Tributylphosphine → 4'-chlorospiro[furo[2,3-f][1,3]benzodioxole-7,3'-indol]-2'(1'H)-one

Participants

Reaction Conditions

Reaction Steps

To a solution of 4-chloro-3-(6-hydroxy-1,3-benzodioxol-5-yl)-1,3-bis(hydroxymethyl)-1,3-dihydro-2H-indol-2-one (3.63 g, 10.0 mmol) in anhydrous tetrahydrofuran (100.0 mL) was added tributylphosphine (2.53 g, 12.5 mmol) at 0° C. followed by the solution of di-tert-butylazodicarboxylate (2.88 g, 12.5 mmol) in anhydrous tetrahydrofuran (25.0 mL). The reaction solution was stirred at 0° C. for 1 h followed by the addition of ammonium hydroxide (100.0 mL). The reaction mixture was continued to stir for another 2 h. The reaction was quenched with 10% aqueous solution of hydrochloric acid (100.0 mL). The reaction solution was extracted with ethyl acetate (3×100 mL). The combined organic solution was dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo to dryness. The residue was purified by flash chromatography with ethyl acetate in hexanes to afford 4′-chlorospiro[furo[2,3-f][1,3]benzodioxole-7,3′-indol]-2′(1′H)-one (0.98 g, 31%) as a colourless solid: mp 175-185° C.; 1H NMR (300 MHz, DMSO-d6) δ 10.81 (s, 1H), 7.24 (t, J=8.0 Hz, 1H), 6.94 (d, J=8.2 Hz, 1H), 6.86 (d, J=7.1 Hz, 1H), 6.59 (s, 1H), 6.28 (s, 1H), 5.90 (d, J=2.5 Hz, 2H), 4.74 (ABq, J=9.5 Hz, 2H); 13C NMR (75 MHz, DMSO-d6) δ 178.4, 157.0, 148.8, 144.2, 141.9, 130.9, 130.3, 129.2, 123.0, 117.5, 109.4, 103.3, 101.9, 93.3, 77.8, 58.9; MS (ES+) m/z 318.3 (M+1), 316.3 (M+1).

Provenance & Evidence