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Journal articles on the topic 'Methyl Substituents'

Author: Grafiati

Published: 5 June 2025

Last updated: 1 August 2025

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1

Bolton, R., RE Burley, and NJ Williams. "Stabilities of Carbonium-Ions. IV. Steric Effects in the Solvolysis of Substituted Diphenylmethyl Chlorides." Australian Journal of Chemistry 39, no. 4 (1986): 625. http://dx.doi.org/10.1071/ch9860625.

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The replacement of ortho-hydrogen atoms by methyl groups in diphenylmethyl chloride has three distinguishable results upon the rate of solvolysis . Firstly, the alkyl groupactivates by its electronic effect; secondly, steric interactions diminish all observed substituent effects regardless of the position of the substituent in the aryl system; and thirdly, steric acceleration of the solvolysis can be seen in the rate of reaction of bis (2,6-dimethylphenyl)methyl chloride. The ortho-methyl substituents inhibit the formation of the planar transition state necessary to allow the greatest resonanc

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2

Fabijanić, Ivana, Atanas Kurutos, Ana Tomašić Paić, et al. "Selenium-Substituted Monomethine Cyanine Dyes as Selective G-Quadruplex Spectroscopic Probes with Theranostic Potential." Biomolecules 13, no. 1 (2023): 128. http://dx.doi.org/10.3390/biom13010128.

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The binding interactions of six ligands, neutral and monocationic asymmetric monomethine cyanine dyes comprising benzoselenazolyl moiety with duplex DNA and RNA and G-quadruplex structures were evaluated using fluorescence, UV/Vis (thermal melting) and circular dichroism (CD) spectroscopy. The main objective was to assess the impact of different substituents (methyl vs. sulfopropyl vs. thiopropyl/thioethyl) on the nitrogen atom of the benzothiazolyl chromophore on various nucleic acid structures. The monomethine cyanine dyes with methyl substituents showed a 100-fold selectivity for G-quadrupl

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3

Kulhánek, Jiří, Oldřich Pytela, and Antonín Lyčka. "Chemometrical Analysis of Substituent Effects. XIII. Comparison of Substituent Effects on Dissociation and Chemical Shift in 13C NMR Spectra of Mono- and Disubstituted Benzoic Acids." Collection of Czechoslovak Chemical Communications 65, no. 1 (2000): 106–16. http://dx.doi.org/10.1135/cccc20000106.

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The 13C chemical shifts have been measured of the carboxyl carbon atoms for all the 2-, 3-, and 4-substituted benzoic acids with H, CH3, CH3O, F, Cl, Br, I, and NO2 substituents, as well as for all 3,4-, 3,5-, and 2,6-disubstituted benzoic acids with combinations of CH3, CH3O, Cl (or Br), NO2 substituents and for symmetrically 2,6-disubstituted derivatives with Et, EtO, PrO, i-PrO, and BuO substituents. The chemical shifts of carboxylic group carbon atoms of the 3- and 4-substituted derivatives show correlation only with the substituent constants σI. For the 2-substituted derivatives was found

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4

Akinyemi, Akintunde, Courtney Thomas, Willis Marsh, Ray J. Butcher, Jerry P. Jasinski, and Lystranne A. Maynard-Smith. "Crystal structures of 4-methyl-2-oxo-2H-chromene-7,8-diyl diacetate and 4-methyl-2-oxo-2H-chromene-7,8-diyl bis(pent-4-ynoate)." Acta Crystallographica Section E Crystallographic Communications 72, no. 5 (2016): 704–8. http://dx.doi.org/10.1107/s2056989016005892.

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In the structures of the two title coumarin derivatives, C14H12O6, (1), and C20H16O6, (2), one with acetate and the other with pent-4-ynoate substituents, both the coumarin rings are almost planar. In (1), both acetate substituents are significantly rotated out of the coumarin plane to minimize steric repulsions. One acetate substituent is disordered over two equivalent conformations, with occupancies of 0.755 (17) and 0.245 (17). In (2), there are two pent-4-ynoate substituents, the C[triple-bond]C group of one being disordered over two positions with occupancies of 0.55 (2) and 0.45 (2). One

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5

Furet, Pascal, George Hallak, Robert L. Matcha, and Richard Fuchs. "Substituent effects on acetylene stability. A comparison of STO-3G, 6-31G, 6-31G**, and 6-311G** calculations." Canadian Journal of Chemistry 63, no. 11 (1985): 2990–94. http://dx.doi.org/10.1139/v85-496.

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Abinitio calculations using STO-3G, 6-31G, 6-31G**, and 6-311G** basis sets and standard geometries, and 6-31G and 6-311G** basis sets with 6-31G optimized geometries have been performed on a series of acetylene derivatives (H—C≡C—R; –R is —CH3, —Li, —C≡N, [Formula: see text] —NH2,—C≡CH, —CH—CH2, and —F). Substituent effects on stability have been studied using isodesmic methyl exchange reactions (H—C≡C—R + CH4 → H—C≡C—H + CH3R). STO-3G and 6-31G calculations have been carried out for methyl exchange reactions involving several large substituents including phenyl, and for the tert-butyl exchan

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6

La Scala, John J., Greg Yandek, Jason Lamb, et al. "The effect of methyl and methoxy substituents on dianilines for a thermosetting polyimide system." High Performance Polymers 32, no. 7 (2020): 801–22. http://dx.doi.org/10.1177/0954008319899141.

