Carbon Dioxide → HCID 10324866, compound

Participants

Reaction Steps

A 500 ml round bottom flask fitted with a magnetic stirrer, thermometer, dropping funnel, and y-tube (connected to an N2 inlet and a drying tube outlet) was charged with dry THF (150 ml), which was cooled (dry ice bath) to -60°. A solution of potassium hexamethyldislazane in toluene (0.653M, 21.0 ml, Callery Chemical Company, Callery, Pa.) was added all at once. The solution was cooled back to -70°, and a solution of the title compound of Example 53 (5.5 g, 10.6 mmol) in THF (100 ml) was added dropwise rapidly, keeping the reaction temperature at or below -62°. The mixture was then stirred in the cold bath for 30 min, and the cold bath was then removed. Stirring at room temperature for another 30 min elevated the reaction tempature to -12°. The reaction mixture was then re-immersed in the cold bath, and the temperature returned to -70°. Methyl iodide (1.05 ml, 2.40 g, 16.9 mmol) was added al at once, and after another 10 min the cold bath was removed. The reaction mixture was permitted to warm to room temperature, and 3 hr after removal of the cold bath the mixture was partitioned between a mixture of H2 0 (200 ml), 0.5N KHSO4 (50 ml), saturated brine (200 ml) and ether (200 ml). The aqueous phase was washed with ether, the organic fractions were combined, dried (MgSO4), filtered, and stripped to an oil. The oil was applied to silica gel column chromatography on using ethyl acetate-hexane eluent, giving the title compound. NMR: α methyl group at ∫2.71 A, 3 protons.

Provenance & Evidence