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.

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.

PCAViz: An Open-Source Python/JavaScript Toolkit for Visualizing Molecular Dynamics Simulations in the Web Browser.

Molecular dynamics (MD) simulations reveal molecular motions at atomic resolution. Recent advances in high-performance computing now enable microsecond-long simulations capable of sampling a wide range of biologically relevant events. But the disk space required to store an MD trajectory increases with simulation length and system size, complicating collaborative sharing and visualization.

[The study of the role of the water medium in the mechanism of action of peptides in low and ultra low doses].

The correlation between the structures and conformations of short peptides KE, EW, AEDG and other, their influence on the dynamic properties of water and dose/biologic effect dependencies in a wide range of concentrations were regarded. Their effects on the dynamic properties of water were studied by temperature dependencies (5-45 degrees C) of infrared spectra of the solutions in the near (5180 cm-1) and far (200 cm-1). In vitro biotesting included the determination of the proliferative activity of thymocytes, a bimodal curve with the second maximum were detected at super-low doses (10(-17)-10(-15) mol/l).