Ethylene Glycol → 3-Methoxy-8-(2-methyl-[1,3]-dioxolan-2-yl)-benzo[c]chromen-6-one

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Reaction Steps

The compound from Step E (5.2 g, 19 mmol), ethylene glycol (4.4 g, 71 mmol) and a catalytic amount of p-toluenesulfonic acid (0.2 g) were dissolved in benzene (300 mL) and refluxed for 28 h. The solvent was removed and the crude product chromatographed on silica gel with hexane/ethyl acetate (2:1) to yield 3.6 g (60%) of the title compound. 1H-NMR (400 MHz, CDCl3) δH 1.75 (3H, s, CH3), 3.82 (2H, t, OCH2), 3.91 (3H, s, OCH3), 4.10 (2H, t, OCH2), 6.93 (1H, s, ArH), 6.98 (1H, d, ArH), 7.47 (3H, m, ArH), 8.04 (1H, s, ArH).

Provenance & Evidence