title: Kopsihainanines A and B, two unusual alkaloids from Kopsia hainanensis.
abstract: Kopsihainanine A (1), an unprecedented skeleton with a 6/5/6/6/6 pentacyclic rearranged ring system, together with a new biogenetically related compound, kopsihainanine B (2), were isolated from Kopsia hainanensis. Their structures were elucidated by means of spectroscopic methods. The absolute configuration of 1 was determined by ECD calculation.
authors.affiliation: State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Lanzhou University, Lanzhou, 730000, People's Republic of China.
authors.forename: Jia
authors.initials: J
authors.lastname: Chen
authors.forename: Jian-Jun
authors.initials: JJ
authors.lastname: Chen
authors.forename: Xiaojun
authors.initials: X
authors.lastname: Yao
authors.forename: Kun
authors.initials: K
authors.lastname: Gao
mesh_terms: D000470:Alkaloids / Q000737:chemistry*; D029062:Apocynaceae / Q000737:chemistry*; D002478:Cells, Cultured; D002800:Cholinesterase Inhibitors / Q000737:chemistry*; D002942:Circular Dichroism; D018360:Crystallography, X-Ray; D006576:Heterocyclic Compounds, 4 or More Rings; D006801:Humans; D020128:Inhibitory Concentration 50; D015394:Molecular Structure; D019906:Nuclear Magnetic Resonance, Biomolecular; D035261:Plant Components, Aerial / Q000737:chemistry
chemical_list: D000470:Alkaloids; D002800:Cholinesterase Inhibitors; D006576:Heterocyclic Compounds, 4 or More Rings; C562138:kopsihainanine A; C562137:kopsihainanine B