Benzene → HCID 86733431, compound

Participants

Reaction Conditions

Reaction Steps

10.5 Parts of 4-acetoxy-1-bromo-2-methyl-2-butene is added dropwise to a mixture of 1.0 part of sodium metal, 10.2 parts of diethyl malonate and 5.3 volume parts of benzene. After the dropwise addition has been completed, the mixture is stirred at 10°C for 1 hour and, following the addition of water, extracted with diethyl ether. The extract is washed with water, dried and evaporated to dryness under reduced pressure. The resultant residue is purified by column chromatography to obtain 6.17 parts of ethyl 4-acetoxy-2-methyl-2-butenylmalonate and 2.55 parts of ethyl 4-hydroxy-2-methyl-2-butenylmalonate. 1.74 part of ethyl 4-acetoxy-2-methyl-2-butenylmalonate and 1.09 part of 2,3,5-trimethylhydroquinone are dissolved in 30 volume parts of dioxane and warmed to 50°C-60°C. Then, under stirring in a current of nitrogen gas, a mixture of 5 volume parts of 47 % boron trifluoride-ethyl ether and 15 volume parts of dioxane is added dropwise. The reaction mixture is stirred for 4 hours and, following the addition of water, extracted with ether. The extract is washed with water, dried and evaporated to dryness under reduced pressure. The residue is dissolved in 30 volume parts of methanol and mixed under vigorous stirring with a 100 volume parts of 30 % solution of ferric chloride. The mixture is extracted with 500 volume parts of diethyl ether and the extract is washed with water, dried and distilled free of the solvent under reduced pressure. The residue is purified by chromatography on silicic acid and the fractions eluted with ether-hexane (1:19) are pooled and evaporated to dryness under reduced pressure. The described procedure gives 1.31 part of 2,3,5-trimethyl-6-(5',5'-diethoxycarbonyl-3'-methyl-2'-pentenyl)-1,4-benzoquinone (the quinone corresponding to Formula (V) wherein R=H3C; OY, OY'=OH, Z=C2H5), as a yellowish oil.

Provenance & Evidence