Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• . The column temperature was controlled at 40 °C and detection wavelength was set at 280 nm. Computational details Molecular Merck force field (MMFF) calculations were done using the Spartan'14 program (Wavefunction Inc., Irvine, CA, USA). Density functional theory (DFT) and time-dependent density

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

• calculations, such as the Møller–Plesset (MP2) method and density functional theory (DFT) calculations, together with experimental techniques have been combined to achieve more accurate results [20][21][22][23][24]. Some amino acid derivatives have been recently studied by our research group, including the

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

• studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine

• stability with onset decomposition temperature of >410 °C. Computational modeling of the three polymers was performed to gain insight into the molecular energy levels along with band gaps using density functional theory (DFT) at the B3LYP/6-31G (d,p) level as implemented in Gaussian-09 software [37]. For

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

• understand the binding mechanism, we have performed a density functional theory (DFT) simulation on the receptor molecules using the GAUSSIAN 09 software package [44]. A closed-shell Becke–Lee–Yang–Parr hybrid exchange–correlation three-parameter functional (B3LYP) [45] along with the 6-311++G(d,p) basis set

Effects of solvent additive on “s-shaped” curves in solution-processed small molecule solar cells

• John A. Love,
• Shu-Hua Chou,
• Ye Huang,
• Guilllermo C. Bazan and
• Thuc-Quyen Nguyen

Beilstein J. Org. Chem. 2016, 12, 2543–2555, doi:10.3762/bjoc.12.249

• measured to be 32 mg/mL for p-SIDT(FBTThCA8)2 compared with over 50 mg/mL for p-SIDT(FBTTh2)2 in chloroform at room temperature. Frontier molecular energy levels were estimated by cyclic voltammograms (CV) in dichloromethane and calculated theoretically by density functional theory (DFT) (Supporting

High performance p-type molecular electron donors for OPV applications via alkylthiophene catenation chromophore extension

• Paul B. Geraghty,
• Calvin Lee,
• Jegadesan Subbiah,
• Wallace W. H. Wong,
• James L. Banal,
• Mohammed A. Jameel,
• Trevor A. Smith and
• David J. Jones

Beilstein J. Org. Chem. 2016, 12, 2298–2314, doi:10.3762/bjoc.12.223

• and overlap, density functional theory (DFT) calculations were performed. Geometry optimization and molecular orbital surfaces were determined and are shown in Figure 11. Geometries of the BXR series were obtained at the D2 dispersion corrected B3LYP/6-311G(d,p) level of theory. Subsequent time

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• density functional theory (DFT) based studies were applied to support and explain the results obtained. Rapid decomposition is observed in acidic aqueous media for all cyclic aminals which occurs as a reversible reaction. Electronic effects do not seem relevant with regard to stability, but the magnitude

• test compounds were predicted using the empirical algorithm of MoKa [38] and validated with density functional theory (DFT) energy calculations of all protonation patterns for compounds 8a and 13b (cf. Supporting Information File 1). We used the B3LYP-D3 functional [39][40][41] in combination with the

Stereo- and regioselectivity of the hetero-Diels–Alder reaction of nitroso derivatives with conjugated dienes

• Lucie Brulíková,
• Aidan Harrison,
• Marvin J. Miller and
• Jan Hlaváč

Beilstein J. Org. Chem. 2016, 12, 1949–1980, doi:10.3762/bjoc.12.184

• nitroso heterodienophiles 29 (Scheme 8) was determined at the B3LYP/6-31G** level [86]. All calculations were performed with density functional theory (DFT) using the B3LYP functional implemented in the Gaussian 98 software. Nitrosomethane (29a) was selected as a model heterodienophile for a preliminary

Synthesis of the C8’-epimeric thymine pyranosyl amino acid core of amipurimycin

• Pramod R. Markad,
• Navanath Kumbhar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2016, 12, 1765–1771, doi:10.3762/bjoc.12.165

• results on conformational preferences of 12 and 13 were corroborated using geometry-optimized density functional theory (DFT). The geometrically optimized preferred conformations of 12 and 13 are depicted in Figure 3, and geometrical parameters for torsion angles and intramolecular hydrogen bonding

Methylpalladium complexes with pyrimidine-functionalized N-heterocyclic carbene ligands

• Dirk Meyer and
• Thomas Strassner

Beilstein J. Org. Chem. 2016, 12, 1557–1565, doi:10.3762/bjoc.12.150

• -NHC ligand [33]. To study the differences between both systems we synthesized palladium [34] and platinum [35] “hybrid complexes” with ligands combining both structural elements the pyrimidine as well as the NHC fragment. We also used density functional theory (DFT) calculations to investigate the