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4,4′-Methylenedianiline (MDA) is widely used in high-temperature polyimide resins, including polymerization of monomer reactants-15. The toxicity of MDA significantly limits the manufacturability using this resin. Modifying the substitution and electronics of MDA could allow for the reduction of toxicity while maintaining the high-performing properties of the materials derived from the modified MDA. The addition of a single methyl substituent, methoxy substituent, location of these substituents, and location of the amine relative to the phenolic bridge were modified as were other non-aniline d

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7

Zhang, Cheng Gen, Ze Min Chen, Shu Yuan Yu, and Hong Chao Wei. "Structural and Electronic Properties of Small Silsesquioxanes: A DFT Study." Advanced Materials Research 548 (July 2012): 281–85. http://dx.doi.org/10.4028/www.scientific.net/amr.548.281.

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Density functional theory (DFT) calculations are performed to investigate the structures of small silsesquioxanes (Si2nO3nX2n) (n=1-5 and X=H, F, Me). The large HOMO–LUMO gaps, which range from 5.41 to 9.17 eV, imply optimal electronic structures for these molecules. Furthermore, the substituent effect analysis indicate that the electron donating methyl group substituents lengthen the Si-O bond and largen the SiOSi bond angle, the electron withdrawing F atom substituents shorten the Si-O bond and lessen the SiOSi bond angle.

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8

Jasiewicz, Beata, Władysław Boczoń, and Joanna Kurek. "Synthesis and Conformational Analysis of New 17-Alkyl Derivatives of Lupanine and Their Perchlorate Salts." Collection of Czechoslovak Chemical Communications 69, no. 11 (2004): 2068–80. http://dx.doi.org/10.1135/cccc20042068.

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New 17-alkyl derivatives of lupanine and their perchlorate salts have been synthesised. Substituents at C-17 are introduced by treatment of C(17)=N(16) immonium perchlorate 2 with alkylmagnesium compounds. NMR spectra of the new compounds have been taken to study the chemical shift changes caused by the introduced alkyl substituents, ethyl and butyl. In 17-alkyl derivatives (17-ethyl- (3) and 17-butyllupanine (4)) the substituent is equatorially oriented. All the lupanine derivatives analysed have the same structure, i.e. ring C in a boat conformation. The reaction of 17-butyllupanine (4) and

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9

Cheng-Sánchez, Iván, José A. Torres-Vargas, Beatriz Martínez-Poveda, et al. "Synthesis and Antitumor Activity Evaluation of Compounds Based on Toluquinol." Marine Drugs 17, no. 9 (2019): 492. http://dx.doi.org/10.3390/md17090492.

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Encouraged by the promising antitumoral, antiangiogenic, and antilymphangiogenic properties of toluquinol, a set of analogues of this natural product of marine origin was synthesized to explore and evaluate the effects of structural modifications on their cytotoxic activity. We decided to investigate the effects of the substitution of the methyl group by other groups, the introduction of a second substituent, the relative position of the substituents, and the oxidation state. A set of analogues of 2-substituted, 2,3-disubstituted, and 2,6-disubstituted derived from hydroquinone were synthesize

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10

Aksenov, Nicolai A., Dmitrii A. Aksenov, Daniil D. Ganusenko, et al. "Synthesis of Dimethyl (Z)-((3-oxoindolin-2-ylidene) (aryl)methyl)phosphonates Through Tandem Cadogan and Arbuzov Reactions." Molbank 2025, no. 2 (2025): M2002. https://doi.org/10.3390/m2002.

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A novel method employing a tandem Cadogan and Arbuzov reaction sequence has been developed, providing access to a series of previously unreported dimethyl (Z)-((3-oxoindolin-2-ylidene)(aryl)methyl)phosphonates. Restricted rotation of the aryl substituent, particularly in the presence of ortho substituents, gives axial chirality to these compounds.

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11

Armano, Edoardo, Alessandro Giraudo, Camillo Morano, Marco Pallavicini, and Cristiano Bolchi. "Methyl 1,4-Benzodioxane-2-Carboxylates Mono-Nitrated at the Aromatic Ring." Molbank 2023, no. 2 (2023): M1661. http://dx.doi.org/10.3390/m1661.

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2-Substituted 1,4-benzodioxanes bearing one or more substituents at benzene are important templates in the design and synthesis of a large variety of biologically active compounds. One of the most straightforward synthetic strategies to prepare them in racemic form and with a 2-substituent susceptible to further synthetically useful conversions is the condensation of commercially available methyl 2,3-dibromopropionate with already suitably functionalized catechol. Here, we obtain methyl 8- and 5-nitro-1,4-benzodioxane-2-carboxylate by reaction of methyl 2,3-dibromopropionate with 3-nitrocatech

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12

Raguse, B., and DD Ridley. "Synthesis and Properties of Coronands Incorporating Lariat Sulfide and Sulfoxide Groups." Australian Journal of Chemistry 41, no. 12 (1988): 1953. http://dx.doi.org/10.1071/ch9881953.

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A series of 8-substituted 19-methoxy-17-methyl-3,6,10,13- tetraoxabicyclo[13.3.1]nonodeca-1(19),15,17-trienes has been prepared and their complexations with alkali metal and ammonium cations studied. When the 8-substituent contained sulfide functionality weak complexes formed, but hosts with lariat sulfoxide substituents formed complexes- with greatest specificity for lithium ions.

