An anomalous addition of chlorosulfonyl isocyanate to a carbonyl group: the synthesis of ((3aS,7aR,E)-2-ethyl-3-oxo-2,3,3a,4,7,7a-hexahydro-1H-isoindol-1-ylidene)sulfamoyl chloride

• Aytekin Köse,
• Aslı Ünal,
• Ertan Şahin,
• Uğur Bozkaya and
• Yunus Kara

Beilstein J. Org. Chem. 2019, 15, 931–936, doi:10.3762/bjoc.15.89

• exact configuration was determined by X-ray crystal analysis. We explain the mechanism of product formation supported by theoretical calculations. Keywords: addition reaction; chlorosulfonyl isocyanate; sulfamoyl chloride; theoretical calculations; Introduction Since its identification in 1959 [1

• demonstrated the addition of chlorosulfonyl isocyanate to the system comprising both independent double bonds and imide functional groups. The mechanism for the addition of CSI to a carbonyl group is explained by theoretical computations. Supported by theoretical calculations, we determined the reaction

Strong hyperconjugative interactions limit solvent and substituent influence on conformational equilibrium: the case of cis-2-halocyclohexylamines

• Camila B. Francisco,
• Cleverton S. Fernandes,
• Ulisses Z. de Melo,
• Roberto Rittner,
• Gisele F. Gauze and
• Ernani A. Basso

Beilstein J. Org. Chem. 2019, 15, 818–829, doi:10.3762/bjoc.15.79

• -iodocyclohexylamine (I) by dynamic NMR and theoretical calculations. The experimental data pointed to an equilibrium strongly shifted toward the ea conformer (equatorial amine group and axial halogen), with populations greater than 90% for F, Cl and Br in both dichloromethane-d2 and methanol-d4. Theoretical

• group and equatorial halogen) and ea (equatorial amine group and axial halogen) conformers (Figure 1) by dynamic NMR (DNMR) and theoretical calculations. Results and Discussion Experimental conformational population Low-temperature NMR experiments allow the identification of the individual conformers

• observed, and this behavior suggests that other effects can be acting. So, theoretical calculations were performed in order to understand which mechanisms control the conformational preference of these compounds. Theoretical study Conformer energy The potential energy surface (PES) for the dihedral C2–C1–N

Conformational signature of Ishikawa´s reagent using NMR information from diastereotopic fluorines

• Laize A. F. Andrade,
• Lucas A. Zeoly,
• Rodrigo A. Cormanich and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2019, 15, 506–512, doi:10.3762/bjoc.15.44

• interactions (nN → σ*C–F), which can be demonstrated by means of 19F chemical shifts. The results were rationalized with the aid of theoretical calculations and natural bond orbital (NBO) analysis, allowing for the evaluation of competing steric, electrostatic and hyperconjugative interactions. Keywords

Study on the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide

• Pedro N. Batalha,
• Luana da S. M. Forezi,
• Maria Clara R. Freitas,
• Nathalia M. de C. Tolentino,
• Ednilsom Orestes,
• José Walkimar de M. Carneiro,
• Fernanda da C. S. Boechat and
• Maria Cecília B. V. de Souza

Beilstein J. Org. Chem. 2019, 15, 388–400, doi:10.3762/bjoc.15.35

• discuss the regioselectivity of the N-ethylation reaction of N-benzyl-4-oxo-1,4-dihydroquinoline-3-carboxamide (5). We correlate the experimental results with theoretical calculations, and with this we propose different hypotheses in the sense of better explaining the observed regioselectivity. Results

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

• Koichi Mitsudo,
• Junya Yamamoto,
• Tomoya Akagi,
• Atsuhiro Yamashita,
• Masahiro Haisa,
• Kazuki Yoshioka,
• Hiroki Mandai,
• Koji Ueoka,
• Christian Hempel,
• Jun-ichi Yoshida and
• Seiji Suga