• (Figure 1). This can be explained by the strong donor character of the carbene which makes the trans isomer less favorable. NMR analysis of the reaction products confirms that only one complex is formed. Additional proof comes from density functional theory (DFT) calculations which predict isomer B to be

Star-shaped and linear π-conjugated oligomers consisting of a tetrathienoanthracene core and multiple diketopyrrolopyrrole arms for organic solar cells

• Hideaki Komiyama,
• Chihaya Adachi and
• Takuma Yasuda

Beilstein J. Org. Chem. 2016, 12, 1459–1466, doi:10.3762/bjoc.12.142

• , rendering the molecules with narrower bandgaps, and broad and strong light absorptions. To gain insight into the geometric and electronic structures of TTA-DPP4 and TTA-DPP2, density functional theory (DFT) calculations were performed at the B3LYP/6-31G(d,p) level. The calculated energy levels and the

Ring-whizzing in polyene-PtL₂ complexes revisited

• Oluwakemi A. Oloba-Whenu,
• Thomas A. Albright and
• Chirine Soubra-Ghaoui

Beilstein J. Org. Chem. 2016, 12, 1410–1420, doi:10.3762/bjoc.12.135

• ; density functional theory (DFT); hapototropic rearrangements; HOMO–LUMO interactions; polyene-ML2 complexes; ring-whizzing; Introduction Polyene–transition metal complexes were found to undergo fluxional rearrangements as early as 1956 with the preparation of Cp2Fe(CO)2 [1]. The migration of an MLn unit

On the mechanism of imine elimination from Fischer tungsten carbene complexes

• Philipp Veit,
• Christoph Förster and
• Katja Heinze

Beilstein J. Org. Chem. 2016, 12, 1322–1333, doi:10.3762/bjoc.12.125

• reaction pathways for the formation of imine E-3 have been considered. For each pathway, density functional theory (DFT) calculations on the B3LYP/LANL2DZ (IEF-PCM toluene) level of theory have been performed to localize minimum structures and energies of the intermediates which are connected by transition

Three new trixane glycosides obtained from the leaves of Jungia sellowii Less. using centrifugal partition chromatography

• Luíse Azevedo,
• Larissa Faqueti,
• Marina Kritsanida,
• Antonia Efstathiou,
• Despina Smirlis,
• Gilberto C. Franchi Jr,
• Grégory Genta-Jouve,
• Sylvie Michel,
• Louis P. Sandjo,
• Raphaël Grougnet and
• Maique W. Biavatti

Beilstein J. Org. Chem. 2016, 12, 674–683, doi:10.3762/bjoc.12.68

• using density functional theory (DFT) at the B3LYP/6-311+g (d,p) level of theory. A check for imaginary frequencies was performed in order to confirm the presence of a real minimum. Calculations of the rotational strengths and excitation energies were realized using time dependent (TD) DFT at the same

Dynamic behavior of rearranging carbocations – implications for terpene biosynthesis

• Stephanie R. Hare and
• Dean J. Tantillo

Beilstein J. Org. Chem. 2016, 12, 377–390, doi:10.3762/bjoc.12.41

• capable of ab initio or density functional theory (DFT) calculations is used to calculate either (1) force constants (via frequency calculation) along the trajectory, either at every point or in periodic increments, or (2) the gradient of the potential energy, depending on the specific integrator chosen

• trajectories initiated from minima and transition states have both been carried out on carbocations [25] and examples of each are described below. While many different quantum chemical methods can be used to carry out trajectory calculations, standard density functional theory (DFT) approaches are most

Versatile deprotonated NHC: C,N-bridged dinuclear iridium and rhodium complexes

• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 117–124, doi:10.3762/bjoc.12.13

• Albert Poater Institut de Química Computacional i Catàlisi, Departament de Química, Universitat de Girona, Campus de Montilivi, E-17071 Girona, Spain 10.3762/bjoc.12.13 Abstract Bearing the versatility of N-heterocyclic carbene (NHC) ligands, here density functional theory (DFT) calculations

Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

• Norbert Vida,
• Jiří Václavík and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 110–116, doi:10.3762/bjoc.12.12

• temperature with exclusive regiochemistry on the less substituted double bond of 12 and complete endo stereochemistry (Scheme 5). Employing density functional theory (DFT) with the B3LYP functional [23] and the aug-cc-pVDZ basis set [24][25], we calculated the reaction coordinates leading to four possible

Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• properties of the monomers were investigated by NMR and UV–vis spectroscopy as well as density functional theory (DFT) calculations. Results and Discussion Synthesis Methyl linker: Synthesis of 3-(2,5-dimethoxybenzyl)-1H-pyrrole (3a) For our target compound 3-(2,5-dimethoxybenzyl)-1H-pyrrole (3a), we

