Phenyl Research Articles

Synthesis and photooxygenation of 3-(p-substituted phenyl)-3a,8a-dihydro-4H-cyclohepta[d]isoxazoles: facial selectivity.

Two 3-(p-substituted phenyl)-3a,8a-dihydro-4H-cyclohepta[d]isoxazoles were synthesized by 1,3-dipolar cycloaddition of the corresponding nitrile oxides with cycloheptatriene. Two endoperoxides were synthesized as facially selective and single products in high yields (93%-95%) from the reactions of isoxazole derivatives with singlet oxygen. The exact configurations of the endoperoxide with a methyl group in the phenyl ring and the diol synthesized from it were confirmed by X-ray analysis. To elucidate the mechanism, the formation energy of the endoperoxide was investigated by simulations using the software package Gaussian 09 and density functional theory calculations via the M06-2X/6-311+G(d,p) level method in dichloromethane. The results were consistent with experimental findings showing the formation of isoxazole products.

A Review of Cinnamic Acid's Skeleton Modification: Features for Antibacterial-Agent-Guided Derivatives.

Antimicrobial resistance has emerged as a significant danger to global health, and the need for more effective antimicrobial resistance (AMR) control has been highlighted. Cinnamic acid is abundant in plant products and is a potential starting material for further modification, focusing on the development of new antimicrobial compounds. In the following review, we describe the classification of critical antibacterial-guided reactions applied to the main skeleton structure of cinnamic acid derivatives over the last decade. Of all of the main parts of cinnamic acids, the phenyl ring and the carboxylic group significantly affect antibacterial activity. The results presented in the following review can provide valuable insights into considerable features in the organic modification of cinnamic acids related to antibacterial medication development and the food industry.

Examining the Importance of Hydrogen Bonding and Proton Transfer in Iron Porphyrin-Mediated Carbon Dioxide Upconversion.

ConspectusThe title should give a sense of the "big picture" of this Account, but what is it really about? An unexpected change in research direction? A series of courageous and creative students? A team taking on challenging problems in chemistry? The answer is a definite "yes" to all of the above. More specifically, the problem in which we are interested is the upconversion or valorization of carbon dioxide. This problem has captured the attention of a great many chemists in earnest following the gas crisis of the 1970s and more recently galvanized due to climate concerns arising from the ongoing release of anthropogenic carbon. Addressing the problem of atmospheric carbon accumulation requires effort in two very broad areas: capture and conversion. Storage is an alternative to conversion, but this eliminates the opportunity to use what might be otherwise a waste product. Our group has investigated a series of modified versions of iron(III)-5,10,15,20-tetraphenylporphyrin (FeTPP) that can convert CO2 to carbon monoxide, which is a versatile and useful precursor for other syntheses. Following pioneering work from Savéant and his colleagues in the 1990s and thereafter, we started with a simple question: how many pendent ancillary groups that can donate H-bonds or protons are needed to support efficient CO2-to-CO conversion? Using a molecule with only one 2-hydroxylphenyl group, we demonstrated that the single prepositioned -OH group gave rise to efficient turnover, but only when experiments were carried out in a weakly H-bond-accepting solvent system. In other words, the ability of a solvent to accept H-bonds can impede CO2 reduction. We followed up with a deeper investigation of the influence of H-bonding interactions with external acids in FeTPP-mediated CO2 reduction. Savéant's framework mechanism appears to be independent of solvent, and rate differences can be approximated by considering H-bonding equilibria. Following that work, we sought to better understand the minimum catalyst design requirements with respect to internal H-bond/proton donors. To that end, we produced all possible isomers of tetraarylpoprhyrins with 2,6-dihydroxyphenyl + phenyl groups. All else being equal, the complexes with a formally trans orientation of the 2,6-dihydroxyphenyl groups performed the best. Most recently, we surveyed the roles of internal and external Brønsted acids with different pKa values. Surprisingly, the best-performing catalysts have more weakly acidic internal groups. Overall, our work has demonstrated that CO2 reduction mediated by porphyrin catalysts can be improved by considering solvent H-bonding, the orientation of internal H-bonding groups, and the balance of the pKa values of internal and external acids. The future for molecular electrocatalysts is promising as more ideas emerge about how to design molecules and conditions for CO2 reduction.

