反应详情

A mixture of Example 78A (0.135 g, 0.5 mmol) and 3,4-diethoxy-3-cyclobutene-1,2-dione (0.22 mL, 1.5 mmol) in ethanol (5 mL) was heated at 70-80° C. for 48 hours, then filtered while still hot. The filtrate was concentrated and the resulting residue was washed with hexanes and diethyl ether, and dried to provide 0.11 g of the desired product. MS (ESI(+)) m/e 395 (M+H)+.

1. filtrationfiltered while still hot
2. concentrationThe filtrate was concentrated
3. washthe resulting residue was washed with hexanes and diethyl ether
4. customdried