Kinetic study of the formation reaction of N‐chloro‐2‐oxazolidinone

The chlorination reactions of 2‐oxazolidinone with hypochlorous acid (HOCl), tert‐butyl hypochlorite (^tBuOCl) and N‐chlorosuccinimide (NCS) were studied at 25 °C, constant ionic strength, and under isolation conditions. The kinetic results obtained in the formation processes of the N‐chloro‐2‐oxazolidinone are summarized in this paper. The kinetics studied showed a first order with respect to the concentration of the each reactant and a complex dependence of the pH on the rate constant. The reactivity order with respect to the chlorinating agent found is k(HOCl) > k(^tBuOCl) > k(NCS). Copyright © 2015 John Wiley & Sons, Ltd.     

N‐Chlorination rate of five‐membered heterocyclic nitrogen compounds

The kinetics of N‐chlorination reaction of pyrrolidine, pyrrolidone, succinimide, 5,5,‐dimethyloxazolidine‐2,4‐dione, 5,5‐dimethylhydantoin and 1‐hydroximethyl‐5,5‐dimethylhydantoin with HOCl in aqueous solution were studied at 25 °C, constant ionic strength and under isolation conditions in a wide pH range. The set of compounds studied in this paper is characterized by having different functional groups and the same cyclic structure, consisting of a five‐member ring with a nitrogen atom in the ring, which is susceptible to be chlorinated. This series of compounds covers nine pK_a units, and the kinetic studies allow us to know, like, the presence of an amino, amide or imide group modify the reactivity of nitrogenous compound. Experimental data were fitted to the first‐order kinetic equation. All reactions were found to be of first order in both HOCl and nitrogenous compound concentration. Kinetics studies demonstrate that some of these compounds are hydrolyzed in alkaline medium. In each case, reaction mechanism in agreement with the experimental results is proposed. The results were compared with other compounds with similar cyclic structure (2‐oxazolidinone and proline). Copyright © 2016 John Wiley & Sons, Ltd.     

Reactions of chlorination with tert‐butyl hypochlorite (TBuOCl)

The chlorination reactions of nitrogenous organic compounds (2,2,2‐trifluoroethylamine, benzylamine, glycine, and dimethylamine) by tert‐butyl hypochlorite (^tBuOCl) were studied at 25 °C, ionic strength 0.5 M and under isolation conditions. The kinetic results obtained in the formation processes of the corresponding N‐chloramines in acid medium (pH = 5–7) are summarized in this paper. Kinetic studies showed a first order with respect to ^tBuOCl concentration. The chlorination reactions involving benzylamine, glycine and dimethylamine were all first order with respect to nitrogenous compound concentration and approximately ?1 order with respect to proton concentration. The reaction with 2,2,2‐trifluoroethylamine was more complex, and the order of reaction with respect to the amine varied with pH. Copyright © 2014 John Wiley & Sons, Ltd.     

Use of N‐chloro‐N‐methyl‐p‐toluenesulfonamide in N‐chlorination reactions

Second‐order rate constants (k₂) were determined for the addition of ten nitrogenous organic compounds (benzylamine, 2,2,2‐trifluoethylamine chlorhidrate, methylamine chlorhidrate, glycine ethyl ester chlorhidrate, glycine, glycylglycine chlorhidrate, morpholine, pyperidine, pyperazine and dimethylamine) to the N‐chloro‐N‐methyl‐p‐toluenesulfonamide (NCNMPT) in the formation reaction of N‐chloramines in aqueous solution at 25 °C and ionic strength 0.5 M. The series of nucleophiles considered is structurally very varied and covers five pK_a units. The kinetic behaviour is similar for all compounds, being the elementary step the transfer of chlorine from the NCNMPT molecule to the nitrogen of the free amino group. These reactions were found first order in both reagents. The values of the rate constants indicate that the more basic amines produce N‐chloramines more readily. Rate constants for the nucleophilic attack are shown to correlate with literature data for some of these nitrogenous organic compounds in their reaction with N‐methyl‐N‐nitroso‐p‐toluenesulfonamide. Both reactions involve that the rate determining step is the attack of nitrogenous compounds upon electrophilic centre (Cl or else NO group). NCNMPT is a particularly interesting substrate, for which has not hitherto been published kinetic information, that allows us to assess the efficiency and the competitiveness of this reaction and compare it with other agents with a Cl⁺ atom. Copyright © 2013 John Wiley & Sons, Ltd.     

