Synthesis of imidazo[1,5-a]pyridines via cyclocondensation of 2-(aminomethyl)pyridines with electrophilically activated nitroalkanes

• Dmitrii A. Aksenov,
• Nikolai A. Arutiunov,
• Vladimir V. Maliuga,
• Alexander V. Aksenov and
• Michael Rubin

Beilstein J. Org. Chem. 2020, 16, 2903–2910, doi:10.3762/bjoc.16.239

• % (101 mg, 0.77 mmol). Mp 50–52 °C (lit. [53] mp 49–50 °C, cyclohexane); Rf 0.32 (EtOAc); 1H NMR (400 MHz, DMSO-d6) δ 8.04 (dd, J = 7.1; 1.0 Hz, 1H, 5-H), 7.48 (dt, J = 9.1; 1.1 Hz, 1H, 8-H), 7.24 (d, J = 0.6 Hz, 1H, 1-H), 6.69 (ddd, J = 9.1; 6.3; 0.8 Hz, 1H, 7-H), 6.61 (ddd, 1H, 6-H), 2.57 (s, 3H, CH3

• , 0.66 mmol). Alternatively, the same compound was obtained via the typical procedure 1 starting with 1-nitropropane (1b, 178 mg, 2.00 mmol) and 2-picolylamine (12, 108 mg, 1.00 mmol), yield 53% (77 mg, 0.53 mmol). Mp 59–62 °C (lit. [54] mp 61 °C, cyclohexane); Rf 0.27 (EtOAc/petroleum ether 1:1, v/v

Using multiple self-sorting for switching functions in discrete multicomponent systems

• Amit Ghosh and
• Michael Schmittel

Beilstein J. Org. Chem. 2020, 16, 2831–2853, doi:10.3762/bjoc.16.233

• SelfSORT-II disassembled the host–guest complex [Zn4(64')4]8+•(C6H12) with the concomitant release of the encapsulated cyclohexane thus generating the state SelfSORT-III. In this process, the 1H NMR signals corresponding to [Zn4(66')4]8+•(NO3−) remained unchanged. At last, heating the mixture to 70 °C for

Synthesis of novel fluorinated building blocks via halofluorination and related reactions

• Attila Márió Remete,
• Tamás T. Novák,
• Melinda Nonn,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2020, 16, 2562–2575, doi:10.3762/bjoc.16.208

• more efficient in anhydrous CH3CN than in anhydrous CH2Cl2; therefore, the reactions were conducted in this medium at room temperature. Similar to halofluorinations, the treatment of the diester (rac)-1 with PhSeBr/Deoxo-Fluor® gave a single product (Scheme 20). The stereochemistry of the cyclohexane

• NOESY was unsuccessful. The reason is that cyclohexenes have a half-chair conformation, and the hydrogen atoms to undergo important NOESY interactions are simply too far away from each other. To solve this problem, the olefin bond of (rac)-35 was hydrogenated to a cyclohexane, affording the fluorinated

A new method for the synthesis of diamantane by hydroisomerization of binor-S on treatment with sulfuric acid

• Rishat I. Aminov and
• Ravil I. Khusnutdinov

Beilstein J. Org. Chem. 2020, 16, 2534–2539, doi:10.3762/bjoc.16.205

• binor-S (2) in cyclohexane in the presence of 98% sulfuric acid ([2]/[H2SO4] = 1:10–50) during 7–15 h affords a mixture of endo-endo-pentacyclo[7.3.1.12,5.18,10]tetradecane (tetrahydrobinor-S, 3c) and diamantane (1) (Table 1). An increase in the sulfuric acid ratio to binor-S (2) ([2]/[H2SO4] = 1:20–50

• what is the hydrogen source in the hydroisomerization of binor-S (С14H16, 2) containing 4 hydrogen atoms less than diamantane (С14H20, 1), we carried out a series of control experiments using deuterated sulfuric acid (98%) in cyclohexane (С6H12, experiment A), in deuterated cyclohexane (C6D12

• , experiment B), or in carbon disulfide (CS2, experiment C). In experiment А, the major isomer 1-D2, which is formed upon hydroisomerization of binor-S (2), contains two deuterium atoms. Two more hydrogen atoms are probably provided by cyclohexane. Unexpectedly, the reaction also gave undeuterated diamantane

