Protosappanin A (I), C15H12O5, mp 250-251°C, was isolated from the heart-wood of Caesalpinia sappan L. (appan Lignum). It yielded a triacetate (II) on acetylation, and an alcohol (III) on reduction with sodium borohybride. On alkali fusion, I afforded sappanin (IV) along with small amounts of catechol and resorcinol. On the basis of chemical and spectroscopic evidence, the structure of I was established as 3, 10, 11-trihydroxy-7, 8-dihydro-6H-dibenz[b, d]oxocin-7-one. The result of an X-ray crystal structure analysis supported this conclusion. Protosappanin A (I) seems to be the precursor of sappanin, 2, 3', 4, 4'-tetrahydroxybiphenyl, which has been known as an artificial component of Sappan Lignum since 1872, and may be a metabolite of sappanchalcone. A possible biogenetic relationship of sappanchalcone, brazilin, and protosappanin A is discussed. Protosappanin A (I) has a weak sedative effect in mice.
                                    原苏木素 A (I),
C15H12O5,熔点 250-251°C,从 Caesalpinia sappan L. (appan Lignum)的心木中分离出来。乙酰化时生成
三乙酸酯(II),用
硼氢化钠还原时生成醇(III)。碱熔后,我得到了苏木素(IV)以及少量
儿茶酚和
间苯二酚。根据
化学和光谱证据,I 的结构被确定为 3, 10, 11-三羟基-7, 8-二氢-6H-二苯并[b, d]
氧杂卓-7-酮。X 射线晶体结构分析结果支持这一结论。
原苏木素 A (I)似乎是苏木素(2, 3', 4, 4'-四羟基
联苯)的前体,自 1872 年以来,人们就知道苏木素是苏木中的人工成分,它可能是苏木
查尔酮的代谢产物。本文讨论了苏木
查尔酮、巴西苷和
原苏木素 A 之间可能存在的
生物遗传学关系。
原苏木素 A (I) 对小鼠有微弱的镇静作用。