Nucleophilic photosubstitutions of o-methoxynitrobenzenes

1989 ◽  
Vol 67 (2) ◽  
pp. 220-226 ◽  
Author(s):  
Nigel J. Bunce ◽  
Karen Labonte Stephenson
Keyword(s):  
Nitro Group ◽  
Methoxy Group ◽  
Second Order ◽  
Hydroxide Ion ◽  
Aromatic Substrates ◽  
New Synthesis

We report a new synthesis of 3-nitroveratrole, based on the directed lithiation of veratrole, and photochemical substitutions of both 3-nitroveratrole and o-nitroanisole with several nucleophiles. Both aromatic substrates undergo photocyanation meta to the nitro group. With hydroxide ion, 3-nitroveratrole reacts meta to the nitro group, but 2-nitroanisole undergoes replacement of either substituent, the proportion of reaction at each site depending upon the OH− concentration. 3-Nitroveratrole undergoes an inefficient reaction with butylamine at each methoxy group; this reaction is apparently second order in amine. The reaction between o-nitroanisole and diethylamine results only in photohydrolysis. Keywords: photosubstitution, nucleophilic, 3-nitroveratrole, o-nitroanisole.

scholarly journals Elongated and substituted triazine-based tricarboxylic acid linkers for MOFs

2016 ◽  
Vol 12 ◽  
pp. 2267-2273 ◽  
Author(s):  
Arne Klinkebiel ◽  
Ole Beyer ◽  
Barbara Malawko ◽  
Ulrich Lüning
Keyword(s):  
Nitro Group ◽  
Carboxylic Acids ◽  
Functional Groups ◽  
Acid Chloride ◽  
Methoxy Group ◽  
Suzuki Coupling ◽  
Tricarboxylic Acid

New triazine-based tricarboxylic acid linkers were prepared as elongated relatives of triazinetribenzoic acid (TATB). Additionally, functional groups (NO2, NH2, OMe, OH) were introduced for potential post-synthetic modification (PSM) of MOFs. Functionalized tris(4-bromoaryl)triazine “cores” (3a,3b) were obtained by unsymmetric trimerization mixing one equivalent of an acid chloride (OMe or NO2 substituted) with two equivalents of an unsubstituted nitrile. Triple Suzuki coupling of the cores 3 with suitable phenyl- and biphenylboronic acid derivatives provided elongated tricarboxylic acid linkers as carboxylic acids 17 and 20 or their esters 16 and 19. Reduction of the nitro group and cleavage of the methoxy group gave the respective amino and hydroxy-substituted triazine linkers.

Syntheses, characterization and second-order nonlinear optical behavior of new ferrocenyl-terminated phenylethenyl oligomers with a pendant nitro group

2001 ◽  
Vol 25 (2) ◽  
pp. 299-304 ◽  
Author(s):  
Jose A. Mata ◽  
Eduardo Peris ◽  
Inge Asselberghs ◽  
Roel Van Boxel ◽  
Andre´ Persoons
Keyword(s):  
Nitro Group ◽  
Nonlinear Optical ◽  
Second Order ◽  
Optical Behavior

scholarly journals Simultaneous displacement of a nitro group during coupling of diazotized o-nitroaniline with phenols

2010 ◽  
Vol 8 (2) ◽  
pp. 300-307 ◽  
Author(s):  
Renata Farkas ◽  
Mercedesz Törincsi ◽  
Pal Kolonits ◽  
Jenö Fekete ◽  
Oscar Alonso ◽  
...  
Keyword(s):  
Nitro Group ◽  
Methoxy Group ◽  
Coupling Reaction ◽  
Building Blocks ◽  
Para Position ◽  
Main Reaction ◽  
Nucleophilic Displacement ◽  
Diazo Coupling ◽  
Diazo Coupling Reaction

AbstractDuring the diazo-coupling reaction, nucleophilic displacement of a nitro group was also observed. This was the main reaction (1→7) when the starting amine bore either a chlorine or methoxy group at the para position (1b–c). The newly prepared compounds (7) might serve as convenient building blocks in synthesis of some heterocycles.

scholarly journals Program synthesis: challenges and opportunities

2017 ◽  
Vol 375 (2104) ◽  
pp. 20150403 ◽  
Author(s):  
Cristina David ◽  
Daniel Kroening
Keyword(s):  
Logic Program ◽  
Program Synthesis ◽  
Second Order ◽  
Point Of View ◽  
Software Systems ◽  
Counter Example ◽  
New Synthesis ◽  
Logical Point ◽  
Challenges And Opportunities ◽  
Recent Trends