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13

Barbry, Didier, Bruno Hasiak, Jean-Michel Augait, and Daniel Couturier. "Evolution thermique de N-oxydes de dimethylamino-5 alcanols-1 substitues en 5. Competition entre rearrangements de cope et de Meisenheimer." Collection of Czechoslovak Chemical Communications 50, no. 4 (1985): 956–61. http://dx.doi.org/10.1135/cccc19850956.

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The effect of the substituent R in the position was studied in the decomposition of 1,5-aminoalcohol N-oxides: Meisenheimer rearrangement takes place when R is the vinyl group but is not observed with the phenyl substituent; elimination to alkenol only affects the more acidic hydrogen atom when R is the allyl or benzyl group; with substituents inducing less important electronic effects (methyl, ethyl), the reaction yields an alkenols mixture with statistical distribution.

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14

Badran, TW, CLL Chai, CJ Easton, JB Harper, and DM Page. "Directing Bromination of Piperazine-2,5-diones." Australian Journal of Chemistry 48, no. 7 (1995): 1379. http://dx.doi.org/10.1071/ch9951379.

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From intermolecular and intramolecular competition experiments, it has been established that, by comparison with an N-methyl substituent, an N-acetyl group deactivates glycine residues in piperazine-2,5-diones towards free-radical bromination. Combined with the ease of introduction and removal of N-acetyl substituents, the deactivating effect provides a method for regiocontrolled functionalization of these compounds.

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15

Dyall, LK, and AL Holmes. "Pyrolysis of Aryl Azides. IX. Azomethines as Weak Neighboring Groups." Australian Journal of Chemistry 41, no. 11 (1988): 1677. http://dx.doi.org/10.1071/ch9881677.

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The following rates of pyrolysis (relative to azidobenzene at 120°) have been measured in decalin solution: 2-azidobenzaldehyde, 28.8; 2-azidobenzylideneaniline, 59.5; 2-azidobenzaldehyde phenylhydrazone, 8.9; 2-azidobenzaldehyde oxime O-methyl ether, 1.3;2-azidoacetophenone oxime O-methyl ether, 23.4; 2-azidobenzophenone phenylhydrazone, 9.7. It is argued that these relative rates are largely determined by the extent to which the ortho substituent is in the reactive conformation for an electrocyclic process. Indazoles substituted on N2 are isolated from pyrolysis of those azides with ortho-az

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16

Chen, Lin, Yakun Guo, Gan Ren, and Ge Sang. "Crystal structure of [Cu(tmpen)](BF4)2{tmpen isN,N,N′,N′-tetrakis[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine}." Acta Crystallographica Section E Crystallographic Communications 73, no. 4 (2017): 640–43. http://dx.doi.org/10.1107/s2056989017004492.

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The mononuclear copper title complex {N,N,N′,N′-tetrakis[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine-κ6N}copper(II) bis(tetrafluoridoborate), [Cu(C30H36N6)](BF4)2, is conveniently prepared from the reaction of Cu(BF4)2·6H2O withN,N,N′,N′-tetrakis[(6-methylpyridin-2-yl)methyl]ethane-1,2-diamine (tmpen) in acetonitrile at room temperature in air. The complex shows a distorted octahedral environment around the CuIIcation (site symmetry 2) and adopts the centrosymmetric space groupC2/c. The presence of the 6-methyl substituent hinders the approach of the pyridine group to the CuIIcore. The bon

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17

Nádvorník, Jiří, and Miroslav Ludwig. "Ortho Effect in Dissociation of Substituted N-Phenylbenzenesulfonamides." Collection of Czechoslovak Chemical Communications 66, no. 9 (2001): 1380–92. http://dx.doi.org/10.1135/cccc20011380.

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Twenty-five 2,2'-disubstituted N-phenylbenzenesulfonamides (2-X-C6H4SO2NHC6H4-Y-2') were synthesised and their purity checked by elemental analysis. This set of model substrates involved all possible combinations of methoxy, methyl, hydrogen, chloro, and nitro substituents. The dissociation constants of the sulfonamides were determined by potentiometric titration in methanol, pyridine, dimethyl sulfoxide, N,N-dimethylformamide, acetone, and acetonitrile. The dissociation constants pKHA obtained were correlated with various sets of substituent constants describing electronic and steric effects

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18

Li, Yongqing, Yanzhen Ma, Yunfan Yang, Wei Shi, Ruifang Lan, and Qiang Guo. "Effects of different substituents of methyl 5-R-salicylates on the excited state intramolecular proton transfer process." Physical Chemistry Chemical Physics 20, no. 6 (2018): 4208–15. http://dx.doi.org/10.1039/c7cp06987a.

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The proton transfer reaction in methyl 5-R-salicylate is found to be highly sensitive to the presence of specific substituents in resonance with the hydroxyl group, leading to different fluorescence behaviors of methyl 5-R-salicylate with different substituents.

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19

Dyall, LK. "Pyrolysis of Aryl Azides. VII. Interpretation of Hammett Correlations of Rates of Pyrolysis of Substituted 2-Nitroazidobenzenes." Australian Journal of Chemistry 39, no. 1 (1986): 89. http://dx.doi.org/10.1071/ch9860089.

