title: Mild synthesis of asymmetric 2'-carboxyethyl-substituted fluoresceins.
abstract: Asymmetric fluoresceins bearing a carboxyethyl group in the chromophoric portion of the dyes were prepared by a reaction of substituted phthalic anhydride with a carboxyethyl substituted resorcinol analogue followed by a condensation with a second resorcinol analogue. In order to avoid an accumulation of symmetric side products, the second step was performed in two substeps: acid-catalyzed formation of a triphenylmethyl intermediate followed by base-catalyzed cyclization which furnished the desired dyes.
authors.affiliation: Nanogen Inc., 21720 23rd Drive SE, Suite 150, Bothell, Washington 98021, USA. elukhtanov@nanogen.com
authors.forename: Eugeny A
authors.initials: EA
authors.lastname: Lukhtanov
authors.forename: Alexei V
authors.initials: AV
authors.lastname: Vorobiev