Direct borylation of terrylene and quaterrylene

• Haruka Kano,
• Keiji Uehara,
• Kyohei Matsuo,
• Hironobu Hayashi,
• Hiroko Yamada and
• Naoki Aratani

Beilstein J. Org. Chem. 2020, 16, 621–627, doi:10.3762/bjoc.16.58

• photophysical properties of TB4 are also unchanged by the substituents because the carbon atoms at 2,5,10,13-positions have less coefficients on its HOMO and LUMO, estimated by theoretical calculations. Finally, the same borylation reaction was applied for quaterrylene, resulting in the formation of soluble

Regioselectively α- and β-alkynylated BODIPY dyes via gold(I)-catalyzed direct C–H functionalization and their photophysical properties

• Takahide Shimada,
• Shigeki Mori,
• Masatoshi Ishida and
• Hiroyuki Furuta

Beilstein J. Org. Chem. 2020, 16, 587–595, doi:10.3762/bjoc.16.53

• estimated to be 2.30, 2,14, 2.35, and 2.21 V, respectively, which is consistent with the calculated HOMO–LUMO energy gaps (vide infra, Figure S24, Supporting Information File 1). Theoretical calculations To gain insight into the substitution effect on the electronic properties of the BODIPY derivatives

p-Pyridinyl oxime carbamates: synthesis, DNA binding, DNA photocleaving activity and theoretical photodegradation studies

• Panagiotis S. Gritzapis,
• Panayiotis C. Varras,
• Nikolaos-Panagiotis Andreou,
• Katerina R. Katsani,
• Konstantinos Dafnopoulos,
• George Psomas,
• Zisis V. Peitsinis,
• Alexandros E. Koumbis and
• Konstantina C. Fylaktakidou

Beilstein J. Org. Chem. 2020, 16, 337–350, doi:10.3762/bjoc.16.33

• ∙1010 s−1, which is a very large value, indicating a fast N−O bond dissociation for compound 12. Equations 1–3 are described in the theoretical calculations section. As soon as the two radicals (amidinyl and p-chlorocarbamoyloxyl) are formed, the second radical starts to decarboxylate according to the

• chemical reaction below (Scheme 3). The activation free energy for the decarboxylation reaction is only 1.09 kcal/mol and by using Equation 4 (see theoretical calculations section) we find a rate constant kr = 9.87∙1011 s−1, characterizing the reaction as an ultrafast one, with a corresponding life-time of

• factor of 1.43 [11]. Theoretical calculations Calculations for the photodegradation of carbamates The structures, properties and the basic photochemistry of compounds 11 and 12 was studied using the density functional theory (DFT) method [86][87][88][89] and the functional B3PW91 along with the 6-31 G(d

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• File 1. ECD theoretical calculations TDDFT-ECD was used to perform theoretical ECD calculations. Conformational searches for the investigated compounds were first performed with a MMFF94S force field and an energy window of 10 kcal/mol using Omega2 software [54][55]. Each resulting conformer was then

A combinatorial approach to improving the performance of azoarene photoswitches

• Joaquin Calbo,
• Aditya R. Thawani,
• Rosina S. L. Gibson,
• Andrew J. P. White and
• Matthew J. Fuchter

Beilstein J. Org. Chem. 2019, 15, 2753–2764, doi:10.3762/bjoc.15.266

• scaffold, the theoretical calculations at the PBE0-D3/6-31G** level indicate that an insertion of electron-poor fluorine atoms in the ortho-position of the aryl ring (4pzH-F1 and 4pzH-F2) leads to an increase in the half-life from ca. 1000 days in 4pzH to 2000 days in 4pzH-F1 and to 4000 days in 4pzH-F2

• above, theoretical calculations indicate that the addition of ortho-fluoro atoms leads to higher Z-isomer stability, whereas the opposite effect is found upon chlorine ortho-substitution (Table 1). The insertion of one and two electron-donating OMe and Pyr groups systematically improve the Z-isomer