Program synthesis is the mechanized construction of software, dubbed ‘self-writing code’. Synthesis tools relieve the programmer from thinking about how the problem is to be solved; instead, the programmer only provides a description of what is to be achieved. Given a specification of what the program should do, the synthesizer generates an implementation that provably satisfies this specification. From a logical point of view, a program synthesizer is a solver for second-order existential logic. Owing to the expressiveness of second-order logic, program synthesis has an extremely broad range of applications. We survey some of these applications as well as recent trends in the algorithms that solve the program synthesis problem. In particular, we focus on an approach that has raised the profile of program synthesis and ushered in a generation of new synthesis tools, namely counter-example-guided inductive synthesis (CEGIS). We provide a description of the CEGIS architecture, followed by recent algorithmic improvements. We conjecture that the capacity of program synthesis engines will see further step change, in a manner that is transparent to the applications, which will open up an even broader range of use-cases. This article is part of the themed issue ‘Verified trustworthy software systems’.

scholarly journals Crystal structure of 2-methoxy-1-nitronaphthalene

2015 ◽  
Vol 71 (10) ◽  
pp. o701-o702
Author(s):  
Hasna Yassine ◽  
Mostafa Khouili ◽  
Lahcen El Ammari ◽  
Mohamed Saadi ◽  
El Mostafa Ketatni
Keyword(s):  
Crystal Structure ◽  
Nitro Group ◽  
Dihedral Angle ◽  
Title Compound ◽  
Methoxy Group ◽  
Ring System ◽  
Asymmetric Unit ◽  
Naphthalene Ring ◽  
Compound C ◽  
Π Stacking

The asymmetric unit of the title compound, C11H9NO3, contains two molecules,AandB. In moleculeA, the dihedral angle between the planes of the naphthalene ring system (r.m.s. deviation = 0.003 Å) and the nitro group is 89.9 (2)°, and the C atom of the methoxy group deviates from the naphthyl plane by 0.022 (2) Å. Equivalent data for moleculeBare 0.008 Å, 65.9 (2)° and −0.198 (2) Å, respectively. In the crystal, molecules are linked by weak C—H...O interactions, forming [100] chains of alternatingAandBmolecules. Weak aromatic π–π stacking contacts, with a range of centroid–centroid distances from 3.5863 (9) to 3.8048 (9) Å, are also observed.

Basic hydrolysis of some N-phenylcarbamates and basic methanolysis of some N-phenylacetamides containing an ortho nitro substituent

1984 ◽  
Vol 37 (10) ◽  
pp. 2005
Author(s):  
TJ Broxton
Keyword(s):  
Induction Period ◽  
Nitro Group ◽  
Resonance Effect ◽  
Kinetic Studies ◽  
Bond Breaking ◽  
Hydroxide Ion ◽  
Tetrahedral Intermediate ◽  
Group Reaction ◽  
Basic Hydrolysis ◽  
Hydrolysis Of

Kinetic studies of the basic methanolysis of N-(2-nitropheny1)acetamides indicate that unlike the 4-nitro isomer, no change of mechanism occurs on inclusion of an N-methyl group. Reaction occurs with rate-determining C-N bond breaking for both the N-H and N-methyl compounds. Basic hydrolysis of some methyl N-(2-nitropheny1)carbamates occurred by the BAC2 mechanism and the tetrahedral intermediate formed during the hydrolysis decomposed with preferential C-O bond breaking. This is in contrast to the basic hydrolysis of methyl N-methyl-N-4-nitrophenyl- carbamate, which has previously been shown to occur with preferential C-N bond breaking. For the hydrolysis of methyl N-methyl-N-(2-nitrophenyl)carbamate, an induction period in amine production was detected at 0.45 M hydroxide ion. This was interpreted to mean that the tetrahedral intermediate breaks down by loss of methoxide ion. At 0.93 M hydroxide ion, however, no induction period in amine production was observed. The possibility of reaction through a dianionic intermediate was raised to explain this observation. The amide ion (2-NO2C6H4NMe-) is a poorer leaving group than its 4-nitro isomer. This is explained by steric crowding in the 2-nitro compound, resulting in twisting of the nitro group out of the plane of the benzene ring and a consequent reduction in the electron-withdrawing resonance effect of the 2-nitro group compared to the 4-nitro group.

