120-44-5Relevant articles and documents
Silica-supported orthophosphoric acid (OPA/SiO2): preparation, characterization, and evaluation as green reusable catalyst for pinacolic rearrangement
Billamboz, Muriel,Banaszak, Estelle
, p. 1029 - 1040 (2019)
In this paper, we report an easy-to-prepare, cost-effective, efficient, and reusable silica-supported orthophosphoric acid (OPA) catalyst for pinacolic rearrangement. The surface properties of this catalyst were successfully characterized with the help of 31P NMR, TGA, DSC, FT-IR, titration, and microscopy. OPA, hydrogen bonded on the surface, is actually the active species and the reaction seems to occur in the liquid phase embedded in the silica support. As a consequence, the extracting solvent should be chosen with cautious to guarantee the recyclability of the catalyst. As example, pinacol rearrangement reactions were successfully realized with this catalyst and OPA/SiO2 proved to be as efficient as homogeneous orthophosphoric acid to promote the reaction of pinacol derivatives. When using dichloromethane as extracting solvent, OPA/SiO2 can be reuse up to ten times without a significant loss of activity. After ten runs, no physical damage of the catalyst has been observed by microscopy proving its suitability for such application.
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Ho,Wong
, p. 161 (1975)
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Tadros,W. et al.
, p. 2808 - 2812 (1972)
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Iron-Catalyzed Enantioselective Radical Carboazidation and Diazidation of α,β-Unsaturated Carbonyl Compounds
Dong, Shunxi,Feng, Xiaoming,He, Jun,Liu, Wen,Liu, Xiaohua,Pu, Maoping,Wu, Yun-Dong,Zhang, Tinghui
supporting information, p. 11856 - 11863 (2021/08/16)
Azidation of alkenes is an efficient protocol to synthesize organic azides which are important structural motifs in organic synthesis. Enantioselective radical azidation, as a useful strategy to install a C-N3 bond, remains challenging due to the inherently instability and unique structure of radicals. Here, we disclose an efficient enantioselective radical carboazidation and diazidation of α,β-unsaturated ketones and amides catalyzed by chiral N,N′-dioxide/Fe(OTf)2 complexes. An array of substituted alkenes was transformed to the corresponding α-azido carbonyl derivatives in good to excellent enantioselectivities, benefiting the preparation of chiral α-amino ketones, vicinal amino alcohols, and vicinal diamines. Control experiments and mechanistic studies proved the radical pathway in the reaction process. The DFT calculations showed that the azido transferred to the radical intermediate via an intramolecular five-membered transition state with the internal nitrogen of the Fe-N3 species.
Synthesis and antiseizure activity of (E)-1,2-diarylethylidenehydrazine carboximidamides against tonic-clonic seizures: an intracerebroventricular and electrophysiological study
Firouzjaei, Fariba Abedi,Heidarli, Elmira,Ravan, Shabnam,Hosseini, Sayed Masoud,Naderi, Nima,Almasyan, Kiarash,Sarvary, Afshin,Irannejad, Hamid
, p. 1520 - 1535 (2020/06/17)
A series of (E)-1,2-diarylethylidenehydrazine carboximidamides 2a–j were synthesized and characterized by NOESY experiment as anticonvulsant agents and their antiseizure activity was evaluated by intracerebroventricular administration of compounds. Most of the compounds had significant protection against tonic-clonic seizures and 2a was found to be as equipotent as carbamazepine in seizures control. In order to find their anticonvulsant mechanism of action, 2a was subjected to further electrophysiological studies using patch-clamp technique. The results confirmed that this compound is neither a voltage-gated sodium channel blocker nor a NMDA/AMPA antagonist. Although 2a did not show any direct GABA agonistic activity, it could decrease EPSP and increase IPSP frequency without any change in amplitude. Finally, the results indicated most likely a presynaptic GABA-mediated mechanism of 2a for its antiseizure activity such as inhibition of the GABA-T which was validated by molecular docking.
