| 摘要: | 蘇木為豆科Caesalpinia sappan L.的乾燥心材，其甲醇抽出物經過精製得到化合物中兩個構造已明瞭，一為Chalcone一為Biphenyl ; Oxocin，兩者均為新的化合物。它們均對小白鼠的Hexobarbital睡眠時間具有延長作用。
Sappan Lignum is the dried heart-wood of Gaesolpinia sappon L. (Leguminosae),This heart-wood has been used as a red colored dye for a long time. We demonstrated that the methand extract of Sappan Lignum bas sleeping-time elongation effect in mice and I started investigion of its chemical components responsible for the sedative effect.Sappanchalcone (I), yellow needles, CI6H1405, mp 199.5-200.5℃was supposed to be a chalcone derivative, because it showed signals of a methoxy group and fifteen sp2-type carbons in its 13C-NMR spectrum and because it has a strong absorpion at 363nm (ε=25000) in its UV spectrum. Furthermore it seems to be a monomethoxy-trihyroxychalcone. Structure I was concluded for sappanchalcone (I) oo the basis of comparison of its MS, UV and NMR spectral date with those of butein (=2,3,4,4-tetrahydroxychalcone). Sappanchalcone (I), 2-methoxy-3, 4, 4-trihydroxychalcone was finally synthesised from isopaeonol and protochatechualdehyde.Protosappanin A (II), colorless needles (MeOH-H20), mp 250-251℃, C15H12O5 showed the absorptions ascribable to hydroxyl, carbonyl and aromatic groups in the IR spectmm md gave a triacetate (III), mp 183-184℃, C21H18O8 on acetylation. The 13C-NMR spectrum of II, revealed the presence of a carbonyl function, two benzene rings and two methylene goups in the molecule. One of the five oxygens of II was found to form an ether linkage between a methylene and a benzene ring. II is unstable even to form an ether linkage between a methylene and a benzene ring. II is unstable even to weak alkali and afforded sappanin (IV) (= 2,3,4,4-tetrahydroxybiphenyl), mp 202-203℃, C12H10O4 along with a small amount of catechol and resorcinol on alkali fusion.The carbonyl group of II was coocluded to be am aliphatic ketone because it was reducable with NaBH4 and observed at 206 ppm in its 13C-NMR spectrum. In the 1H-NMR spectrum of the triacetate (III), each of the two methylene groups of II was observed as a 2H-singlet at 3.59 ppm and 4.56 ppm. Furthermore one of the benzene rings of II was found to have the substituents at the positions 1, 2,4 and 5 (two 1H singlets) and the other, at positions 1,2 and 4 (ABX parttern). From the above findings two altenative structures were possibly presumed for protosappanin A (II). Only one of them, 3, 4-dihydro-2, 3, 3"-tihydroxy-5:6-7:8-dibenzo-2H-oxocin-3-one, satisfactorily explained the IH-NMR chemcal shifts of triacetate (III). The result of X-ray cystal structure analysis also supported the above conclusion for protosappanin A (II). Sappanchalcone (I) seems to be the biosynthetic precursor of brazilin, the dyestuff of Sappan Lignum. protosappanin A (II) is a parental compound of sappanin which has been known as a component of Sappan Lignum since 1872 and seems to be a metabolite of sappanchalcone (I). Compounds I and II extended sleeping time caused by hexobarbital in mice. |