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Rates and products of pyrolysis have been obtained for ten 2- nitroazidobenzenes with 4- or 5-substituents. Rate data at 100° are correlated with Hammett constants of the 4- or 5-substituents, with respect to both the azido (A) and nitro (N) reaction centres, and yield the equation log k = -3.23 + 1.20σ-/A -0.716σN. Dissection of this equation into σI and σR components was usefully attempted. The results are consistent with an electrocyclic process in which delocalization of negative charge from the innermost azido nitrogen is important at the transition state, whereas substituent effects on b

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20

Dunn, E. J., J. G. Purdon, R. A. B. Bannard, K. Albright та E. Buncel. "Correlation of 31P nuclear magnetic resonance chemical shifts in aryl phosphinates with Hammett substituent constants: Inductive versus resonance interactions and relevance to pπ–dπ bonding". Canadian Journal of Chemistry 66, № 12 (1988): 3137–42. http://dx.doi.org/10.1139/v88-484.

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Substituent-induced chemical shifts and coupling constants in the 31P, 13C, and 1H nuclear magnetic resonance spectra of meta- and para-substituted phenyl dimethylphosphinates (1), methylphenylphosphinates (2), and diphenylphosphinates (3) have been determined in CDCl3 solvent. For all three series, a correlation of δ 31P with Hammett–Taft σ0 (or σ) constants is preferred over σ− on the basis of the correlation coefficient and standard deviations of the slope and intercept values. Electron-withdrawing substituents induce downfield shifts in δ 31P, in contrast to the inverse trends observed for

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21

Grodner, Błażej, Mariola Napiórkowska, and Dariusz Maciej Pisklak. "In Vitro and In Silico Kinetic Studies of Patented 1,7-diEthyl and 1,7-diMethyl Aminoalkanol Derivatives as New Inhibitors of Acetylcholinesterase." International Journal of Molecular Sciences 23, no. 1 (2021): 270. http://dx.doi.org/10.3390/ijms23010270.

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Two aminoalkanol derivatives of 1,7-diEthyl-8,9-diphenyl-4azatricyclo (5.2.1.02.6) dec-8-ene-3,5,10-trione and two derivatives of 1,7-diMethyl-8,9-diphenyl-4-azatricyclo (5.2.1.02.6) dec-8-ene-3,5,10-trione were evaluated in vitro for their inhibition efficacy of acetylcholinesterase. The Km, Vmax, slope angles of Lineweaver–Burk plots, Ki and IC50 values showed that all four aminoalkanol derivatives are competitive inhibitors of acetylcholinesterase whose inhibitory potency depends, to a varying extent, on the nature of the four different substituents present in the main compound structure. S

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22

Xu, Beihua, and Yongzhou Hu. "A Facile synthesis of 2-Methyl-1,2,3-Triazoles." Journal of Chemical Research 2003, no. 2 (2003): 96–97. http://dx.doi.org/10.3184/030823403103173084.

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Reaction of α-bromoacetophenone bearing various substituents on the benzene rings with methylhydrazine in refluxing acetic acid afforded 2-methyl-4-phenyl-1,2,3-triazoles. The relation between the substituents and the yields is briefly discussed.

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23

Jia, Xu, Xiujuan Zhang, Wenhui Peng, et al. "Effect of Substituents on the Homopolymerization Activity of Methyl Alkyl Diallyl Ammonium Chloride." Molecules 27, no. 15 (2022): 4677. http://dx.doi.org/10.3390/molecules27154677.

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Among nitrogen-containing cationic electrolytes, diallyl quaternary ammonium salt is a typical monomer with the highest positive charge density, which has attracted the most attention, especially in the research on homopolymers and copolymers of dimethyl diallyl ammonium chloride (DMDAAC), which occupy a very unique and important position. In order to improve the lipophilicity of substituted diallyl ammonium chloride monomers under the premise of high cationic charge density, the simplest, most direct, and most efficient structure design strategy was selected in this paper. Only one of the sub

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24

Kostryukov, Sergey G., Sergey V. Araslankin, Pavel S. Petrov, Valentin A. Kalyazin, and Angam Adil Ismail Al-Rubaye. "DETERMINATION OF CHEMICAL STRUCTURE OF METHYL HYDROXYETHYLCELLULOSE BY 13C NMR SPECTROSCOPY." IZVESTIYA VYSSHIKH UCHEBNYKH ZAVEDENII KHIMIYA KHIMICHESKAYA TEKHNOLOGIYA 62, no. 8 (2019): 102–12. http://dx.doi.org/10.6060/ivkkt.20196208.5910.

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This paper discusses the determination of the structural parameters of methyl hydroxyethylcellulose (MHEC) by 13C NMR spectroscopy. Four samples of methyl hydroxyethylcellulose (MHEC, DS ~ 1.7) of different viscosity aqueous solutions were analyzed to determine the distribution of methyl and hydroxyethyl groups in different positions of the anhydroglucose unit of the polymer chain. For this purpose, MHEC samples were subjected to acid-catalyzed hydrolysis in the presence of sulfuric acid. Optimal conditions for complete hydrolysis leading to methyl and hydroxyethyl substituted D-glucose deriva

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25

Zoghbi, Michel, та John Warkentin. "Substituent effects of rate constants for thermal [4π + 2π] cycloreversion of spiro-fused β-lactam oxadiazolines". Canadian Journal of Chemistry 71, № 6 (1993): 907–11. http://dx.doi.org/10.1139/v93-120.