Unique Organic Crystal Skeleton Based on N-Phenyl-Carbazole Derivatives with Adjustable Room Temperature Phosphorescence and Highly Stable Inclusion Ability to Dichloromethane.

Monosubstituted 9-(2-bromophenyl)-carbazole (1Br1CZ) and disubstituted 9,9'-(2,4-dibromo-1,3-phenylene) bis(9H-carbazole) (2Br2CZ) are synthesized by introducing bromine into ortho-phenyl position of 9-phenyl-carbazole (PhCZ). The decomposition temperature with 5% mass loss and melting point of 2Br2CZ crystal are 360 and 230°C. The highest occupied molecular orbital energy level of PhCZ is the highest, and that of 2Br2CZ is the lowest. The crystals of PhCZ, 1Br1CZ, and 2Br2CZ are monoclinic, orthorhombic, and triclinic system, which exhibit room temperature phosphorescence with lifetimes of 171.81, 37.15, and 28.77ms, and their corresponding phosphorescence quantum yields are 0.83%, 0.16%, and 4.58%. It theoretically reveals that six triplet energy levels (T1-T6) exist under S1 in 2Br2CZ crystal, and the spin orbit coupling constants between S1 and Tn in 2Br2CZ are also greater than those in PhCZ and 1Br1CZ, which promotes the intersystem crossing. Meanwhile, through crystal structure and Hirshfeld surface analysis, the torsion angles between the carbazole unit of 2Br2CZ and the central phenyl group reached 85.28°. The 2Br2CZ crystal exhibits the richest intermolecular interactions. A cavity of 4.498Å is formed within the crystal skeleton of 2Br2CZ, which can precisely fixe dichloromethane with a record-high desorption temperature over 145°C.

Adsorption of Nefazodone on single-wall carbon nanotube as an antidepressant drug delivery: A DFT study

Nefazodone, a derivative of triazolones, belongs to a group of heterocyclic aromatic compounds. It is used as an antidepressant for treating depression, including major depressive disorder. Unlike other antidepressant groups such as selective serotonin reuptake inhibitors, tricyclic antidepressants, or monoamine oxidase inhibitors, Nefazodone does not share chemical similarities. Recent research has focused on studying the reactivity and chemical structure influenced by Nefazodone's medicinal features in the drug's adsorption process on single-wall Carbon Nanotube (CNT) as an adsorbent in the gas phase using density functional theory (DFT), Becke, 3-parameter, Lee–Yang–Parr (B3LYP) 6-311+G(d,p) basis set (DFT/B3LYP/6-311+G(d,p)). The effect of electronegative atoms and phenyl groups on the adsorption of Nefazodone on CNT has been studied by calculating the adsorption energy for all active sites. On the other hand, thermodynamic values, such as Gibbs free energy (−4873.09 kJ), Enthalpy (−4872.83 kJ), and Entropy (903.09 J/mol.kelvin), as well as thermodynamic capacity (497.45 J/mol.kelvin), were calculated to show the reactivity of Nefazodone. The stability and reactivity were examined through the energies of the highest occupied molecular orbital (HOMO) (−5.53 eV) and lowest unoccupied molecular orbital (LUMO) (−0.58 eV) of Nefazodone, highlighting ten regions with chemical activity, all of which are thermodynamically stable. Some Electronic parameters such as chemical potential (µ), electronegativity (χ), softness (σ), hardness (η), and electrophilicity index (ω) were calculated. The comparison of chemical potential values between Nefazodone(−3.05 eV) and the more stable complex (−3.81 eV) illustrates the more reactivity for the complex. This suggests that Nefazodone can be transferred to biological systems through such an adsorption mechanism.

