Aromatic substituent effects. Medical search. Frequent questions

The compounds with electron donating substituents were found to be better antioxidants with IIIa to be most effective. (ijpsonline.com)
In general, nitroaromatic compounds appear to be fairly persistent and exhibit either hematologic or metabolic effects at high levels of exposure. (epa.gov)
In aromatic compounds with more than one substituent only bonds on activated positions can be strategic. (uni-erlangen.de)
The nature of the substituents of the heterocyclic ring (tail) and the oligomethylene spacer between the head group and the heterocyclic ring was found to affect the activity and toxicity of these compounds leading to a significantly improved understanding of their structure-activity relationships. (bvsalud.org)
The binding modes differ slightly between the UC-10/UC-781 and UC-38/UC-84 pairs of compounds, apparently related to the shorter isopropylmethanoyl substituents of the anilide rings of UC-38/UC-84, which draws these rings closer to residues Tyr181 and Tyr188. (rcsb.org)
This in turn explains the differences in the effect of mutated residues on the binding of these compounds. (rcsb.org)
Aromatic compounds. (stuba.sk)
In this paper, detailed comparative analyses on the reliability of 14 methods are carried out and three series of molecules, carbonyl compounds, aromatic hydrocarbons and pyridine derivatives are exploited as test systems. (springer.com)

The inductive and resonance properties compete with each other but the resonance effect dominates for purposes of directing the sites of reactivity. (wikipedia.org)
Interestingly, the presence of an amine group strongly increases the reactivity of the aromatic ring, due to an electron-donating effect. (newworldencyclopedia.org)
Substituent effects on the reactivity of benzoquinone derivatives with thiols. (cdc.gov)

Aliphatic, fluorinated aliphatic or substituted aromatic hydrocarbon substituents are the hydrophobic entities which enable silanes to induce surface hydrophobicity. (gelest.com)

It has been shown by 1 H and 13 C NMR spectroscopy that 2-mercaptobenzoyl- hydrazones of aliphatic and aromatic aldehydes exist in solution as tautomeric mixtures of linear and cyclic benzo-1,3,4-thiadiazepine forms. (scirp.org)
In the series of the aromatic aldehydes 2- mercaptobenzoylhydrazones the linear tautomer prevails, and the logarithms of the tautomeric equilibrium constants K T correlate with the σ-constants of the substituents in the aromatic nucleus. (scirp.org)
Tautomerism of 2-mercaptobenzoylhydrazones of aromatic aldehydes 3a-3h. (scirp.org)
Similarly, the allylation of α-aryl aldehydes proceeded well with the same level of regio- and stereoselectivity as the allylation of aromatic amines. (elsevierpure.com)
An efficient and convenient method has been developed for the synthesis of 2-amino-5-oxo-4-phenyl-4, 5-dihydropyrano[3,2-c]chromene-3-carbonitrile derivatives from one-pot multicomponent reaction between 4-hydroxy-2H-chromen-2-one, aromatic aldehydes and malononitrile catalyzed by DTP/SiO2 as an efficient and reusable heterogeneous catalyst. (samipubco.com)

Applying a high yielding synthetic procedure, we synthesized constitutional isomeric derivatives to distinguish between substitution effects at the aromatic and aliphatic position on the rotor fragment. (uni-muenchen.de)
Aliphatic bonds to aromatic rings are not considered in this disconnection strategy but are handled in the strategy for Aromatic Substitution . (uni-erlangen.de)
An aliphatic bond can be either in a non-aromatic ring or in a carbon chain. (uni-erlangen.de)

The hydrophobic effect of the organic substitution can be related to the free energy of transfer of hydrocarbon molecules from an aqueous phase to a homogeneous hydrocarbon phase. (gelest.com)

