Sodium hydride → [2-(2-{2-[2-(2-{3,5-Bis-[2-(2-{2-[2-(2-benzyloxy-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-phenoxy}-ethoxy)-ethoxy]-ethoxy}-ethoxy)-ethoxy]-acetic acid tert-butyl ester

Participants

Reaction Steps

To an ice-cooled suspension of sodium hydride (175 mg, 4.4 mmol; 60% in mineral oil) in THF/DMF (4/1 mixed fluid 5 ml), a solution of Compound 47 (1.05 g, 1.09 mmol) in THF (5 ml) was gradually added, and this was followed by stirring for 30 minutes. A solution of bromoacetic acid tert-butyl ester (847 mg, 4.3 mmol) in THF (6 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, and this was followed by extraction from ethyl acetate, and the combined organic phases were washed with saturated brine and dried with anhydrous sodium sulfate. Filtration and concentration under reduced pressure were conducted, after which 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 48 (light-yellow oil 530 mg, 45%).

Provenance & Evidence