Transition-Metal-Catalyzed Directed C-H Functionalization in/on Water

Directing group assisted C-H bond functionalization using transition-metal-catalysis has emerged as a reliable synthetic tool for the construction of regioselective carbon-carbon/heteroatom bonds. Off late, "in/on water directed transition-metal-catalysis", though still underdeveloped, has appeared as one of the prominent themes in sustainable organic chemistry. This article covers the advancements, mechanistic insights and application of the sustainable directed C-H bond functionalization of (hetero)arenes in/on water in the presence of transition-metal-catalysis.

Natural products as sources of acetylcholinesterase inhibitors: Synthesis, biological activities, and molecular docking studies of osthole-based ester derivatives

Osthole is a natural coumarin compound which isolated from Cnidium monnieri (L.) Cusson, has extensive pharmacological activities and could be used as a leading compound for drug research and development. In a continuous effort to develop new acetylcholinesterase inhibitors from natural products, eighteen osthole esters were designed, synthesized, and confirmed by ¹H NMR, ¹³C NMR and HRMS. The anti-AChE activity of These derivatives was measured at a concentration of 1.0 mol/mL in vitro by Ellman's method, and the result showed that 4m and 4o had moderate inhibitory activities with 68.8% and 62.6%, respectively. Molecular docking study results further revealed AChE interacted optimally with docking poses 4m and 4o. Network pharmacology also predicted that compound 4m could be involved in Ras signaling pathway, which made it a potential therapeutic target of AD.

Synthesis and crystal structure of 3-N-acetyl-5-(pyridin-3-yl)-2-(quinolin-2-yl)-1,3,4-oxadiazoline, C18H14N4O2

C18H14N4O2, triclinic, P1̄ (no. 2), a = 7.6557(7) Å, b = 11.0905(8) Å, c = 11.3544(9) Å, α = 61.6430(10)°, β = 73.600(2)°, γ = 75.397(2)°, V = 805.86(11) Å3, Z = 2, R gt(F) = 0.0609, wR ref(F 2) = 0.1633, T = 298 K.

The crystal structure of N′-((1E,2E)-4-(7-methoxy-2-oxo-2H-chromen-8-yl)-2-methylbut-2-en-1-ylidene)-3-methylbenzohydrazide, C23H22N2O4

C23H22N2O4, monoclinic, P21/c (no. 14), a = 17.7478(4) Å, b = 10.0041(2) Å, c = 24.4749(6) Å, β = 111.111(2)°, V = 4053.88(17) Å3, Z = 8, Rgt(F) = 0.0614, wRref(F2) = 0.1749, T = 290 K.

Crystal structure of N′-((1E,2E)-4-(7-methoxy-2-oxo-2H-chromen-8-yl)-2-methylbut-2-en-1-ylidene)-4-methylbenzenesulfonohydrazide, C22H22O5N2S

C22H22O5N2S, monoclinic, P21/n (no. 14), a = 8.1080(2) Å, b = 14.4763(4) Å, c = 18.2819(5) Å, β = 95.270(3)°, V = 2136.75(10) Å3, Z = 4, R gt(F) = 0.0488, wR ref(F 2) = 0.1220, T = 291 K.

Synthesis of Piperine Analogs Containing Isoxazoline/Pyrazoline Scaffold and Their Pesticidal Bioactivities

In continuation of our program to discover new potential pesticidal agents, thirty-one piperine analogs containing isoxazoline/pyrazoline scaffold were prepared, and confirmed by infrared spectra, proton/carbon-13 nuclear magnetic resonance spectra, and high-resolution mass spectra. The structures of compounds VIIb and VIIIc were further determined by ¹H-¹H COSY spectra. Especially the configuration of compound VIIIc was unambiguously confirmed by single-crystal X-ray diffraction. Their pesticidal activities were evaluated against three serious and typically crop-threatening agricultural pests, Tetranychus cinnabarinus Boisduval (spider mite), Mythimna separata Walker (Oriental armyworm), and Plutella xylostella Linnaeus (diamondback moth). Compounds VIIIb and VIIIc exhibited greater than 40-fold more potent acaricidal activity than the lead compound piperine against T. cinnabarinus. Notably, compounds VIa-c exhibited more pronounced oral toxicity against P. xylostella than toosendanin; compounds VIb and VIc displayed more promising growth inhibitory activity against M. separata than toosendanin. It demonstrated that the methylenedioxy and isoxazoline scaffolds were important for the oral toxicity and growth inhibitory activity against P. xylostella and M. separata, respectively; the ethylenedioxy and isoxazoline scaffolds were vital for the acaricidal activity against T. cinnabarinus. Moreover, compounds VIb, VIIf, and VIIIc showed very low toxicity against NRK-52E cells.