Synthesis of Cluster Mannosides Carrying a Photolabile Diazirine Group

Abstract

AbstractWe are investigating the mechanisms underlying the carbohydrate‐specific adhesion of bacteria such as Escherichia coli to the glycocalyx of their potential host cells. E. coli possess protein appendages, which are called type 1 fimbriae. Part of type 1 fimbriae is a protein named FimH, which is a mannose‐specific lectin. We wish to use photoaffinity labeling to elucidate mannose binding sites on FimH. Thus we report the synthesis of di‐ and trivalent cluster mannosides, which carry a photolabile diazirine group. The diazirine group was introduced by a convergent approach using thiourea bridging (products 6, 13, 17, and 27) or in a divergent synthesis leading to the divalent cluster mannoside 31. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)