In electrophilic aromatic substitution reactions, existing substituent groups on the aromatic ring influence the overall reaction rate or have a directing effect on positional isomer of the products that are formed. (wikipedia.org)
As a result of these electronic effects, an aromatic ring to which such a group is attached is more likely to participate in electrophilic substitution reaction. (wikipedia.org)
Electron donating groups are generally ortho/para directors for electrophilic aromatic substitutions, while electron withdrawing groups are generally meta directors with the exception of the halogens which are also ortho/para directors as they have lone pairs of electrons that are shared with the aromatic ring. (wikipedia.org)
Activating substituents favour electrophilic substitution about the ortho and para positions. (wikipedia.org)
The partial rate factor of electrophilic aromatic substitution on fluorobenzene is often larger than one at the para position, making it an activating group. (wikipedia.org)
Electrophilic aromatic substitution of benzene. (stuba.sk)
Effects of substituents on relative rates and regioselectivity of electrophilic attack. (stuba.sk)
Esteves PM, de M. Carneiro JW, Cardoso SP, Barbosa AGH, Laali KK, Rasul G, Surya Rrakash GK, Olah GA. Unified mechanistic concept of electrophilic aromatic nitration: convergence of computational results and experimental data. (springer.com)

The aromatic ring strongly decreases the basicity of the amine, depending on its substituents. (newworldencyclopedia.org)
Synthesis and spectroscopic properties of rosamines with cyclic amine substituents. (tamu.edu)

It is also possible to have four alkyl substituents on the nitrogen. (newworldencyclopedia.org)
therewith the logarithms of the constants of the chain-ring tautomeric equilibrium correlate with the E S steric constants of the alkyl substituents. (scirp.org)

as $\ce{CH3}$ is an electron donating group and it would make the hydrogen less positive, and inductive effect is distance dependent. (stackexchange.com)
An electron donating group (EDG) or electron releasing group (ERG, Z in structural formulas) is an atom or functional group that donates some of its electron density into a conjugated π system via resonance (mesomerism) or inductive effects (or induction)-called +M or +I effects, respectively-thus making the π system more nucleophilic. (wikipedia.org)
Due to a stronger resonance effect and inductive effect than the heavier halogens, fluorine is anomalous. (wikipedia.org)
Because of the full or partial positive charge on the element directly attached to the ring for each of these groups, they all have a moderate to strong electron-withdrawing inductive effect (known as the -I effect). (wikipedia.org)
Due to the electronegativity difference between carbon and oxygen / nitrogen, there will be a slight electron withdrawing effect through inductive effect (known as the -I effect). (wikipedia.org)
WODCA calculates a set of physicochemical properties to reflect the mesomeric and inductive effects of substituents on the aromatic ring system. (uni-erlangen.de)
Quantity calculated for the inductive effect of a substituent (= I Effect ). (uni-erlangen.de)
Since the inductive effect operates through bonds, it diminishes rapidly with increasing distance from the carboxyl group (i.e., the number of o bonds in between). (pharmacyscope.com)

Tyrrell, E , Tesfa, KH , Mann, A and Singh, K (2007) Enantioselective alkynylation reactions to substituted benzaldehyde and salicylaldehyde derivatives: The effect of substituents upon the efficiency and enantioselectivity. (kingston.ac.uk)
The effect of activating and deactivating substituents on the allergenicity of benzoquinone and benzoquinone derivatives. (cdc.gov)

By considering the carboxyl group at number 1, the substituents or the position of the side-chain may then be indicated in the name. (pharmacyscope.com)
When hepatic UROD activity falls below the critical threshold, porphyrin by-products of the heme biosynthetic pathway with 4-8 carboxyl group substituents are overproduced. (medscape.com)

KOWWIN's "reductionist" fragment constant methodology (i.e. derivation via multiple regression) differs from the "constructionist" fragment constant methodology of Hansch and Leo (Hansch, C. and Leo, A.J., Substituent Constants for Correlation Analysis in Chemistry and Biology, Wiley, New York, 1979). (europa.eu)
Structural variations in Ar have been studied by adopting Series B as the standard Schiff base series and by generating substituent constants for each structure. (mun.ca)

Conversely, it is moderately deactivated at the ortho and meta positions, due to the proximity of these positions to the electronegative fluoro substituent. (wikipedia.org)

But that question only deals with the ortho effects of substituents, not the para. (stackexchange.com)
begingroup$ There would be resonance but when you draw resonance hybrid(expecting you know how to draw it) of benzene you will observe that the slight(+ or -) charges will be at ortho and para position not at meta position so that is the reason that resonance effect is not observed at meta position. (stackexchange.com)
In ortho-substituted benzoic acids, a bulky substituent located close to the - COOH, prevents the nearly coplanar alignment of the phenyl and carboxylic groups thought to be essential for the stability of the molecule. (pharmacyscope.com)
This steric hindrance of bulky substituent placed ortho to COOH, leads to a substantial increase in the acidity value. (pharmacyscope.com)

