| 摘要 |
<p>NEW MATERIAL:DL-threo-2-(3, 4-Di-lower-alkyloxy-alpha-hydroxybenzyl)isovaleric alkyl ester of formula I (R<1>-R<3> are alkyl). EXAMPLE:Ethyl DL-threo-2-(3,4-Dimethoxy-alpha-hydroxybenzyl)isovalerate. USE:A starting substance of DL-threo-3-isopropylmalic acid of formula II. PREPARATION:The aldol-condensation reaction between alkyl isovalerate of formula III and 3,4-di-lower-alkyloxybenzaldehyde of formula IV is carried out in the presence of lithium diisopropylamide in hexamethylphosphorus- triamide to give the compound of formula I. The product is protected with an acyl group in its hydroxyl into a novel compound of formula V. Then, the product is allowed to react with such an oxidizing agent as it can oxidize RuCl3, in the presence of RuCl3 as a catalyst. The compound of formula VI is hydrolyzed to give the compound of formula II.</p> |
