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Microwave‐Assisted Facile Synthesis of Red‐Shifted Azobenzene Glycoconjugates
Author(s) -
Poonthiyil Vivek,
Reise Franziska,
Despras Guillaume,
Lindhorst Thisbe K.
Publication year - 2018
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201801078
Subject(s) - azobenzene , glycoconjugate , chemistry , moiety , photochemistry , isomerization , combinatorial chemistry , stereochemistry , molecule , organic chemistry , biochemistry , catalysis
Azobenzene glycoconjugates are important tools used to study the effect of sugar orientation in molecular recognition. This is possible through the reversible photoinduced trans/cis isomerization of the N=N double bond in the sugar‐presenting azobenzene units. However, all the azobenzene glycoconjugates used so far need ultraviolet light for trans ‐to‐ cis switching, restricting their use in in vivo applications. Herein, we report the first synthesis of red‐shifted azobenzene glycoconjugates. After tetra‐ ortho ‐chlorination of the azobenzene moiety, the respective glycoazobenzenes can be switched from the trans to the cis state with visible light. We report scope and limitations of microwave‐assisted late‐stage C–H chlorination to afford tetra‐ ortho ‐chloroazobenzene glycoconjugates. Furthermore, synthesis of a red‐shifted azobenzene glycoconjugate carrying a thioacetate‐terminated linker is reported to allow for fabrication of red‐shifted photoswitchable glyco‐SAMs on gold surface. The photochromic properties of all red‐shifted azobenzene glycoconjugates are described.