A two-step method for the preparation of 3-0-(beta-carboxypropionyl-18-beta-glycyrrhetic acid (carbenoxolone) is disclosed, which comprises the steps of condensing beta-glycyrrhetic acid with anhydrous beta-carbobenzyloxypropionic acid (or a derivative thereof such as its chloride or anhydride), the result being 3-O-(beta-carbobenzyloxypropionyl)-11-oxo-18-beta-olean-12-en-30-oic acid, the latter compound being then debenzylated with hydrogen under normal temperature and pressure conditions, in an alcoholic solvent (alcohols having from C.sub.1 to C.sub.5) and in the presence of catalytic amounts of a noble metal (e.g. palladium), thus obtaining the expected compound.
揭示了一种用于制备3-0-(β-羟基丙酰基-18-β-
甘草酸(卡贝诺醇)的两步方法,包括以下步骤:将β-
甘草酸与无
水β-羟基苄氧基
丙酸(或其衍
生物,如其
氯化物或酸酐)缩合,结果得到3-O-(β-羟基苄氧基丙酰基)-11-酮-18-β-齐墩-12-烯-30-酸,然后在醇溶剂(碳数为C.sub.1至C.sub.5的醇)中,在常温和常压条件下,以催化量的贵
金属(例如
钯)的存在下,用
氢气脱苄基,从而获得预期的化合物。