3-Isopropoxy-4-(tri-n-butylstannyl)-3-cyclobutene-1,2-dione → HCID 86750789, compound

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Reaction Steps

A mixture of the product of Example 30 (c) (0.8 g), 3-isopropoxy-4-tributylstannylcyclobut-3-ene-1,2-dione (0.9 g), tetrakis(triphenylphosphine)palladium(0) (0.2 g), cuprous iodide (0.1 g) and dry dimethylformamide (5 ml) was stirred at ambient temperature under a nitrogen atmosphere for approximately 17 hours. The solvent was evaporated under reduced pressure and the resulting residue was dissolved in diethyl ether (150 ml). The solution obtained was washed with saturated aqueous ammonium chloride solution (50 ml), then with saturated aqueous potassium fluoride solution (2×50 ml) and then dried over magnesium sulphate. The solvent was evaporated and the residue obtained was purified by flash chromatography on silica gel (eluting with dichloromethane/methanol (50:1)) to give the intermediate compound (E)-methyl 2-benzyl-3-[2-butyl-4-chloro-1-[4-(2-isopropoxy-3,4-dioxocyclobut-1-en-1-yl)benzyl]-1H-imidazol-5-yl]propenoate as an oil (0.4 g).

Provenance & Evidence