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Twelve Δ3-1,3,4-oxadiazolines in which C-2 is also C-4 of a β-lactam moiety (spiro-fused β-lactam oxadiazoline system) were thermolyzed as solutions in benzene. Substituents in the β-lactam portion affect the rate constant for thermal decomposition of the oxadiazolines to N2, acetone, and a β-lactam-4-ylidene. The total spread of first-order rate constants at 100 °C was 47-fold and the average value was 6.7 × 10−4 s−1. A phenyl substituent at N-1 or at C-3 was found to be rate enhancing, relative to methyl. At C-3, H and Cl were also rate enhancing, relative to methyl. The data are interpreted

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26

Stec, Katarzyna, Joanna Kozłowska, Anna Wróblewska-Kurdyk, Bożena Kordan, Mirosław Anioł, and Beata Gabryś. "Effect of Naringenin and Its Derivatives on the Probing Behavior of Myzus persicae (Sulz.)." Molecules 25, no. 14 (2020): 3185. http://dx.doi.org/10.3390/molecules25143185.

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Substances that alter insect behavior have attracted a lot of attention as potential crop protection agents. Naringenin (5,7,4′-trihydroxyflavanone) is a naturally occurring bioactive flavanone. We evaluated the influence of naringenin on aphid activities during individual phases of probing and feeding and the effect of structural modifications of naringenin on its activity towards aphids. We monitored the probing behavior of Myzus persicae (Sulz.) (Hemiptera: Aphididae) using the Electrical Penetration Graph (EPG) technique. The chemical modifications were the substitution of hydrogen atoms w

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Happer, DAR, and BE Steenson. "The Determination of Substituent Effects by 13C Nuclear Magnetic Resonance Spectrometry. The Effect of Solvent on CH2X Groups." Australian Journal of Chemistry 38, no. 2 (1985): 337. http://dx.doi.org/10.1071/ch9850337.

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A previous study of the effect of meta- and para-CH2X substituents on the 13C n.m.r. chemical shifts of the α and β side-chain carbons of β- methoxycarbonylstyrenes (methyl cinnamates ) in ethanol has been extended to cover five additional solvents (Me2SO, Me2CO, CDCl3, CCl4 and C6H6). The results support the earlier claim that, for most substituents , the magnitudes of the substituent -induced shifts are proportional to the inductive effect of X. The major contributor to the latter appears to be the field effect generated by the C-X dipole, with the lines of force passing mainly through the m

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28

Ben Ali, Karim, and Pascal Retailleau. "(3R,4S)-3-Methyl-4-phenyl-2-[(R)-1-phenylethyl]-3,4-dihydroisoquinolin-2-ium tetrafluoridoborate." Acta Crystallographica Section E Structure Reports Online 70, no. 3 (2014): o255. http://dx.doi.org/10.1107/s160053681400230x.

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The title salt, C24H24N+·BF4−, is one of two possible diastereoisomers having a different configuration of the asymmetric centre in the α-phenylethyl substituent, whose absolute configuration was established to beR. The two phenyl substituents of the cation have a cofacial orientation, albeit with a long centroid–centroid separation of 4.129 (3) Å. The crystal structure exhibits numerous C—H...F contacts between counter-ions, with the tetrafluoridoborate anion surrounded by five iminium cations.

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29

Giri, Rajan, Hari K. Namballa, Vishwashiv Emogaje, and Wayne W. Harding. "Structure–Activity Relationship Studies on 6-Chloro-1-phenylbenzazepines Leads to the Identification of a New Dopamine D1 Receptor Antagonist." Molecules 28, no. 16 (2023): 6010. http://dx.doi.org/10.3390/molecules28166010.

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The 1-phenylbenzazepine template has yielded a number of D1R-like ligands, which, though useful as pharmacological tools, have significant drawbacks in terms of selectivity versus D5R as well as pharmacokinetic behavior. A number of 1-phenylbenzazepines contain a 6-chloro functional group, but extensive SAR studies around the 6-chloro-1-phenylbenzazepine framework have not been reported in the literature. To further understand the tolerance of the 6-chloro-1-phenylbenzazepine template for various substituent groups towards affinity and selectivity at D1R, we synthesized two series of analogs w

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30

Newcomb, Martin, Seung-Yong Choi, and Patrick H. Toy. "Picosecond radical kinetics. Rate constants for ring openings of 2-aryl-substituted cyclopropylcarbinyl radicals." Canadian Journal of Chemistry 77, no. 5-6 (1999): 1123–35. http://dx.doi.org/10.1139/v99-094.

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The kinetics of ring openings of a series of eight (trans-2-arylcyclopropyl)methyl radicals (1) were studied by indirect kinetic methods using Barton's PTOC esters as radical precursors and reaction with PhSeH as the competition reaction. The substituents were CF3, F, Me, and OMe located on both the para and meta positions of the aromatic ring. Syntheses of the radical precursors and the products of the radical reactions are described. Kinetics were determined between -43 and 25°C in four cases (CF3 and OMe substituents) and at 0 and 25°C in the other four cases. The rate constants at 25°C ran

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31

Jollimore, Jason V., Marc Vacheresse, Keith Vaughan, and Donald L. Hooper. "The effect of ortho and para substituents on the formation of the E and Z isomers of the arylhydrazones obtained from diazonium coupling with methyl 3-aminocrotonate and 3-aminocrotononitrile." Canadian Journal of Chemistry 74, no. 2 (1996): 254–62. http://dx.doi.org/10.1139/v96-029.