A proposed sustainability index for synthesis plans based on input provenance and output fate: application to academic and industrial synthesis plans for vanillin as a case study

• John Andraos

Beilstein J. Org. Chem. 2020, 16, 2346–2362, doi:10.3762/bjoc.16.196

• descending order of impact according to OSI values given in Table 1: benzene (12.000), aniline (10.350), toluene (10.150), nitrobenzene (10.130), cyclohexane (8.777), diethyl ether (8.421), acetic anhydride (8.309), petroleum ether (7.734), ethyl acetate (7.597), N,N-dimethyltoluidine (7.592), methyl tert

• cyclohexane. Ranking of vanillin plans Once numerical values of PMI, SR, IEE, RSGI, and SI are available for a given set of synthesis plans to a common target product, it is possible to use some kind of ranking algorithm to identify which ones have the highest overall performances based on these five

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• inserted product 61 in 65% along with the dimer 62 in 18% yield with cyclohexane, confirming that the reaction precedes via the singlet state, albeit it was a triplet species in the ground-state. They further reported the applicability of the carbene precursor 59 by reacting it with different thiocarbonyl

Photosensitized direct C–H fluorination and trifluoromethylation in organic synthesis

• Shahboz Yakubov and
• Joshua P. Barham

Beilstein J. Org. Chem. 2020, 16, 2151–2192, doi:10.3762/bjoc.16.183

• photoexcitation by a CFL to afford the C(sp3)–H fluorinated product in 85% yield (Scheme 13). Through the use of longpass filters, the authors found that wavelengths between 370–400 nm were necessary for the reaction to proceed. The authors then subjected cyclohexane (39) to similar conditions to examine the

Synthesis of new dihydroberberine and tetrahydroberberine analogues and evaluation of their antiproliferative activity on NCI-H1975 cells

• Giacomo Mari,
• Lucia De Crescentini,
• Serena Benedetti,
• Francesco Palma,
• Stefania Santeusanio and
• Fabio Mantellini

Beilstein J. Org. Chem. 2020, 16, 1606–1616, doi:10.3762/bjoc.16.133

• magnetic stirring until the complete disappearance of the starting hydrazono-DHBERs 2a–n (2.0–3.0 h, TLC monitoring). The reaction solvent was then evaporated under reduced pressure. The crude mixture was then purified by column chromatography on silica gel (elution with cyclohexane/ethyl acetate mixtures

• -phenylethylidene)hydrazinecarboxylate (3a): 3a was isolated by chromatographic column on silica gel (ethyl acetate/cyclohexane, 30:70) in 95% yield (109 mg). White amorphous solid; mp: 162–164 °C; 1H NMR (400 MHz, DMSO-d6, 25 °C) δ 1.45 (s, 9H, C(CH3)3), 2.29–2.34 (m, 1H, C(15)H2), 2.62–2.75 (m, 3H, C(15)H2, C(5

Heterogeneous photocatalysis in flow chemical reactors

• Christopher G. Thomson,
• Ai-Lan Lee and
• Filipe Vilela

Beilstein J. Org. Chem. 2020, 16, 1495–1549, doi:10.3762/bjoc.16.125

[3 + 2] Cycloaddition with photogenerated azomethine ylides in β-cyclodextrin

• Margareta Sohora,
• Leo Mandić and
• Nikola Basarić

Beilstein J. Org. Chem. 2020, 16, 1296–1304, doi:10.3762/bjoc.16.110

• determine stability constants for the inclusion complexes 2@β-CD and 3@β-CD. The NMR titration for 2 with β-CD was carried out in CD3CN/D2O (3:7 v/v). The addition of β-CD to the solution of 2 induced downfield shifts of the H-signals corresponding to the cyclohexane 2 and 6 positions, as well as H-signals

• and intercepted with AN to yield cycloadducts 7 or 11, respectively. However, the formation of cycloadducts is very inefficient, which may be ascribed to a smaller rate constant for the quenching due to steric hindrance imposed by the bulky cyclohexane or adamantine moiety. Thus, irradiation of 2 gave

