The Preparation, Paper Chromatography, and Color Reactions of Several 5,6-Dihydroxyindoles and 5,6-Diacetoxyindoles

The paper chromatographic behavior of several 5,6-dihydroxyindoles has been studied. The colors given by nine dihydroxyindoles with 16 chromogenic reagents are reported. The R f values of this group of compounds on Whatman No. 1 paper with 2% acetic acid in water or n-butanol/acetic acid/water (6:1:2) as running solvents have been determined. The 5,6-dihydroxyindoles can be chromatographed satisfactorily using Zaffaroni-type systems (i.e. formamide-treated paper and non-polar running solvents). Satisfactory R f values can also be obtained for the 5,6-diacetoxyindoles on formamide-treated paper using a suitable non-polar mobile phase. The preparations of several new 5,6-dihydroxyindoles and 5,6-diacetoxyindoles are described and improved procedures for the syntheses of some known members of these groups are reported.