title: Absolute configurations of four resorcylic acid lactones, paecilomycins J-M, by CD/TDDFT calculations.
abstract: The absolute configurations of four resorcylic acid lactones (RALs), paecilomycins J-M (1-3 and 5), were assigned by Time-Dependent Density-Functional Theory (TDDFT) calculations of their electronic circular dichroism (CD) spectra. The previously reported structure 4 for paecilomycin M was found to be incorrect and should be changed to structure 5. Analysis of structure-spectrum relationship for this group of RALs suggested that V'-shape conformations give type I CD spectra (two negative Cotton effects around 300 and 260 nm, a positive Cotton effect around 220 nm) while V-shape conformations yield type II spectra (signs of three Cotton effects were opposite to those in type I).
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, China.
authors.forename: Liang-Xiong
authors.initials: LX
authors.lastname: Xu
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Xue
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Xiao-Ying
authors.initials: XY
authors.lastname: You
authors.forename: Xiao-Yi
authors.initials: XY
authors.lastname: Wei
mesh_terms: D002942:Circular Dichroism; D062385:Hydroxybenzoates / Q000737:chemistry*; D007783:Lactones / Q000737:chemistry*; D018942:Macrolides / Q000737:chemistry*; D011789:Quantum Theory; D012118:Resorcinols / Q000737:chemistry*; D013729:Terpenes / Q000737:chemistry*; D013816:Thermodynamics
chemical_list: D062385:Hydroxybenzoates; D007783:Lactones; D018942:Macrolides; D012118:Resorcinols; D013729:Terpenes; C520312:paecilomycine A
keywords: Paecilomyces sp; RALs; chiroptical properties; circular dichroism; fungi; natural products, polyketides; quantum chemical calculation