Trifluoromethylated hydrazones and acylhydrazones as potent nitrogen-containing fluorinated building blocks

• Zhang Dongxu

Beilstein J. Org. Chem. 2023, 19, 1741–1754, doi:10.3762/bjoc.19.127

• trifluoroacetaldehyde hydrazones. Jasiński et al. demonstrated that the CF3 group offered an appropriate electronic balance through experimental spectral analysis and computational DFT methods, and the hydrazones could be readily used to provide convenient access to azo tautomers under the acidic conditions [43]. The C

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• liquors and, in both cases, XRD confirmed the obtention of the (E)-isomer, in an anti-conformation. Computational calculations (gas and water phases) were performed in order to confirm some of the structural and vibrational aspects of the compounds. An important intramolecular H bond involving the

• calculate the electrostatic potential over an electronic density map as well. For hdz-NO2, results show the alternated slipped stack motif involves the assembly of portions with opposite electrostatic potentials. Computational calculations were performed in order to confirm some of the structural and

• maintained in DMSO-d6 solution. It is worth noting that the presence of the electron-withdrawing nitro substituent in hdz-NO2 makes the interaction stronger. An IR spectroscopy study, which was supported by computational calculations, as well as a complete NMR characterization of both compounds, align with

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• compound with the donor polymer PM6 to create BHJ nanoparticles and employed it in the hydrogen evolution reaction. This approach substantially reduced trap density, increasing the hydrogen evolution rate by 2–3 times compared to conventional inorganic/organic hybrid photocatalysts [30]. Computational

• ]. Several computational studies have also been performed to design dyes for optimized performance in DSSCs [46][47]. Shi and colleagues’ quantum modeling study sheds light on the optoelectronic properties of Qx-based dyes containing DPQ (Qx44a) or methoxy-substituted DPQ (Qx44b) as π units, highlighting the

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• reduce computational costs (Figure 3a). The calculated ECD curve for 1′ agreed well with the experimental ECD spectra of 1 and 6, indicating that the aglycones of these compounds had an absolute configuration of 1R,3R,4R,6S,7R,9S,11S,12R,16S,17S (Figure 3b). Similarly, the absolute configurations of

• -arabinose), 16.20 (ᴅ-arabinose), and 22.14 (ʟ-rhamnose) min. Computational method Conformers of 1′, 2′, and 3 were generated using CONFLEX 8 with the MMFF94s force field [19] and a search limit of 5 kcal/mol, respectively. Similar conformers were excluded, yielding 9 conformers for 1′, 10 conformers for 2

Unraveling the role of prenyl side-chain interactions in stabilizing the secondary carbocation in the biosynthesis of variexenol B

• Moe Nakano,
• Rintaro Gemma and
• Hajime Sato

Beilstein J. Org. Chem. 2023, 19, 1503–1510, doi:10.3762/bjoc.19.107

• , computational chemistry including DFT [5][6][7][8][9], QM/MM [10][11][12][13][14][15][16] and QM/MM MD [14][15][16][17] calculations have been used for the biosynthetic studies of terpene/terpenoids [18]. Terpene-forming reactions, which involve various types of carbocation species stabilized by

• biosynthesis of trichobrasilenol [22], by combined methods of computational and experimental chemistry. Recently, Dickschat et al. reported the synthesis of a novel diterpene compound, variexenol B, using a substrate analogue called iso-GGPP (Scheme 1) [23]. This biosynthetic pathway has two interesting

• investigated the biosynthetic pathways using DFT calculations to validate the above-mentioned aspects. Results and Discussion The detailed structures of the intermediates and transition states were elucidated by computational analysis. Interestingly, we have found an interaction between the secondary

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• ). Computational results Computations were performed using density functional theory (DFT) for the ground state and time-dependent DFT (TD-DFT) with Tamm–Dancoff approximation [24][25] for the excited states calculations, using the global hybrid MN15 functional by Truhlar [26] in combination with the def2-TZVP

Exploring the role of halogen bonding in iodonium ylides: insights into unexpected reactivity and reaction control

