Synthesis and luminescence properties of biphenyl-type firefly luciferin analogs with a new, near-infrared light-emitting bioluminophore

Beyond D-luciferin: expanding the scope of bioluminescence imaging in vivo

“…Even large fluorescent dyes can be appended to aminoluciferins ( 8 ) to red-shift emission over 650 nm by bioluminescence resonance energy transfer (BRET), yet not destroy the ability of luciferase to catalyze light emission [20]. Moreover, the core benzothiazole can be replaced with other heterocycles ( 9 – 13 ) [21–24], or be removed altogether and replaced by extended π-conjugation ( 14 – 17 ) [25*,26]. Of particular interest, Iwano et al have reported a luciferin analog with maximal bioluminescence emission over 650 nm ( 17 , Figure 1) [25*].…”

Total Synthesis of the Depsipeptide FR901375 and Preliminary Evaluation of Its Biological Activity

“…Reactions were monitored using glass-supported Merck silica gel 60 F254 TLC plates. 13 C NMR (100 MHz, CDCl 3 ): δ = 19.9, 40.0, 47.0, 52.5, 53.9, 57.3, 67.1, 67.2, 67.9, 119.9 (2 C), 125.0 (2 C), 126.9 (2 C), 127.0 (3 C), 127.66, 127.68, 128.0 (6 C), 129.5 (6 C), 141.2 (2 C), 143. 8 Hz,2 H) ppm.…”

“…The organic layer was washed successively with HCl (10 % aq. 13 C NMR (100 MHz, CDCl 3 ): δ = -5.3, -4.5, 17.8, 18.0, 18.3, 19.14, 19.16, 20.8, 25.6 (3 C), 31.1, 31.3, 31.4, 31.5, 33.8, 42.7, 52.0, 52.2, 58.0 (2 C), 58.7, 66.6, 67.2, 68.8, 69.1, 126.6 (3 C), 126.9 (3 C), 127.8 (6 C), 128.1 (6 C), 129.5 (6 C), 129.6 (6 C), 129.9, 132.3, 144.3 (3 C), 144.9 (3 C), 170.2, 170.3, 170.7, 170.9, 171.8 ppm. The solvent was removed in vacuo, and the residue was purified by column chromatography (hexane/EtOAc, 2:1) to give 19 (473 mg, 95 %) as a colourless amorphous solid.…”

“…The synthesis of segment 23 was carried out starting from known D-cysteine derivative 25, [13] as shown in Scheme 5. Condensation of 25 with N-Fmoc-D-valine (12) gave dipeptide 28 in 82 % yield.…”

“…iPr 2 NEt (0.51 mL, 3.0 mmol) was added dropwise to a stirred solution of crude 29 (353 mg, 0.74 mmol) and Fmoc-D-Val-OH (12; 326 mg, 0.96 mmol) in MeCN (15 mL) containing PyBOP (576 mg, 1.1 mmol) at room temperature under argon. 13 C NMR (100 MHz, CDCl 3 ): δ = 18. The resulting residue containing Fmoc-D-Val-D-Val-D-Cys-OMe (30; 591 mg) was used in the next reaction without further purification.…”