• '-Hydroxy-5'-oxo-1',2',5',9b'-tetrahydrospiro[cyclohexane-1,3'-pyrrolo[2,1-a]isoindole]-1'-carbonitrile (7): 2 mg (2%), oily crystals; 1H NMR (CD3OD, 600 MHz) δ 7.81 (dd, J = 1.0, 7.6 Hz, 1H), 7.70 (dt, J = 1.3, 7.6 Hz, 1H), 7.65 (dt, J = 1.3, 7.6 Hz, 1H), 7.48 (dd, J = 1.0, 7.6 Hz, 1H), 4.55 (br s, 3H

The charge-assisted hydrogen-bonded organic framework (CAHOF) self-assembled from the conjugated acid of tetrakis(4-aminophenyl)methane and 2,6-naphthalenedisulfonate as a new class of recyclable Brønsted acid catalysts

• Svetlana A. Kuznetsova,
• Alexander S. Gak,
• Yulia V. Nelyubina,
• Vladimir A. Larionov,
• Han Li,
• Michael North,
• Vladimir P. Zhereb,
• Alexander F. Smol'yakov,
• Artem O. Dmitrienko,
• Michael G. Medvedev,
• Igor S. Gerasimov,
• Ashot S. Saghyan and
• Yuri N. Belokon

Beilstein J. Org. Chem. 2020, 16, 1124–1134, doi:10.3762/bjoc.16.99

• efficiency of the reaction dropping as the size of the alcohol was increased and its polarity decreased (Table 2, runs 1–3). Water could also be used as the nucleophile (Table 2, runs 4 and 5) and led to the trans-cyclohexane diol 6 under the same experimental conditions used for the styrene oxide ring

Recent applications of porphyrins as photocatalysts in organic synthesis: batch and continuous flow approaches

• Rodrigo Costa e Silva,
• Luely Oliveira da Silva,
• Aloisio de Andrade Bartolomeu,
• Timothy John Brocksom and
• Kleber Thiago de Oliveira

Beilstein J. Org. Chem. 2020, 16, 917–955, doi:10.3762/bjoc.16.83

• -bromo amides (Scheme 6). Many metalloporphyrins are applied as catalysts in industrial processes, such as in the oxidation of cyclohexane to cyclohexanone catalyzed by Co(II) tetraphenylporphyrin on a ton-scale [21]. Recently, Sarkar and co-workers reported the use of nickel(II) tetraphenylporphyrin

One-pot synthesis of dicyclopenta-fused peropyrene via a fourfold alkyne annulation

• Ji Ma,
• Yubin Fu,
• Junzhi Liu and
• Xinliang Feng

Beilstein J. Org. Chem. 2020, 16, 791–797, doi:10.3762/bjoc.16.72

• , peropyrene and the dicyclopenta-fused peropyrene reported in this work. Synthetic route towards compound 1. a) B2pin2, dtbpy, [Ir(OMe)cod]2, cyclohexane, 70 °C, 20 h, 67%; b) Pd(PPh3)4, bromobenzene, Na2CO3, toluene/EtOH/H2O, Aliquit 336, 90 °C, 48 h, 77%; c) Br2, nitrobenzene, 120 °C, 5 h, 86%; d) 1,2

Synthesis of organic liquid crystals containing selectively fluorinated cyclopropanes

• Zeguo Fang,
• Nawaf Al-Maharik,
• Peer Kirsch,
• Matthias Bremer,
• Alexandra M. Z. Slawin and
• David O’Hagan

Beilstein J. Org. Chem. 2020, 16, 674–680, doi:10.3762/bjoc.16.65

• dielectric anisotropic liquid crystals and the more rigid 1,1,6,7-tetrafluoroindane 4 led to an enhanced polarity and improved negative dielectric anisotropy character [8]. Other liquid crystals of this class are the recently reported fluorinated cyclohexane 5 and 1,1,2,2-tetrafluorocyclohexane 6 [9][10

• . The synthesis of the diastereoisomers of spiro LC candidates 11a and 11b also started from ketone 15 as illustrated in Scheme 4. Treatment of ketone 15 with methylenetriphenylphosphine which was generated in situ from methyltriphenylphosphonium bromide (PPh3CH3Br), generated exo-methylene cyclohexane