• compared to E to allow for efficient Z–E photoswitching. Theoretical calculations indicate that the family of ortho-substituted 4pzH-X photoswitches provide a weak n–π* transition, with oscillator strengths f < 0.020. In contrast, 4pzMe-X derivatives show a relatively intense n–π* excitation, with f

Plasma membrane imaging with a fluorescent benzothiadiazole derivative

• Pedro H. P. R. Carvalho,
• Jose R. Correa,
• Karen L. R. Paiva,
• Daniel F. S. Machado,
• Jackson D. Scholten and
• Brenno A. D. Neto

Beilstein J. Org. Chem. 2019, 15, 2644–2654, doi:10.3762/bjoc.15.257

• bioimaging experiments and proved to be stable under constant light irradiation for more than 4 hours (see Figure S4 in Supporting Information File 1). Theoretical calculations were then performed for a better comprehension of the photophysical data obtained for BTD-4APTEG by means of the time-dependent

• affinity for the plasma membrane as depicted in the imaging (qualitative and quantitative) experiments. Theoretical calculations were found to be in accordance with the experimental data and helped to understand the ICT stabilizing process of the designed fluorophore. The developed green emitter was

• ) 156.4, 155.8, 144.1, 130.9, 129.2, 126.4, 123.3, 120.1, 111.9. 71.50, 71.47, 70.2, 69.9, 69.3, 38.9; HRMS (ESI-Q-TOF) calcd. for C18H23N4O3S+, 375.1485; found, 375.1460. Theoretical calculations. All DFT calculations were performed using the Gaussian 09 suite of programs [64]. Geometry optimizations

AgNTf₂-catalyzed formal [3 + 2] cycloaddition of ynamides with unprotected isoxazol-5-amines: efficient access to functionalized 5-amino-1H-pyrrole-3-carboxamide derivatives

• Ziping Cao,
• Jiekun Zhu,
• Li Liu,
• Yuanling Pang,
• Laijin Tian,
• Xuejun Sun and
• Xin Meng

Beilstein J. Org. Chem. 2019, 15, 2623–2630, doi:10.3762/bjoc.15.255

• carbene pathway presumed by mechanistic studies and theoretical calculations. Following our ongoing interest in the alkyne chemistry [36][37][38], we recently envisaged that the reaction of ynamides with isoxazoles could proceed under silver catalysis conditions, involving the generation of α-imino silver

Anion-driven encapsulation of cationic guests inside pyridine[4]arene dimers

• Anniina Kiesilä,
• Jani O. Moilanen,
• Anneli Kruve,
• Christoph A. Schalley,
• Perdita Barran and
• Elina Kalenius

Beilstein J. Org. Chem. 2019, 15, 2486–2492, doi:10.3762/bjoc.15.241

• the pyridine[4]arene dimer, and all mass spectrometric data and theoretical calculations show undoubtedly that the cation is located inside the cavity of the dimer in the gas phase. It is an interesting fact, that the binding properties of pyridine[4]arene differ from earlier reports [7][8]. However

Current understanding and biotechnological application of the bacterial diterpene synthase CotB2

• Ronja Driller,
• Daniel Garbe,
• Norbert Mehlmer,
• Monika Fuchs,
• Keren Raz,
• Dan Thomas Major,
• Thomas Brück and
• Bernhard Loll

Beilstein J. Org. Chem. 2019, 15, 2355–2368, doi:10.3762/bjoc.15.228

• followed by a 1,5-hydride shift. The sequential 1,2-hydride shift (C to E) route was initially suggested by theoretical calculations, which supported the overall mechanism [33][34], and this was verified via isotope labeling [34]. Such series of two 1,2-hydride shifts have previously been demonstrated

• in terpene biosynthesis. The enzyme could be understood as passive catalyst, essentially chaperoning the intermediates during the reaction cascade. It is clear that much of terpene biosynthesis can be understood by this concept. “Inherent reactivity” largely relies on theoretical calculations