• Carlee A. Montgomery and
• Graham K. Murphy

Beilstein J. Org. Chem. 2023, 19, 1171–1190, doi:10.3762/bjoc.19.86

• have been evaluated extensively through both qualitative and quantitative means. Methods of evaluation have included X-ray crystallography and spectroscopy (e.g., microwave, IR, Raman, NMR, NQR), as well as through computational determination of their electrostatic VS,max potentials (Figure 2), their

• positively charged. Halogen-bonded adducts of these have also been observed, which further illustrated the existence and properties of σ-holes in such HVI compounds. For example, I-7-pyr was characterized by X-ray crystallography and by computational methods, where molecular orbital (MO) analysis showed that

• halogen bonding had been invoked for years when describing reactions of such ylides. In 2022, Murphy et al. used computational analysis to assess iodonium ylides for their σ-holes, and found that two of these existed, with one situated opposite the arene and the other opposite the β-dicarbonyl motif

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• coupling, i.e., the 3LE mediate 3CS → 1CS rISC in TADF [27]. The photochemical properties of each compound in different solvents are summarized in Table 5. Computational investigations The optimized ground state geometry of the dyads at the DFT-B3LYP/6-31G (d) level of theory determined with Gaussian 09

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• absolute configurations, were identified by comprehensive spectroscopic analyses and computational methods. Inspired by our previous study on the same kinds of skeletons, we speculated that the new compounds have anticancer and anti-inflammatory activities. The results did not show any activity, but they

Asymmetric tandem conjugate addition and reaction with carbocations on acylimidazole Michael acceptors

• Brigita Mudráková,
• Renata Marcia de Figueiredo,
• Jean-Marc Campagne and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 881–888, doi:10.3762/bjoc.19.65

• scope. Results of selected optimization experiments. Supporting Information Supporting Information File 174: Characterization data for all compounds, computational details, and picture of NMR spectra. Funding This work was supported by the Slovak Research and Development Agency under the Contract no

Pyridine C(sp²)–H bond functionalization under transition-metal and rare earth metal catalysis

• Haritha Sindhe,
• Malladi Mounika Reddy,
• Karthikeyan Rajkumar,
• Akshay Kamble,
• Amardeep Singh,
• Anand Kumar and
• Satyasheel Sharma

Beilstein J. Org. Chem. 2023, 19, 820–863, doi:10.3762/bjoc.19.62

• functionalization of chelating molecules under action of a Rh(NHC) system. Based on the computational studies and experimental data, the proposed mechanism (Scheme 40b) describes that the Rh(I) complex ligated to tert-butoxide and NHC (IMes·HCl) 215 is a catalytically active species. The Rh–hydride species 217 is

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• , accompanied by two known flavan derivatives 5 and 6 and a known olefine acid (9) were isolated from whole bodies of Kronopolites svenhedini (Verhoeff). The structures of the new compounds were determined by 1D and 2D nuclear magnetic resonance (NMR) and other spectroscopic methods, as well as computational

• Table 4. Kronoponoid B (8): light yellow gum; [α]D25 +2.50 (c 0.40, MeOH); UV (MeOH) λmax, nm (log ε): 202 (3.81); HRESIMS (m/z): [M + H]+ calcd for C17H31O3, 283.2268; found, 283.2268 ; 1H and 13C NMR data, see Table 4. Computational methods The CONFLEX 7 searches, considering the Molecular Merck force

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• Kutateladze claimed that based on an applied machine learning-augmented DFT method for computational NMR that the structure of the product, (1R,2R,3S,4S,7s)-2,3,7-tribromobicyclo[2.2.1]heptane was wrong. With the aid of their computational method, they revised a number of published structures, including ours

• erroneous mechanistic pathway. Keywords: bromination; computational NMR; γ-gauche effect; NMR; NOE-Diff experiments; Introduction Nuclear magnetic resonance (NMR) spectroscopy is one of the most important analytical tools used to determine the structure of organic compounds. NMR not only confirms the

