Cipacinoids E-O: Eleven limonoids represent two different scaffolds from Cipadessa cinerascens

Eleven new limonoids named cipacinoids E-O (1-11) including nine methyl angolensate-type limonoids (1-9) and two havanensin-type limonoids (10 and 11), as well as seven reported limonoids (12-18), were isolated from the leaves of Cipadessa cinerascens. The structures of these limonoids were identified by analyses of spectroscopic data and by using the methods of quantum-chemical calculation. Cipaci-noids E-G (1-3) are the first cases possessing an additional six-membered lactone ring formed by intramolecular transesterification between 9-OH and C-7 methyl ester. (c) 2021 Elsevier Ltd. All rights reserved.