Cesium carbonate → HCID 59352350, compound

Participants

Reaction Steps

A suspended mixture of 5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-2′(1′H)-one (1.00 g, 3.3 mmol), methyl 2-(chloromethyl)oxazole-4-carboxylate (2.00 g, 11.4 mmol) and cesium carbonate (4.00 g, 12.3 mmol) in butanone (50 mL) was refluxed for 5 h under nitrogen. The reaction mixture was cooled to ambient temperature and filtered. The solid was washed with acetone (50 mL). The filtrate was concentrated in vacuo to dryness. The residue was purified by column chromatography with a 30% to 70% gradient of ethyl acetate in hexanes to afford methyl 2-[(2′-oxo-5,6-dihydrospiro[benzo[1,2-b:5,4-b′]difuran-3,3′-indol]-1′(2′H)-yl)methyl]-1,3-oxazole-4-carboxylate (0.88 g, 61%) as a colorless solid: 1H NMR (300 MHz, DMSO-d6) δ 8.17 (s, 1H), 7.27-6.91 (m, 4H), 6.53 (s, 1H), 6.38 (s, 1H), 5.12 (ABq, 2H), 4.81 (ABq 2H), 4.51 (t, J=8.7 Hz, 2H), 3.89 (s, 3H), 3.04-2.91 (m, 2H); 13C NMR (75 MHz, DMSO-d6) δ177.6, 161.9, 161.2, 161.2, 159.2, 145.0, 141.0, 133.6, 132.5, 129.0, 124.1, 120.1, 119.9, 199.1, 108.8, 93.2, 80.5, 72.4, 57.7, 52.3, 37.2, 29.0; MS (ES+) m/z 419.2 (M+1).

Provenance & Evidence