PURPOSE: To obtain the titled compound in high yield in short reaction steps, by preparing a Grignard reagent from an easily available p-chloroprenylbenzene as a raw material with metallic magnesium, and reacting the resultant Grignard reagent with acetaldehyde.
CONSTITUTION: p-Dichlorobenzene of formulaIis reacted with metallic magnesium in a solvent, and then reacted with a prenyl halide of formula II to afford p-chloroprenylbenzene of formula III easily in high yield. The resultant compound of formula III is then reacted with metallic magnesium in an amount of 0.8W 1.5 atomic equivalents based on the compound of formula III in a solvent, e.g. tetrahydrofuran, preferably in the presence of a small amount of I2, CH3Br, etc. for activating the Mg at 100W150°C to prepare a Grignard reagent, which is then racted with acetaldehyde of formula IV at -40W+20°C to afford the aimed compound of formula V useful as an intermediate for 2-(p-prenylphenyl) propionic acid having anti-inflammatory and analgesic actions.
YOSHIKAWA YOSHINARI
SANO TATSUHIKO
OOUCHI YUTAKA
ISHIGURO MICHIHIRO
SHIONO MANZOU
FUJITA YOSHIJI
NISHIDA TAKUJI
KURARAY CO