| 摘要 |
NEW MATERIAL:A compound shown by formula I[R<1> is H, (substituted) 1-10C alkyl or (substituted) 3-10C cycloalkyl; R<2> and R<3> are H, tri(1-7C)hydrocarbon silyl or group which is linked to 0atom of OH group to form acetal bond or ester bond; R<4> is H or OR<5> (R<5> is as shown for R<2> and R<3>)]. EXAMPLE:23-Hydroxy-3beta-methoxymethoxy-cholesta-5, 25-dien-26-oic acid ethyl ester. USE:An intermediate for synthesizing vitamin D3 compound, having antiulcer activity, antiviral activity, etc. PREPARATION:A 2-halomethylpropenoic acid ethyl ester shown by formula III[X is Cl, Br or I; R'' is (substituted) alkyl or (substituted) cycloalkyl is added to a steroid-23-aldehyde shown by formula II[R<31> is tri(1-7C)hydrocarbon silyl or group which is linked to 0atom of OH to form acetal bond or ester bond; R<41> is H or OR<51> (R<51> is as shown for R<31>)] in the presence of a low lavence metal having reducing power.
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