Cesium carbonate → Sodium (E)-2-((2Z,4E)-3-(3-(2-Carboxyethyl)phenyl)-5-(5-chloro-3,3-dimethyl-7-(3-sulfonatopropyl)-3H-pyrrolo[2,3-b]pyridin-7-ium-2-yl)penta-2,4-dienylidene)-3,3-dimethyl-1-(3-sulfonatopropyl)indoline-5-sulfonate

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Reaction Steps

Compound 9 (80 mg), 3-(2-carboxyethyl)phenylboronic acid (40 mg), and cesium carbonate (20 mg) were stirred into water (20 mL) under nitrogen at room temperature. Tetrakis(triphenylphosphine)palladium (0) (10 mg) were added to the reaction mixture. The mixture was refluxed for 4 h, and the solvent and volatile compounds then were evaporated under vacuum. The crude product was purified by flash chromatography on silica 60, 200-400 mesh, eluting with a 20/80 acetonitrile/water mixture. The purified compound 56 had λMeOH=680 nm, λPBS=672 nm, ε=160,000. The absorption and emission data is shown in Table 2 and FIG. 1.

Provenance & Evidence