Solving the puzzling competition of the thermal C²–C⁶ vs Myers–Saito cyclization of enyne-carbodiimides

• Anup Rana,
• Mehmet Emin Cinar,
• Debabrata Samanta and
• Michael Schmittel

Beilstein J. Org. Chem. 2016, 12, 43–49, doi:10.3762/bjoc.12.6

• costly multi-reference techniques. An alternative is to apply the unrestricted broken symmetry (U–BS) density functional theory (DFT) approach, which is often in use for larger systems due to its good results [36][37][38][39][40][41][42][43][44][45][46][47][48][49]. Hence, we applied the U–BS DFT

2-Hetaryl-1,3-tropolones based on five-membered nitrogen heterocycles: synthesis, structure and properties

• Yury A. Sayapin,
• Inna O. Tupaeva,
• Alexandra A. Kolodina,
• Eugeny A. Gusakov,
• Vitaly N. Komissarov,
• Igor V. Dorogan,
• Nadezhda I. Makarova,
• Anatoly V. Metelitsa,
• Valery V. Tkachev,
• Sergey M. Aldoshin and
• Vladimir I. Minkin

Beilstein J. Org. Chem. 2015, 11, 2179–2188, doi:10.3762/bjoc.11.236

• intramolecular N–H···O hydrogen bond. The mechanism of the formation of 1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil in acetic acid solution has been studied using density functional theory (DFT) methods. The reaction of 2-(2-benzoxa(thia)zolyl)-5,6,7-trichloro

• -1,3-tropolones and 4,5,6,7-tetrachloro-1,3-tropolones in the reaction of methylene-active five-membered heterocycles with o-chloranil using density functional theory (DFT) quantum chemical methods. Molecular and crystal structures of three representative 2-hetaryl-1,3-tropolones have been determined

Investigation of the role of stereoelectronic effects in the conformation of piperidones by NMR spectroscopy and X-ray diffraction

• Cesar Garcias-Morales,
• David Ortegón-Reyna and
• Armando Ariza-Castolo

Beilstein J. Org. Chem. 2015, 11, 1973–1984, doi:10.3762/bjoc.11.213

• Gaussian 09 package [70], and molecular visualization was performed with ChemCraft 1.7 (2013) software [71]. Geometry optimization and natural bond orbital (NBO) analysis was performed for compounds 1 and 3 using density functional theory (DFT) with the long-range corrected ωB97XD functional [72][73] and

Mechanism, kinetics and selectivity of selenocyclization of 5-alkenylhydantoins: an experimental and computational study

• Biljana M. Šmit,
• Radoslav Z. Pavlović,
• Dejan A. Milenković and
• Zoran S. Marković

Beilstein J. Org. Chem. 2015, 11, 1865–1875, doi:10.3762/bjoc.11.200

• selenocyclization of 5-alkenylhydantoins leading to fused bicyclic products [24]. To our best knowledge, no previous theoretical work has reported on this reaction. In this paper, density functional theory (DFT) [25][26][27][28] is utilized to understand the mechanism and selectivity of this key step in the

• the internal nucleophile, the amidic nitrogen, to the seleniranium cation yielding the intermediate imidazolinium cations. Their deprotonation is followed by the formation of the fused bicyclic reaction products. Important intermediates and key transition states are studied by using density functional

• theory (DFT) methods. The pathways of the reaction are investigated in detail. There are two regioselective pathways related to 5-exo and 6-endo products. Theoretical calculations and the monitoring of the cyclization reaction using 1H NMR spectroscopy are in a good agreement with the proposed mechanism

A comprehensive study of olefin metathesis catalyzed by Ru-based catalysts

• Albert Poater and
• Luigi Cavallo

Beilstein J. Org. Chem. 2015, 11, 1767–1780, doi:10.3762/bjoc.11.192

• species is also discussed, with either pyridine or phosphine ligands to dissociate. Keywords: cis; density functional theory (DFT); N-heterocyclic carbene; olefin metathesis; ruthenium; Introduction Organic synthesis is based on reactions that drive the formation of carbon–carbon bonds [1]. Olefin

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• ]. Based on these results, we here use CH acidities of the aromatic substrates in THF (calculated using the homodesmic reaction approach within the density functional theory (DFT) framework) to attempt a rationalization of the practical results. Results Synthetic aspects In order to prepare the different

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• 5a or 14 (1.829, 1.845 and 1.842 Å, respectively). DFT calculations Density functional theory (DFT) calculations were performed with the aim to learn more about the compounds under investigation especially in view of their peculiar trans–cis isomerization behavior. Geometry optimizations were