Sodium hydride → [2-(2-{2-[2-(2-{4-[2-(2-{2-[2-(2-Benzyloxy-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-phenoxy}-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]acetic acid tert-butyl ester

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Reaction Steps

To an ice-cooled suspension of sodium hydride (180 mg, 4.5 mmol; 60% in mineral oil) in THF/DMF (5/1 mixed solution 7 ml), a solution of Compound 24 (817 mg, 1.28 mmol) in THF (6 ml) was gradually added; this was followed by stirring for 30 minutes. A solution of bromoacetic acid tert-butyl ester (1.0 g, 5.1 mmol) in THF (7 ml) was added thereto. After the ice bath was removed, stirring was further conducted at room temperature for 2 hours. Water was carefully added to stop the reaction, this was followed by extraction from ethyl acetate, and the combined organic phases were washed with saturated brine and dried with anhydrous sodium sulfate. After filtration and concentration under reduced pressure, the residue obtained was purified by silica gel column chromatography (Yamazen YFLC Gel, eluent (ethyl acetate-ethyl acetate solution containing 5% methanol)) to yield Compound 25 (light-yellow oil 655 mg, 68%).

Provenance & Evidence