86-98-6Relevant articles and documents
Highly chemoselective deoxygenation of N-heterocyclic: N -oxides under transition metal-free conditions
Kim, Se Hyun,An, Ju Hyeon,Lee, Jun Hee
supporting information, p. 3735 - 3742 (2021/05/04)
Because their site-selective C-H functionalizations are now considered one of the most useful tools for synthesizing various N-heterocyclic compounds, the highly chemoselective deoxygenation of densely functionalized N-heterocyclic N-oxides has received much attention from the synthetic chemistry community. Here, we provide a protocol for the highly chemoselective deoxygenation of various functionalized N-oxides under visible light-mediated photoredox conditions with Na2-eosin Y as an organophotocatalyst. Mechanistic studies imply that the excited state of the organophotocatalyst is reductively quenched by Hantzsch esters. This operationally simple technique tolerates a wide range of functional groups and allows high-yield, multigram-scale deoxygenation. This journal is
Highly Chemoselective Deoxygenation of N-Heterocyclic N-Oxides Using Hantzsch Esters as Mild Reducing Agents
An, Ju Hyeon,Kim, Kyu Dong,Lee, Jun Hee
supporting information, p. 2876 - 2894 (2021/02/01)
Herein, we disclose a highly chemoselective room-temperature deoxygenation method applicable to various functionalized N-heterocyclic N-oxides via visible light-mediated metallaphotoredox catalysis using Hantzsch esters as the sole stoichiometric reductant. Despite the feasibility of catalyst-free conditions, most of these deoxygenations can be completed within a few minutes using only a tiny amount of a catalyst. This technology also allows for multigram-scale reactions even with an extremely low catalyst loading of 0.01 mol %. The scope of this scalable and operationally convenient protocol encompasses a wide range of functional groups, such as amides, carbamates, esters, ketones, nitrile groups, nitro groups, and halogens, which provide access to the corresponding deoxygenated N-heterocycles in good to excellent yields (an average of an 86.8% yield for a total of 45 examples).
Preparation method 4-7 -dichloroquinoline (by machine translation)
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Paragraph 0035-0040, (2020/10/20)
The method comprises the steps of: adding 4 chloroaniline and ethoxymethyl diethyl malonate as raw materials, carrying out decarboxylation reaction, carrying out decarboxylation through condensation, cyclization and hydrolysis, carrying out decarboxylation reaction, adding sulfuric acid to 7 - under 3 - pressure, 4 and washing to obtain solid 7 - hydroxyl 3 - chloroquinolines. 230 - 260 °C. The method comprises the following steps: carrying out decarboxylation reaction, adding sulfuric acid to reaction completely, layering, organic layer recovery and water layer reaction till 90 - 100 °C 6.0 - 6.5 kg reaction until reaction is complete 90 - 100 °C, layering, organic layer recovery and water layer reaction; and the steps and chlorination are carried out 150 -170 °C pH4 - 5 4 -7 . Reaction conditions are mild, yield is high, and quality is good. (by machine translation)