Chromophore-Supported Purification in Parallel Synthesis

The requirement for chromatographic separation and purification of product mixtures of greater or lesser degrees of complexity slows down every synthesis and is especially unfavorable when a series of parallel reactions is carried out in order to produce a library of structurally diverse compounds. To speed up chromatography, we have employed guajazulene derivatives to “dye” the starting material of a given reaction. The blue color of the chromophore‐marked reaction products facilitates visual inspection of the separation process during column chromatography, allowing many columns to be carried out in parallel. In addition to their function as color markers, the employed blue guajazulene derivatives can also be used as protecting groups during the synthesis. We have named this methodology “chromophore‐supported purification” (CSP) and have demonstrated its value in two parallel syntheses: in parallel acylations of the 6‐position of a chromophore‐marked mannoside on the one hand, and in the employment of CSP for workup after parallel 1,3‐dipolar cycloadditions between guajazulene‐marked alkynes and sugar azides on the other. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)