This report considers the large number of chemicals which contain at least one nitro substituent on an aromatic ring. (epa.gov)
As can be seen in Table 4 , a nitro bond to an aromatic ring system is rated in one compound with 100, in another compound with 2, and in a third compound it is not strategic at all. (uni-erlangen.de)

EDGs are therefore often known as activating groups, though steric effects can interfere with the reaction. (wikipedia.org)
One organic reaction involving aromatic amines is the Goldberg reaction. (newworldencyclopedia.org)
This effect is quantified in terms of the Hammett relationship where a linear correlation between the substituent constant (σ i ) and rate is established and a reaction constant (ρ) 0.639. (unab.cl)
Regardless of the substituent (electron withdrawing or electron donating) on the aromatic ring, the reaction proceeded well. (elsevierpure.com)
Azo dyes are produced by the reaction of aryl diazonium salts with a second aromatic compound. (openstax.org)
Mechanism of the acid-promoted intramolecular schmidt reaction: theoretical assessment of the importance of lone pair-cation, cation-, and steric effects in controlling regioselectivity. (tamu.edu)
Effect of structure of substrate and reaction conditions on the nucleophilic substitution. (stuba.sk)

Additionally, the substitution pattern on the aromatic ring is considered to perceive activated ring positions. (uni-erlangen.de)

Structurally amines resemble ammonia , wherein one or more hydrogen atoms are replaced by organic substituents such as alkyl and aryl groups. (newworldencyclopedia.org)
As displayed in the images below, primary amines arise when one of three hydrogen atoms in ammonia is replaced by an organic substituent. (newworldencyclopedia.org)
Secondary amines have two organic substituents bound to N together with one H. In tertiary amines all three hydrogen atoms are replaced by organic substituents. (newworldencyclopedia.org)
Aromatic amines have the nitrogen atom connected to an aromatic ring as in anilines . (newworldencyclopedia.org)
The aromatic amines, such as aniline , have their lone pair electrons conjugated into the benzene ring, thus their tendency to engage in hydrogen bonding is diminished. (newworldencyclopedia.org)
The allylation of aromatic amines with alkynes proceeded smoothly in the presence of catalytic amounts of Pd(PPh 3 ) 4 and benzoic acid. (elsevierpure.com)
abstract = "The allylation of aromatic amines with alkynes proceeded smoothly in the presence of catalytic amounts of Pd(PPh3)4 and benzoic acid. (elsevierpure.com)

The correlation between results of simple MO calculation and spectral data in aromatic hydrocarbons, and correlation between results of simple MO calculation and spectral data in conjugated linear polyenes are discussed. (elsevier.com)
Effects of Replacement of Carbon π Centers by Heteroatom π Centers and of Introduction of Nonmesomeric Substituents on Spectra of Conjugated Hydrocarbons Chapter 11. (elsevier.com)

The effect of various groups on the nitrogen atom of anilines was studied. (elsevierpure.com)

the nitrogen atom bears four distinct substituents counting the lone pair. (newworldencyclopedia.org)

Quantitative study of interactions between oxygen lone pair and aromatic rings: substituent effect and the importance of closeness of contact. (tamu.edu)

The sulfonation of an aromatic ring with SO 3 and H 2 SO 4 is reversible. (openstax.org)

The activating groups are mostly resonance donors (+M). Although many of these groups are also inductively withdrawing (-I), which is a deactivating effect, the resonance (or mesomeric) effect is almost always stronger, with the exception of Cl, Br, and I. In general, the resonance effect of elements in the third period and beyond is relatively weak. (wikipedia.org)
Quantity calculated for the mesomeric effect of a substituent (= M Effect ). (uni-erlangen.de)

They also exhibit electron-withdrawing resonance effects, (known as the -M effect): Thus, these groups make the aromatic ring very electron-poor (δ+) relative to benzene and, therefore, they strongly deactivate the ring (i.e. reactions proceed much slower in rings bearing these groups compared to those reactions in benzene. (wikipedia.org)
Reactions of substituents on benzene ring. (stuba.sk)