Steric effect in alkylation reactions by N‐alkyl‐N‐nitrosoureas: a kinetic approach

The alkylation reactions of 4‐(p‐nitrobenzyl)pyridine (NBP), a trap for alkylating agents with nucleophilic characteristics similar to DNA bases, by five N‐alkyl‐N‐nitrosoureas (methyl‐, ethyl‐, propyl‐, butyl‐, and allylnitrosourea) were investigated in 7:3 (v/v) water/dioxane medium in the 5.0–6.5 pH range. Decomposition of alkylnitrosoureas (ANU) gives rise to alkyldiazonium ions that yield NBP‐R adducts directly or through carbocations in certain instances. The NBP alkylation rate constants by these species were determined. The following sequence of alkylating potential was found: methyl‐ > ethyl‐ > allyl‐ > propyl‐ > butyl group. Application of Ingold–Taft correlation analysis to the kinetic results revealed that the NBP alkylation reactions occur mainly through steric control. The values of the molar absorption coefficients of the NBP‐R adducts also reveal the determinant influence of a steric effect in the formation of alkylation adducts. The kinetic results are consistent with the biological activity of ANU. Copyright © 2008 John Wiley & Sons, Ltd.     

Investigation of N‐carbamoylamino acid nitrosation by {NO + O2} in the solid‐gas phase. Effects of NOx speciation and kinetic evidence for a multiple‐stage process

Nitrosation of N‐carbamoylamino acids (CAA) by gaseous NO + O₂, an interesting synthetic pathway to amino acid N‐carboxyanhydrides (NCA), alternative to the phosgene route, was investigated on N‐carbamoyl‐valine either in acetonitrile suspension or solventless conditions, and compared to the classical nitrosating system NaNO₂ + CF₃COOH (TFA), the latter being quite less efficient in terms of either rate, stoichiometric demand, or further tractability of the product. The rate and efficiency of the NO + O₂ reaction mainly depends on the O₂/NO ratio. Evaluation of the contribution of various nitrosating species (N₂O₃, N₂O₄, HNO₂) through stoichiometric balance showed the reaction to be effected mostly by N₂O₃ for O₂/NO ratios below 0.3, and by N₂O₄ for O₂/NO ratios above 0.4. The relative contribution of (subsequently formed) HNO₂ always remains minor. Differential scanning calorimetry (DSC) monitoring of the reaction in the solid phase by either HNO₂ (from NaNO₂ + TFA), gaseous N₂O₄ or gaseous N₂O₃, provides the associated rate constants (ca. 0.1, 2 and 10⁸ s^?1 at 25°C, respectively), showing that N₂O₃ is by far the most reactive of these nitrosating species. From the DSC measurement, the latent heat of fusion of N₂O_3, 2.74 kJ · mol^?1 at ?105 °C is also obtained for the first time. The kinetics was investigated under solventless conditions at 0°C, by either quenching experiments or less tedious, rough calorimetric techniques. Auto‐accelerated, parabolic‐shaped kinetics was observed in the first half of the reaction course, together with substantial heat release (temperature increase of ca. 20°C within 1–2 min in a 20‐mg sample), followed by pseudo‐zero‐order kinetics after a sudden, important decrease in apparent rate. This kinetic break is possibly due to the transition between the initial solid‐gas system and a solid‐liquid‐gas system resulting from water formation. Overall rate constants increased with parameters such as the specific surface of the solid, the O₂/NO ratio, or the presence of moisture (or equivalently the hydrophilicity of the involved CAA), however without precise relationship, while the last two parameters may directly correlate to the increasing acidity of the medium. Copyright © 2007 John Wiley & Sons, Ltd.     

An experimental and theoretical study on the preparation of 4,4′‐methylene‐bis(N,N‐dimethylaniline) in ionic liquid

The reaction of N,N‐dimethylaniline with tetrachloromethane in ionic liquid was found to give 4,4′‐methylene‐bis (N,N‐dimethylaniline) in considerable yield. The ionic liquid was prepared from N,N‐dimethylaniline which is also the one of raw materials for the preparation of 4,4′‐methylene‐bis (N,N‐dimethylaniline), and acts as both solvent and catalyst in the reaction. Mild reaction conditions, enhanced rates, improved yields, and reagents' reactivity which is different from that in conventional organic solvents are the remarkable features observed in ionic liquids. In addition, the results of calculations are in good accordance with the experimental outcomes. Copyright © 2016 John Wiley & Sons, Ltd.     

