反应详情

1-Bromo-2-pentadecyne (0.01 mole) and triphenylphosphine (0.01 mole) are mixed in ether to give pentadec-2-ynyl-triphenylphosphonium bromide. The salt (0.01 mole) is dissolved in absolute ethanol containing one equivalent of sodium ethoxide. Ethyl 5-oxopentanoate (0.01 mole) is added and the mixture is refluxed for 24 hours to give a mixture of cis-and-trans ethyl 5-eicosen-7-ynoate. The isomers are separated by chromatography and the trans isomer is converted to 5-hydroxy-6-(1,4-dimethyl-5-carboxy-2-imidazolylthio)-7-eicosynoic acid as described in Example 14(c).