A facile, efficient and unprecedented method for the synthesis of spiro-2H-pyrroles is reported. When reacted with 1-ethynylcyclohexylamine, α,β-alkynic ketones produced cyclohexane-embedded N-propargylic β-enaminones, which in the presence of cesium carbonate underwent nucleophilic cyclization to afford 1-azaspiro[4.5]deca-1,3-diene derivatives in good to excellent yields. This cyclization was found to be general for a variety of cyclohexane-embedded N-propargylic β-enaminones and demonstrated good tolerance to a broad range of aliphatic, aromatic and heteroaromatic groups with electron-withdrawing and electron-donating substituents. The decoration of pyrrole compounds with a spiro framework may exhibit potential for the synthesis of molecules of pharmacological interest.

A simple and general one-pot method for the synthesis of spiro-2H-pyrroles has been developed. Initially, cyclohexane-embedded β-enaminones with internal alkyne functionality were synthesized by conjugate addition of 1-ethynylcyclohexylamine to α,β-alkynic ketones, followed by palladium-catalyzed coupling of the resulting N-propargylic β-enaminones with aryl iodides. When subjected to basic conditions, the cyclohexane-embedded β-enaminones with internal alkyne functionality underwent tandem nucleophilic cyclization and benzylic C–H oxidation to furnish 3,4-diaryloyl-1-azaspiro[4.5]deca-1,3-diene derivatives in good yields.

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Mechanical behavior of acrylonitrile butadiene styrene (ABS) was investigated in this study with experimental and numerical studies. Specimens were fabricated by using a three-dimensional (3D) printer with horizontal and vertical deposition directions. Quasistatic tension tests at strain rates of 0.01/s and 0.1/s and dynamic compression tests at strain rates of 3,500/s, 6,000/s, and 7,500/s were performed at room temperature. Dynamic deformation behavior of test specimen was investigated via 3D Lagrangian method in LS-Dyna software with Johnson-Cook and Piecewise Linear Plasticity material models. Simulations were conducted with an adequate element size determined by a mesh dependency study. Johnson-Cook strength model parameters of ABS were determined and validated by simulation studies. Experimental results showed that increase of strain rate at tension and compression conditions led to increase of strengths for both vertically and horizontally deposited specimens. Under low strain rates, specimens were exposed to strain softening followed by strain hardening. However, under high strain rates, strain softening was observed after maximum stress was achieved. Strain softening behavior observed in dynamic compression tests was attributed to adiabatic heating in the specimen during testing. Furthermore, it has been observed that deposition direction of specimen with regard to applied load direction is significant for the mechanical strength of the material in quasistatic and dynamic tests. Simulation results for dynamic compression tests under high strain rates showed good agreement with test results in terms of final dimensions of test specimens. Results showed that Johnson-Cook material model is more accurate for modelling dynamic behavior of ABS than Piecewise Linear Plasticity model. Additionally, higher error values were observed with increasing strain rates in simulations.