Mild synthesis of asymmetric 2'-carboxyethyl-substituted fluoresceins

The development of a mild two-step synthesis of asymmetric 2'-carboxyethyl-substituted fluoresceins and other fluorescein analogues is reported. The reaction involved substituted phthalic anhydride and a carboxyethyl substituted resorcinol analogue followed by a condensation with a second resorcinol analogue.