• have developed a machine learning-augmented DFT method for computational NMR, DU8ML, for fast and ‘accurate’ computational approaches [2]. They applied this computational method to a number of previously published organic compounds and claimed to have revised some structures and proposed new mechanisms

Cassane diterpenoids with α-glucosidase inhibitory activity from the fruits of Pterolobium macropterum

• Sarot Cheenpracha,
• Ratchanaporn Chokchaisiri,
• Lucksagoon Ganranoo,
• Sareeya Bureekaew,
• Thunwadee Limtharakul and
• Surat Laphookhieo

Beilstein J. Org. Chem. 2023, 19, 658–665, doi:10.3762/bjoc.19.47

• with an α,β-butenolide-type, whereas compound 3 is a dimeric caged cassane diterpenoid with unique 6/6/6/6/6/5/6/6/6 nonacyclic ring system. The structures of 1 and 3 were characterized by extensive spectroscopic analysis combined with computational ECD analyses. The α-glucosidase inhibitory activity

Phenanthridine–pyrene conjugates as fluorescent probes for DNA/RNA and an inactive mutant of dipeptidyl peptidase enzyme

• Josipa Matić,
• Tana Tandarić,
• Marijana Radić Stojković,
• Filip Šupljika,
• Zrinka Karačić,
• Ana Tomašić Paić,
• Lucija Horvat,
• Robert Vianello and
• Lidija-Marija Tumir

Beilstein J. Org. Chem. 2023, 19, 550–565, doi:10.3762/bjoc.19.40

• 54, 10000 Zagreb, Croatia Laboratory for the Computational Design and Synthesis of Functional Materials, Division of Organic Chemistry and Biochemistry, Ruđer Bošković Institute, Bijenička cesta 54, 10000 Zagreb, Croatia Laboratory for Physical Chemistry and Corrosion, Department of Chemistry and

• simulations additionally supported the pronounced hypochromic effect (chapter Computational analysis). Fluorescence spectra Fluorescence emission of Phen-Py-1 and Phen-Py-2 measured at pH 5 and pH 7 (cacodylate buffer, Ic = 0.05 mol dm−3) was linearly dependent on the concentration up to 4 × 10−6 mol dm−3

• dielectric constant and a lower polarity that influenced intramolecular stacking. To the best of our knowledge, this is the first reported phenanthridine–pyrene excimer in solution. Molecular dynamics calculations (see chapter Computational analysis) and hypochromism observed from UV–vis spectra pointed

Computational studies of Brønsted acid-catalyzed transannular cycloadditions of cycloalkenone hydrazones

• Manuel Pedrón,
• Jana Sendra,
• Irene Ginés,
• Tomás Tejero,
• Jose L. Vicario and
• Pedro Merino

Beilstein J. Org. Chem. 2023, 19, 477–486, doi:10.3762/bjoc.19.37

• experimentally. In this work, we present our results on the computational study of the transannular reaction illustrated in Scheme 1 for several nonsymmetric tether combinations between the hydrazone and double bond moieties leading to a sort of condensed cyclohexanes (series a–f) and other bicyclic systems

• cyclopentanes, with the exception of the highly constrained system 5-5. Considering the simplest bimolecular model 3, the fused cyclohexanes contribute with ca. 6–8 kcal/mol while the fused cyclopentanes contribute with ca. 15 kcal/mol (Table 5). Conclusion In conclusion, the computational topological study

• energies (kcal/mol) between transition structure terms of distortion analysis. Supporting Information Supporting Information File 16: Computational methods, energies, and Cartesian coordinates. Acknowledgements The authors thankfully acknowledge the resources from the supercomputers "Memento" and “Cierzo

Total synthesis: an enabling science

• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 474–476, doi:10.3762/bjoc.19.36

• [12], as illustrated in this thematic issue with the synthesis of pheromones [16]. This requires permanent technological progress. Thus, the recent boom of artificial intelligence, machine learning, and computational chemistry for retrosynthetic analyses and beyond foreshadows a renewed interest in

Combretastatins D series and analogues: from isolation, synthetic challenges and biological activities

