title: [Studies on circular dichroism of some reactional intermediates of artemisinine and artemisinine in B].
abstract: This paper reports circular dichroism, sector and the olefin octant projection of 6-pair synthetic intermediates of qinghaosu (artemisinine) and qinghaosu B (artemisinine B): gamma-lactone (compounds 1-4, 7-10), delta-lactone (compounds 5-6) and endo-alpha, beta-unsaturated-gamma-lactone (compounds 11-12). The relationship between double bond in the ring A and Cotton effect signs of different lactone chromophore has been studied. By using lactone sector rule, the olefin octant rule, allylic oxygen rule and Beecham rule with C = C-C-O and C = C-C = O chromophore, their absolute configurations were assigned. The results show that the Cotton effect signs of lactone chromophore of compounds 2, 4, 6, and 12 should be inverted while compounds 8 and 10 are independent on the double bond in ring A.
authors.affiliation: Shanghai Institute of Materia Medica, Academia Sinica.
authors.forename: J F
authors.initials: JF
authors.lastname: Mi
mesh_terms: D037621:Artemisinins; D002942:Circular Dichroism; D007783:Lactones; D008968:Molecular Conformation; D012717:Sesquiterpenes / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D037621:Artemisinins; D007783:Lactones; D012717:Sesquiterpenes; C073954:artemisinin B; C031327:artemisinin