768-90-1Relevant articles and documents
Osawa
, p. 115,116 (1974)
H-coupled electron transfer in alkane C-H activations with halogen electrophiles
Fokin, Andrey A.,Shubina, Tatyana E.,Gunchenko, Pavel A.,Isaev, Sergey D.,Yurchenko, Alexander G.,Schreiner, Peter R.
, p. 10718 - 10727 (2002)
The mechanisms for the reactions of isobutane and adamantane with polyhalogen electrophiles (HHal2+, Hal3+, Hal5+, and Hal7+, Hal = Cl, Br, or I) were studied computationally at the MP2 and B3LYP levels of theory with the 6-31G** (C, H, Cl, Br) and 3-21G* (I) basis sets, as well as experimentally for adamantane halogenations in Br2, Br2/HBr, and I+Cl-/CCl4. The transition structures for the activation step display almost linear C···H···Hal interactions and are characterized by significant charge transfer to the electrophile; the hydrocarbon moieties resemble the respective radical cation structures. The regiospecificities for polar halogenations of the 3°C-H bonds of adamantane, the high experimental kinetic isotope effects (kH/kD = 3-4), the rate accelerations in the presence of Lewis and proton (HBr) acids, and the high kinetic orders for halogen (7.5 for Br2) can only be understood in terms of an H-coupled electron-transfer mechanism. The three centered-two electron (3c-2e) electrophilic mechanistic concept based on the attack of the electrophile on a C-H bond does not apply; electrophilic 3c-2e interactions dominate the C-H activations only with nonoxidizing electrophiles such as carbocations. This was shown by a comparative computational analysis of the electrophilic and H-coupled electron-transfer activation mechanisms for the isobutane reaction with an ambident electrophile, the allyl cation, at the above levels of theory.
Grinberg,Dzenitis
, (1977)
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Landa et al.
, (1955)
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Electrochemical-induced radical allylation via the fragmentation of alkyl 1,4-dihydropyridines
Chen, Xiaoping,Luo, Xiaosheng,Wang, Ping
, (2022/02/02)
Aldehydes are abundant chemical motifs presented in natural products and pharmaceuticals. As a radical precursor, its application is limited. Dihydropyridines (DHPs) can act as masked aldehydes, providing alkyl radicals under the activation of Lewis acid, heat, SET oxidant and light irradiation. Herein, we report the direct activation of 4-alkyl DHPs via single electron transfer at the anode. C–C bond homolysis at the C4-position of DHP generated the corresponding alkyl radical, which was captured subsequently by 2-phenyl and 2-ethoxy carbonyl allyl bromide. The following intramolecular elimination reaction afforded 20 different radical allylation products bearing various alkyl substituents with yields up to 92%.
Method for synthesizing and preparing amantadine dry product
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Paragraph 0057-0063; 0068, (2021/03/13)
The invention discloses a synthesis and preparation method of an amantadine dry product, and relates to the technical field of amantadine preparation. The method mainly comprises adamantane, nitrogendioxide, ozone, hydrazine hydrate, ethanol, diethyl ether, ferric chloride hexahydrate and activated carbon, and comprises the following steps: synthesis of a nitro compound: adding adamantane and dichloromethane into a flask according to a ratio of 1g: 120ml, stirring at a certain temperature, introducing 30 equivalents of nitrogen dioxide under a certain condition, introducing ozone at a low speed, reacting for 30 minutes, adding a sodium bicarbonate solution, washing the organic phase to be neutral, performing drying, and carrying out rotary evaporation to obtain the product 1-nitro adamantane. The dry amantadine product is prepared through a hydrazine hydrate reduction method, corresponding purification is conducted, the whole reaction process is mild, the process steps are simple andconvenient, the requirement for equipment is simple, the conversion rate is very high, and the method has the value of industrial batch production popularization.
Thiourea-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.