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.

Kinetics of the Imidazolium Ring-Opening of mRNA 5'-cap Analogs in Aqueous Alkali

2006 ◽  
Vol 71 (4) ◽  
pp. 567-578 ◽  
Author(s):  
Alicja Stachelska ◽  
Zbigniew J. Wieczorek ◽  
Janusz Stępiński ◽  
Marzena Jankowska-Anyszka ◽  
Harri Lönnberg ◽  
...  
Keyword(s):  
Electrostatic Interaction ◽  
Ring Opening ◽  
Nucleophilic Attack ◽  
Amino Groups ◽  
Hydroxide Ion ◽  
Methyl Group ◽  
Structural Modifications ◽  
Alkyl Groups ◽  
Imidazolium Ring ◽  
Kinetics Of

Second-order rate constants for the hydroxide-ion-catalyzed imidazolium ring-opening of several mono- and dinucleosidic analogs of mRNA 5'-cap have been determined. Intramolecular stacking of the two nucleobases in the dinucleosidic analogs, m7GpppN (m7G = 7-methylguanosine, N = 5'-linked nucleoside), and electrostatic interaction between the N-alkylated imidazolium ring and phosphate moiety have been shown to shield the m7G moiety against the nucleophilic attack of hydroxide ion. In addition, the effect of methylation of the nucleobase amino groups and replacement of the 7-methyl group with other alkyl groups have been studied. The influence of all the structural modifications studied turned out to be modest, the cleavage rates of the most and least reactive analogs (with the exception of non-phosphorylated nucleosides) differing only by a factor of 5.

Isomerizations akin to the Dimroth rearrangement. IV. Formation of simple s-Triazolo[1,5-c]pyrimidines via their [4,3-c] isomers

1978 ◽  
Vol 31 (11) ◽  
pp. 2505 ◽  
Author(s):  
DJ Brown ◽  
T Nagamatsu
Keyword(s):  
Acetic Acid ◽  
Glacial Acetic Acid ◽  
Methyl Groups ◽  
Dimroth Rearrangement ◽  
Methyl Group ◽  
Alkyl Groups ◽  
Ring Fission

Pyrimidin-4-ylhydrazines and simple orthoesters are used in combination (1) to give N-ethoxyalkyl-idene-N'-pyrimidinylhydrazines (2) and thence s-triazolo[4,3-c]pyrimidine (3a) and its 3-, 5-, 7- or 8-alkylated derivatives (3b-s). In glacial acetic acid, these undergo rearrangement into the corresponding s-triazolo[1,5-c]pyrimidines (5) via the acylaminoalkenyltriazoles (4); in aqueous buffers, these reactions stop at the triazoles (4) except in the presence of a 7-methyl group which stimulates completion of the sequence. The ring-fission step, (3) → (4), is retarded markedly by 5- and/or 8-methyl groups but accelerated slightly by 3- and/or 7-alkyl groups; the slower ring-fission of triazolo[1,5-c]-pyrimidines (5) to the same triazoles (4) is retarded by 2-, 5- or 8-alkylation and precluded totally by a 7-methyl group. The recorded u.v. and N.M.R. spectra afford a ready means of distinguishing between the systems (3)-(5).

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.

Intramolecular 1,2-alkyl shifts in unsymmetric dialkoxycarbenes studied by very low vapour pressure (VLVP) pyroiysis – mass spectrometry

1996 ◽  
Vol 74 (4) ◽  
pp. 544-558 ◽  
Author(s):  
Dennis Suh ◽  
David L. Pole ◽  
John Warkentin ◽  
Johan K. Terlouw
Keyword(s):  
Mass Spectrometry ◽  
Transition State ◽  
Vapour Pressure ◽  
Negative Charge ◽  
Radical Cations ◽  
Pyrolysis Mass Spectrometry ◽  
Multiple Collision ◽  
Methyl Group ◽  
Alkyl Groups ◽  
Electron Reduction

Methoxy-(2,2,2-trifluoroethoxy)carbene radical cations, CH3O-C-OCH2CF3•+, 1•+, are cleanly generated by the dissociative electron ionization (EI) of 2-methoxy-5,5-dimethyl-2-(2,2,2-trifluoroethoxy)-Δ3-1,3,4-oxadiazoline I. Neutralization–reionization (NR) mass spectrometry of the neutral carbene 1, generated by one-electron reduction of 1•+, shows no recovery ion signal and thus 1 is not a viable species within the μs time scale of the experiment. Very low vapour pressure (VLVP) pyrolysis – mass spectrometry of I in conjunction with (multiple) collision experiments shows that 1 completely isomerizes, via a 1,2-trifluoroethyl shift, into methyl 3,3,3-trifluoropropionate, CF3CH2C(=O)OCH3, 1a. This technique was also used to study the related dialkoxycarbenes C2H5O-C-OCH2CF3, 2, CH3O-C-OC2H5, 3, and CH3O-C-OCH(CH3)2, 4, generated from the corresponding 2,2-dialkoxy-5,5-dimethyl-Δ3-1,3,4-oxadiazolines. The pyrolytically generated carbene 2 behaves analogously to 1 and completely isomerizes to ethyl 3,3,3-trifluoropropionate, 2a. The neutral carbenes 3 and 4 undergo only a partial isomerization via 1,2-alkyl shifts in which the ethyl and isopropyl groups show a slightly greater migratory aptitude, respectively, than the methyl group. The differences in migratory aptitude are explained in terms of a transition state model similar to that of a 1,2-H shift in carbenes, with development of negative charge in the migrating group. The greater migratory aptitude of CF3CH2, as compared to CH3 and CH3CH2, is attributed to the stabilization of negative charge in the transition state by strongly electron-withdrawing β-fluorines whereas the differences in migratory aptitude between the alkyl groups in 3 and 4 are largely due to the greater polarizability of isopropyl and ethyl groups, as compared to the methyl group. Key words: dialkoxycarbenes, pyrolysis, tandem mass spectrometry.

