反应详情

A stirred mixture of the compound of Step C, Example 2, (11.5 gm, 56.51 mmol), (carbethoxymethyl)triphenylphosphonium bromide (24.2 gm, 56.51 mmol) and triethylamine (50 mL) in benzene (200 mL), under N2, was heated to reflux for 1 hour. Water (200 mL) and ethyl acetate (200 mL) were added. The organic layer was separated, dried over magnesium sulfate and evaporated under reduce pressure to dryness. The residue was chromatographed on silica gel using hexane:EtOAc (15:5) mixture as eluent. The fractions were combined and evaporated under reduce pressure to obtain the title compound of Step D (9.3 gm, 60%) as a yellow solid; m.p. 86°-88° C.,

1. temperatureunder N2, was heated
2. temperatureto reflux for 1 hour
3. customThe organic layer was separated
4. dry with materialdried over magnesium sulfate
5. customevaporated
6. customThe residue was chromatographed on silica gel
7. customevaporated