Cipatrijugin G, a new trijugin-type limonoid bearing an uncommon γ-hydroxybutenolide unit from the aerial parts of Cipadessa cinerascens

Photoredox Catalyzed Conia-Ene-Type Cyclization/Smiles Rearrangement Cascade Reactions to Access Substituted Methylenecarbocycles

We report a novel visible-light-driven photoredox-catalyzed cascade reaction involving Conia-ene-type cyclization and Smiles rearrangement initiated from alkyne-tethered α-sulfonyl esters. This methodology not only facilitates the rapid synthesis of a broad spectrum of highly substituted methylenecarbocycles but also introduces a new mechanistic pathway with aryl group migration, surpassing the conventional 1,5-hydrogen shift typically observed in Conia-ene reactions.

Cooperative Tertiary Amine/Palladium-Catalyzed Sequential [4 + 3] Cyclization/[1,3]-Rearrangement for Stereoselective Synthesis of Spiro [Methylenecyclopentane-1,3'-oxindolines]

A cooperative tertiary amine/palladium-catalyzed sequential reaction process, proceeding via a [4 + 3] cyclization of isatin-derived Morita-Baylis-Hillman Expansion (MBH) carbonates and tert-butyl 2-(hydroxymethyl)allyl carbonates followed by a [1,3]-rearrangement, has been found and developed. A range of structurally diverse spiro[methylene cyclopentane-1,3'-oxindolines] bearing two adjacent β,γ-acyl quaternary carbon stereocenters, which are difficult to obtain by conventional strategies, were obtained in good yields. Further synthetic utility of this protocol is highlighted by its excellent regio- and stereocontrol as well as the large-scale synthesis and diverse functional transformations of the synthetic compounds. Moreover, the control experiments probably established the plausible mechanism for this sequential [4 + 3] cyclization/[1,3]-rearrangement process.

Pd(0)-Catalyzed Diastereo- and Enantioselective Intermolecular Cycloaddition for Rapid Assembly of 2-Acyl-methylenecyclopentanes

A highly regio-, diastereo-, and enantioselective trimethylenemethane (TMM) cycloaddition reaction for the rapid assembly of 2-acyl-methylenecyclopentane in an atom-economic fashion is described. This intermolecular protocol allows for facile and divergent access to an array of structurally attractive cyclic adducts. The choice of a robust chiral diamidophosphite ligand, developed by our group, proved to be crucial for the success of this transformation.

Triterpenoids

Covering: 2013. Previous review: Nat. Prod. Rep., 2015, 29, 1028-1065This review covers the isolation and structure determination of triterpenoids reported during 2013 including squalene derivatives, lanostanes, holostanes, cycloartanes, cucurbitanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, quassinoids, lupanes, oleananes, friedelanes, ursanes, hopanes, serratanes, isomalabaricanes and saponins; 350 references are cited.

Limonoids with Anti-HIV Activity from Cipadessa cinerascens

Sixteen new limonoids, named ciparasins A-P (1-16), comprising three structural categories of trijugin-type (1-7), cipadesin-type (8-15), and prieurianin-type (16) compounds, as well as 15 known limonoid analogues (17-31), were isolated from Cipadessa cinerascens. Ciparasins E-G (5-7) were found to possess a rare γ-hydroxylbutenolide moiety at C-17. Ciparasins B (2) and P (16) showed significant anti-HIV activities, with EC50 values of 5.5 ± 0.6 (SI >7.2) and 6.1 ± 0.7 (SI >6.5) μM, respectively.

A new butenolide cinnamate and other biological active chemical constituents from Polygonum glabrum

Phytochemical investigation of the methanol extract of the aerial parts of Polygonum glabrum afforded one new natural product (-)-2-methoxy-2-butenolide-3-cinnamate (1) along with six known compounds, β-hydroxyfriedalanol (2), 3-hydroxy-5-methoxystilbene (3), (-) pinocembrin (4), sitosterol-(6'-O-palmitoyl)-3-O-β-D-glucopyranoside (5), (-) pinocembrin-5-methyl ether (6) and sitosterol-3-O-β-D-glucopyranoside (7). Compound 1 showed promising in vitro anti-HIV-1 activity against primary isolates HIV-1(UG070) (X4, subtype D) and HIV-1(VB59) (R5, subtype C) assayed using TZM-bl cell line with IC50 in the range of 15.68-22.43 μg/mL. The extract showed TI in the range of 19.19-27.37 with IC50 in the range of 10.90-15.55 μg/mL. Compounds 1, 3 and 4 exhibited in vitro anti-mycobacterium activity against Mycobacterium tuberculosis H37Ra with IC50 values of 1.43, 3.33 and 1.11 μg/mL in dormant phase and 2.27, 3.33 and 1.21 μg/mL in active phase, respectively. Compound 4 was found to be the most active antiproliferative with IC50 values of 1.88-11.00 μg/mL against THP-1, A549, Panc-1, HeLa and MCF7 cell lines.

Terpenoids and their anti-feedant activity from Cipadessa cinerascens

Eight tetranortriterpenoids (1-8) and two sesquiterpenoids (9 and 10) including two new compounds, cineracipadesin G (1) and 1β-hydroperoxy-6α-hydroxy-eudesm-4(15)-ene (9), were isolated from the EtOAc extract of branches of Cipadessa cinerascens. The structures of two new compounds were elucidated by 1D and 2D NMR and MS spectroscopic analyses. The anti-feedant activity of two tetranortriterpenoids (1 and 7) was tested and obvious anti-feedant effects were detected.