Micromechanism of the effect of coal functional groups on the catalytic/esterification reaction of acetic acid

Acidification modification has proven to be a successful approach for enhancing the permeability of low-permeability coal seams and increasing coalbed methane extraction. To explore the influence of acetic acid on the organic structure of coal, a combined approach of experimental research and quantum chemical calculation is employed to examine the reaction mechanism of coal organic structure in response to acetic acid. Fourier transform infrared spectroscopy reveals a reduction in the content of hydroxyl and C–O bonds in the treated samples, along with the appearance of an absorption peak of C=C bonds. This demonstrates that the main site of acetic acid acidification modification on coal molecules is the hydroxyl functional group. Therefore, glycerol can be used as a simplified model of coal molecules for further investigation. In addition, three typical functional groups (phenyl, hydroxyl, amino) are selected as the research objects. The electronic density topological properties, molecular surface electrostatic potential, Mayer bond orders and CM5 charge of coal molecules were calculated based on quantum chemical theory. This reveals the intrinsic strength of each chemical bond between single atoms in a molecule, thereby predicting potential reaction pathways between acetic acid and coal molecules. The micro-mechanism of acetic acid catalyzing/esterifying the organic structure of coal is studied using transition state methods. The computational results show that there are two main modes of reaction between acetic acid and coal molecules: (1) acetic acid catalyzes the dehydration reaction of coal molecules; (2) acetic acid reacts with coal molecules to form ester intermediates, followed by decomposition through various reactions. Among the 14 reaction pathways, acetic acid provides protons or groups to trigger the dehydration of coal molecules. Interestingly, it is found that the overall hydroxyl group participates in the reaction is easier than the individual hydrogen atom on the hydroxyl group, and the overall carboxyl group participates in the reaction is easier than the individual hydroxyl group. This indicates that the higher the overall atomic reactivity of acetic acid, the lower the reaction barrier. Compared with catalytic reactions, acetic acid tends to undergo esterification reactions with hydroxyl groups, with the phenyl ring functional group significantly affecting the reaction barrier. The introduction of various oxygen-containing functional groups like ketone, aldehyde, and ester in the reaction products will hinder the adsorption of non-polar methane, reduce the adsorption capacity of coal seams for gas, and play an essential role in promoting gas desorption. The research findings can provide theoretical guidance for the organic acidification modification of low-permeability coal seams to enhance gas permeability and coalbed methane extraction.

Modulating the isomerization of bpp-modified azoheteroarene by transition metal ions coordination

A new photoswitchable azoheteroarene L was design and synthesized by replacing one of the phenyl rings of azobenzene moiety with a 2,6-di[pyrazol-1-yl]pyridine(bpp) unit. The assembly of L with transition metal ions results in the formation of three metal complexes, namely, M(L)2(OTf)2 (M=ZnII, FeII and CoII). These complexes are fully characterized by ESI-TOF-MS, UV–vis spectrum, 1H NMR spectrum and single-crystal X-ray diffraction. Upon irradiation with 380 nm light, L exhibits excellent E to Z photoisomerization in solution, achieving up to 82 % Z-configuration with a thermotropic isomerization half-life time of 301 days. After coordination with ZnII, FeII and CoII, the photoisomerization properties of L were significantly varied. Coordinating with the ZnII ion, the conversion of Z-L slightly decreased from 82 % to 77 %. However, this coordination significantly extends thermal isomerization half-life time to 564 days, resulting in a 1.9-fold enhancement compared to free Z-L. In contrast, the coordination with open-shell transition metal ions FeII and CoII noticeably inhibits the formation of Z-L and only yields E-L isomers. Moreover, the spin-crossover behavior of Fe(E-L)2(OTf)2 was also investigated. The analysis of variable temperature NMR indicates that Fe(E-L)2(OTf)2 shows a spin transition temperature of 265 K in solution. This work provides valuable insights into tunning conformational transitions of azoheteroarene molecules.

