The absolute configuration of the antifungal antibiotic cercosporamide was established as C-9b-(−)-(S) by correlation with synthetic (+)-8-methylcercosporamide. This was accomplished via conversion of the isoxazole (6) available from (+)-usnic acid. Structure revision of the key isoxazole (6), previously assigned structure (5), is described; some of the 13C-assignments for usnic acid made by previous
                                    通过与合成的(+)-8-甲基cercosporamide相关,将抗真菌抗生素cercosporamide的绝对构型确定为C-9b-(-)-(S)。这通过转化可得自(+)-
松香酸的
异恶唑(6)来完成。描述了关键的
异恶唑(6)的结构修改,它是先前指定的结构(5);以前的工作人员针对
松萝酸所做的13个C分配中的一些也已得到纠正。