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Reaction of arene diazonium salts with 3-aminocrotononitrile or methyl 3-aminocrotonate affords the 2-aryl-hydrazono-3-oxobutanenitrile (1 or 3 and 3′) or the methyl 2-arylhydrazono-3-oxobutanoate (2 and 2′ or 4 and 4′). A series of these hydrazones has been prepared with a range of electron-withdrawing and -donating substituents in the ortho or para position of the aryl moiety. The hydrazones have been characterized by spectroscopic methods, with emphasis on the 1H NMR spectra, which have been used to determine the configuration of the hydrazones as E or Z or a mixture of the two. The para-su

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32

Shaibah, Mohammed A. E., Hemmige S. Yathirajan, Nagaraj Manju, Balakrishna Kalluraya, Ravindranath S. Rathore, and Christopher Glidewell. "Two isostructural 3-(5-aryloxy-3-methyl-1-phenyl-1H-pyrazol-4-yl)-1-(thiophen-2-yl)prop-2-en-1-ones: disorder and supramolecular assembly." Acta Crystallographica Section E Crystallographic Communications 76, no. 1 (2020): 48–52. http://dx.doi.org/10.1107/s205698901901658x.

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Two new chalcones containing both pyrazole and thiophene substituents have been prepared and structurally characterized. 3-(3-Methyl-5-phenoxy-1-phenyl-1H-pyrazol-4-yl)-1-(thiophen-2-yl)prop-2-en-1-one, C23H18N2O2S (I), and 3-[3-methyl-5-(2-methylphenoxy)-1-phenyl-1H-pyrazol-4-yl]-1-(thiophen-2-yl)prop-2-en-1-one, C24H20N2O2S (II), are isomorphous as well as isostructural, and in each the thiophene substituent is disordered over two sets of atomic sites having occupancies 0.844 (3) and 0.156 (3) in (I), and 0.883 (2) and 0.117 (2) in (II). In each structure, the molecules are linked into sheet

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33

Thirunarayanan, Ganesamoorthy, and K. G. Sekar. "Spectral QSAR and QPR Study of some (E)-4-(((2-Hydroxy-6-(Substituted Phenyl)-1,6 Dihydropyrimidin-4-yl)Methyl)Diazenyl)Benzoic Acid Derivatives." International Letters of Chemistry, Physics and Astronomy 36 (July 2014): 10–20. http://dx.doi.org/10.18052/www.scipress.com/ilcpa.36.10.

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A series of titled compounds were synthesized and recorded the infrared and NMR spectra. The assigned spectral group frequencies were correlated with Hammett substituent constants, F and R parameter. From the statistical analysis results, the effect of substituents on the spectral group frequencies has been studied.

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34

Fiedler, Pavel, and Otto Exner. "Conformation of Aromatic Carbonyl Derivatives: An Infrared Study." Collection of Czechoslovak Chemical Communications 69, no. 4 (2004): 797–810. http://dx.doi.org/10.1135/cccc20040797.

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Infrared spectra of 14 methyl- and polymethyl-substituted acetophenones and of 14 equally substituted methyl benzoates were investigated in the carbonyl region in tetrachloromethane solution and correlated with their conformation. The ν(C=O) frequency depends moderately on the inductive effect of substituents and more sensitively on the steric effect of ortho substituents. Steric effects are not simply related to the torsion angle ϕ (calculated by the density functional theory) but are better described by dividing the methyl substituents into three classes: nonplanar derivatives with methyl gr

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35

Hambley, TW, TW Hambley, B. Raguse, B. Raguse, DD Ridley, and DD Ridley. "Chiral Induction in the Methylation of N-Ethoxycarbonylmethyl Sulfoximines." Australian Journal of Chemistry 39, no. 11 (1986): 1833. http://dx.doi.org/10.1071/ch9861833.

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Chiral inductions in the C- methylations of four optically active N-ethoxycarbonylmethyl-S-p-tolylsulfoximines were explored by using the reagents lithium diisopropylamide (in tetrahydrofuran at -78°) then methyl iodide. When the fourth substituent at sulfur was a methyl group, complex mixtures of products were formed. However, when the fourth substituent was an aryl group, moderate yields of methylated compounds were formed and the ratio of diastereomers produced were 50 : 50 ( Ar = phenyl), 76 : 24 ( Ar = o- methoxyphenyl ) and 100 : 0 [ Ar = o-(2-methoxyethoxy)phenyl]. The diastereoselectiv

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36

Szczesio, Małgorzata, Andrzej Olczak, Katarzyna Gobis, et al. "Planarity of benzoyldithiocarbazate tuberculostatics. II. Diesters of benzoyldithiocarbazic acid." Acta Crystallographica Section C Structural Chemistry 72, no. 1 (2016): 75–79. http://dx.doi.org/10.1107/s2053229615024201.

