The ultraviolet spectra of O-(2,4-dinitrophenyl)oximes and 2,4-dinitrophenylhydrazones: transmission of electronic effects through O and NH groups
作者:Zvi Rappoport、Tuvia Sheradsky
DOI:10.1039/j29670000898
日期:——
The λmax values in the ultraviolet spectra of 61 pairs of 2,4-dinitrophenylhydrazones (DNP) and O-(2,4-dinitrophenyl)oximes (DNO) were compared. The λmax(DNP)–λmax(DNO)=Δλ values are 61 ± 1 mµ for aliphatic carbonyl compounds, 69 ± 1 mµ for aromatic aldehydes and ketones, and 71 ± 1 mµ for diaryl ketones. Deviations were found for several ortho substituents or for para substituents having strong +M
Thiophene-Fused Heteroaromatic Systems Enabled by Internal Oxidant-Induced Cascade Bis-Heteroannulation
作者:Huawen Huang、Zhenhua Xu、Xiaochen Ji、Bin Li、Guo-Jun Deng
DOI:10.1021/acs.orglett.8b02049
日期:2018.8.17
concise access to thiophene-fused polycyclic π-conjugated systems is described. Methyl aromatic ketoxime acetates, aromatic aldehydes, and elemental sulfur are efficiently assembled in a facile copper-catalytic system through a novel cascade bis-heteroannulation to afford a fused thieno[3,2-d]thiazole motif. The robust nature of this reaction system is reflected by the remarkable simplicity-to-complexity
描述了对噻吩稠合的多环π-共轭体系的简明访问。甲基芳族酮肟肟乙酸酯,芳族醛和元素硫可通过新颖的级联双-杂环化反应在便捷的铜催化系统中高效组装,从而得到稠合的噻吩并[3,2- d ]噻唑基序。该反应系统的鲁棒性体现在一锅操作中从简单到复杂的转换,高产量的克级合成以及在高性能光电材料合成中的潜在应用。
Visible-Light-Mediated Generation of Nitrogen-Centered Radicals: Metal-Free Hydroimination and Iminohydroxylation Cyclization Reactions
作者:Jacob Davies、Samuel G. Booth、Stephanie Essafi、Robert A. W. Dryfe、Daniele Leonori
DOI:10.1002/anie.201507641
日期:2015.11.16
formation and use of iminyl radicals in novel and divergent hydroimination and iminohydroxylationcyclizationreactions has been accomplished through the design of a new class of reactive O‐aryl oximes. Owing to their low reduction potentials, the inexpensive organic dye eosin Y could be used as the photocatalyst of the organocatalytic hydroiminationreaction. Furthermore, reaction conditions for a unique