• properties significantly, however, we were interested in assessing the energy required for the bispirocyclohexane ring to adopt an axial rather than the lower energy equatorial arrangement. For 11a, the lowest energy conformer found was a rotamer around the central C–C bond linking the cyclohexane rings, but

Synthesis and herbicidal activities of aryloxyacetic acid derivatives as HPPD inhibitors

• Man-Man Wang,
• Hao Huang,
• Lei Shu,
• Jian-Min Liu,
• Jian-Qiu Zhang,
• Yi-Le Yan and
• Da-Yong Zhang

Beilstein J. Org. Chem. 2020, 16, 233–247, doi:10.3762/bjoc.16.25

• modifying pyrazole derivatives and the carbon−carbon bond between 1,3-dicarbonyl and aroyl moieties. Previously, a series of 2-(aryloxyacetyl)cyclohexane-1,3-diones was synthesized by Wang et al. [24]. We have been interested in inserting a carbon−oxygen bond between the triketone and aroyl moieties of HPPD

• electron-withdrawing group at the 2-position provides enhanced activity compared to the 4-position. In addition, electron-donating groups were found to be detrimental to HPPD inhibition activity (I1 > I33, I38). We observed that methyl groups at the 5-position of the 1,3-cyclohexane ring were unfavorable

• I11 and I12 displayed enhanced activities relative to compound I9, which contains a cyclohexanedione ring. We also observed that the introduction of methyl groups at the 5-position of the 1,3-cyclohexane ring was detrimental to herbicidal activity (I17 > I18, I26 > I27, II1 > II2). Compounds with

Starazo triple switches – synthesis of unsymmetrical 1,3,5-tris(arylazo)benzenes

• Andreas H. Heindl and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2020, 16, 22–31, doi:10.3762/bjoc.16.4

• . The mixture was separated by flash column chromatography (SiO2, cyclohexane/EtOAc, 2:1, v/v) to yield 16a as red solid (mixture of isomers, 248 mg, 10%). The product was used without further purification. See Supporting Information File 1 for the 1H NMR spectrum. HRESIMS (m/z): [M + Na]+ calcd for

• toluene (42 mL). The mixture was stirred at rt for 30 min and the tube was sealed and heated to 110 °C for 2 d. After cooling to rt, the reaction mixture was filtered through a plug of silica gel using EtOAc, concentrated, and the residue was separated by flash column chromatography (SiO2, cyclohexane

• tube was sealed, and the mixture was heated to 110 °C for 2 d. After cooling to rt, the mixture was filtered through a plug of silica gel using EtOAc, and the filtrate was concentrated. The crude mixture was separated by two consecutive flash column chromatography steps (SiO2, cyclohexane/EtOAc, 1:1, v

Influence of the cis/trans configuration on the supramolecular aggregation of aryltriazoles

• Sara Tejera,
• Giada Caniglia,
• Rosa L. Dorta,
• Andrea Favero,
• Javier González-Platas and
• Jesús T. Vázquez

Beilstein J. Org. Chem. 2019, 15, 2881–2888, doi:10.3762/bjoc.15.282

• 3.62 (d, J = 8.4 Hz, 2H), 1.85 (m, 2H), 1.64 (m, 4H), 1.38 ppm (m, 2H); 13C NMR (150 MHz, CDCl3) δ 61.4, 27.3, 21.6 ppm. (1R,2S)-1,2-Bis(4-(4-bromophenyl)-1H-1,2,3-triazol-1-yl)cyclohexane (14): To a solution of (1R,2S)-1,2-diazidocyclohexane (13, 363 mg, 2.19 mmol) in H2O (22 mL, 22 mmol), 1-bromo-4

• -glucopyranosyltriazoles 1a–g and 2a–g [15]. Synthesis of 1,2-cis-/trans-bistriazoles 7a–7g and 8a–8g [15]. Compounds 9 (trans) and 10 (cis) [15]. Synthesis of (1R,2R)- and (1R,2S)-1,2-bis-(4-(4-bromophenyl)-1H-triazol-1-yl)cyclohexane (12 and 14). Gelation test results for compounds 7f, 8a, 8b, 8e, 8f, 9, 10, 12, and 14

