Total synthesis of plagiochin G and derivatives as potential cancer chemopreventive agents

Visible-Light-Induced Oxidative Decarboxylative Coupling of Phenylacetic Acid Derivatives Using SF6 as an Oxidant

A visible-light-mediated decarboxylative coupling reaction of phenylacetic acid derivatives, featuring sulfur hexafluoride (SF6) as the oxidant, has been developed. This metal-free method allows for the synthesis of a series of bibenzyl derivatives and complex all-carbon skeletons, facilitating efficient utilization and degradation of the greenhouse gas SF6.

Redox Inversion: A Radical Analogue of Umpolung Reactivity for Base- and Metal-Free Catalytic C(sp3)-C(sp3) Coupling

The construction of alkyl-alkyl bonds is a powerful tool in organic synthesis. Redox inversion, defined as switching the donor/acceptor profile of a functional group to its acceptor/donor profile, is used for C(sp³)-C(sp³) coupling. We report a photocatalytic coupling of carboxylic acids to form bibenzyls through a radical-radical coupling. Mechanistic insight is gained through control reactions. This unexplored redox-opposite relationship between a carboxylic acid and its redox-active ester is implemented in catalysis.

Bis-bibenzyls, Bibenzyls, and Terpenoids in 33 Genera of the Marchantiophyta (Liverworts): Structures, Synthesis, and Bioactivity

The Marchantiophyta (liverworts) are rich sources of phenolic substances, especially cyclic and acyclic bis-bibenzyls, which are rare natural products in the plant kingdom, together with bibenzyls and characteristic terpenoids. At present, more than 125 bis-bibenzyls have been found in liverworts. They are biosynthesized from the dimerization of lunularic acid via dihydrocoumaric acid and prelunularin. The structurally unusual cyclic and acyclic bis-bibenzyls show various biological activities such as antimicrobial, antifungal, cytotoxic, muscle relaxation, antioxidant, tubulin polymerization inhibitory, and antitrypanosomal activities, among others. The present review article deals with the distribution and structure of bis-bibenzyls, bibenzyls, and several characteristic ent-sesqui- and diterpenoids in liverworts. Furthermore, the biosynthesis and total syntheses and biological activities of bis-bibenzyls are also surveyed.

Design, Synthesis and Biological Evaluation of Phenyl Urea Derivatives as IDO1 Inhibitors

Indoleamine 2,3-dioxygenase 1 (IDO1) is a heme-containing intracellular enzyme that catalyzes the first and rate-determining step of tryptophan metabolism and is an important immunotherapeutic target for the treatment of cancer. In this study, we designed and synthesized a new series of compounds as potential IDO1 inhibitors. These compounds were then evaluated for inhibitory activity against IDO1 and tryptophan 2,3-dioxygenase (TDO). Among them, the three phenyl urea derivatives i12, i23, i24 as showed potent IDO1 inhibition, with IC₅₀ values of 0.1–0.6 μM and no compound exhibited TDO inhibitory activity. Using molecular docking, we predicted the binding mode of compound i12 within IDO1. Compound i12 was further investigated by determining its in vivo pharmacokinetic profile and anti-tumor efficacy. The pharmacokinetic study revealed that compound i12 had satisfactory properties in mice, with moderate plasma clearance (22.45 mL/min/kg), acceptable half-life (11.2 h) and high oral bioavailability (87.4%). Compound i12 orally administered at 15 mg/kg daily showed tumor growth inhibition (TGI) of 40.5% in a B16F10 subcutaneous xenograft model and 30 mg/kg daily showed TGI of 34.3% in a PAN02 subcutaneous xenograft model. In addition, the body weight of i12-treated mice showed no obvious reduction compared with the control group. Overall, compound i12 is a potent lead compound for developing IDO1 inhibitors and anti-tumor agents.

Chemotypes and Biomarkers of Seven Species of New Caledonian Liverworts from the Bazzanioideae Subfamily

Volatile components of seven species of the Bazzanioideae sub-family (Lepidoziaceae) native to New Caledonia, including three endemic species (Bazzania marginata, Acromastigum caledonicum and A. tenax), were analyzed by GC-FID-MS in order to index these plants to known or new chemotypes. Detected volatile constituents in studied species were constituted mainly by sesquiterpene, as well as diterpene compounds. All so-established compositions cannot successfully index some of them to known chemotypes but afforded the discovery of new chemotypes such as cuparane/fusicoccane. The major component of B. francana was isolated and characterized as a new zierane-type sesquiterpene called ziera-12(13),10(14)-dien-5-ol (23). In addition, qualitative intraspecies variations of chemical composition were very important particularly for B. francana which possessed three clearly defined different compositions. We report here also the first phytochemical investigation of Acromastigum species. Moreover, crude diethyl ether extract of B. vitatta afforded a new bis(bibenzyl) called vittatin (51), for which a putative biosynthesis was suggested.

Direct evidence of specific localization of sesquiterpenes and marchantin A in oil body cells of Marchantia polymorpha L

Liverworts are a rich source of a diverse array of specialized metabolites, such as terpenoids and benzenoids, which are potentially useful for pharmaceutical or agrochemical applications, and also provide clues to elucidate the strategy by which liverworts adapt to the terrestrial environment. Liverworts, belonging to orders Marchantiales and Jungermanniales, possess oil bodies. In Marchantia polymorpha L., oil bodies are confined to scattered idioblastic oil body cells. It has been assumed that the specialized metabolites in M. polymorpha specifically accumulate in the oil bodies in oil body cells; however, no direct evidence was previously available for this specific accumulation. In this study, direct evidence was obtained using micromanipulation techniques coupled with MS analysis that demonstrated the specific accumulation of sesquiterpenoids and marchantin A in the oil body cells of M. polymorpha thalli. It was also observed that the number of oil body cells increased in thalli grown in low-mineral conditions. The amounts of sesquiterpenoids and marchantin A detected in crude extract prepared from the whole thallus were roughly proportional to the number of oil body cells found in a given volume of thallus, suggesting that oil body cell differentiation and sesquiterpenoid and marchantin A biosynthetic pathways are coordinated with each other.