2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → HCID 10060389, compound

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Reaction Steps

Compound 12 (3.00 g, 12.2 mmol) was dissolved in 25 mL of benzene and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (2.80 g, 12.2 mmol) was added slowly with stirring and stirring was continued for 3 h. The reaction mixture was filtered through a short column of alumina which was washed with dichloromethane. The solvent was evaporated from the colorless eluant and the residual product was crystallized from petroleum ether to give 2.83 g (11.6 mmol, 95%) of 18 as colorless microcrystalline plates: mp 62-63° C.; 1H NMR: δ1.51 (d, J=7.2 Hz, 6H), 2.50 (s, 3H), 3.88 (s, 3H), 3.90 (sept, J=7.2 Hz, 1H), 3.94 (s, 3H), 7.01 (s, 1H), 7.20 (d, J=8.3 Hz, 1H), 7.60 (d, J=8.3 Hz, 1H), 7.88 (s, 1H). Anal. (C16H20O2) C, H. 8-Deoxyhemigossypol dimethyl ether (19; 2,3-dimethoxy-6-methyl-4-(1-methylethyl)-1-naphthaldehyde. A reaction mixture consisting of 18 (2.5 g, 10.2 mmol) and dichloromethyl methyl ether (3 g, 2.4 ml, 26.5 mmol) in 20 mL of dichloromethane under nitrogen was cooled in an ice bath. Titanium tetrachloride (1.5 ml, 14 mmol) was added slowly with stirring. The mixture was stirred into 100 g of ice with 10 mL of 6 M HCl and the reaction mixture was extracted with ether. The ether layer was washed with water and brine and dried over magnesium sulfate. Petroleum ether was added, the solution was concentrated and the product was allowed to crystallize to give 2.28 g (8.36 mmol, 82%) of 19 as light yellow crystals: mp 103-104° C.; IR 16865 (aldehyde); 1H NMR δ1.52 (d, J=7.2 Hz, 6H), 2.50 (s, 3H), 3.91 (s, 3H), 3.99 (sept, J=7.2 Hz, 1H), 4.02 (s, 3H), 7.38 (d, J=8.7 Hz, 1H), 7.93 (br s, 1H), 9.16 (d, J=8.7 Hz, 1H), 10.75 (s, 1H). Anal. (C17H20O3) C, H.

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