Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

Abstract

SummaryThe effective and efficient removal of the BF2 moiety from F-BODIPY derivatives has been achieved using two common Brønsted acids; treatment with trifluoroacetic acid (TFA) or methanolic hydrogen chloride (HCl) followed by work-up with Ambersep® 900 resin (hydroxide form) effects this conversion in near-quantitative yields. Compared to existing methods, these conditions are relatively mild and operationally simple, requiring only reaction at room temperature for six hours (TFA) or overnight (HCl).

Azido‐Substituted BODIPY Dyes for the Production of Fluorescent Carbon Nanotubes

“…Compound 5 is easily obtained from 2,4‐dimethylpyrrole ( 2 ) and 4‐nitrobenzaldehyde ( 3 ). Among the several different procedures that have been reported, we found more convenient to use the mechanochemical approach11 up to the intermediate 3 , while the treatment with BF 3 ⋅Et 2 O was performed in dry CH 2 Cl 2 10. The reduction of the nitro group with Fe powder/HCl afforded the corresponding amino group,12 and the final conversion into the azido derivative 5 was performed with TMS‐N 3 and isoamyl nitrite (Scheme ) 13.…”

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

“…In the case of silyl BODIPYs 6 and 8,t reatment with HCl/methanol (entries 9a nd 11,r espectively)c aused desilylation accompanied by nitrogen-boron cleavage on the BODIPY core leading to the corresponding, non-fluorescent, dipyrromethenes. [37] This could be confirmed in the case of 6-OTBDPS, for which treatment of the crude desilylation mixture with BF 3 ·OEt 2 produced BODIPY 6 (entry 9; 47 %y ield). [37] Finally,i nk eeping with literature precedents, [38] TBAF caused considerable decomposition of the BODIPY-core in all the derivatives ( Table 1, entries 1-4).…”

“…[37] This could be confirmed in the case of 6-OTBDPS, for which treatment of the crude desilylation mixture with BF 3 ·OEt 2 produced BODIPY 6 (entry 9; 47 %y ield). [37] Finally,i nk eeping with literature precedents, [38] TBAF caused considerable decomposition of the BODIPY-core in all the derivatives ( Table 1, entries 1-4).…”

Selective Displacement of a Scorpionand Triazole Ligand from Metallocyclam Complexes Visualised with NMR Spectroscopy

“…The synthetic route to the required phenyl–triazolyl–cyclam ligands 7 and 8 and metal complexes 4 – 6 was adapted from published methods, proceeding from tri‐Boc–cyclam 9 , via tri‐Boc–azidoethyl–cyclam 10 or tri‐Boc–propargyl–cyclam 11 as precursors for the copper‐catalysed azide/alkyne cycloaddition (CuAAC) or “click” reaction (Scheme ) …”