N‐protonated and O‐protonated tautomers of 1‐azabicyclo[3.3.1]nonan‐2‐one: observation of individual 13C‐NMR carbonyl peaks and comparisons with protonated tautomers of planar and other distorted lactams

An earlier study fit calculated dynamic ¹³C‐NMR spectra in trifluoroacetic acid (TFA) (with added sulfuric acid) to slow exchange between N‐protonated and O‐protonated tautomers of 1‐azabicyclo[3.3.1]nonan‐2‐one. The present study reports simultaneous observation of both carbonyl ¹³C peaks in 40% sulfuric acid/60% TFA at ?40 °C. This furnishes the only example in which experimental carbonyl ¹³C chemical shifts may be compared with a neutral lactam (in TFA or CDCl₃) with its N‐protonated and O‐protonated derivatives. The seemingly anomalous upfield chemical shifts (experimental and computational) of the ¹³C carbonyl peaks in this N‐protonated lactam (and other twisted N‐protonated lactams) relative to the free bases are compared with data for unstrained protonated lactams and amides. The results are rationalized through conventional resonance structures. Copyright © 2012 John Wiley & Sons, Ltd.     

Synthesis and Raman spectroscopic investigation of a new self‐assembly monolayer material 4‐[N‐phenyl‐N‐(3‐methylphenyl)‐amino]‐benzoic acid for organic light‐emitting devices

We have synthesized 4‐[N‐phenyl‐N‐(3‐methylphenyl)‐amino]‐benzoic acid (4‐[PBA]) and investigated its molecular vibrations by infrared and Raman spectroscopies as well as by calculations based on the density functional theory (DFT) approach. The Fourier transform (FT) Raman, dispersive Raman and FT‐IR spectra of 4‐[PBA] were recorded in the solid phase. We analyzed the optimized geometric structure and energies of 4‐[PBA] in the ground state. Stability of the molecule arising from hyperconjugative interactions and charge delocalization was studied using natural bond orbital analysis. The results show that change in electron density in the σ* and π* antibonding orbitals and E₂ energies confirm the occurrence of intramolecular charge transfer within the molecule. Theoretical calculations were performed at the DFT level using the Gaussian 09 program. Selected experimental bands were assigned and characterized on the basis of the scaled theoretical wavenumbers by their total energy distribution. The good agreement between the experimental and theoretical spectra allowed positive assignment of the observed vibrational absorption bands. Finally, the calculation results were applied to simulate the Raman and IR spectra of the title compound, which show agreement with the observed spectra. Copyright © 2011 John Wiley & Sons, Ltd.     

Mechanistic insights into N‐heterocyclic carbene (NHC)‐catalyzed N‐acylation of N‐sulfonylcarboxamides with aldehydes

In the current work, density functional theory calculations were performed to elucidate the detailed reaction mechanism for N‐heterocyclic carbene (NHC)‐catalyzed oxidative N‐acylation reaction of amides with aldehydes affording imide products. According to the calculated results, the reaction is initiated by the nucleophilic attack of NHC to aldehydes forming zwitterionic intermediate, which can then form Breslow intermediate via proton transfer. The Breslow intermediate can then be oxidized affording the oxidative intermediate, which can then go through 1,2‐addition with the deprotonated N‐sulfonylcarboxamides. Subsequently, elimination of NHC catalyst produces the final imide product. Our results reveal that the proton in N‐sulfonylcarboxamides is probably abstracted by base t‐BuOK or DPQH, and the deprotonation process is barrier‐less. Moreover, for the second step, ie, the formation of Breslow intermediate, direct proton transfer is impossible to occur. On the contrary, the results reveal that t‐BuOH can mediate the proton transfer in this step and significantly lower the energy barrier to 24.1 kcal/mol, which is also the highest energy barrier for the whole reaction. The work provides not only valuable clues for elucidating the detailed reaction mechanism for the invaluable NHC‐catalyzed oxidative reactions but also mechanistic insights for the rational design of novel NHC‐catalyzed oxidative reactions in the future.     

