Lithium Hexamethyldisilazide → HCID 21476927, compound

Participants

Reaction Steps

To a magnetically stirred solution of 0.531 g (1.47 mmol) of the product of Example 1 dissolved in 2.0 mL of DMSO was added 4.40 mL of a 1.0M solution of lithium bis(trimethylsilyl)amide in THF under a nitrogen atmosphere at a temperature just warm enough to prevent the DMSO from solidifying (approximately 18° C.). During the addition of the base, the reaction mixture was further cooled to 0°-50° C. with an ice-water bath. When the addition was complete, the reaction mixture was stirred for 1 hour at 0°-5° C., then a solution of 0.496 g (1.84 mmol) of the product of Step E dissolved in 2.0 mL of THF was added via syringe. The ice-water bath was then removed and the reaction mixture was stirred at room temperature for an additional hour. The mixture was next partitioned between EtOAc and 10% aqueous NaHSO4, and extracted. The organic layer was separated, washed with saturated brine, dried (MgSO4), filtered, and evaporated. The residue was partially purified on a silica gel flash chromatography column eluted with 1% MeOH--CHCl3. After evaporation of the product containing fractions the residue was rechromatographed on a silica gel flash chromatography column eluted with 5% EtOAc--CHCl3. Evaporation of the product containing fractions and drying in vacuo afforded 0.284 (36%) of the title compound as an amorphous white solid.

Provenance & Evidence