Fluorinated azobenzenes as supramolecular halogen-bonding building blocks

• Esther Nieland,
• Oliver Weingart and
• Bernd M. Schmidt

Beilstein J. Org. Chem. 2019, 15, 2013–2019, doi:10.3762/bjoc.15.197

• boxes [35]. Therefore, we herein present a comprehensive investigation of the photochemistry of highly fluorinated azobenzenes. Our efforts are supported by theoretical calculations, showing that these azobenzenes are suitable for the use as building blocks in supramolecular architectures. Results and

Tautomerism as primary signaling mechanism in metal sensing: the case of amide group

• Vera Deneva,
• Georgi Dobrikov,
• Aurelien Crochet,
• Daniela Nedeltcheva,
• Katharina M. Fromm and
• Liudmil Antonov

Beilstein J. Org. Chem. 2019, 15, 1898–1906, doi:10.3762/bjoc.15.185

• , based on 4-(phenyldiazenyl)naphthalen-1-ol. According to the theoretical calculations the enol form stabilization could be achieved through a strong intramolecular hydrogen bond formed between the tautomeric hydroxy group and the carbonyl group from the tautomeric backbone. However, intermolecular

• still not appear even after 1024 scans. Theoretical calculations Quantum-chemical calculations were performed using the Gaussian 09 D.01 program suite [17]. The M06-2X functional [18][19] was used with the 6-31++G** basis set for the calculations. This fitted hybrid meta-GGA functional with 54% HF

Synthesis, photophysical and electrochemical properties of pyridine, pyrazine and triazine-based (D–π–)₂A fluorescent dyes

• Keiichi Imato,
• Toshiaki Enoki,
• Koji Uenaka and
• Yousuke Ooyama

Beilstein J. Org. Chem. 2019, 15, 1712–1721, doi:10.3762/bjoc.15.167

• due to the increase in the electron-withdrawing ability of the azine ring in the order of pyridyl < pyrazyl < triazyl, resulting in a decrease in the energy gap between the HOMO and the LUMO. Theoretical calculations In order to examine the HOMO and LUMO distributions of OUY-2, OUK-2 and OUJ-2, the

Superelectrophilic carbocations: preparation and reactions of a substrate with six ionizable groups

• Sean H. Kennedy,
• Makafui Gasonoo and
• Douglas A. Klumpp

Beilstein J. Org. Chem. 2019, 15, 1515–1520, doi:10.3762/bjoc.15.153

• electrophiles based on the triarylmethyl cation scaffold (3–5, Scheme 1) [11][12]. These systems utilized pyridyl rings to produce increasing amounts of positive charge adjacent to the carbocation center. Both theoretical calculations and experimental results indicated that the carbocation center undergoes a

• position and deprotonation of the para-carbon to complete the arylation step. For the cyclization product 11, theoretical calculations indicate that cyclization requires deprotonation at the pyridinium ring [11]. Thus, either the tetracation 15 or the pentacation 16 is the likely precursor to the pyrido

Selenophene-containing heterotriacenes by a C–Se coupling/cyclization reaction

• Pierre-Olivier Schwartz,
• Sebastian Förtsch,
• Astrid Vogt,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2019, 15, 1379–1393, doi:10.3762/bjoc.15.138

• (Figure 2b), because a completely flat geometry of the isolated molecule DST 3 (in the gas phase) was obtained from theoretical calculations (vide infra). Molecules of DST 3 order in a typical herringbone fashion, where the terminal hydrogen atoms form hydrogen bond-like C–H heteroatom interactions (2.819

• the crystal structure analysis. The analysis of the theoretical calculations gave also insight into the electronic properties of the heterotriacene series. The energies of the calculated frontier orbitals and electronic transitions are summarized in Table 3. In this respect, the energy of the HOMO

• to the planar π-conjugated system. Gaussian deconvolution of the experimental spectra exemplarily shown for DDT 1 (Figure 6, right) evidenced the coexistence of two electronic transitions under the absorption curve in correlation with the theoretical calculations (vide infra). The absorption maxima

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