2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → Pregna-1,4,20-trien-3-one

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Reaction Steps

Pregna-4,20-dien-3-one (1, 1.19 g. 3.99 mmol) was refluxed for 24 h with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ, 2.72 g, 12.1 mmol) in 40 mL of benzene under Argon. The cooled suspension was diluted with ether and washed with two 100 mL portions of 5% (w/w) sodium hydroxide, two 100 mL portions of water and once with 100 mL of brine. Ether (100 mL) was added to the resulting emulsion, which was dried over sodium sulfate and then filtered through a column of sodium sulfate (20 g). After washing the residue twice with 50 mL portions of ether the combined filtrates were concentrated under reduced pressure and then flash chromatographed (25% ethyl acetate/hexanes on silica gel) to give a slightly yellow crystalline solid (0.26 g, 0.88 mmol, 22%). (NA-119B-64)

Provenance & Evidence