Activity-guided fractionation of a methanol extract of the leaves of Ilex kudincha led to the isolation of seven acyl CoA cholesteryl acyl transferase (ACAT) inhibitory triterpenes. Four of them were identified by spectroscopic methods as ulmoidol (4), 23-hydroxyursolic acid (5), 27-trans-p-coumaroyloxyursolic acid (6), and 27-cis-p-coumaroyloxyursolic acid (7), and three were new compounds named ilekudinols A-C (1-3). The structures of these new triterpenoids were elucidated as 2alpha, 3beta-dihydroxy-24-nor-urs-4(23),11-dien-28,13beta- olide (1), 2alpha, 3beta-dihydroxy-24-nor-urs-4(23),12-dien-28-oic acid (2), and 3beta, 24,28-trihydroxylupane (3). Compounds 1-7 showed potent inhibitory activity in the ACAT assay.

A contracted doubly N-confused dioxohexaphyrin derivative served as a dinucleating metal ligand for unsymmetrical coordination. The complexation of two palladium(II) cations led to the formation of π-radical species that were persistent in atmospheric air in the presence of moisture. Effective delocalization of an unpaired electron over the hexaphyrin backbone could contribute to the distinct chemical stability.

Ten new triterpene saponins, ilekudinosides A-J (2, 6-8, 10, 13-17), together with seven known triterpene saponins, ilexoside XLVIII (1); cynarasaponin C (5); latifolosides A (9), C (3), G (12), and H (4); and kudinoside G (11), were isolated from an aqueous extract of the leaves of Ilex kudincha. They possessed oleanane- and ursane-type triterpenoids as the aglycons. The structures were elucidated by 1D and 2D NMR experiments, including ROE difference, HOHAHA difference, 1H-1H COSY, and 1H-13C COSY (HMQC, HMBC) methods and sugar analysis. Compounds 1 and 5 exhibited acyl CoA cholesteryl acyl transferase (ACAT) inhibitory activity.

Macrocyclic compounds generally possess flexible skeletons, which results in them having a variety of conformations or molecular shapes. In the case of macrocycles with p systems, the conformation governs their electronic states, as well as their reactivity. As a result of the recent developments in the synthesis of expanded porphyrins, [1] many studies of the relationships between their conformations and electronic properties have been reported. [2] Peripheral modification of expanded porphyrins to construct rigid frameworks have also been investigated. [3] Importantly, expanded porphyrins purely composed of regular pyrroles (connected to the meso-carbon atoms at the a,a'-positions) are often less stable or in a metastable state, and undergo skeletal transformation induced by external stimuli. In particular, metal coordination can trigger unique skeletal transformations. For example, heptaphyrins and octaphyrins were split in two upon metal coordination. [4,5] A notable example of such a skeletal transformation is a "confusion reaction", for example, the conversion of a regular hexaphyrin into doubly N-confused dioxohexaphyrin through oxidative copper metalation. [6] The results of this particular reaction suggest that N-confused pyrroles (connected to the meso-carbon atoms at the a,b'positions) would stabilize the skeleton of expanded porphyrins. Herein, we describe a palladium-induced unique skeletal rearrangement from a singly N-confused hexaphyrin to a doubly N-confused hexaphyrin, to give a bis(Pd II ) complex of doubly N-confused [26]hexaphyrin 2 with a markedly decreased HOMO-LUMO band gap of less than 1 eV. This is the first example of organometallic doubly N-confused hexaphyrin complexes and of a cis-configured doubly Nconfused hexaphyrin.The palladium-induced skeletal rearrangement reaction was discovered during a study on palladium coordination chemistry of the singly N-confused [26]hexaphyrin 1 (Scheme 1 a). [7] A solution of 1 and 5 equivalents of PdCl 2 in acetonitrile was heated at reflux for 30 min and, after the usual workup and chromatographic separation, the bis(Pd II ) complex of doubly N-confused [26]hexaphyrin 2 was isolated in 24 % yield. Complex 2 was stable both as a solid and in solution under ambient conditions. The laser desorption/ ionization mass spectrum of 2 displayed the parent ion signal around m/z = 1670, thus indicating that it could be the bis(Pd) complex. The 1 H NMR and 19 F NMR spectra of 2 in CDCl 3 at room temperature suggest a C s symmetric structure. A singlet signal assignable to the b-CH of N-confused pyrrole rings was observed at d = 8.80 ppm (2 H). In the 1 H NMR spectrum, a pair of doublet signals corresponding to two regular pyrrole rings appeared at 8.34 and 8.25 ppm (both 2 H, J = 4.9 Hz) and a singlet signal corresponding to the remaining two regular pyrrole rings appeared at 8.50 ppm (4 H). Signals for six meso-C 6 F 5 groups are observed in a 2:2:1:1 ratio, thus supporting the C s symmetric structure. [8] When the reaction of 1 was performed with 1 equiva...

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