Beilstein J. Org. Chem. 2018, 14, 1192–1202, doi:10.3762/bjoc.14.100

• -acyliminium ion C4 with several nucleophiles. Reaction of N-acyliminium ion C5 with several nucleophiles. Reaction of N-acyliminium ion C6 with several nucleophiles. Supporting Information Supporting Information File 155: Experimental details, ORTEP drawings of 1a, 1b, 1d–1f, theoretical calculations of C1

Are dispersion corrections accurate outside equilibrium? A case study on benzene

• Tim Gould,
• Erin R. Johnson and
• Sherif Abdulkader Tawfik

Beilstein J. Org. Chem. 2018, 14, 1181–1191, doi:10.3762/bjoc.14.99

• Council (ARC DP160101301). Theoretical calculations by TG and SAT were undertaken with resources provided by the National Computational Infrastructure (NCI) supported by the Australian Government and, for SAT, by the Pawsey Supercomputing Centre funded by the Australian Government and the Government of

One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

Two novel blue phosphorescent host materials containing phenothiazine-5,5-dioxide structure derivatives

• Feng-Ming Xie,
• Qingdong Ou,
• Qiang Zhang,
• Jiang-Kun Zhang,
• Guo-Liang Dai,
• Xin Zhao and
• Huai-Xin Wei

Beilstein J. Org. Chem. 2018, 14, 869–874, doi:10.3762/bjoc.14.73

• time, the photophysical properties, electrochemical properties and their thermal stability were studied and the expected results were obtained. Results and Discussion Synthesis and theoretical calculations The synthesis route for CEPDO and CBPDO is shown in Scheme 1. The detailed synthesis procedures

Phosphodiester models for cleavage of nucleic acids

• Satu Mikkola,
• Tuomas Lönnberg and
• Harri Lönnberg

Beilstein J. Org. Chem. 2018, 14, 803–837, doi:10.3762/bjoc.14.68

• (Scheme 3) by more than two orders of magnitude, in spite of the fact that sulfur is less electronegative than oxygen and, hence, a weaker withdrawer of electrons from phosphorus [90][91]. According to theoretical calculations, the reaction is accelerated since a less strained five-membered ring is formed

An uracil-linked hydroxyflavone probe for the recognition of ATP

• Márton Bojtár,
• Péter Zoltán Janzsó-Berend,
• Dávid Mester,
• Dóra Hessz,
• Mihály Kállay,
• Miklós Kubinyi and
• István Bitter

Beilstein J. Org. Chem. 2018, 14, 747–755, doi:10.3762/bjoc.14.63

• this probe to include complementary base-pairing interactions. The theoretical calculations revealed the availability of multiple complex structures. The synthesis was performed using click chemistry and the nucleotide recognition properties of the probe were evaluated using fluorescence spectroscopy

• nucleobase were the main aspects in the design of UHF. The influence of the side arm with the uracil group on the ability of UHF to act as an ATP sensor was investigated first by theoretical calculations, in which the structures and energies for the UHF∙ATP complex and – as a reference – for the DEHF∙ATP

Mannich base-connected syntheses mediated by ortho-quinone methides

• Petra Barta,
• Ferenc Fülöp and
• István Szatmári

Beilstein J. Org. Chem. 2018, 14, 560–575, doi:10.3762/bjoc.14.43

• respect to the use of an enantiomeric cyclic imine in this type of reaction [83]. The formation of the possible naphthoxazino-quinoxalinone diastereomers 46 was investigated and studied by theoretical calculations (Scheme 5). In this and all previous cases, the conformational behaviour of the

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

• noticed that the photophysical properties and the geometry of molecules that are suspected to be TADF emitters are often investigated by theoretical calculations prior to synthesis, optimizing the chance to get suitable energy levels and the desired ΔEST. This strategy was notably applied to the design of

• TADF blue emitters containing triarylboron accepting units. Besides, as we will see in this review, the design of a good TADF material by optimizing its structure by theoretical calculations is not sufficient to ensure the fabrication of highly emissive OLEDs. As observed for phosphorescent emitters