Reactivity of phenyl N‐phenylcarbamates in the alkaline hydrolysis reaction

In the present study, we explore the application of several theoretically estimated indices that characterize the reactivity of a series of phenyl N‐phenylcarbamates in the alkaline hydrolysis reaction. The rate constants (at 25 °C) for the hydrolysis of several derivatives were spectrophotometrically determined. The obtained kinetic data in this study, combined with literature data for other derivatives, were then correlated with theoretically estimated reactivity indices: Hirshfeld and NBO atomic charges, the Parr electrophilicity index (ω), and the electrostatic potential at the carbon and oxygen atoms of the reaction centre (V_C, V_O). The predictive ability of these quantities is discussed in a comparative context. Copyright © 2011 John Wiley & Sons, Ltd.     

Joint theoretical and experimental study of the gas‐phase elimination kinetics of tert‐butyl ester of carbamic,N, N‐dimethylcarbamic,N‐hydroxycarbamic acids and 1‐(tert‐butoxycarbonyl)‐imidazole

The gas‐phase elimination kinetics of the title compounds were carried out in a static reaction system and seasoned with allyl bromide. The working temperature and pressure ranges were 200–280 °C and 22–201.5 Torr, respectively. The reactions are homogeneous, unimolecular, and follow a first‐order rate law. These substrates produce isobutene and corresponding carbamic acid in the rate‐determining step. The unstable carbamic acid intermediate rapidly decarboxylates through a four‐membered cyclic transition state (TS) to give the corresponding organic nitrogen compound. The temperature dependence of the rate coefficients is expressed by the following Arrhenius equations: for tert‐butyl carbamate logk₁ (s^?1) = (13.02 ± 0.46) – (161.6 ± 4.7) kJ/mol(2.303 RT)^?1, for tert‐butyl N‐hydroxycarbamate logk₁ (s^?1) = (12.52 ± 0.11) – (147.8 ± 1.1) kJ/mol(2.303 RT)^?1, and for 1‐(tert‐butoxycarbonyl)‐imidazole logk₁ (s^?1) = (11.63 ± 0.21)–(134.9 ± 2.0) kJ/mol(2.303 RT)^?1. Theoretical studies of these elimination were performed at Møller–Plesset MP2/6‐31G and DFT B3LYP/6‐31G(d), B3LYP/6‐31G(d,p) levels of theory. The calculated bond orders, NBO charges, and synchronicity (Sy) indicate that these reactions are concerted, slightly asynchronous, and proceed through a six‐membered cyclic TS type. Results for estimated kinetic and thermodynamic parameters are discussed in terms of the proposed reaction mechanism and TS structure. Copyright © 2007 John Wiley & Sons, Ltd.     

Cyclic voltammetry of nitrophenyl N‐glycosides on mercury electrode

Ten nitrophenyl N‐glycosides have been studied electrochemically in neutral (at pH 7) water–organic solutions by cyclic voltammetry using static mercury drop electrode. For all compounds under investigation the two electrochemical processes have been observed: the four‐electron irreversible reduction of their nitro groups to the corresponding phenylhydroxylamine derivatives, as well as the two‐electron quasi‐reversible process between phenylhydroxylamine and nitroso derivatives. For three compounds the additional electrochemical processes have been also observed, which can be connected with the formation of azoxybenzene derivatives. The potentials of both redox processes: a two‐electron quasi‐reversible R? NHOH/R? NO (E_f) and four‐electron irreversible R? NO₂/R? NHOH (E_pc(I)) systems have been determined and discussed according to crystal structures of selected compounds. E_f and E_pc(I) depended strongly on the positive mesomeric effect (caused by glycosidic nitrogen atom), as well as on the intramolecular hydrogen bond between electroactive nitro group and the hydrogen atom at the glycosidic atom observed in N‐o‐nitrophenyl‐2,3,4,6‐tetra‐O‐acetyl‐β‐D ‐glucopyranosylamine. Moreover, the chirality of selected reactants has had the pronounced effect on the E_pc(I). Copyright © 2011 John Wiley & Sons, Ltd.     

pH‐dependent surface‐enhanced Raman scattering studies of N‐acetylalanine monolayers self‐assembled on a silver surface

Monolayers of N‐acetylalanine on a metallic surface can serve as a biocompatible functional interface to construct biosensors. In the present paper, the surface‐enhanced Raman scattering (SERS) spectra of N‐acetylalanine monolayers self‐assembled on a silver surface under different pH were recorded. Assignments of the obtained spectra were carried out by density functional theory (DFT) calculations (BLYP/6‐311G). On the basis of the SERS effect, the nature of adsorption of N‐acetylalanine on a silver surface was deduced. It can be concluded that the fully protonated N‐acetylalanine is adsorbed on the silver surface via the imine group together with the carboxylate group, while it anchored onto the surface not only through both the imine and the carboxylate groups but also through the amide group after being completely deprotonated in the basic solution. Copyright © 2007 John Wiley & Sons, Ltd.     