Indole-core inhibitors of influenza a neuraminidase: iterative medicinal chemistry and molecular modeling

Influenza viruses that cause seasonal and pandemic flu are a permanent health threat. The surface glycoprotein, neuraminidase, is crucial for the infectivity of the virus and therefore an attractive target for flu drug discovery campaigns. We have designed and synthesized more than 40 3-indolinone derivatives. We mainly investigated the role of substituents at the 2 position of the core as well as the introduction of substituents or a nitrogen atom in the fused phenyl ring of the core for inhibition of influenza virus neuraminidase activity and replication in vitro and in vivo. After evaluating the compounds for their ability to inhibit the viral neuraminidase, six potent inhibitors 3c, 3e, 7c, 12o, 12v, 18d were progressed to evaluate for cytotoxicity and inhibition of influenza virus A/PR/8/34 replication in in MDCK cells. Two hit compounds 3e and 12o were tested in an animal model of influenza virus infection. Molecular mechanism of the 3-indolinone derivatives interactions with the neuraminidase was revealed in molecular dynamic simulations. Proposed inhibitors bind to the 430-cavity that is different from the conventional binding site of commercial compounds. The most promising 3-indolinone inhibitors demonstrate stronger interactions with the neuraminidase in molecular models that supports proposed binding site.

Cu‐Catalyzed Formal Addition of Aliphatic C(sp3)−H Bonds to Alkenes via Phenyl Radical Involved Intermolecular HAT

AbstractA copper catalyzed aerobic formal addition of aliphatic C(sp3)−H bonds to alkenes via a phenyl radical mediated intermolecular HAT process is reported herein, in which the phenylhydrazine not only acts as a HAT reagent precursor, but also as a hydrogen atom donor. This reaction affords an alternative method for the direct formal addition of aliphatic C(sp3)−H bonds to alkenes utilizing air as the radical initiator without additional reductants at ambient temperature. A variety of alkanes and electron‐deficient alkenes are successfully incorporated, furnishing a series of aliphatic C(sp3)−H formal addition products in 20–93% yield. Preliminary mechanistic studies show that the 2‐tetrahydrofuranyl and phenyl radical are formed in this reaction.

Conjoining the benefits of an additional phenyl ring in a simple benzophenone hydrazone-based platform @ discriminatory recognition of F− over CN− with quantitation of aqueous Cu2+: New tricks for an old dog

Herein, benzophenone hydrazone derived two π-conjugative networks viz.DMHMN and DMHMP have been judiciously designed for competitive recognition of F− (LOD: 6.8 ppm; Ka: 7.2 × 103 M−1) over CN− (LOD: ∼0.3 ppm; Ka: 20.3 × 104 M−1) along with Cu2+. Interestingly, the presence of an extra phenyl ring in DMHMN played a pivotal role for discriminative colorimetric recognition of F− over CN− despite having greater hydration energy of F−. Deliberate implantation of an extra phenyl ring leads to enhanced acidity of the benzophenone platform, rationalizing structure-performance synergies. While the presence of dangling OH group and azomethine functionality enables both the chemosensors to exhibit selective recognition toward Cu2+ in purely aqueous phase with the detection limit of ∼0.7 ppm and ∼0.16 ppm by DMHMP and DMHMN respectively, which are far below the safe limit set by World Health Organization (WHO). The sensing phenomenon by the redox non-innocent sensory receptors has been thoroughly investigated by UV–Vis, cyclic voltammetry and 1H NMR spectroscopic studies validated by density functional theory (DFT). Moreover, relay recognition of Al3+ by [DMHMN·F−] ensemble made it a suitable contender for complex logic circuitry fabrication like IMPLICATION/INHIBIT circuit. Additionally, the sensory probes have the capability of quantitative estimation of Cu2+ from unknown water samples, which was cross-examined with the help of the lab-based market available portable device. Lastly, smartphone assisted point-of-care testing (POCT) application has been performed for on-field detection of F− by DMHMN.

Metal-free phenothiazine dyes with alkoxy chains modified at different position for dye-sensitized solar cells

