorins with carbon skeleton of purpurin-18 imide were accomplished and their chemical structures were characterized by elemental analysis, UV, IR and ¹H NMR spectra. The different effects on the tetrapyrrol macrocycle by hydroxylation and acylation were discussed.

Key words: chlorophyll-a, chlorin, purpurin-18 imide, chemical modification, synthesis