Kinetics and mechanisms of gas‐phase elimination of 2,2‐diethoxyethyl amine and 2,2‐diethoxy‐N,N‐diethylethanamine

The gas‐phase elimination kinetics of 2,2‐diethoxyethyl amine and 2,2‐diethoxy‐N,N‐diethylethanamine (320–380 °C; 40–150 Torr) in a seasoned reaction vessel are homogeneous, unimolecular and obey a first‐order rate law. These elimination processes involve two parallel reactions. The first gives ethanol and the corresponding 2‐ethoxyethenamine. The latter compound further decomposes to ethylene, CO and the corresponding amine. The second parallel reaction produce ethane and the corresponding ethyl ester of an α‐amino acid. The following Arrhenius expressions are given as: For 2,2‐diethoxyethyl amine For 2,2‐diethoxy‐N,N‐diethylethanamine Comparative kinetic and thermodynamic parameters of the overall, the parallel and the consecutive reactions lead to consider two types of mechanisms in terms of a concerted polar cyclic transition state structures. Copyright © 2008 John Wiley & Sons, Ltd.     

Synthesis and thermochemical study of quinoxaline‐N‐oxides: enthalpies of dissociation of the N–O bond

The synthesis of three new quinoxaline mono‐N‐oxides derivatives, namely, 2‐tert‐butoxycarbonyl‐3‐methylquinoxaline‐N‐oxide, 2‐phenylcarbamoyl‐3‐ethylquinoxaline‐N‐oxide, and 2‐carbamoyl‐3‐methylquinoxaline‐N‐oxide, from their corresponding 1,4‐di‐N‐oxides is reported. Samples of these compounds were used for a thermochemical study, which allowed derivation of their gaseous standard molar enthalpies of formation, , from their enthalpies of formation in the condensed phase, , determined by static bomb combustion calorimetry, and from their enthalpies of sublimation, , determined by Calvet microcalorimetry. Finally, combining the for the quinoxaline‐N‐oxides derived in this work with literature values for the corresponding 1,4‐di‐N‐oxides and atomic oxygen, the bond dissociation enthalpies for cleavage of the first N?O bond in the di‐N‐oxides, DH₁(N–O), were obtained and compared with existing data. Copyright © 2011 John Wiley & Sons, Ltd.     

Hydrogen‐bonded nucleophile effects in ANS: the reactions of 1‐chloro and 1‐fluoro‐2,4‐dinitrobenzene with 2‐guanidinobenzimidazole, 1‐(2‐aminoethyl)piperidine and N‐(3‐aminopropyl)morpholine in aprotic solvents

The kinetics of the reactions of 2,4‐dinitrofluorobenzene (DNFB) and 2,4‐dinitrochlorobenzene (DNClB) with 2‐guanidinobenzimidazole (2‐GB) at 40 ± 0.2 °C in dimethylsulphoxide (DMSO), toluene, and in toluene–DMSO mixtures, and with 1‐(2‐aminoethyl)piperidine (2‐AEPip) and N‐(3‐aminopropyl)morpholine (3‐APMo) in toluene at 25 ± 0.2 °C were studied under pseudo first‐order conditions. For the reactions of 2‐GB carried out in pure DMSO, the second‐order rate coefficients were independent of the amine concentration. In contrast, the reactions of 2‐GB with DNFB in toluene, showed a kinetic behaviour consistent with a base‐catalysed decomposition of the zwitterionic intermediate. These results suggest an intramolecular H‐bonding of 2‐GB in toluene, which is not present in DMSO. To confirm this interpretation the reactions were studied in DMSO–toluene mixtures. Small amounts of DMSO produce significant increase in rate that is not expected on the basis of the classical effect of a dipolar aprotic medium; the effect is consistent with the formation of a nucleophile/co‐solvent mixed aggregate. For the reactions of 3‐APMo with both substrates in toluene, the second‐order rate coefficients, k_A, show a linear dependence on the [amine]. 3‐APMo is able to form a six‐membered ring by an intramolecular H‐bond which prevents the formation of self‐aggregates. In contrast, a third order was observed in the reactions with 2‐AEPip: these results can be interpreted as a H‐bonded homo‐aggregate of the amine acting as a better nucleophile than the monomer. Most of these results can be well explained within the frame of the ‘dimer nucleophile’ mechanism. Copyright © 2010 John Wiley & Sons, Ltd.     

