Triethylsilane → 6-Methoxy-5-methylspiro[1-benzofuran-3,3'-indol]-2'(1'H)-one

Participants

Reaction Steps

A stirred solution of 1′-(diphenylmethyl)-6-methoxy-5-methylspiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (7.2 g, 16.1 mmol), triethylsilane (15 mL) and trifluoroacetic acid (50 mL) was refluxed for 14 h. The solution was concentrated in vacuo and precipitated from hexanes to afford 6-methoxy-5-methylspiro[1-benzofuran-3,3′-indol]-2′(1′H)-one (3.9 g, 86%) as a colorless solid: mp>250° C.; 1H NMR (300 MHz, DMSO-d6) δ10.54 (s, 1H), 7.23-7.14 (m, 1H), 7.03 (d, J=6.9 Hz, 1H), 6.95-6.86 (m, 2H), 6.58 (s, 1H), 6.41 (s, 1H), 4.68 (ABq, 2H), 3.73 (s, 3H), 1.91 (s, 3H); 13C NMR (75 MHz, DMSO-d6) δ179.2, 160.4, 158.9, 142.2, 133.4, 129.1, 124.4, 124.2, 122.7, 120.3, 118.5, 110.2, 94.3, 80.1, 58.0, 56.0, 16.0; MS (ES+) m/z 282.2 (M+1).

Provenance & Evidence