Long alkyloxy or alkoxyphenyl chains are commonly introduced to organic dye sensitizers in dye-sensitized solar cells (DSSCs) to inhibit the aggregation of sensitizer on the TiO2, thereby minimizing charge recombination. Here, we synthesized four D-D-π-A sensitizers (TP-C6, TP-PhOC6, C6O-TP-C6, C6O-TP-PhOC6), that feature alkyl-/alkoxyphenyl- moiety in phenothiazine (PTZ) donor’s N-position, and either alkoxy or no alkoxy groups in triphenylamine (TPA) auxiliary donor. Then, their photophysical, electrochemical and DSSCs properties were investigated. The UV-Vis and electrochemical studies revealed that all four dyes exhibited good light absorption ability and appropriate HOMO-LUMO energy levels. The introduction of alkoxy at the donor or auxiliary donor can result in a significant redshift in absorption. Among them, TP-PhOC6, which incorporates an alkoxy phenyl group at the N-position of PTZ and lacks alkoxy in TPA, induces a greater redshift in ICT absorption with strong absorption intensity. Additionally, in TP-PhOC6 based DSSC, mitigated charge recombination was observed. As a result, this device exhibited the strongest and widest IPCE spectrum, the highest Jsc (12.77 mA/cm²) and Voc (0.85 V), leading to the highest PCE (6.59 %).

The vibrational spectra of a model boron dipyrromethene molecule in condensed phase: Experimental and theoretical insights

Boron dipyrromethene (BODIPY) derivatives are an important class of organic molecular dyes. Their chemical structure can be easily modified by synthetic methods, introducing various substituent groups on a tricyclic core that represents the characteristic unit of these compounds. As a consequence, BODIPY optical properties can be designed to tune their absorption and emission in an especially wide wavelength range. A large amount of experimental and computational studies has been performed to investigate the electronic excited states of many structurally different BODIPY dyes. On the other hand, vibrational properties are by far less known for these compounds. We have therefore measured detailed infrared and Raman spectra of a model compound, namely, a BODIPY derivative with four methyl groups and a phenyl ring as substituents. The experimental spectra of the solid sample have been contrasted with ab initio spectra computed at the CAM-B3LYP/6-31G+(d) level. Computations have been performed both for the isolated molecule and including the crystalline environment. In the latter case, better agreement has been observed. An assignment is proposed for the 123 vibrational modes. These results form the basis for further spectroscopic studies on complex BODIPY derivatives.

Crystal structure of (1,4,7,10,13,16-hexa-oxa-cycloocta-decane-κ6 O)potassium-μ-oxalato-tri-phenylstannate(IV), the first reported 18-crown-6-stabilized potassium salt of tri-phenyl-oxalatostannate.

The title complex, (1,4,7,10,13,16-hexa-oxa-cyclo-octa-decane-1κ6 O)(μ-oxalato-1κ2 O 1,O 2:2κ2 O 1',O 2')triphenyl-2κ3 C-potassium(I)tin(IV), [KSn(C6H5)3(C2O4)(C12H24O6)] or K[18-Crown-6][(C6H5)3SnO4C2], was synthesized. The complex consists of a potassium cation coordinated to the six oxygen atoms of a crown ether mol-ecule and the two oxygen atoms of the oxalatotri-phenyl-stannate anion. It crystallizes in the monoclinic crystal system within the space group P21. The tin atom is coordinated by one chelating oxalate ligand and three phenyl groups, forming a cis-trigonal-bipyramidal geometry around the tin atom. The cations and anions form ion pairs, linked through carbonyl coordination to the potassium atoms. The crystal structure features C-H⋯O hydrogen bonds between the oxygen atoms of the oxalate group and the hydrogen atoms of the phenyl groups, resulting in an infinite chain structure extending along a-axis direction. The primary inter-chain inter-actions are van der Waals forces.

CALCULATION of HOMA AND BIRD AROMATICITY INDICES, NLO and NBO PROPERTIES OF BENIDIPINE

Benidipine hydrochloride, being the derivate of 1,4-dihydropyridine is a calcium channel blocker antihypertensive drug. The aromaticity, natural bond orbital (NBO) and Nonlinear Optical (NLO) parameters properties of Benidipine (BEN) and BENHCl compounds were theoretically investigated using density functional theory (DFT) electronic structure method. Among the values of common aromaticity indices, the Harmonic Oscillator Aromaticity Model (HOMA) and BIRD's (Aromaticity Index) for electronic delocalization show that the aromaticity of the nitrophenyl group is higher in BEN and BENHCl compounds, and also the aromaticity in the gas phase is higher than that in water, octanol and DMF phase. In compound BEN, it was observed that as the dielectric constant of the medium increased, the aromaticity difference increased slightly. In the compound BEN, the correlation coefficient between HOMA values and aromatic fluctuation index (FLU), para delocalization index (PDI) and para-linear response (PLR) for the nitrophenyl group is higher than that the phenyl group. Donor-acceptor transitions, stabilization energies, intramolecular charge transfer were determined by natural population analyses. NLO parameters such as dipole moment, polarisibility and first order hyperpolarizability values of the BEN and BENHCl compound were also studied.