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The emergence of drug-resistant strains ofMycobacterium tuberculosishas intensified efforts to identify new lead tuberculostatics. Our earlier studies concluded that the planarity of a molecule correlates well with its tuberculostatic activity. According to our hypothesis, only derivatives whose molecules are capable of adopting a planar conformation may show tuberculostatic activity. The structures of three new potentially tuberculostatic compounds, namelyN′-[bis(methylsulfanyl)methylidene]-N-methyl-4-nitrobenzohydrazide (denotedG1), C11H13N3O3S2,N′-[bis(benzylsulfanyl)methylidene]-N-methyl-4

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37

Schaefer, Ted, and James D. Baleja. "Motion about the Csp2—S bond in thioanisole and some derivatives by the J method." Canadian Journal of Chemistry 64, no. 7 (1986): 1326–31. http://dx.doi.org/10.1139/v86-227.

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Conformations about the Csp2—S bond in thioanisole and eight of its derivatives in solution are investigated by means of long-range spin–spin coupling constants over six bonds between the sidechain 13C nucleus and the para ring proton or 19F nucleus. According to geometry optimized STO 3G MO calculations the internal barrier to rotation is predominantly twofold in the gas phase in thioanisole and is 6.2 kJ/mol. In benzene solution the coupling constant yields 5.5(4) kJ/mol. Para fluorine and methyl substituents reduce the magnitude of the internal barrier, but meta methyl or chlorine substitue

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38

Ockenfels, Andreas, Igor Schapiro, and Wolfgang Gärtner. "Rhodopsins carrying modified chromophores – the ‘making of’, structural modelling and their light-induced reactivity." Photochemical & Photobiological Sciences 15, no. 2 (2016): 297–308. http://dx.doi.org/10.1039/c5pp00322a.

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Vitamin-A aldehydes (retinals) with modified alkyl group substituents (9-demethyl-, 9-ethyl-, 9-isopropyl-, 10-methyl, 10-methyl-13-demethyl-, and 13-demethyl retinal) were synthesized to probe the chromophore-proteininteractions in rhodopsin.

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39

Fernández-Alvarez, Victor M., Sarah K. Y. Ho, George J. P. Britovsek, and Feliu Maseras. "A DFT-based mechanistic proposal for the light-driven insertion of dioxygen into Pt(ii)–C bonds." Chemical Science 9, no. 22 (2018): 5039–46. http://dx.doi.org/10.1039/c8sc01161c.

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40

Sakhautdinov, I. M., R. N. Malikova, and M. S. Yunusov. "Synthesis of Methyl Maleopimarates with Adamantyl Substituents." Chemistry of Natural Compounds 54, no. 1 (2018): 102–5. http://dx.doi.org/10.1007/s10600-018-2269-3.

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41

Bonnier, Catherine, David S. Josey, and Timothy P. Bender. "Aryl-Substituted Boron Subphthalocyanines and their Application in Organic Photovoltaics." Australian Journal of Chemistry 68, no. 11 (2015): 1750. http://dx.doi.org/10.1071/ch15381.

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A family of five axial aryl-substituted boron subphthalocyanine (BsubPc) derivatives bearing a hydrido, methyl, methoxy, phenyl, or fluoro substituent at the para position of the aryl were synthesised from Br-BsubPc and the corresponding aryl Grignard reagent in moderate yields. The physicochemical characterisation of these derivatives gave similar absorption, photoluminescence, and cyclic voltammetry profiles and photoluminescence quantum yields, indicating that the nature of the substituent at the para position does not influence the basic photophysical properties of this generic class of Bs

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42

Adeleke, A., S. Islam, K. Olofinsan, V. Salau, and B. Omondi. "Mononuclear discrete Ag(I) complexes of aryl substituted (E)-N-phenyl-1-(pyridin-3-yl)methanimine: In vitro biological activities and interactions with biomolecules." South African Journal of Chemistry 77 (2023): 48–60. http://dx.doi.org/10.17159/0379-4350/2023/v77a08.

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The synthesis of three pyridinyl imines (L1-L3) with electron-donating and electron-withdrawing functional groups, as well as their silver(I) complexes (1a-3a, 1b-3b and 1c-3c), resulted from our ongoing search for novel metallodrugs with potential pharmacological activity. Various analytical and spectroscopic analyses were used to characterize the Ag(I) complexes. The single crystal X-ray diffraction analysis of complexes 3a and 3b in the solid state confirmed their linear geometry around the Ag(I) center. In vitro antibacterial properties of the complexes evaluated using the minimum inhibito

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43

Exner, Otto, and Miloš Buděšínský. "Correlation of substituent – inducted chemical shifts of aromatic protons: Substituted benzonitriles and methyl benzoates." Collection of Czechoslovak Chemical Communications 56, no. 11 (1991): 2234–50. http://dx.doi.org/10.1135/cccc19912234.

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Proton NMR spectra in deuteriochloroform are reported for 53 meta- and para-substituted benzonitriles and 61 methyl benzoates. The substituent-induced chemical shifts (SCS) were correlated with dual substituent parameters (DSP), with 13C SCS of the adjoining carbon, and with the other 1H SCS using the principal component analysis (PCA). They are controlled by different factors in each position to the variable substituent. In the position 4 the long-range polar effects, as expressed by DSP, are decisive, the conjugative component being more important. Remarkable is also very close correlation o

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44

Thirunarayanan, Ganesamoorthy, and K. G. Sekar. "Spectral QSAR and QPR Study of some (<i>E</i>)-4-(((2-Hydroxy-6-(Substituted Phenyl)-1,6 Dihydropyrimidin-4-yl)Methyl)Diazenyl)Benzoic Acid Derivatives." International Letters of Chemistry, Physics and Astronomy 36 (July 15, 2014): 10–20. http://dx.doi.org/10.56431/p-l8rcqg.

