Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• s−1. Keywords: dithienothiophene (DTT); fused ring system; organic field-effect transistor (OFET); organic semiconductor; thienoacene; Introduction In recent years, organic molecules with several fused aromatic rings have gained much attention. Fusing aromatic rings leads to planar structures

On the application of 3d metals for C–H activation toward bioactive compounds: The key step for the synthesis of silver bullets

• Renato L. Carvalho,
• Amanda S. de Miranda,
• Mateus P. Nunes,
• Roberto S. Gomes,
• Guilherme A. M. Jardim and
• Eufrânio N. da Silva Júnior

Beilstein J. Org. Chem. 2021, 17, 1849–1938, doi:10.3762/bjoc.17.126

• action of Meerwein’s salt (Me3OBF4) and a mild base (proton sponge) to afford a methoxy cedrene derivative. Next, oxidative cleavage of the double bond using NaIO4/RuCl3·xH2O enabled a ring opening, followed by lactonization promoted by CuBr2 via an intramolecular acyloxylation. The 5,5-fused ring system

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

• acyclic substrate GGDP (3) is stereospecifically cyclized by CotB2 to cyclooctat-9-en-7-ol (4), with a fusicoccane 5–8–5 fused ring system. Two cytochrome P450 enzymes, CotB3 and CotB4, subsequently functionalize cyclooctat-9-en-7-ol (4) to the bioactive compound cyclooctatin (5). The bacterial diterpene

Steroid diversification by multicomponent reactions

• Leslie Reguera,
• Cecilia I. Attorresi,
• Javier A. Ramírez and
• Daniel G. Rivera

Beilstein J. Org. Chem. 2019, 15, 1236–1256, doi:10.3762/bjoc.15.121

• hormonal ones. All steroids are based on a common skeleton containing three fused six-membered rings and one five membered ring. This fused-ring system provides a readily available source of rigidity and chirality, whose substituents can be oriented either towards the α- or the β-face. Steroids feature a

6’-Fluoro[4.3.0]bicyclo nucleic acid: synthesis, biophysical properties and molecular dynamics simulations

• Sibylle Frei,
• Andrei Istrate and
• Christian J. Leumann

Beilstein J. Org. Chem. 2018, 14, 3088–3097, doi:10.3762/bjoc.14.288

• ’) oxygen were minimized. The analysis of the backbone torsion angles revealed that the fused ring system affected all backbone torsion angles (Figure 5c and d). Specifically, the angle α adopted values in the +ap to −sc range which was in contrast to the canonical parameters (DNA: ±sc, −ac; RNA +ac, +ap

Synthesis of cis-hydrindan-2,4-diones bearing an all-carbon quaternary center by a Danheiser annulation

• Gisela V. Saborit,
• Carlos Cativiela,
• Ana I. Jiménez,
• Josep Bonjoch and
• Ben Bradshaw

Beilstein J. Org. Chem. 2018, 14, 2597–2601, doi:10.3762/bjoc.14.237

• from an acyclic compound by a cascade radical process using Mn(OAc)3 [21], although a trans-fused ring system was formed. Also of note, is the approach of Mori [22] to a dihydroindenedione based on an initial cyclization of an allyl iodide in a 1,3-cyclohexanedione side chain via an allyl anion

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

• ]. These o-QM precursors by a thermal elimination of dimethylamine were then reacted with different cyclic dienophiles to give various inverse electron-demand Diels–Alder adducts 35–37. In case of 36, the cis-fused ring system found to be similar to bioactive xyloketals isolated from fungi (Scheme 4) o-QMs

Pd(OAc)₂/Ph₃P-catalyzed dimerization of isoprene and synthesis of monoterpenic heterocycles

• Dominik Kellner,
• Maximilian Weger,
• Andrea Gini and
• Olga García Mancheño

Beilstein J. Org. Chem. 2017, 13, 1807–1815, doi:10.3762/bjoc.13.175

• maleimides in toluene provided a ready access to the fused ring-system 6a–c in excellent yields (81–91%; Scheme 3, middle). Finally, the [4 + 1]-cycloaddition with nitrenes was carried out (Scheme 3, right). To attain this transformation the required nitrene was formed in situ from an iminoiodinane precursor