Some Terminally Alkenyl-substituted Porphyrins: Synthesis and Attempts of Heck Reaction Leading to Porphyrin–Azulene Dyads

: The synthesis of meso-tetraphenylporphyrin derivatives, double functionalized in one of the phenyl rings (with a nitro group and carbon substituents), is described. 5-(4- Nitroaryl)-10,15,20-triarylporphyrinates react, in the presence of a base (t-BuOK), with carbanions containing a leaving group at the carbanionic center to give products of substitution of hydrogen at ortho-position to the nitro group via vicarious nucleophilic substitution scheme. Their alkylation with allyl bromide or 4-bromobut-1-en (t-BuOK/DMF, at 0-5°C) leads to porphyrins bearing side alkyl chain with a terminal double bond in yields of up to 82%. The above-mentioned double-substituted intermediates are very convenient substrates for Heck cross-coupling reaction. In this study, the synthesis of porphyrin–azulene dyads is reported. In some cases, the formation of highly conjugated systems is observed, with moderate yield. Their structures are interesting from both the porphyrin and azulene point of view.

Facile Synthesis and Global Aromaticity of Aza‐Superbenzene and Aza‐Supernaphthalene at Different Oxidation States

AbstractAll‐benzenoid polycyclic aromatic hydrocarbons or macrocycles usually display localized aromaticity. On the other hand, incorporation of quinoidal units into the skeleton could lead to effective electron delocalization and global (anti)aromaticity. In this work, fully π‐conjugated macrocycle 1 and bismacrocycle 2 containing both para‐quinodimethane and triphenylamine units are efficiently synthesized mainly through intermolecular Friedel–Crafts alkylation reaction. They can be considered as a tetraazasuperbenzene and a hexaazasupernaphthalene, respectively, due to their similar geometry and electronic structures to the benzene and naphthalene. X‐ray crystallographic analyses reveal a largely planar geometry for both 1 and 2 and variable‐temperature NMR measurements disclose slow dynamic processes owing to restricted ring flipping of the phenyl rings. 1 and 2 can be easily oxidized into higher‐oxidation‐state species. NMR and theoretical calculations indicate that 12+ and 14+ show global anti‐aromaticity and aromaticity, respectively, with a dominant 32π and 30π conjugation pathway, while for the bismacrocycle 2, its dication 22+, tetracation 24+ and hexacation 26+ exhibit global aromaticity, antiaromaticity, and aromaticity with a 54π, 52π and 50π conjugation pathway along the outermost backbone, respectively.

A Metal‐Free Amination of 1,2‐Diaza‐1,3‐dienes Using Hydrazine Hydrate Through N‐N Bond Cleavage

: Herein, we have developed a metal‐free, atom‐economical, intrinsically sustainable approach for synthesizing unprotected 4,5‐diamino pyrazoles from readily available 1,2‐diaza‐1,3‐dienes. This approach utilizes inexpensive hydrazine hydrate as the aminating source. Further, we have explored the reactivity of 4,5‐diamino pyrazole to synthesize fused pyrazolo[3,4‐d]‐1,2,3‐triazole heterocyclic compounds. We have also successfully demonstrated the synthetic utility of this methodology in synthesizing two drug analogs: analgesic difenamizole and anti‐psychotic CDPPB. The role of the phenyl ring of 3‐substituted‐1,2‐diaza‐1,3‐diene was explained with the help of control experimental and density functional theory (DFT) computation studies.

Facile Synthesis and Global Aromaticity of Aza-Superbenzene and Aza-Supernaphthalene at Different Oxidation States.

