BODIPYs as Chemically Stable Fluorescent Tags for Synthetic Glycosylation Strategies towards Fluorescently Labeled Saccharides

Abstract

As eries of fluorescent boron-dipyrromethene (BODIPY,4,,4a-diaza-s-indacene)d yes have been designed to participate, as aglycons, in synthetic oligosaccharide protocols. As such, they served ad ual purpose:f irst, by being incorporated at the beginning of the process( at the reducing-endof the growing saccharide moiety), they can function as fluorescent glycosyl tags, facilitating the detection and purification of the desired glycosidic intermediates,a nd secondly,t he presence of these chromophores on the ensuing compounds grants access to fluorescently labeled saccharides. In this context, as ought-after feature of the fluorescent dyes has been their chemical robustness. Accordingly, some BODIPY derivatives described in this work can withstand the reactionc onditions commonly employed in the chemical synthesiso fs accharides;n amely, glycosylation and protecting-group manipulations. Regarding their photophysical properties,t he BODIPY-labeled saccharides obtained in this work display remarkable fluorescence efficiency in water,r eaching quantum yield values up to 82 %, as well as notable lasing efficienciesa nd photostabilities.[a] Dr.

Development of a multi faceted platform containing a tetrazine, fluorophore and chelator: synthesis, characterization, radiolabeling, and immuno-SPECT imaging

“…To the best of our knowledge there has only been one example of an investigation incorporating 4,4'-dicyano-BODIPYs into a chemical synthesis with protecting groups. 39 To reassure the stability of the cyano BODIPY core in acidic conditions, 7 was treated with TFA in CDCl 3 and monitored via 1 H NMR (see Supplementary Material Figure S11). 38 Unlike the BF 2 counterpart, there was no indication of instability even after 11 days.…”

Bringing Color to Sugars: The Chemical Assembly of Carbohydrates to BODIPY Dyes

“…For this reason, we decided to evaluate a second generation of BODIPY acceptors based on highly fluorescent and chemically stable 4,4'‐dicyano‐BODIPYs, e. g. 65 (Scheme 14). [54] In our design, [55] we also included the presence of peripheral alkyl substitution aimed at shielding the BODIPY core towards electrophilic reagents, commonly used as promotors in glycosylation.…”

“…The validity of the approach was confirmed with the synthesis of BODIPY‐labelled branched‐ and linear‐trisaccharides 69 and 72 , respectively from 65 (Scheme 14). Thus, for instance, the glycosylation of BODIPY 65 with mannopyranosyl trichloroacetimidate 66 produced an intermediate BODIPY monosaccharide, which upon deprotection furnished a BODIPY mannopyranosyl 2,3,4,6‐tetraol that underwent two selective glycosylations, first at the primary O ‐6 hydroxyl group with thioglycoside donor 67 , and then a regioselective second glycosylation at position O ‐3 with n ‐pentenyl orthoester 68 [55] …”

A Concise Synthesis of a BODIPY-Labeled Tetrasaccharide Related to the Antitumor PI-88

“…Based on these precedents, we thought it would be of interest to investigate the feasibility of a synthetic approach to BODIPY-labeled PI-88 saccharide components, where the fluorescent dye is incorporated from the beginning of the synthetic sequence. Additionally, we envisioned that the incorporation of the lipophilic BODIPY moiety at the reducing end of a PI-88 saccharide analogue would bring one additional advantage by facilitating the visualization and detection of the synthetic intermediates along the saccharide synthesis [ 19 ]. Additionally, in light of some reported literature precedents [ 20 ], the incorporation of the lipophilic BODIPY core to the saccharidic ensemble could lead to ameliorated biological activity in the ensuing saccharides.…”