Triethylamine → 2-(6-Hydroxy-3-oxo-3H-xanthen-9-yl)benzoic acid

Participants

Reaction Steps

Under argon atmosphere, to a solution of the crude 21 obtain as above in DMF (3 mL) were successively added triethylamine (29.0 μL, 208 μmol) and fluorescein isothiocyanate isomer I (FITC, 17, commercial product) (90%, HPLC) (45.0 mg, 104 μmol) at room temperature. After stirring for 17 hours at the same temperature, the reaction solution was concentrated under reduced pressure. The residue was purified by flash column chromatography (silica-gel 8 g, dichloromethane/methanol=12/1) to give 1-[2-{(11,12-didehydro-5,6-dihydrodibenzo[a,e]cycloocten-5-yl)oxycarbonylamino}ethyl]-3-(5-fluoresceinyl)thiourea (22) (59.0 mg, 84.8 μmol, 80.7% based on 17) as a yellow solid.

Provenance & Evidence