Beilstein J. Org. Chem.2025,21, 736–748, doi:10.3762/bjoc.21.57
]. Specifically, the reversible E/Z isomerization of the azo group in azobenzeneglycosides is suited to control the spatial presentation of glycoligands and, for example, switch carbohydrate-specific bacterial adhesion on and off [20][21][22][23]. Indeed, glycoazobenzene derivatives are excellent tools to
following conclusions can be drawn. (i) In all inspected azobenzene glycoconjugates (1, 2, 4, and 5), a terminal α-ᴅ-mannopyranoside unit is complexed within the FimH CRD, as expected. (ii) The isomeric state of the azo group in the monovalent azobenzeneglycosides 4 and 5 alters the orientation of the non
bivalent azobenzeneglycosides 1 and 2 in the various isomeric states (EE, EZ, ZE, and ZZ) and the lectin FimH reach a complexity which obscures the effect of azo group isomerization. (iv) Calculated binding energies for the highest affinity isomers of 1 and 2, respectively, (−107.61 and −96.22 kcal mol−1
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Graphical Abstract
Figure 1:
Cartoon of the photoswitchable glycoconjugates investigated in this account. The previously describ...
Beilstein J. Org. Chem.2013,9, 223–233, doi:10.3762/bjoc.9.26
adhesive surfaces.
Keywords: azobenzeneglycosides; 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 azobenzeneglycosides 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 azobenzeneglycosides 6 and 2 at hand
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Graphical Abstract
Figure 1:
The α-(1→3)-linked mannobioside α-D-Man-(1→3)-D-Man 1 (B) is a potent disaccharide ligand for the b...