Phonon spectra of ortho -dinitrotetramethylbenzene crystals

1987 ◽  
Vol 65 (9) ◽  
pp. 2122-2125 ◽  
Author(s):  
Paolo Sgarabotto ◽  
Mario Braghetti ◽  
Rosario Sergio Cataliotti ◽  
Giulio Paliani ◽  
Salvatore Sorriso ◽  
...  
Keyword(s):  
Group Theory ◽  
Phase Transitions ◽  
Solid State ◽  
Melting Point ◽  
Nitro Group ◽  
Vibrational Spectra ◽  
Lattice Dynamics ◽  
Solid Phase ◽  
Methyl Group ◽  
Phonon Spectra

We have studied the vibrational spectra and thermal behaviour of ortho-dinitrotetramethylbenzene (o-DNTMB) to learn more about its molecular and lattice dynamics. The molecule undergoes two solid–solid phase transitions, close to the melting point, which could be explained by the relaxation of forces hindering the methyl-group and nitro-group free rotations. We have deduced the nature of the solid state vibrational motions, particularly those of lattice phonons, using group theory.

scholarly journals A convenient and practical synthesis of β-diketones bearing linear perfluorinated alkyl groups and a 2-thienyl moiety

2018 ◽  
Vol 14 ◽  
pp. 3106-3111 ◽  
Author(s):  
Ilya V Taydakov ◽  
Yuliya M Kreshchenova ◽  
Ekaterina P Dolotova
Keyword(s):  
Methyl Group ◽  
Alkyl Radicals ◽  
Alkyl Groups ◽  
Practical Synthesis ◽  
Copper Chelates

A versatile and robust synthetic protocol for the preparation of β-diketones bearing 2-thienyl and perfluorinated alkyl radicals of different length or a methyl group was developed. This protocol is suitable for the preparation of multigram quantities of diketones without cumbersome purification procedures. Moreover, the known method for purification of diketones via copper chelates was improved considerably.

scholarly journals Polymerizable Ionic Liquids for Solid-State Polymer Electrolytes

Molecules ◽  
2019 ◽  
Vol 24 (2) ◽  
pp. 324 ◽  
Author(s):  
Robert Löwe ◽  
Thomas Hanemann ◽  
Andreas Hofmann
Keyword(s):  
Ionic Liquids ◽  
Ionic Conductivity ◽  
Polymer Electrolytes ◽  
High Yield ◽  
Dsc Analysis ◽  
Energy Storage Devices ◽  
Methyl Group ◽  
Storage Devices ◽  
Alkyl Groups ◽  
Phase Transition Temperatures

Eight new polymerizable ammonium-TFSI ionic liquids were synthesized and characterized with respect to an application in energy storage devices. The ionic liquids feature methacrylate or acrylate termination as polymerizable groups. The preparation was optimized to obtain the precursors and ionic liquids in high yield. All products were characterized by NMR and IR spectroscopy. Phase transition temperatures were obtained by DSC analysis. Density, viscosity and ionic conductivity of the ionic liquids were compared and discussed. The results reveal that the length of attached alkyl groups as well as the methyl group at the polymerizable function have significant influences on the ionic liquids physicochemical properties. Ionic conductivity values vary between 0.264 mS cm−1 for [C2NA,22]TFSI and 0.080 mS cm−1 for [C8NMA,22]TFSI at 25 °C. Viscosity values are within a range of 0.762 Pa s for [C2NA,22]TFSI and 1.522 Pa s for [C6NMA,22]TFSI at 25 °C.

Ionic and Radical Mechanisms in Olefinic Systems, with Special Reference to Processes of Double-Bond Displacement, Vulcanization and Photogelling

1942 ◽  
Vol 15 (4) ◽  
pp. 774-779
Author(s):  
Ernest Harold Farmer
Keyword(s):  
Double Bond ◽  
Special Reference ◽  
Methyl Substituent ◽  
Benzene Nucleus ◽  
Methyl Group ◽  
Unsaturated System ◽  
Alkyl Groups ◽  
Electron Release

Abstract The α-methylenic reactions discussed in the preceding two papers recall a series of interesting observations by Baker and Nathan, which indicate that a p-methyl substituent attached to the benzene nucleus can permit electron release to the nucleus in a manner that appears only in lesser degree in higher alkyl groups, and may be absent in some (e.g., Buγ). Thus in p-methylbenzyl bromide, the suggested function of the methyl group (dotted arrows in (I) permits (see PDF for diagram) additional electron release at the C—Br bond, and so facilitates the anionization of the bromine. Baker and Nathan suggest that the electrons of the duplet constituting the C—H bond of the methyl group are less localized than those in a similarly placed C—C bond, and hence that a methyl group attached to the necessary conjugated unsaturated system is capable of electron-release by a mechanism similar to the tautomeric effect:

A Convenient Method for Replacing theN-Methyl Group of Morphine, Codeine, and Thebaine by Other Alkyl Groups

Synthesis ◽  
1983 ◽  
Vol 1983 (10) ◽  
pp. 809-812 ◽  
Author(s):  
Thomas Samuel Manoharan ◽  
Kattigari Madhava Madyastha ◽  
Bajrang Bali Singh ◽  
Surendra P. Bhatnagar ◽  
Ulrich Weiss
Keyword(s):  
Convenient Method ◽  
Methyl Group ◽  
Alkyl Groups

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.

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