Sodium Hydroxide → Zeaxanthin

Participants

Reaction Conditions

Reaction Steps

32.88 g (95.8%; 2.03 eq.) of [5-(4-hydroxy-2,6,6-trimethyl-1-cyclohexenyl)-3-methyl-2,4-pentadienyl]triphenylphosphonium chloride and 4.92 g (1 eq.) of 2,7-dimethyl-2,4,6-octatrien-1,8-dial (C10 -dial) in 490 ml of ethanol were placed in a 500 ml four-necked sulphonation flask equipped with an internal thermometer, stirrer and reflux condenser and cooled to -10° C. while stirring. A solution of 3.60 g of sodium hydroxide in 50 ml of ethanol was added dropwise to the resulting yellowish suspension at -10° C. while stirring and subsequently the reaction mixture was stirred at -10° C. for one hour. After heating to about 80° C. internal temperature within 30 minutes the product suspension was heated at reflux temperature during the following 17 hours. Subsequently, it was cooled to 0° C. and stirred for a further 1 hour, and the thus-obtained zeaxanthin was isolated by suction filtration. Then the filter cake was washed well with ethanol and subsequently freed from neutral salt with water.

Provenance & Evidence