Studies on the photochemical oxidation of N,N-diacyl-1,4-dihydropyrazine derivatives
摘要:
The photochemical oxidation of N,N-diacyl-1,4-dihydropyrazines was investigated by irradiation from a medium-pressure mercury lamp. The main products of the photooxygenation were isolated and unambiguously confirmed by H-1 NMR spectra, C-13 NMR spectra, H-H, C-H correlation spectra, high-resolution mass spectrometry, and single-crystal x-ray diffraction analysis. The complicated NMR spectra of main products were studied by variable-temperature NMR experiments. The mechanism of the photooxygenation of N,N-diacyl-1,4-dihydropyrazines is suggested to be a [2+2] cycloaddition of oxygen to the double bond.[GRAPHICS]
Structural analysis of N,N-diacyl-1,4-dihydropyrazine by variable-temperature NMR and DFT calculation
作者:Xiu-qing Song、Hong-bo Tan、Hong Yan、Yu Chang
DOI:10.1016/j.molstruc.2017.01.019
日期:2017.4
unambiguously confirmed by NMRspectra and high-resolution mass spectrometry. The NMRspectra of 1 showed complicated rather than conventional spectroscopy. Variable-temperature experiments and DFT calculation (PES) were used to investigate this phenomenon. DFT calculations confirmed that the structures of the two rotamers of 1 correspond to those determined by NMR in solution, and gave the syn-anti interconversion
Catalytic Desaturation of Aliphatic Amides and Imides Enabled by Excited-State Base-Metal Catalysis
作者:Chenyang Wang、Luis Miguel Azofra、Phong Dam、Michael Sebek、Norbert Steinfeldt、Jabor Rabeah、Osama El-Sepelgy
DOI:10.1021/acscatal.2c01723
日期:2022.8.5
Herein, we report a photoexcited base-metal-catalyzed selective desaturation of aliphaticamides and imides. The reaction is catalyzed by a base-metal cobalt complex under visible-light irradiation. This transformation can be efficiently processed at room temperature and enables the synthesis of valuable cyclic and acyclic enamides and enimides from abundant chemicals. Density functional theory (DFT)