Alkyl transfer from C–C cleavage: replacing the nitro group of nitro-olefins

2014 ◽  
Vol 50 (47) ◽  
pp. 6246-6248 ◽  
Author(s):  
Guangxun Li ◽  
Lei Wu ◽  
Gang Lv ◽  
Hongxin Liu ◽  
Qingquan Fu ◽  
...  
Keyword(s):  
Nitro Group ◽  
Alkyl Transfer ◽  
Alkyl Groups

Hydrogenation is only the beginning: alkyl groups are mildly transferred from alkyl substituted Hantzsch esters to replace the nitro groups of nitro olefins to providetrans-olefins in moderate to excellent yields.

Oxidation of alkyl groups accompanying the Zinin reduction of nitroarenes

1977 ◽  
Vol 30 (4) ◽  
pp. 927 ◽  
Author(s):  
DA Burgess ◽  
ID Rae
Keyword(s):  
Nitro Group ◽  
Methyl Group ◽  
Alkyl Groups

p-Aminobenzaldehydes have been prepared from several nitroxylenes and trimethylnitrobenzenes by reaction with aqueous alcoholic sodium polysulphide. The oxidation of the methyl group accompanying the Zinin reduction proceeds most readily when the nitro group is unhindered.

The Stereochemistry of SRN1 Reactions in Nitroacenaphthenes

1987 ◽  
Vol 40 (3) ◽  
pp. 523 ◽  
Author(s):  
FI McLure ◽  
RK Norris
Keyword(s):  
Nitro Group ◽  
Reaction Site ◽  
Aromatic Rings ◽  
Ethyl Group ◽  
Benzylic Carbon ◽  
Alkyl Groups ◽  
The Face

The reaction of the 2-chloro-1,l-dialkyl-6-nitroacenaphthenes (1)-(3) with azide and p- toluenethiolate ions takes place by the SRN1 mechanism, to give the substitution products (27)-(32), despite the fact that the nitro group and the chlorine-bearing benzylic carbon are attached to different aromatic rings. The reaction of the stereoisomers (2) and (3) of 2-chloro-1-ethyl-1-methyl-6-nitroacenaphthene takes place through an effectively planar benzylic radical (35), which is preferentially attacked from the face remote from the a-ethyl group. The presence of geminal alkyl groups α to the reaction site in the rigid acenaphthene system restricts the scope of the substitution processes to sterically unhindered nucleophiles, and the reaction fails with reagents such as sodium p- toluenesulfinate (23) and the salts, (24) and (25), derived from 2-ethylmalononitrile and 2-nitropropane.

Selective Reduction of Nitro Group in Aryl Halides Catalyzed by Silver Nanoparticles Modified with β-CD

2018 ◽  
Vol 18 (12) ◽  
pp. 8201-8206
Author(s):  
Xu Ding ◽  
Geng Zhu ◽  
Jian-Ning Guan ◽  
Guo-Zhi Han
Keyword(s):  
Silver Nanoparticles ◽  
Nitro Group ◽  
Aromatic Ring ◽  
Aromatic Amines ◽  
Nmr Spectra ◽  
Selective Reduction ◽  
Aryl Halides ◽  
First Report ◽  
Alkyl Groups ◽  
Donor Acceptor

In this paper, we first report the selective reduction of nitro group in aryl halides catalyzed by silver nanoparticles modified with β-CD. Taking advantage of hydrophobic lumen and donor–acceptor behavior of β-CD, the halogenated alkyl groups on the aromatic ring can be enveloped in the inner cavity that thereby inhibits the reduction of the halogen. For validating the mechanism proposed by us, different silver nanoparticles were applied in parallel experiments. In our experiments, UV-vis spectra and NMR spectra were used to characterize the selectivity. This strategy represents an outstanding improvement on the synthesis of halogenated aromatic amines in comparison with the traditional route, and greatly expands the application of silver nanoparticles in catalytic field.

ChemInform Abstract: Alkyl Transfer from C-C Cleavage: Replacing the Nitro Group of Nitro-Olefins.

ChemInform ◽  
2014 ◽  
Vol 45 (44) ◽  
pp. no-no
Author(s):  
Guangxun Li ◽  
Lei Wu ◽  
Gang Lv ◽  
Hongxin Liu ◽  
Qingquan Fu ◽  
...  
Keyword(s):  
Nitro Group ◽  
Alkyl Transfer

Electrochemical Vicinal Difluorination of Alkenes: Sustainable, Scalable, and Amenable to Electron-rich Substrates

2019 ◽  
Author(s):  
Sayad Doobary ◽  
Alexi Sedikides ◽  
Henry caldora ◽  
Darren poole ◽  
Alastair Lennox
Keyword(s):  
Bioactive Compounds ◽  
Hypervalent Iodine ◽  
Electrochemical Generation ◽  
Oxidative Decomposition ◽  
Alkyl Groups ◽  
Rich Functionality

Fluorinated alkyl groups are important motifs in bioactive compounds, positively influencing pharmacokinetics, potency and F conformation. The oxidative difluorination of alkenes represents an H important strategy for their preparation, yet current methods are limited in their alkene-types and tolerance of electron-rich, readily oxidized functionalities, as well as in their scalability. Herein, we report a method for the difluorination of a number of unactivated alkene-types that is tolerant of electron-rich functionality, giving products that are otherwise unattainable. Key to success is the electrochemical generation of a hypervalent iodine mediator (in the presence of nucleophilic fluoride and HFIP) using an ‘ex-cell’ approach, which avoids the oxidative decomposition of the substrate. The more sustainable conditions give good to excellent yields of product in up to decagram scales<br>