Phosphazene-catalyzed desymmetrization of cyclohexadienones by dithiane addition

• Matthew A. Horwitz,
• Elisabetta Massolo and
• Jeffrey S. Johnson

Beilstein J. Org. Chem. 2017, 13, 762–767, doi:10.3762/bjoc.13.75

• nucleophilic group were appended to the para-quinol, it would be possible to construct a 5–6–5 fused ring system. Indeed, when R = CH2CH2NHBoc (1f), the desired tricyclic product 2f was obtained. In all cases only a single diastereomer was observed. In a substrate where a β-methyl group is present on the

Inclusion complexes of β-cyclodextrin with tricyclic drugs: an X-ray diffraction, NMR and molecular dynamics study

• Franca Castiglione,
• Fabio Ganazzoli,
• Luciana Malpezzi,
• Andrea Mele,
• Walter Panzeri and
• Giuseppina Raffaini

Beilstein J. Org. Chem. 2017, 13, 714–719, doi:10.3762/bjoc.13.70

• any disorder: this finding is largely predictable for the rigid tricyclic moiety of 1 but it is remarkable in 2. Indeed, literature data on isolated amitriptyline point out that the fused ring system of 2 shows conformational transitions [10], especially those involving the torsion about the C9–C10

Assembly of synthetic Aβ miniamyloids on polyol templates

• Sebastian Nils Fischer and
• Armin Geyer

Beilstein J. Org. Chem. 2015, 11, 2646–2653, doi:10.3762/bjoc.11.284

• ester even under the dilution conditions of an NMR tube (Figure 4). The signal set of boronic ester 7 is significantly shifted compared to the 1H NMR spectra of the educts, because the central δ-valerolactam of the 5,6,5-membered tricyclic fused ring system is locked in the boat conformation. Increasing

The diketopiperazine-fused tetrahydro-β-carboline scaffold as a model peptidomimetic with an unusual α-turn secondary structure

• Francesco Airaghi,
• Andrea Fiorati,
• Giordano Lesma,
• Manuele Musolino,
• Alessandro Sacchetti and
• Alessandra Silvani

Beilstein J. Org. Chem. 2013, 9, 147–154, doi:10.3762/bjoc.9.17

• -turn conformation. The synthesis is based on a diastereoselective Pictet–Spengler condensation to give the THBC core, followed by an intramolecular lactamization to complete the tetracyclic THBC-DKP fused ring system. The presence of conformers bearing the intramolecular thirteen-membered hydrogen bond

Flow photochemistry: Old light through new windows

• Jonathan P. Knowles,
• Luke D. Elliott and
• Kevin I. Booker-Milburn

Beilstein J. Org. Chem. 2012, 8, 2025–2052, doi:10.3762/bjoc.8.229

• competitive [29]. In a similar [2 + 2] photocycloaddition (Scheme 5), the authors demonstrated that by extending the chain length by one carbon, the 4,6-fused ring system 14 could be formed, albeit with some formation of regioisomer 15. In this instance the batch reaction gave slightly better selectivity than

Expanding the chemical diversity of spirooxindoles via alkylative pyridine dearomatization

• Chunhui Dai,
• Bo Liang and
• Corey R. J. Stephenson

Beilstein J. Org. Chem. 2012, 8, 986–993, doi:10.3762/bjoc.8.111

• products 8a–c were isolated in moderate yields. Finally, the structure of compound 8a was established by single-crystal X-ray analysis (Figure 3). Conclusion In summary, we developed a practical and efficient method to synthesize spirooxindole derivatives with a [1,3]oxazine fused-ring system. The reaction

Perhydroazulene-based liquid-crystalline materials with smectic phases

• Zakir Hussain,
• Henning Hopf and
• S. Holger Eichhorn

Beilstein J. Org. Chem. 2012, 8, 403–410, doi:10.3762/bjoc.8.44

• , by increasing its polarity through the addition of dichloromethane (~50%). The major product was found to be the one with the cis-fused ring system, as expected (5a, 1.06 g, ~80%); this eluted first from the column followed by the isomer with the trans-fused system (always containing traces of the