Synthesis and testing of the first azobenzene mannobioside as photoswitchable ligand for the bacterial lectin FimH

• Vijayanand Chandrasekaran,
• Katharina Kolbe,
• Femke Beiroth and
• Thisbe K. Lindhorst

Beilstein J. Org. Chem. 2013, 9, 223–233, doi:10.3762/bjoc.9.26

• adhesive surfaces. Keywords: azobenzene glycosides; bacterial adhesion; E/Z photoisomerisation; FimH antagonists; mannobiosides; molecular switches; sweet switches; Introduction Adhesion of bacteria to surfaces can be a severe problem both in vivo and in vitro. Hence, inhibition of bacterial adhesion by

• ) in order to make a photoswitchable FimH antagonist available. Photoirradiation of azobenzene glycosides at ~365 nm effects E→Z isomerisation of the N=N double bond, and thermal relaxation or irradiation at ~450 nm leads to Z→E back isomerisation [13][14]. In the case that the E→Z isomerisation

• , glycosylation of the key intermediate 10 by using the mannosyl donor 3 gave the desired mannobioside 11 in 76% yield. Finally, removal of the O-acetyl groups according to Zemplén led to the unprotected 1,3-linked target mannobioside α-D-Man-(1→3)-D-Man (2). With the two azobenzene glycosides 6 and 2 at hand