Tetrahydrofuran → (S)-2-amino-7'-(pyridin-3-yl)-5H-spiro[oxazole-4,9'-xanthen]-2'-ol

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Reaction Steps

A 75-mL pressure vessel was charged with (R)-2-amino-2′-bromo-5H-spiro[oxazole-4,9′-xanthen]-7′-ol (3.25 g, 9.36 mmol), pyridin-3-ylboronic acid (2.88 g, 23.40 mmol), tetrakis(triphenylphosphine)palladium(0) (1.081 g, 0.936 mmol), THF (46.8 mL), and potassium carbonate (23.40 mL, 46.8 mmol) (as a 2.0 M aq. solution). The vessel was sealed and placed in a 100° C. oil bath for 6 hours. The mixture was partitioned between EtOAc (50 mL) and water (50 mL). The layers were separated, and the aqueous layer was extracted with EtOAc (2×30 mL. The combined mixture was dried over sodium sulfate and filtered with the aid of 10% MeOH/CH2Cl2. The filtrate was evaporated to give a yellow solid. This solid was taken up in CH2Cl2 (80 mL) and sonicated for 5 min. The solid was filtered and washed with CH2Cl2 (2×40 mL), then air-dried on the filter. The filtrate was evaporated and again taken up in CH2Cl2 (80 mL). The mixture was sonicated for 10 min, then filtered and washed with CH2Cl2 (30 mL). The solid was air-dried and combined with the first solid to give (S)-2-amino-7′-(pyridin-3-yl)-5H-spiro[oxazole-4,9′-xanthen]-2′-ol. MS m/z=346.0 [M+H].

Provenance & Evidence