Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• successfully obtained in 30% yield. In the final step, the target POA-type structure containing naphthazarin 69 was synthesized by aromatization under acidic conditions. The attempts to conduct complexation experiments using BF3·OEt2 to obtain a stable BF2 complex were unsuccessful, primarily due to solubility

• problems encountered with substrate 69 and its BF2 complex. Based on the UV–vis analysis of compounds 65 and 69, it was observed that compound 65 displayed a low-energy absorption band at λmax = 568 nm, whereas compound 69 exhibited absorption at λmax = 557 nm. Unfortunately, the unsuccessful BF2

• complexation step to isolate stable BF2 complex of 69, likely attributable to solubility issues encountered with substrate 69, prevented the incorporation of the acene backbone into the structure. Consequently, the anticipated red-shift in the absorption spectrum could not be observed as expected. Boron-doped

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• investigated. Furthermore, a strategy for the hydrolysis of the BF2 group has been established using aqueous methanol and sodium hydroxide or triethylamine. Keywords: BF2 complex; curcumin; dyes; fluorescence; hydrolysis; spectroscopy; Introduction In recent years curcumin, a pigment naturally occurring in

• reaction was altered by Zhang et al. to be carried out in toluene (Scheme 1b) [14]. This reaction produces the BF2 complex of the corresponding curcuminoid in yields up to 98% and high purity as an insoluble solid, which requires only a minimum of work-up. The BF2 complexes by themselves have attracted

• decided to synthesise a range of curcuminoids bearing propargyl and pent-1-yn-5-yl ether groups as partners for “click” reactions [26]. We already observed that for the BF2 complex of bispropargyl functionalised bisdemethoxycurcumin, the BF2 group was hydrolysed under regular “click” reaction conditions