Methanolysis of ustilagic acid and hydrolysis of the methyl esters formed yielded a crystalline acidic fraction which was essentially a mixture of two substances termed the ustilic acids A and B. The acids were separated as their iso-propylidene derivatives. The ustilic acids cocrystallize to mixtures with melting points intermediate between those of the pure compounds. Conversion of ustilic acid A, m.p. 112–113 °C, [α]D −8° in methanol, which made up about 70% of the mixture, by hydrogenolysis to palmitic acid, by oxidation with chromic oxide to pentadecanedioic acid, and by lead tetraacetate oxidation followed by hydrogenation to 15-hydroxypentadecanoic acid showed the substance to be an optically active form of 15,16-dihydroxyhexadecanoic acid. Conversion of ustilic acid B, m.p. 140–141 °C, [α]D−10° in methanol, by sodium bismuthate oxidation followed by hydrogenation to 1,14-dihydroxytetradecane, by chromic acid oxidation of its methyl ester followed by hydrolysis of the product, and peroxide oxidation of the α-keto acid thus formed to tetradecanedioic acid, and by hydrogenolysis of the C2-carbon atom through a series of reactions to ustilic acid A, showed the substance to be an optically active form of 2,15,16-trihydroxy-hexadecanoic acid. Optically active forms of 2,15-dihydroxypentadecanoic and 2-hydroxypentadecanoic acids were prepared from ustilic acid B. Application of certain empirical rules of rotation to derivatives of these 2-hydroxyacids showed them to possess the D-configuration. Reduction of ustilic acid B with lithium aluminum hydride gave meso-1,2,15,16-tetrahydroxyhexadecane. Thus, ustilic acid B was the 2D,15D,16-trihydroxyhexadecanoic acid and the ustilic acid A was the 15D,16-dihydroxyhexadecanoic acid. Several derivatives of the above described acids were prepared.
乌斯提酸的甲醇解和形成的甲酯的水解产物产生了一个结晶酸性分数,基本上是两种物质的混合物,称为乌斯提酸A和B。这些酸被分离为它们的异丙基亚甲基衍生物。乌斯提酸与纯化合物的熔点之间的中间熔点混合物共结晶。乌斯提酸A,熔点112-113°C,[α]D -8°(在甲醇中),约占混合物的70%,通过氢解为棕榈酸,通过铬酸氧化为戊二酸,通过乙酸铅氧化后经氢化为15-羟基戊二酸的转化表明该物质是15,16-二羟基十六烷酸的旋光活性形式。乌斯提酸B,熔点140-141°C,[α]D -10°(在甲醇中),通过硼酸钠氧化后经氢化为1,14-二羟基十四烷,通过其甲酯的铬酸氧化后经产物的水解,以及过氧化物氧化所形成的α-酮酸到戊二酸,以及通过一系列反应将C2-碳原子氢解为乌斯提酸A,表明该物质是2,15,16-三羟基十六烷酸的旋光活性形式。从乌斯提酸B制备了2,15-二羟基十五烷酸和2-羟基十五烷酸的旋光活性形式。将这些2-羟基酸的衍生物应用于某些经验旋转规则,表明它们具有D-构型。用锂铝氢化物还原乌斯提酸B得到中间-1,2,15,16-四羟基十六烷。因此,乌斯提酸B是2D,15D,16-三羟基十六烷酸,乌斯提酸A是15D,16-二羟基十六烷酸。制备了上述酸的几种衍生物。