ABSTRACT
A novel class of alkyne-tethered amides facilitates an unprecedented photoinduced palladium-catalyzed radical relay formal [5 + 2] reaction. This innovative strategy allows for the rapid construction of diverse fused benzoazepine structures, yielding structurally novel and compelling compounds. With a broad substrate scope and excellent functional group tolerance, the methodology synthesizes biologically active compounds. Notably, the resulting tricyclic benzo[b]azepines offer diversification opportunities through simple transformations. DFT calculations elucidate a seven-membered ring closure mechanism involving the alkenyl radical and Pd(I) rebound alongside a concerted metalation-deprotonation (CMD) process.
ABSTRACT
Here, a palladium-catalyzed photoinduced N-to-alkyl radical relay Heck reaction of o-alkylbenzamides at benzylic sites with vinyl arenes is described. The reaction employs neither exogeneous photosensitizers nor external oxidants. It is proposed to proceed via a N-to-alkyl hybrid palladium-radical mechanism which occurs under mild conditions that are compatible with a wide range of functional groups. The products are easily transformed to azepinone derivatives, which are prevalent in pharmaceuticals and natural products.
ABSTRACT
A palladium-catalyzed aryl-to-alkyl radical relay Heck reaction of amides at α-C(sp3)-H sites with vinyl arenes is described. This process displays a broad substrate scope with respect to both amide and alkene components and provides access to a diverse class of more complex molecules. The reaction is proposed to proceed via a hybrid palladium-radical mechanism. The core of the strategy is that the fast oxidative addition of aryl iodide and fast 1,5-HAT overcome the slow oxidative addition of alkyl halides, and the photoexcitation effect suppresses the undesired ß-H elimination. It is anticipated that this approach would inspire the discovery of new palladium-catalyzed alkyl-Heck methods.
ABSTRACT
Soil microbial biofilms (SMBs) are a biological community of soil bacteria and their accumulative extracellular polymeric substances (EPS), which are the initial status and the most important components of biological soil crusts. SMBs, as the most common mode of soil bacterium survival, not only greatly contribute to the survival of free-living cells, but also stick to soil particles and roots, performing a variety of important ecological functions. Based on the structure and composition analysis of SMBs, we gave a summary of eco-physiological functions of SMBs involving soil quality and plant health. SMBs have higher metabolic activity than free-living cells. It promotes EPS secretion and organic turnover, which is important for soil fertility, pollutant decomposition, and aggregate formation. SMBs help improve plant nutrient utilization and stress resistance through the synergy of microorganisms, promotion of plant growth, promoting substance secretion and immobilization of EPS. In the future, it will be critical to uncover the micro-mechanisms underlying SMBs' eco-physiological functions and to screen functional soil bacterium strains.
Subject(s)
Soil Microbiology , Soil , Bacteria , Biofilms , Plant Roots/microbiology , PlantsABSTRACT
The antierbB2 scFvFcIL2 fusion protein (HFI) is the basis for development of a novel targeted anticancer drug, in particular for the treatment of HER2positive cancer patients. HFI was fused with the antierbB2 antibody and human IL2 by genetic engineering technology and by antibody targeting characteristics of HFI. IL2 was recruited to target cells to block HER2 signaling, inhibit or kill tumor cells, improve the immune capacity, reduce the dose of antibody and IL2 synergy. In order to analyse HFI drug ability, HFI plasmid stability was verified by HFI expression of the trend of volume changes. Additionally, HFI could easily precipitate and had progressive characteristics and thus, the buffer system of the additive phosphatecitric acid buffer, arginine, Triton X100 or Tween80, the establishment of a microfiltration, ion exchange, affinity chromatography and gel filtration chromatographybased purification process were explored. HFI samples were obtained according to the requirements of purity, activity and homogeneity. In vivo, HFI significantly delayed HER2 overexpression of nonsmall cell lung cancer (Calu3) in human nonsmall cell lung cancer xenografts in nude mice, and the inhibition rate was more than 60% (P<0.05) in the group treated with 1 mg/kg the HFI dose; HFI significantly inhibited HER2 expression of breast cancer (FVB/neu) transgenic mouse tumor growth in 1 mg/kg of the HFI dose group, and in the following treatment the 400 mm3 tumors disappeared completely. Combined with other HFI test data analysis, HFI not only has good prospects, but also laid the foundation for the development of antibodycytokine fusion proteinlike drugs.