• diphenylamine unit of D1 by a tert-butyl-substituted carbazole unit in D3, the 3ππ* state was considerably destabilized, raising its energy level and decreasing ΔEST. Parallel to this, a greater separation of the HOMO and LUMO orbitals was evidenced by theoretical calculations for D3, as a result of a larger

Halogen-containing thiazole orange analogues – new fluorogenic DNA stains

• Aleksey A. Vasilev,
• Meglena I. Kandinska,
• Stanimir S. Stoyanov,
• Stanislava B. Yordanova,
• David Sucunza,
• Juan J. Vaquero,
• Obis D. Castaño,
• Stanislav Baluschev and
• Silvia E. Angelova

Beilstein J. Org. Chem. 2017, 13, 2902–2914, doi:10.3762/bjoc.13.283

• the theoretical calculations. Theoretically calculated absorption maximа for the couples 5a/5c and 5b/5d differ by 8 nm and 11 nm, respectively. The first excited states are determined by HOMO (highest occupied molecular orbital)→LUMO (lowest unoccupied molecular orbital) transitions with oscillator

• ) in methanol for compounds 5a–d, TO and TO-7Cl in methanol. Supporting Information Supporting Information File 486: Characterisation data for the compounds: NMR and GS–MS spectra; validation of the theoretical computations; photostabilities at 532 nm. Acknowledgements The theoretical calculations

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• protein FhuA ΔCVFtev. The theoretical calculations are in line with the experimental findings, that FhuA ΔCVFtev is properly folded using refolding buffer with 50 mM MPD, which was confirmed by CD spectroscopy (Figure S1, Supporting Information File 1). 2-Methyl-2,4-pentanediol stabilizes FhuA ΔCVFtev up

Conformational study of L-methionine and L-cysteine derivatives through quantum chemical calculations and ³J_HH coupling constant analyses

• Weslley G. D. P. Silva,
• Carolyne B. Braga and
• Roberto Rittner

Beilstein J. Org. Chem. 2017, 13, 925–937, doi:10.3762/bjoc.13.94

• shown good results for other amino acid derivatives, when comparing theoretical with experimental data [22][23][24]. Although 2 could not be experimentally studied, the theoretical calculations carried out strongly suggest that the conformational equilibrium of 2 and the populations of its conformers

• , experimental NMR spectroscopy measurements and spin-spin coupling constant (3JHH) calculations were performed. The experimental 1H NMR data for 1 (Table 3) indicate that the 3JHaHb1 and 3JHaHb2 coupling constants are almost constant in the studied solvents, supporting our findings through theoretical

• calculations that the conformational equilibria of 1 are not affected by the solvent change. The two different observed values for 3JHaHb1,obs (approximately 5.0 Hz) and 3JHaHb2,obs (approximately 7.0 Hz) confirm that conformers in form b are favored in the equilibrium of 1, since these constants are dependent

Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

• Vinila N. Viswanathan,
• Arun D. Rao,
• Upendra K. Pandey,
• Arul Varman Kesavan and
• Praveen C. Ramamurthy

Beilstein J. Org. Chem. 2017, 13, 863–873, doi:10.3762/bjoc.13.87

• higher HOMO energy is due to the incorporation of the electron-donating thienothiophene bridge in the polymer backbone. The experimentally obtained values of frontier molecular energy levels follow the same trends with respect to the theoretical calculations. All polymers have deep-lying HOMO energy

• 1.87 eV, respectively. Again, a lower band gap is observed for P3 owing to the extended conjugation over the other polymers. The combined optical, electrochemical, and theoretical calculations are summarized in Table 2. Photoluminescence (PL) quenching studies were performed with pure donor polymers

• . Electrochemical and optical properties along with theoretical calculations. Photovoltaic properties of the devices based on polymers P1, P2 and P3. Supporting Information Supporting Information File 82: Experimental details and characterization data. Acknowledgements The authors gratefully acknowledge the

Regiochemistry of cyclocondensation reactions in the synthesis of polyazaheterocycles

