Triphenylphosphine → 3-amino-1'-(4-methoxybenzyl)spiro[furo[3,2-f][1,2]benzisoxazole-5,3'-indol]-2'(1'H)-one

Participants

Reaction Steps

To a solution of N′,6-dihydroxy-1′-(4-methoxybenzyl)-2′-oxo-1′,2′-dihydrospiro[1-benzofuran-3,3′-indole]-5-carboximidamide (0.90 g, 2.1 mmol) and triphenylphosphine (0.71 g, 2.7 mmol) in tetrahydrofuran (30 mL) was added diethyl azodicarboxylate (0.43 mL, 2.7 mmol) at 0° C. The reaction mixture was allowed to warm to ambient temperature and was stirred for 16 h. 10% w/v aqueous sodium hydroxide (10 mL) was added and the mixture was stirred for 3 h. Most of the tetrahydrofuran was removed in vacuo and the resultant mixture was extracted with ethyl acetate (3×50 mL). The combined organic extracts were washed with water and brine, dried over anhydrous sodium sulfate and filtered. The filtrate was concentrated in vacuo. The residue was purified by column chromatography to afford 3-amino-1′-(4-methoxybenzyl)spiro[furo[3,2-f][1,2]benzisoxazole-5,3′-indol]-2′(1′H)-one (0.16 g, 19%): mp 214-216° C.; 1H NMR (300 MHz, DMSO-d6) δ 7.29-7.20 (m, 5H), 7.14-7.12 (m, 1H), 7.05 (s, 1H), 7.02-6.98 (m, 2H), 6.90-6.87 (m, 2H), 6.29 (s, 1H), 4.92-4.69 (m, 4H), 3.69 (s, 3H); 13C NMR (75 MHz, DMSO-d6) δ 177.3, 162.8, 159.1, 155.3, 148.8, 142.6, 138.1, 132.5, 129.1, 128.7, 124.5, 124.1, 123.4, 114.5, 109.9, 109.2, 93.0, 79.9, 57.9, 55.5, 42.9; MS (ES+) m/z 413.9 (M+1).

Provenance & Evidence