| 摘要 |
<p>NEW MATERIAL:A 25-hydroxy-3,24-dioxochelesta-1,4,6-triene shown by the formula I (R is H or OH-protecting group). EXAMPLE:25-Acetoxy-3,24-dioxocholesta-1,4,6-triene. USE:An intermediate for an active type vitamin D3(e.g, 1alpha,24,25-trihydroxy VD3 or 1alpha, 25-dihydroxy-24-oxo VD3). PROCESS:A 3alpha-25-dihydroxy-24-oxocholesto-5-ene shown by the formula II is reacted with 2,3-dichloro-5,6-dicyanobenzoquinone in an inert solvent(e.g., hexane, THF, etc.), and, if necessary, the protecting group(e.g., acyl) is removed to give a compound shown by the formula I. The reaction is carried out using 2,3-dichloro-5,6- dicyanobenzoquinone in an amount 1-10 times as much as the equivalent of the compound shown by the formula II at 70-200 deg.C for 1-50 hours.</p> |
