Publications by authors named "M A Medvedev"

The selective reaction of cyclic aminoperoxides with FeCl proceeds through a sequence of O-O and C-C bond cleavages, followed by intramolecular cyclization, yielding functionalized tetrahydrofurans in 44-82% yields. Replacing the peroxyacetal group in the peroxide structure with a peroxyaminal fragment fundamentally alters the reaction pathway. Instead of producing linear functionalized ketones, this modification leads to the formation of hard-to-access substituted tetrahydrofurans.

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6-Bromo- and 6,7-dibromo-1,3-dimethyl-1-perimidin-2(3)-ones were arylated with arylboronic acids under Suzuki-Miyaura reaction conditions to afford 6-aryl-, 6-bromo-7-aryl- and 6,7-diaryl-1,3-dimethyl-1-perimidin-2(3)-ones. A comparison of the X-ray structural parameters of -diaryl derivatives of 1,3-dimethyl-1-perimidin-2(3)-one, naphthalene and 1,8-bis(dimethylamino)naphthalene (proton sponge) was performed. Based on the data of dynamic H NMR spectroscopy and quantum-chemical calculations, barriers to /-isomerization of 6,7-diaryl-1,3-dimethyl-1-perimidin-2(3)-ones were estimated.

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Further progress in constructing highly accurate density functionals by enforcing known laws of interelectron interactions is slow, so fitting techniques are usually employed nowadays. These approaches were shown to lead to overfitting when a functional becomes unreliable for properties on which it was not trained on. An approach to maintain the correct physical behavior of a functional during its training is required to build more complex and accurate functionals, including those based on neural networks.

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Article Synopsis
  • - A new model has been developed to explain the high-frequency interpulse (HFIP) emission pattern of the Crab pulsar, suggesting that the emission bands are actually diffraction fringes influenced by the pulsar's magnetosphere acting as a diffraction screen.
  • - The model accounts for specific features like band spacing, high polarization, and a constant position angle, effectively enabling the "tomography" of the pulsar's magnetosphere and directly revealing its plasma density profile.
  • - The model is designed to be testable with future predictions made, and it proposes a connection between the observed "high-frequency components" and the HFIP emissions.
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Kangaroo mother care (KMC) is an evidence-based method to improve newborn survival. However, scale-up even for stable newborns has been slow, with reported barriers to implementation. We examined facilitators and barriers to initiating KMC before stabilisation amongst neonates recruited to the OMWaNA study in Uganda.

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