Hydrochloric Acid → HCID 23051869, compound

Participants

Reaction Steps

A solution of 20 g (8.12 mmol) of methyl (E)-4-hydroxy-6-(4-methoxyphenyl)-5-hexen-2-ynoate and 62 mg (~5 mol %) of 2,8-diazabicyclo[5.4.0]undec-7-ene in 80 ml of methylene chloride was stirred at 0° under argon for 35 hours. Thereafter, 25 ml of 0.1N hydrochloric acid were added and the phases are separated. The aqueous phase was extracted twice with 25 ml of methylene chloride. The combined organic fractions were dried over magnesium sulphate, filtered and evaporated. The residue was chromatographed on 130 g of silica gel with petroleum ether/ether (1:1), and there were obtained first methyl (E,E)-6-(4-methoxyphenyl)-4-oxo-2,5-hexadienoate of melting point 103°-103.5° and then methyl (2Z,5E)-6-(4-methoxyphenyl)-4-oxo-2,5-hexadienoate of melting point 54°-55°.

Provenance & Evidence