• Patrick T. Campos,
• Leticia V. Rodrigues,
• Andrei L. Belladona,
• Caroline R. Bender,
• Juliana S. Bitencurt,
• Fernanda A. Rosa,
• Davi F. Back,
• Helio G. Bonacorso,
• Nilo Zanatta,
• Clarissa P. Frizzo and
• Marcos A. P. Martins

Beilstein J. Org. Chem. 2017, 13, 257–266, doi:10.3762/bjoc.13.29

• compounds 11a–e were washed with acetonitrile (1 × 1 mL). The reactions done with non-symmetric dinucleophiles 8b, 8e, and 8f furnished isomeric product mixtures. Data obtained from DFT-B3LYP theoretical calculations showed that in the three α-ketoesters 5–7, the carbonyl of the ketone has a larger LUMO

• between β-enaminodiketone and aromatic amidines was highly regioselective. Results obtained from DFT-B3LYP theoretical calculations were in agreement with the experimental data. Using data from HOMO and LUMO coefficients, it was possible to conclude that the reaction is controlled by frontier molecular

• product mixtures were formed when non-symmetric diamines were used as dinucleophiles. Theoretical calculations provided data regarding the stability of these isomeric mixtures. However, the synthesis of imidazolone heterocycles was not achieved. Nevertheless, the N-acylated product was formed from the

Spectral and DFT studies of anion bound organic receptors: Time dependent studies and logic gate applications

• Srikala Pangannaya,
• Neethu Padinchare Purayil,
• Shweta Dabhi,
• Venu Mankad,
• Prafulla K. Jha,
• Satyam Shinde and
• Darshak R. Trivedi

Beilstein J. Org. Chem. 2017, 13, 222–238, doi:10.3762/bjoc.13.25

• upon anion binding (Supporting Information File 1, Table S1). Theoretical calculations afforded absorption maxima at 352 nm and 416 nm for receptor R1 and 361 and 487 nm for R2, respectively. The shift in the absorption maxima for R1–F− and R1–AcO− to 451 and 455 nm and for R2–F− and R2–AcO− to 572 and

Synthesis of spiro[isoindole-1,5’-isoxazolidin]-3(2H)-ones as potential inhibitors of the MDM2-p53 interaction

• Salvatore V. Giofrè,
• Santa Cirmi,
• Raffaella Mancuso,
• Francesco Nicolò,
• Giuseppe Lanza,
• Laura Legnani,
• Agata Campisi,
• Maria A. Chiacchio,
• Michele Navarra,
• Bartolo Gabriele and
• Roberto Romeo

Beilstein J. Org. Chem. 2016, 12, 2793–2807, doi:10.3762/bjoc.12.278

• failed, leading to the degradation of the nitrone and the isolation of the unaltered dipolarophile, so clearly indicating that the steric factors play a crucial role in the cycloaddition process (see computational data). Theoretical calculations The obtained results and stereochemical outcome of the 1,3

Selective and eco-friendly procedures for the synthesis of benzimidazole derivatives. The role of the Er(OTf)₃ catalyst in the reaction selectivity

• Natividad Herrera Cano,
• Jorge G. Uranga,
• Mónica Nardi,
• Antonio Procopio,
• Daniel A. Wunderlin and
• Ana N. Santiago

Beilstein J. Org. Chem. 2016, 12, 2410–2419, doi:10.3762/bjoc.12.235

• , which is frequently associated with these reactions. Theoretical calculations helped to understand the different reactivity established for these reactions. Thus, we found that the charge density on the oxygen of the carbonyl group has a significant impact on the reaction pathway. For instance, electron

• , differences in reactivity were investigated by by means of theoretical calculations. Results and Discussion The benzimidazole core was obtained by air oxidative cyclocondensation of o-phenylenediamine with benzaldehyde under different conditions. In water and in the presence of Er(OTf)3, the diamine and

• -deficient aldehydes under the same conditions. To shed light on this observation, we decided to carry out theoretical calculations, using the BPW91 functional at 6-31+G* level, as implemented in Gaussian 09 [43]. In order to evaluate the effect of the substituent on the reactivity of aldehydes, we used a

