Resumen de Synthesis of Triarylmethane and Xanthene Dyes Using Electrophilic Aromatic Substitution Reactions.
James V. McCullagh, Kelly A. Daggett
The synthesis of dyes has long been a popular topic in organic chemistry laboratory experiments because it allows students to see first hand that reactions learned in class can be used to make compounds with useful applications. In this experiment electrophilic aromatic substitution reactions are used to synthesize several triarylmethane and xanthene dyes (fluorescein, erythrosin B, thymolphthalein, and rhodamine B). These dyes can be readily synthesized using equipment found in most common second-year organic labs. Hydroscopic Lewis acids, which are often troublesome to use in a typical lab setup, are avoided. The dyes synthesized in this experiment can each be completed in one four-hour laboratory session. Approximately 30 minutes in a subsequent period will be required for UV�vis analysis, and the student samples give UV�vis spectra that match commercially available dye samples.