Nucleophilic decomposition of α-disulfones

1969 ◽  
Vol 47 (6) ◽  
pp. 873-877 ◽  
Author(s):  
Paul Allen Jr. ◽  
Patrick J. Conway
Keyword(s):  
Activation Energy ◽  
Order Reaction ◽  
Second Order ◽  
Hammett Equation ◽  
Second Order Reaction ◽  
Kcal Mole ◽  
Arrhenius Activation Energy ◽  
Hydroxide Ion ◽  
First Order ◽  
Sulfur Bond

The sulfur–sulfur bond of α-disulfones is attacked by hydroxide ion in alcohol to yield sulfinate and sulfonate ion by a second-order reaction, first order in each of the reactants. With aromatic disulfones the ρ value of the Hammett equation is 0.2. The Arrhenius activation energy of the reaction of p-tolyl disulfone is 7.95 kcal/mole.

Kinetics and mechanism of phenoxide anions addition to 4-nitrobenzofurazan in aqueous solution

2017 ◽  
Vol 95 (7) ◽  
pp. 723-728 ◽  
Author(s):  
S. Ben Salah ◽  
T. Boubaker ◽  
R. Goumont
Keyword(s):  
Aqueous Solution ◽  
Electron Transfer ◽  
Rate Constants ◽  
Second Order ◽  
Kinetics And Mechanism ◽  
Single Electron ◽  
Single Electron Transfer ◽  
Hydroxide Ion ◽  
Order Rate

Second-order rate constants (k1) for the σ-complexation of 4-nitrobenzofurazan 1 with four 4-X-substituted phenoxide anions 2a–2d (X = OCH3, CH3, H and Cl) were measured in aqueous solution at 20 °C. Using this series of phenoxide anions as a reference, the electrophilicity parameter (E) of this electrophile 1 has been evaluated according to Mayr’s approach. With the E value of –9.42, Mayr’s equation was found to correctly predict the rate constants for the reactions of 1 with hydroxide ion in H2O and a 1:1 ratio of H2O to CH3CN. However, the large βnuc value of 1.12 obtained in the present work is clearly consistent with a single electron transfer (SET) mechanism.

Kinetics of the reduction of 1-methylquinolinium cations by 1-benzyl-1,4-dihydronicotinamide

1985 ◽  
Vol 63 (3) ◽  
pp. 655-662 ◽  
Author(s):  
John W. Bunting ◽  
Norman P. Fitzgerald
Keyword(s):  
Rate Constants ◽  
Isotope Effects ◽  
Hydride Transfer ◽  
Second Order ◽  
Hydroxide Ion ◽  
Order Rate ◽  
Kinetic Isotope ◽  
One Step ◽  
High Concentrations ◽  
Kinetics Of

The reduction of a series of 3-W-1-methylquinolinium cations (1: W = H, Br, CONH2, CO2CH3, CN, NO2) by 1-benzyl-1,4-dihydronicotinamide has been investigated. In all cases the kinetically controlled product from these reactions is the appropriate 3-W-1,4-dihydro-1-methylquinoline. Only for W = Br is any significant amount of the 1,2-dihydro isomer obtained (15% in this case). This kinetic preference for C-4 attack over C-2 attack in dihydronicotinamide reductions contrasts with the kinetically preferred attack at C-2 by hydroxide ion and in borohydride reductions. Rates of reduction were measured for each 1 and also 1,2-dimethyl- and 1,4-dimethylquinolinium cations in 20% CH3CN – 80% H2O, ionic strength 1.0 at 25 °C, under pseudo-first-order conditions. Kinetic saturation due to nonproductive 1:1 complex formation was observed for several cations at high concentrations (> 0.1 M). Second-order rate constants [Formula: see text] were evaluated for each W, and also kinetic isotope effects from second-order rate constants [Formula: see text] for reduction by 1-benzyl-4,4-dideuterio-1,4-dihydronicotinamide. Second-order rate constants are correlated with σp− for W with ρ = 4.5, and are also closely correlated with [Formula: see text] for pseudobase formation at C-4 of these quinolinium cations by: [Formula: see text]. Values of [Formula: see text] vs. [Formula: see text] describe a Westheimer curve reaching a maximum of 5.8 for W = Br and falling to 1.5 for W = NO2 and 4.2 for W = H. These data are consistent with an intrinsic barrier of 2.9 ± 0.5 kcal/mol for hydride transfer between this 1,4-dihydronicotinamide and quinolinium cations. However, quinolinium cations display a dramatically enhanced rate of dihydronicotinamide reduction relative to hydroxide ion attack when compared with isoquinolinium cations. This observation, and the predominance of C-4 rather than C-2 reduction, suggests that these reactions may not be simple one-step hydride transfer processes.

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