Tunable Zinc-Mediated Reductive Cyclization of Diastereomeric 3-Nitro-4-phenacyl-2-(trihalomethyl)chromanes to Fused Pyrroline -Oxides, Pyrrolines, and Pyrrolidines.

Reductive cyclization of trans,trans- and trans,cis-isomers of the 2-CF-substituted 3-nitro-4-phenacylchromanes with Zn-based reductive systems, depending on the conditions, affords 4-CF-substituted 1,3a,4,9b-tetrahydrochromeno[3,4-]pyrrole 3-oxides, 1,3a,4,9b-tetrahydrochromeno[3,4-]pyrroles, or 1,2,3,3a,4,9b-hexahydrochromeno[3,4-]pyrroles in good yields without changing the relative configuration of the pyran ring. A similar process involving the 2-CCl-substituted 3-nitro-4-phenacylchromanes is accompanied by reductive dehalogenation to form the corresponding 4-dichloromethyl-substituted fused chromanes along with the 3-(2-hydroxyaryl)-2-(2,2-dichlorovinyl)-5-phenyl-2-pyrroline 1-oxides as pyran ring opening products. The structure and relative configuration of the obtained products was reliably confirmed by X-ray diffraction analysis and 2D NMR spectroscopy.

Different Behavior of 2-Substituted 3-Nitro-2-chromenes in the Reaction with Stabilized Azomethine Ylides Generated from α-Iminoesters.

The AgOAc-catalysed reaction of 3-nitro-2-phenyl-2-chromenes with stabilized azomethine ylides generated from the imines based on methyl glycinate and arylaldehydes leads to a mixture of and ' isomers of the corresponding chromeno[3,4-]pyrrolidines in a ratio of 2.0-2.3:1 in 85-93% total yields as a result of a Michael addition/Mannich reaction sequence.

Analysis of Polarization Images in the Microphysical Blood Parameters Research for the Hematocrit Diagnostics.

The development of non-invasive optoelectronic technologies for human blood monitoring is one of the important research areas for medicine. A critical analysis of optoelectronic methods of blood research and the micromechanical systems based on them is carried out in this article. A design realization of a polarizing portable system for non-invasive monitoring of hematocrit as one of the basic homeostatic constants of the human body containing information about the microphysical parameters of blood cells has been substantiated.

Green and Efficient Construction of Chromeno[3,4-]pyrrole Core via Barton-Zard Reaction from 3-Nitro-2-chromenes and Ethyl Isocyanoacetate.

A regioselective one-pot method for the synthesis of 1-ethyl 2,4-dihydrochromene[3,4-]pyrroles in 63-94% yields from available 2-phenyl-, 2-trifluoro(trichloro)methyl- or 2-phenyl-2-(trifluoromethyl)-3-nitro-2-chromenes and ethyl isocyanoacetate through the Barton-Zard reaction in ethanol at reflux for 0.5 h, using KCO as a base, has been developed.

Estimation of dump and landfill waste volumes using unmanned aerial systems.

The paper discusses how the choice of software and hardware components used in unmanned aerial systems (UAS) affects the accuracy of estimating volume on landfills and dumpsites, and the amount of ground work needed to create a high-altitude justification of reference geodetic network. A non-specialized low-cost unmanned aerial vehicle (UAV) and a specialized UAV of a geodetic class were compared in scenarios with different numbers of ground control points. In addition, the use of desktop and cloud software for photogrammetric data-processing was assessed.