• Jorge de Lima Neto and
• Paulo Henrique Menezes

Beilstein J. Org. Chem. 2023, 19, 399–427, doi:10.3762/bjoc.19.31

• combretastatin D on the use of computational calculations in order to find the intermediates with the lowest torsional energy for the cyclization step [43][44][45]. The authors came to the conclusion that both the formation of the double bond in compound 2 and the formation of the epoxide in compound 1 would

• biological studies remains highly desirable. The pharmacological potential of these compounds also requires further studies since most of them showed activity on a micromolar scale in in vitro assays, with the compounds containing the cis double bond being the most active. However, the use of computational

CuAAC-inspired synthesis of 1,2,3-triazole-bridged porphyrin conjugates: an overview

• Dileep Kumar Singh

Beilstein J. Org. Chem. 2023, 19, 349–379, doi:10.3762/bjoc.19.29

• conjugates (99a–d, 103a,b) were utilized for the preparation of porphyrin-fullerene dyads 100a–d and 104a,b in 30–70% yield by the reaction with C60 and sarcosine in toluene under microwave conditions. The photophysical and computational studies of these ZnP-Tri-C60 conjugates revealed that the 1,2,3

Group 13 exchange and transborylation in catalysis

• Dominic R. Willcox and
• Stephen P. Thomas

Beilstein J. Org. Chem. 2023, 19, 325–348, doi:10.3762/bjoc.19.28

• kinetic and computational analyses, the B‒C(sp2)/B‒H transborylation transition state was determined to have a free energy barrier of approximately 20 kcal mol−1 (ΔG‡calc = 19.7 kcal mol−1; ΔG‡exp = 20.3 kcal mol−1) (Scheme 2). The borane-catalysed hydroboration of alkenes has been less explored, with

• frustrated Lewis pair (FLP)-mediated C‒H functionalisation (Scheme 4a). Using computational analysis, the mechanism of the reaction was proposed to occur by borane dimer [9]2 dissociation, followed by a concerted deprotonation of the heterocycle 10 to give a zwitterionic intermediate 11. The zwitterion then

• of allenes, using various boronates as the terminal reductant (Scheme 5) [68]. Experimental and computational studies suggested the reaction proceeded by hydroboration of the allene 14 by bis(pentafluorophenyl)borane to give an allylborane 15, which underwent allylation of a second equivalent of the

Recommendations for performing measurements of apparent equilibrium constants of enzyme-catalyzed reactions and for reporting the results of these measurements

• Robert N. Goldberg,
• Robert T. Giessmann,
• Peter J. Halling,
• Carsten Kettner and
• Hans V. Westerhoff

Beilstein J. Org. Chem. 2023, 19, 303–316, doi:10.3762/bjoc.19.26

• reactions that involve the same or a similar change in chemical bonding, e.g., by using group contribution methods [32][33][34][35]. And, one should not overlook the use of computational chemistry as a means to obtain the desired property values. Finally, there is a close relationship between equilibrium

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• combined computational and experimental approach that in this enzyme the main chain carbonyl oxygen of Gly182 near the helix G kink and an active site water are involved in the deprotonation–reprotonation sequence in the biosynthesis of 10 (Scheme 8B) [69]. γ-Selinene (10) has been synthesised from ketone

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

• . HPLC was used to quantify the cumulative percentage of CPT released for each time point [9]. Release kinetics study In vitro release profiles of CD nanoparticles were analyzed using DDSolver 1.0 [73], designed to reduce computation time and minimize computational errors, and the data were fitted to

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• (trifluoromethanesulfonic acid), and the N-acyliminium cation was proposed to be protonated with the super acidic TfOH to form a dicationic species, which was shown by computational studies to be crucial for the success of this transformation. In a later study, the same research group showed that benzamides 2 bearing an

• ) group via the β-silicon stabilization effect [36][37][38] as supported by computational studies [35]. The desilylation of intermediate 9 with the chloride of another molecule of 8 would result in the formation of final aza-Nazarov product 7 along with TMSCl (Scheme 1d). Five-membered nitrogen