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A series of titled compounds were synthesized and recorded the infrared and NMR spectra. The assigned spectral group frequencies were correlated with Hammett substituent constants, F and R parameter. From the statistical analysis results, the effect of substituents on the spectral group frequencies has been studied.

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45

Asanbaeva, Nargiz B., Larisa Yu Gurskaya, Yuliya F. Polienko, et al. "Effects of Spiro-Cyclohexane Substitution of Nitroxyl Biradicals on Dynamic Nuclear Polarization." Molecules 27, no. 10 (2022): 3252. http://dx.doi.org/10.3390/molecules27103252.

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Spiro-substituted nitroxyl biradicals are widely used as reagents for dynamic nuclear polarization (DNP), which is especially important for biopolymer research. The main criterion for their applicability as polarizing agents is the value of the spin–spin exchange interaction parameter (J), which can vary considerably when different couplers are employed that link the radical moieties. This paper describes a study on biradicals, with a ferrocene-1,1′-diyl-substituted 1,3-diazetidine-2,4-diimine coupler, that have never been used before as DNP agents. We observed a substantial difference in the

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46

Zabielska-Matejuk, Jadwiga, Joanna Feder-Kubis, Anna Stangierska, and Piotr Przybylski. "Chiral ionic liquids with a (−)-menthol component as wood preservatives." Holzforschung 71, no. 9 (2017): 751–57. http://dx.doi.org/10.1515/hf-2016-0216.

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Abstract Research has been conducted on the biotic activity of eight chiral ionic liquids (CILs) with a natural component in the form of (−)-menthol with the configuration (1R,2S,5R) against Basidiomycetes and Fungi imperfecti. Optically active imidazolium salts were tested as follows: several asymmetric 3-alkyl-1-[(1R,2S,5R)-(−)-menthoxymethyl]imidazolium chlorides with various alkyl substituents (from methyl to dodecyl) and one symmetric 1,3-bis[(1R,2S,5R)-(−)-menthoxymethyl]imidazolium chloride containing two (1R,2S,5R)-(−)-menthol substituents. Mycological tests were carried out with brown

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47

Wagenknecht, Hans-Achim, Robert Hofsäß, and David Rombach. "Thieme Chemistry Journal Awardees – Where are They Now? The Influence of Electron-Withdrawing Groups at the 2- and 2′-Positions of Dibenzothienylethenes on Molecular Switching." Synlett 28, no. 12 (2017): 1422–26. http://dx.doi.org/10.1055/s-0036-1588796.

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Three dibenzothienylethenes that carry a methyl, a trifluoromethyl, or a fluoro substituent in the 2- and 2′-position were synthesised in short multistep syntheses, respectively. The trifluoromethyl and fluoromethyl substituents significantly improve the absorption properties of the corresponding open and closed isomers (both in the UV-A and in the visible range). The increasing electron deficiency (i) enlarges the portion of the closed and coloured diarylethene isomer in the corresponding photostationary states and slows down the closing and opening isomerisation, (ii) the switching reactions

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48

Kurbanova, Malahat M., Atash V. Gurbanov, Kamran T. Mahmudov, Abel M. Maharramov, and Seik Weng Ng. "9-(2-Hydroxy-4,4-dimethyl-6-oxocyclohex-1-en-1-yl)-3,3-dimethyl-2,3,4,9-tetrahydro-1H-xanthen-1-one." Acta Crystallographica Section E Structure Reports Online 68, no. 6 (2012): o1606. http://dx.doi.org/10.1107/s1600536812018934.

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The cyclohexene ring that constitutes a part of the tetrahydroxanthene fused-ring system of the title compound, C23H26O4, adopts a flattened half-chair conformation that approximates an envelope conformation (in which the methylene C atom bearing the two methyl substituents represents the flap) as five of the six atoms lie approximately on a plane (r.m.s. deviation = 0.020 Å). The mean plane of the cyclohexene ring with the hydroxy substituent is approximately perpendicular to the mean plane of the tetrahydroxanthene system. In the crystal, adjacent molecules are linked by O—H...Ocarbonyl hydr

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49

Perfetto, Alessandra, Valerio Bertolasi, Chiara Costabile, et al. "Methyl and phenyl substituent effects on the catalytic behavior of NHC ruthenium complexes." RSC Advances 6, no. 98 (2016): 95793–804. http://dx.doi.org/10.1039/c6ra20608e.

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50

Francis, CL, and AD Ward. "Attempted Heterocyclic Syntheses Through Electrophilic Ring Closure Reactions of 2-Allylaniline Systems Containing Larger Side Chains." Australian Journal of Chemistry 47, no. 11 (1994): 2109. http://dx.doi.org/10.1071/ch9942109.

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The electrophile-initiated cyclization of some 2-allylanilines and their amide derivatives has been further investigated. Although 2-allylanilines with small, allylic substituents such as methyl reacted with iodine to yield 3-iodo-1,2,3,4-tetrahydroquinolines the 2-allylanilines with larger substituents related to those of virantmycin provided low yields of the tetrahydroquinoline as part of a complex product mixture.

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