New Xanthene Structures

Fluoresceine (C.I. 45350) is the best known representative of the class of hydroxy-xanthene dyes, and is obtained through the reaction between phthalic anhydride and resorcinol. In a similar way with the synthesis of fluoresceine, methods of synthesis were explored for obtaining novel xanthene structure compounds, starting from intermediates of the type anhydride with polyphenolic compound. Xanthene dyes are a very valuable class of organic compounds and have modern, non-conventional applications[1-4]. As oxidation agents Na2Cr2O7 and the peracetic acid are proposed, with the remark that in the case of naphthalic anhydride, oxidation was performed using sulfuric acid. At the same time it was tested the possibility to increase the reaction yield using a more diluted solution.