All-benzenoid polycyclic aromatic hydrocarbons or macrocycles usually display localized aromaticity. On the other hand, incorporation of quinoidal units into the skeleton could lead to effective electron delocalization and global (anti)aromaticity. In this work, fully π-conjugated macrocycle 1 and bismacrocycle 2 containing both para-quinodimethane and triphenylamine units are efficiently synthesized mainly through intermolecular Friedel-Crafts alkylation reaction. They can be considered as a tetraazasuperbenzene and a hexaazasupernaphthalene, respectively, due to their similar geometry and electronic structures to the benzene and naphthalene. X-ray crystallographic analyses reveal a largely planar geometry for both 1 and 2 and variable-temperature NMR measurements disclose slow dynamic processes owing to restricted ring flipping of the phenyl rings. 1 and 2 can be easily oxidized into higher-oxidation-state species. NMR and theoretical calculations indicate that 12+ and 14+ show global anti-aromaticity and aromaticity, respectively, with a dominant 32π and 30π conjugation pathway, while for the bismacrocycle 2, its dication 22+, tetracation 24+ and hexacation 26+ exhibit global aromaticity, antiaromaticity, and aromaticity with a 54π, 52π and 50π conjugation pathway along the outermost backbone, respectively.

Electrochemical α‐Functionalization of N‐Aryl‐Activated Tertiary Amines

AbstractNumerous appropriately substituted pyridyl or phenyl groups serve as a particularly advantageous activation motif for the electrochemical oxidation of amines. Such groups enable a general, mild method for the electrochemical α‐functionalization of tertiary amines across numerous activating groups and amine scaffolds. Notably, the method accommodates an unprecedented range of nucleophile classes, allowing for the introduction of diverse functional groups to the readily prepared amine substrates. The utility of this method is then demonstrated through applications to unsymmetrical bisfunctionalization, site‐selective functionalization of N‐pyridyl amines vs. other activated amines, a formal synthesis of ivosidenib and the diversification of FDA‐approved drugs or natural product substrates.

Presenting a new fluorescent probe, methyl(10-phenylphenanthren-9-yl)sulfane sensitive to the polarity and rigidity of the microenvironment: applications toward microheterogeneous systems.

A molecule, methyl(10-phenylphenanthren-9-yl)sulfane (MPPS), with a straightforward structure, has been synthesized, characterized, and explored as a new fluorescent probe for microheterogeneous systems. The photophysical properties of MPPS have been studied through experimental and theoretical calculations using the range-separated hybrid functional CAM-B3LYP in conjunction with a 6-311++g(d,p) basis set. Theoretical calculations show that the freely rotating phenyl ring forms a 94° dihedral angle with the phenanthrene ring in the ground state. Experimentally found two absorption bands correspond to the n → π* and π → π* transitions supported by the frontier molecular orbital calculations. Two excited singlet states, E-1 and E-2 (the former being more stable than the latter in the gas phase), exist with dihedral angles between the phenyl and phenanthrene rings as 142° and 133°, respectively, in the gas phase. Two emitting states in a condensed medium of varying polarities are supported by the steady-state fluorescence and fluorescence intensity decay data. Emission energies, fluorescence intensities, and excited singlet state lifetimes change with the polarity of the solvents. To support that the free rotation in the molecule is responsible for these changes, the fluorescence properties of another molecule, methyl(10-(o-tolyl)phenanthren-9-yl)sulfane (MTPS), with restricted rotation of the substituted benzene, i.e., o-tolyl ring have been studied. The fast-intensity decay component of MPPS is ascribed to the conformer in the E-1 state. The molecule has proved to be an excellent polarity probe explored to determine the critical micelle concentrations (cmc) values of different surfactants, which agree well with the literature reports. Different regions of binding isotherm (specific, non-cooperative, cooperative, and massive binding) of a gemini surfactant, 12-6-12,2Br- with bovine serum albumin (BSA) have been successfully demonstrated by the steady-state and time-resolved fluorescence and fluorescence anisotropic properties of MPPS. Docking results show that MPPS resides in the hydrophobic pocket of BSA. The fluorescence quenching of BSA by MPPS reveals the location of Trp residues of BSA. Thus, a polarity and molecular rigidity-sensitive fluorescent molecule, MPPS has been presented here that can potentially be used to monitor the changes in the microenvironment of biomolecules in different processes.