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All total 43 Articles be found
All total 43 Articles be foundThiourea-Mediated Halogenation of Alcohols
Mohite, Amar R.,Phatake, Ravindra S.,Dubey, Pooja,Agbaria, Mohamed,Shames, Alexander I.,Lemcoff, N. Gabriel,Reany, Ofer
, p. 12901 - 12911 (2020/11/26)
The halogenation of alcohols under mild conditions expedited by the presence of substoichiometric amounts of thiourea additives is presented. The amount of thiourea added dictates the pathway of the reaction, which may diverge from the desired halogenation reaction toward oxidation of the alcohol, in the absence of thiourea, or toward starting material recovery when excess thiourea is used. Both bromination and chlorination were highly efficient for primary, secondary, tertiary, and benzyl alcohols and tolerate a broad range of functional groups. Detailed electron paramagnetic resonance (EPR) studies, isotopic labeling, and other control experiments suggest a radical-based mechanism. The fact that the reaction is carried out at ambient conditions, uses ubiquitous and inexpensive reagents, boasts a wide scope, and can be made highly atom economic, makes this new methodology a very appealing option for this archetypical organic reaction.
The Mn-catalyzed paired electrochemical facile oxychlorination of styrenes: Via the oxygen reduction reaction
Tian, Siyu,Jia, Xiaofei,Wang, Ling,Li, Baoying,Liu, Siyuan,Ma, Li,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 12104 - 12107 (2019/10/14)
Reported herein is the electrochemical engendering of chlorine radicals by a manganese catalyst with a controllable pattern, and inexpensive MgCl2 as the chlorine source. In combination with the oxygen reduction reaction, chloroacetophenones were synthesized with abundant styrene as the feedstock in good to excellent yields.
High yield preparation method of selexipag intermediate compound under middle conditions
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Paragraph 0057-0058, (2019/03/15)
The invention relates to a high yield preparation method of a selexipag intermediate compound under middle conditions. According to the method, styracitol and halogen acid carry out halogenation reactions, and the reaction product and N-aminoacetyl-N-isopropyl n-butanol carry out condensation, ammoxidation, and ring forming reactions to obtain 2-(N-isopropyl-N-4-hydroxylbutyl)amino-5,6-diphenylpyrazine. The compound can be used to prepare selexipag. The raw materials are cheap and easily available, the operation is simple, convenient and safe, the reaction selectivity is good, the yield and purity are high, and the cost is low.
CV-driven Optimization: Cobalt-Catalyzed Electrochemical Expedient Oxychlorination of Alkenes via ORR
Tian, Siyu,Lv, Shide,Jia, Xiaofei,Ma, Li,Li, Baoying,Zhang, Guofeng,Gao, Wei,Wei, Yingqin,Chen, Jianbin
supporting information, p. 5626 - 5633 (2019/11/22)
Instead of screening reaction conditions by yield-based chemical trial-and-error, potential-based cyclic voltammetry was alternatively employed for optimization of electrochemical oxychlorination of alkenes. With this unconventional screening method, the catalyst system including catalysts, molar ratio of chloride sources and solvents were identified in a rational, time- and energy-efficient manner. The optimal catalytic system in combination with oxygen reduction reaction enabled broad substrate scopes for the desired transformation by taking advantages of persistent radical effect. UV-vis and CV titration experiments confirmed the in-situ formed catalytic species [CoCl5]. Moreover, cyclic voltammetry was applied to obtain mechanistic insights in our reaction system. (Figure presented.).
Access to α,α-dihaloacetophenones through anodic C[dbnd]C bond cleavage in enaminones
Bu, Jiping,Huang, Zijun,Li, Shaoke,Ma, Xiantao,Wu, Kairui,Yang, Jiusi,Yu, Renjie,Zhang, Zhenlei
, (2021/12/20)
We have developed a method to synthesize α,α-dihaloketones under electrochemical conditions. In this reaction, the Cl- or Br- is oxidized to Cl2 or Br2 at the anode, which undergoes two-step addition reactions with the N,N-dimethyl enaminone, and finally breaks C[dbnd]C of the N,N-dimethyl enaminone to generate α,α-dihaloketones. The electrosynthesis reaction can be conveniently carried out in an undivided electrolytic cell at room temperature. In addition, various functional groups are compatible with this green protocol which can be applied simultaneously to the gram scale without significantly lower yield.
