Dimethyl 7-Oxabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate synthesis

Yield:1829-60-3 70%

Reaction Conditions:

in diethyl ether at 20; for 168 h;

Steps:

1
Furan (0.64 mL, 10 mmol) and dimethyl acetylenedicarboxylate (DMAD, 1.22 mL, 10 mmol) were dissolved in 4 mL ether. The mixture was stirred for 7 days at room temperature. Water (10 mL) was added and the layers were separated. The water layer was extracted with ether (15 mL). The combined ether layers were washed with brine (20 mL). The organic layer was dried over Na2SO₄ and concentrated in vacuo. The obtained liquid was purified by column chromatography (EtOAc/n-heptane, 1/1) resulting in the desired product (1.48 g (70%), light yellow liquid). R_f = 0.6 (EtOAc/n-heptane 1/1). ¹H- NMR (300 MHz, CDCl₃) δ (ppm): 7.22 (s, 2H), 5.68 (s, 2H), 3.83 (s, 6H). ¹³C-NMR (75 MHz, CDCl₃) δ (ppm): 162.7, 152.5, 142.8, 84.6, 51.9. LCQ MS(ESI+) m/z (%) 210.9 (100) [M+H]⁺.

References:

STICHTING VOOR DE TECHNISCHE WETENSCHAPPEN;STICHTING KATHOLIEKE UNIVERSITEIT NIJMEGEN WO2008/75955, 2008, A2 Location in patent:Page/Page column 16

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