4-Chlorophenol → HCID 69339060, compound

Participants

Reaction Steps

(2R)-Acetylamino-2-methyl-4-[5-(3-hydroxypropynyl)thiophen-2-yl]butyl acetate (285 mg, 0.88 mmol) obtained in Example 52(a) and 4-chlorophenol (136 mg, 1.06 mmol) were dissolved in anhydrous tetrahydrofuran (5 ml), and then azodicarboxylic acid diethylester (230 mg, 1.32 mmol) and triphenylphosphine (346 mg, 1.32 mmol) were added thereto in an ice bath followed by stirring for 4 hours at room temperature. Into the reaction mixture was poured water, and the resulting solution was extracted with ethyl acetate. The ethyl acetate layer was dried over anhydrous magnesium sulfate, and the solvent was evaporated under reduced pressure. The residue was purified by chromatography on a silica gel column (elution solvent; hexane:ethyl acetate=2:1-1:3) to give (2R)-acetylamino-2-methyl-4-{5-[3-(4-chlorophenoxy)propynyl]thiophen-2-yl}butyl acetate (195 mg, 51% yield) as a yellow oil. This product was dissolved in 6 ml of a mixture solvent (tetrahydrofuran:methanol:water=1:1:1), and lithium hydroxide monohydrate (370 mg, 8.82 mmol) was added thereto followed by stirring for 6 hours at 50° C. The reaction solution was poured into water, extracted with dichloromethane, and after the dichloromethane layer was dried over anhydrous sodium sulfate, the solvent was evaporated in vacuo. The residue (175 mg, 0.50 mmol) was dissolved in ethyl acetate (5 ml), and oxalic acid (45 mg, 0.50 mmol) was added thereto to precipitate crystals. The crystals were filtered off to afford the title compound (198 mg, 86% yield) as white crystals.

Provenance & Evidence