Methylenelactide: vinyl polymerization and spatial reactivity effects

• Judita Britner and
• Helmut Ritter

Beilstein J. Org. Chem. 2016, 12, 2378–2389, doi:10.3762/bjoc.12.232

• also shows additional postulated radical reactions including the formation of a bicyclic lactide radical to initiate the main polymerization. Since the spontaneous homolytically C–H cleavage may represent the first step in the reaction cascade, theoretical calculations on a DFT level were conducted

• polymers were obtained, the C–H bonds in the linear MLA-polymer units must be more stable than in the monomeric MLA. Otherwise, crosslinking should take place via spontaneous C–H cleavage and chain recombination. This important point could be verified by IR spectroscopy and also by theoretical calculations

• pull-type α-methylene-δ-valerolactone (MVL). A deviation from classical free-radical polymerization kinetics was found and correlated with significant self-initiation. A mechanism for the radical formation was proposed and supported by theoretical calculations. With the help of a strongly colored 1,1

Determination of the absolute stereostructure of a cyclic azobenzene from the crystal structure of the precursor containing a heavy element

• Reji Thomas and
• Nobuyuki Tamaoki

Beilstein J. Org. Chem. 2016, 12, 2211–2215, doi:10.3762/bjoc.12.212

• enantiomer formed by the reductive debromination. In the previous study with the combination of density functional theoretical calculations (DFT) and electronic circular dichroism (ECD), we have assigned the first and second eluted enantiomers of (E)-2 as R-(−)-(E)-2 and S-(+)-(E)-2, respectively, on a

• with structural data of S-(−)-(E)-1 the absolute stereostructure of its reduced product is determined as R-(−)-(E)-2. The experimentally derived stereostructure completely matches with the absolute structure previously predicted from theoretical calculations. In summary, we demonstrated the

Synthesis and properties of fluorescent 4′-azulenyl-functionalized 2,2′:6′,2″-terpyridines

• Adrian E. Ion,
• Liliana Cristian,
• Mariana Voicescu,
• Masroor Bangesh,
• Augustin M. Madalan,
• Daniela Bala,
• Constantin Mihailciuc and
• Simona Nica

Beilstein J. Org. Chem. 2016, 12, 1812–1825, doi:10.3762/bjoc.12.171

• can influence the emission behavior and it may be changed from dominant S2→S0 fluorescence to either dual fluorescence or to dominant S1→S0 fluorescence. Theoretical calculations Methods The geometries of 4a and 4b with initial atomic coordinates taken from X-ray crystal structure were optimized with

Cp₂TiCl/D₂O/Mn, a formidable reagent for the deuteration of organic compounds

• Antonio Rosales and
• Ignacio Rodríguez-García

Beilstein J. Org. Chem. 2016, 12, 1585–1589, doi:10.3762/bjoc.12.154

• -ordination of water to Cp2TiCl might weakens the strength of the O–H bond. In this way a single electron transfer from titanium to oxygen might facilitate the HAT from the titanocene aqua-complex to the free radicals. Theoretical calculations supported that the coordination of water to Cp2TiIIICl weakens the

• cyclic voltammetry, theoretical calculations and electro-paramagnetic resonance techniques studies [28][34]. These results are in agreement with the previously reported results by Wood et al. [35] and Renaud et al. [36] describing the effect of complexation with a Lewis acid on the strength of the O–H

Is conformation a fundamental descriptor in QSAR? A case for halogenated anesthetics

• Maria C. Guimarães,
• Mariene H. Duarte,
• Josué M. Silla and
• Matheus P. Freitas

Beilstein J. Org. Chem. 2016, 12, 760–768, doi:10.3762/bjoc.12.76

• suggesting that these 2D MD´s can be advantageous over some three-dimensional descriptors. Keywords: conformational analysis; isoflurane; QSAR; theoretical calculations; volatile anesthetics; Introduction Quantitative structure–activity relationship (QSAR) studies try to find a correlation between chemical