12-(2,5-Dimethoxy-3,4,6-trimethylphenyl)dodeca-2,7-diyn-1-ol → HCID 20435432, compound

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Reaction Steps

By a similar manner to Example 1, 3.56 g (10 mmoles) of 1-(12-hydroxydodeca-5,10-diynyl)-2,5-dimethoxy-3,4,6-trimethylbenzene (II: R=R1 =CH3, Y=CH2OH) was oxidized with chromic acid-sulfuric acid, whereby 12.62 g of 1,4-dimethoxy-2,3,5-trimethyl-6-(11-carboxyundeca-5,10-diynyl)benzene was obtained as an oily substance. In a mixed solvent of acetonitrile (40 ml) and water (20 ml) were dissolved 2.60 g (7.0 mmole) of the compound obtained above and 3.80 g (7.0×3 mmoles) of 2,6-dicarboxypyridine N-oxide, and the solution was stirred under cooling with ice. An ice-cooled solution of ceric ammonium nitrate (11.4 g, 7.0×3 mmoles) in 50% aqueous acetonitrile (60 ml) was added dropwise to the above solution over a period of 30 minutes, followed by stirring under the same conditions for 30 minutes and at room temperature for 30 minutes. After the completion of the reaction, insolubles were filtered out, and the acetonitrile was distilled off under reduced pressure. To the residue were added isopropyl ether (100 ml) and water (20 ml) for extraction, and the organic layer was washed with saturated sodium bicarbonate and aqueous sodium chloride, successively and dried (over MgSO4), followed by distilling off the organic solvent under reduced pressure. The residue was chromatographed on a column of silica gel developing with isopropyl ether:ethyl acetate (98:2 to 95:5) to give 2.10 g of 2,3,5-trimethyl-6-(11-carboxyundeca-5,10-diynyl)-1,4-benzoquinone. m.p. 49°-51° C.

Provenance & Evidence