title: Diterpenoid acids from Grindelia nana.
abstract: Two new norditerpenoid acids of the labdane-type (norgrindelic acids), 4,5-dehydro-6-oxo-18-norgrindelic acid (1) and 4beta-hydroxy-6-oxo-19-norgrindelic acid (2), as well as a new grindelic acid derivative, 18-hydroxy-6-oxogrindelic acid (3), were isolated from the aerial parts of Grindelia nana. In addition, the known compounds, 6-oxogrindelic acid, grindelic acid, methyl grindeloate, 7alpha,8alpha-epoxygrindelic acid, and 4alpha-carboxygrindelic acid were also isolated. The structures of the new compounds were characterized on the basis of spectroscopic analysis.
authors.affiliation: Department of Chemistry, Faculty of Science, El-Minia University, El-Minia 61519, Egypt.
authors.forename: A A
authors.initials: AA
authors.lastname: Mahmoud
authors.forename: A A
authors.initials: AA
authors.lastname: Ahmed
authors.forename: T
authors.initials: T
authors.lastname: Tanaka
authors.forename: M
authors.initials: M
authors.lastname: Iinuma
mesh_terms: D019659:Asteraceae / Q000737:chemistry*; D004224:Diterpenes / Q000737:chemistry / Q000302:isolation & purification*; D015394:Molecular Structure; D013057:Spectrum Analysis
chemical_list: C407787:4,5-dehydro-6-oxo-18-norgrindelic acid; C407788:4-hydroxy-6-oxo-19-norgrindelic acid; D004224:Diterpenes