Effects of Ultrasounds on Neat nitrobenzene

2019 ◽  
Vol 70 (8) ◽  
pp. 3085-3088
Author(s):  
Carmen Eugenia Stavarache ◽  
Yasuaki Maeda ◽  
Mircea Vinatoru
Keyword(s):  
Nitro Group ◽  
Radical Cation ◽  
Reaction Mechanisms ◽  
Diphenyl Ether ◽  
Argon Atmosphere ◽  
Phenyl Radical ◽  
Dissolved Gas ◽  
Decomposition Products ◽  
Oxygenated Compounds ◽  
Phenyl Cation

Neat nitrobenzene was continuously irradiated at two ultrasonic frequencies: 40 and 200 kHz, under air and argon atmosphere, respectively. Samples taken at intervals of 1, 5, 10 and 24 h were analyzed by GC-MS and decomposition products were identified. Possible reaction mechanisms are discussed. Presence of air as dissolved gas leads to oxygenated compounds such as 1,4-benzoquinone, 2,4-dinitrophenol, m-dinitrobenzene while argon inhibits the decomposition of nitrobenzene, especially at sonication times under 5 h. Based on the nature of the compounds identified we advanced a mechanism, involving a divergent splitting of unstable radical cation of NB in air and argon respectively. Thus, under air, the phenyl cation formation is preferred leading to 1,4-benzoquinone nitro-biphenyls and dinitrobenzene, while under argon, the phenyl radical formation seems to be favored, leading to phenol and diphenyl ether. The oxygenated compounds detected under argon clearly are a consequence of the nitro group splitting.

Alkyl 1-[2-(oxido anion)-, 3-, 4-, 5-alkyl substituted]phenyl ketyl radicals

1979 ◽  
Vol 44 (6) ◽  
pp. 1731-1741 ◽  
Author(s):  
Andrej Staško ◽  
Ľubomír Malík ◽  
Alexander Tkáč ◽  
Vladimír Adamčík ◽  
Eva Maťašová
Keyword(s):  
Electron Donor ◽  
Unpaired Electron ◽  
Grignard Reagents ◽  
Slight Effect ◽  
Benzene Nucleus ◽  
Alkyl Groups ◽  
Splitting Constant

Reactions of R2,R3-alkyl substituted 2-hydroxybenzenecarboxylic acids 2-HO-C6H2R2-COOH with Grignard reagents R1MgBr in the presence of nickel give stable aryl alkyl ketyl radicals 2-O--R2-, R3-C6H2-CO--R1 where R1 = CH3, C2H5, C2D5, n-C3H7 and R2,R3 = CH3, C2H5, i-C3H7, t-C4H9. The β protons of ketyl group are equivalent (splitting constant 1.25 mT) and non-equivalent (splitting constants within 0.5 to 1.5 mT) for R1 = methyl and other alkyl groups, respectively. Interaction of the γ protons with the unpaired electron was only observed in the case of R1 = n-propyl (splitting constants about 0.07 mT). The substituents R1 have but slight effect on values of splitting constants of the protons in R2,R3 and vice versa. Also splitting constants of the benzene nucleus (a4H = 0.55 mT, a6H = 0.44 mT) are only slightly affected by the substituents R1,R2,R3, which indicates dominant electron-donor effect of the oxido-anion group eliminating the relatively smaller contributions of the alkyl substituents.

Regioselectivity of nucleophilic aromatic photosubstitution in the biphenyl series. Photohydrolysis of some dimethoxynitrobiphenyls

1987 ◽  
Vol 52 (10) ◽  
pp. 2482-2491 ◽  
Author(s):  
Ján Urban ◽  
Petr Kuzmič ◽  
David Šaman ◽  
Milan Souček
Keyword(s):  
Nitro Group ◽  
Steric Hindrance ◽  
The Other ◽  
Quantum Yields ◽  
Hydroxide Anion ◽  
Tert Butanol ◽  
Nitro Derivatives

Anaerobic photolysis of dimethoxynitrobiphenyls IIIa-VIa in aqueous alkaline tert-butanol gave products of nucleophilic photosubstitution of methoxyl by hydroxide anion, while the dimethoxybiphenyls Ia and IIa were found unreactive. Regioselectivity of the reaction was examined in view of a possible “extended meta activation” by the nitro group. The most reactive substrate IIIa gives both C-3 and C-4 substitution products with an unsubstantial preference for the latter, which opposes the “extended meta selectivity” rule. All of the other compounds obey the rule, and 3,4-dimethoxy-3'-nitrobiphenyl (IVa) even displayed absolute selectivity by yielding C-3 substituted compound as the only product. 2,5-Dimethoxy substituted compounds underwent photosubstitution which much lower quantum yields than their 3,4-substituted counterparts, most probably due to some steric hindrance of conjugation. Similarly, 3-nitro-substituted biphenyls exhibited much lower overall reactivity than 4-nitro derivatives.

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