Propose a mechanism for the iodination of an aromatic ring with ICl. (openstax.org)
In the product, the aromatic rings are linked by a diazo bridge ( - N=N - ). From the reactants provided, propose a structure for each azo dye and draw the electron-pushing mechanism. (openstax.org)
Isotope effects and the mechanism of epoxidation of cyclohexenone with tert-butyl hydroperoxide. (tamu.edu)

Due to the resonance effect, the phenyl group increases the acidity of carboxylic acid. (pharmacyscope.com)
CH 3 ) 3 , is one of the few groups that is a meta-directing deactivator yet has no electron- withdrawing resonance effect. (openstax.org)

For all four complexes the anilide rings of the inhibitors overlap aromatic rings of many other NNIs bound to RT. (rcsb.org)
Through a combination of X-ray and ITC studies it was shown that ligands containing rigid and aromatic functional groups bound with a higher [delta]H° than the more flexible alkyl ligands, and that this effect correlates well with more direct vdW contacts made in the pocket. (utexas.edu)

In combination with a detailed theoretical description, a comparative analysis of substituent effects on the thermal helix inversions of the rotation cycle is now possible. (uni-muenchen.de)
Comparative analysis of aromatic diisocyanate conjugation to human albumin utilizing multiplexed tandem mass spectrometry. (cdc.gov)

The nature and position of substituents account for the relative strengths of substituted benzoic acids. (pharmacyscope.com)

We have shown through ITC analysis that the added substituents probed in this study provided binding increases to our Grb2 SH2 ligands as expected, but that the thermodynamic driving force of binding affinities depended greatly upon the specific nature and flexible mobility of the ligands in the binding pocket. (utexas.edu)

Due to steric inhibition of Resonance (SIR) effect, compound (A) will be the most acidic, as its anion will be the least stable. (stackexchange.com)

Substituent effects have been examined in terms of the Hammett ϭ-ρ relationship and also in terms of a substituent constant, ϭSB, generated from the data of the Schiff bases (Series B) having the general formula C₆H₅CH=NC₆H₄X. (mun.ca)

Correction factors are values for various steric interactions, hydrogen-bondings, and effects from polar functional substructures. (europa.eu)

In order to properly ascertain the effects of the cyclopropane constraint, a flexible control containing the same number of heavy atoms was synthesized and tested, and it was found to be at least 200 fold less potent than the constrained analog. (utexas.edu)

This suggests, in the polarographic reduction of Schiff bases in dimethylformamide, that solvent effects are virtually absent. (mun.ca)

[ 16 ] Reduction of hepatic UROD activity to approximately 25% of normal, most often reflecting effects of multiple genetic and/or exogenous inhibitory factors, is required for clinical disease expression. (medscape.com)

Halogen substituents are an exception: they are resonance donors (+M). With the exception of the halides, they are meta directing groups. (wikipedia.org)

At meta position the M effect is not considered. (stackexchange.com)
The position of substituent on phenyl ring is also important. (pharmacyscope.com)

Density functional studies on photophysical properties and chemical reactivities of the triarylboranes: effect of the constraint of planarity. (springer.com)

while the ones reflecting electrostatic effect, such as atomic charge analysis and electrostatic potential analysis, have evidently worse overall performance. (springer.com)
This area of research has lagged con- siderably behind the field of developing new effect markers, such as semen analysis and early pregnancy loss. (cdc.gov)

In order to decide whether a bond to a substituent is activated or not the directing influence of the other substituents is considered. (uni-erlangen.de)

The presence of electron-donating substituents is shown to decrease NO 2 reduction rate. (unab.cl)

abstract = "This study is based on 1%Ir/ZrO2 catalyst which was studied in the hydrogenation of aromatic meta-substituted nitrobenzene in liquid phase. (unab.cl)

ce{CH3}$ shows +I and hyperconjugation, $\ce{OCH3}$ shows +M and -I and $ce{NO2}$ shows -R and -I effect. (stackexchange.com)

They are either factors involving aromatic ring substituent positions, or miscellaneous factors. (europa.eu)

Anatomy1

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