2,3-Dichloro-5,6-dicyano-1,4-benzoquinone → 25-Hydroxycholesta-1,4,6-trien-3-one

Beteiligte Stoffe

Reaktionsschritte

25-Hydroxycholesterol (I) (10.0 gm, 0.0248 mol) was dissolved in 290 ml of dry dioxane. 2,3-Dichloro-5,6-dicyano-1,4-benzoquinone (18.62 gm, 0.082 mol) was added and the reaction was refluxed 14 hours. The reaction mixture was allowed to cool and then filtered. The filtrate was concentrated, in vacuo, to give 14.7 gm red-brown solid. This solid was taken up in 40 ml ethyl acetate and chromatographed on 250 gm neutral alumina, eluting with ethyl acetate. Product-containing fractions were combined, concentrated and recrystallized from 50 ml ethyl acetate giving 5.80 g of the title compound (58%): m.p. 179.5°-181.5° C.; nmr (CDCl3): δ0.76 (s,3H,C19CH3), 1.20 (s,9H,C18 +C26 +C27CH3 's), 2.04 (s,1H,OH), 6.10 (m,4H,C2 +C4 +C6 +C7H's), 7.10 (d,J=12 Hz, 1H,C1H); UV (ethanol) λmax 225, 257, 299 nm.

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