A photochemical determination of luminescence efficiency of upconverting nanoparticles

• Baptiste Amouroux,
• Clément Roux,
• Jean-Claude Micheau,
• Fabienne Gauffre and
• Christophe Coudret

Beilstein J. Org. Chem. 2019, 15, 2671–2677, doi:10.3762/bjoc.15.260

• cyclohexane. Photolysis experiments The description of the setup is summarized in Figure 2. The sample in a thermostated quartz cuvette was irradiated with a fibered, collimated CW 976 nm-laser beam. The transmitted laser intensity was measured using a calibrated power-meter. This measurement informed us

• about the fraction of light effectively absorbed by the medium and also the possibility of particle sedimentation. All this set-up was placed inside a UV–visible spectrophotometer (Figure 2). Using cyclohexane as a common solvent for both diarylethene 1 and UCNPs, we have chosen to work on mixtures of

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• structures of 4 and 9 have one. The cyclohexane rings of all molecules have chair conformations, the cyclohexene rings of all molecules have half-chair conformations, and the furan rings of all molecules have flattened envelope conformations. See Supporting Information File 1 for detailed methods. Genomics

Chiral terpene auxiliaries V: Synthesis of new chiral γ-hydroxyphosphine oxides derived from α-pinene

• Anna Kmieciak and
• Marek P. Krzemiński

Beilstein J. Org. Chem. 2019, 15, 2493–2499, doi:10.3762/bjoc.15.242

• Adams catalyst was carried out in cyclohexane with 1 atm of hydrogen. The hydrogen pressure was increased to 10 atm for the reaction performed in an autoclave on a larger scale maintaining the high selectivity of hydrogen addition from the less hindered side of the molecule. (1R,2S,5R)-(+)-Verbanone (3

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• reduced pressure. The formed precipitate was collected by filtration and recrystallized from EtOAc. The product was obtained as colourless crystals (0.55 g, 2.45 mmol, 49%): Rf = 0.25 (cyclohexane/THF 1:1); mp: 196.4 °C; 1H NMR (400 MHz, DMSO-d6) δ (ppm) 8.93 (d, J = 2.0 Hz, 1H), 8.90 (d, J = 2.1 Hz, 1H

• ) and dired over MgSO4. The solvent was evaporated under reduced pressure and the residue purified by silica gel column chromatography (cyclohexane/EtOAc 3:1). The product was obtained as orange solid (431 mg, 1.67 mmol, 42%): Rf = 0.52 (cyclohexane/EtOAc 3:1); mp: 103.6 °C; 1H NMR, H,H-COSY (400 MHz

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• hydroxide (1 M, 2 × 5 mL), then with water (10 mL), dried over magnesium sulfate, and evaporated. The crude product was purified by column chromatography on silica gel using cyclohexane/AcOEt (3:7) to furnish the titled product in 48% yield (348 mg) as a yellow solid. 1H NMR (CDCl3) δ 1.38 (s, 9H), 3.67 (t

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• hydrogens at positions 2 and 6 of the cyclohexane ring [22]. It has been reported that EPR spectra of pyrrolidine or imidazolidine nitroxides with pair(s) of geminal ethyl groups at α-carbon atoms may feature large doublet hyperfine splittings [23][24][25]. For imidazolidine nitroxides, these splittings

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

• solvent. However, the tautomeric equilibrium has not been switched fully to either of the tautomers in solution. For instance, the experimentally determined ΔG values at room temperature range from 1.42 kcal/mol, which corresponds to around 8% (in cyclohexane) or 10% (in methylcyclohexane/toluene) of the

A heteroditopic macrocycle as organocatalytic nanoreactor for pyrroloacridinone synthesis in water

• Piyali Sarkar,
• Sayan Sarkar and
• Pradyut Ghosh

Beilstein J. Org. Chem. 2019, 15, 1505–1514, doi:10.3762/bjoc.15.152

• the 4,5-dihydropyrrolo derivatives, we were interested to synthesize fully aromatic products by using C5–H containing cyclohexane-1,3-dione derivatives in place of dimedone. Thus, using cyclohexane-1,3-dione (5) or 5-phenylcyclohexane-1,3-dione (6) allowed the isolation of novel substituted pyrrolo