Vibrational spectroscopy and DFT calculations of N,N′‐dicyclohexylcarbodiimide

Infrared (IR) and Raman spectra were obtained for N,N′‐dicyclohexylcarbodiimide (DCC) in the solid state and in CHCl₃ solution. Structures and vibrational spectra of isolated, gas‐phase DCC molecules with C₂ and C_i symmetries, computed at the B3‐LYP/cc‐pVTZ level, show that the IR and Raman spectra provide convincing evidence for a C₂ structure in both the solid state and in CHCl₃ solution. Using a scaled quantum‐chemical force field, these density functional theory calculations have provided detailed assignments of the observed IR and Raman bands in terms of potential energy distributions. Comparison of solid‐state and solution spectra, together with a Raman study of the melting behaviour of DCC, revealed that no solid‐state effects were evident in the spectra. Copyright © 2010 John Wiley & Sons, Ltd.     

Synthesis of N‐alkoxybenzimidoyl azides and their reactions in electrophilic media

A new general route to N‐alkoxybenzimidoyl azides [ArC(N₃)=NOR] from a reaction of N‐alkoxybenzimidoyl bromide [ArC(Br)=NOR] with sodium azide in DMSO is described. These reactions result in the Z‐geometric configuration. These compounds show a moderate degree of thermal stability as assessed by differential scanning calorimetry, and lack reactivity in traditional 1,3‐dipolar cycloaddition ‘click’ reactions. Upon exposure to electrophilic compounds (trifluoroacetic acid or acetyl chloride), these azide compounds can react by two pathways: a Schmidt‐type rearrangement to form an N‐alkoxyurea or an isomerization–cyclization reaction pathway to form an N‐alkoxytetrazole. The route of the reaction has no dependence on solvent polarity and appears to depend upon the electrophile (H⁺ vs. CH₃CO⁺): reaction of the azide with trifluoroacetic acid results predominantly in the urea; reaction with acetyl chloride results solely in the tetrazole. Calculations indicate that the urea product is thermodynamically favored over the tetrazole product. They also indicate that both reaction conditions result in an equilibration between the starting azide and the tetrazole with the tetrazole being the major component in this equilibrium mixture. The fact that the azide also undergoes a Schmidt‐type rearrangement to form an N‐alkoxyurea when treated with trifluoroacetic acid appears to indicate that the barrier for aromatic ring migration is lower in the protonated azide produced on reaction with trifluoroacetic acid than in the acetylated azide produced on reaction with acetyl chloride. Copyright © 2009 John Wiley & Sons, Ltd.     

Palladium‐catalyzed cyclization of 2‐alkynyl‐N‐ethanoyl anilines to indoles: synthesis,structural, spectroscopic,and mechanistic study

This study reports a facial regio‐selective synthesis of 2‐alkyl‐N‐ethanoyl indoles from substituted‐N‐ethanoyl anilines employing palladium (II) chloride, which acts as a cyclization catalyst. The mechanistic trait of palladium‐based cyclization is also explored by employing density functional theory. In a two‐step mechanism, the palladium, which attaches to the ethylene carbons, promotes the proton transfer and cyclization. The gas‐phase barrier height of the first transition state is 37 kcal/mol, indicating the rate‐determining step of this reaction. Incorporating acetonitrile through the solvation model on density solvation model reduces the barrier height to 31 kcal/mol. In the presence of solvent, the electron‐releasing (–CH₃) group has a greater influence on the reduction of the barrier height compared with the electron‐withdrawing group (–Cl). These results further confirm that solvent plays an important role on palladium‐catalyzed proton transfer and cyclization. For unveiling structural, spectroscopic, and photophysical properties, experimental and computational studies are also performed. Thermodynamic analysis discloses that these reactions are exothermic. The highest occupied molecular orbital?lowest unoccupied molecular orbital gap (4.9–5.0 eV) confirms that these compounds are more chemically reactive than indole. The calculated UV–Vis spectra by time‐dependent density functional theory exhibit strong peaks at 290, 246, and 232 nm, in good agreement with the experimental results. Moreover, experimental and computed ¹H and ¹³C NMR chemical shifts of the indole derivatives are well correlated. Copyright © 2015 John Wiley & Sons, Ltd.