Sesquiterpenes from the soil-derived fungus Trichoderma citrinoviride PSU-SPSF346

• Wiriya Yaosanit,
• Vatcharin Rukachaisirikul,
• Souwalak Phongpaichit,
• Sita Preedanon and
• Jariya Sakayaroj

Beilstein J. Org. Chem. 2022, 18, 479–485, doi:10.3762/bjoc.18.50

• as the chemical shifts of C-7 and C-15 (δC 69.2) constructed a cyclohexane ring with both a hydroxymethyl group and an oxy substituent at C-7, the isopropyl group at C-10 and other substituents at C-5 (δC 47.0) and C-6. The substituent at C-6 was assigned as a carboxyl group on the basis of the HMBC

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• -state photoluminescence (PL) spectra were acquired (Figure 2, and the summary of the properties presented in Table 1). The solutions were prepared with a variety of organic solvents at concentrations of ca. 10−5 M. It is noted that the solubility of 1 in cyclohexane is quite low, and thereby the

• concentration of the cyclohexane solution and the molar absorption coefficient ε were not determined. As is clearly seen from Figure 2, the absorption spectra were not affected by the dielectric constant of the solvents. In contrast, the emission peaks of the PL spectra drastically red-shifted from cyclohexane

• -type compound (λPL = 521 nm for POZ-DBPHZ) in cyclohexane. These data indicate that the effective length of π-conjugation is not affected by the number of donors, probably due to the right D–A dihedral angle for both compounds in the ground state. In contrary, the slight blue-shift of the PL spectra of

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• and hexameric capsule A (16·8H2O) Compound 1 (500 mg) was triturated with cyclohexane (10 mL) and the latter was removed under vacuum with gentle heating in order to remove the azeotropic mixture of water/cyclohexane. The treatment with cyclohexane was repeated two more times. The solid product was

• left under high vacuum for 20 h to remove traces of cyclohexane. A mother solution of 1 (0.27 mmol, 6 equiv with respect to the hexameric capsule, 45 mM) was prepared with 6 mL of chloroform-d previously passed on basic alumina which provide sufficiently dry solvent. To favor dissolution the mixture

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• realised by increasing the flow rate of the thiosulphate solution to remove sufficient DMSO in view of satisfactory separation being achieved. Due to the high polarity of the reaction mixture, moderately non-polar chromatographic conditions were required (3% EtOAc, 97% cyclohexane at start), with a

Asymmetric organocatalytic Michael addition of cyclopentane-1,2-dione to alkylidene oxindole

• Estelle Silm,
• Ivar Järving and
• Tõnis Kanger

Beilstein J. Org. Chem. 2022, 18, 167–173, doi:10.3762/bjoc.18.18

• molecular complexity. There are many examples of the organocatalytic synthesis of fused cycles starting from the cyclohexane-1,3-dione. For example, Rueping et al. demonstrated that the cyclohexane-1,3-dione undergoes a cascade reaction with α,β-unsaturated aldehydes [4] and they later employed the method

Iron-catalyzed domino coupling reactions of π-systems

• Austin Pounder and
• William Tam

Beilstein J. Org. Chem. 2021, 17, 2848–2893, doi:10.3762/bjoc.17.196

• observed. The efficiency of the reaction seems to be dependent on the deprotonation of the α-position of the olefinic malonate species. The authors noted decarbonylated products were obtained when cyclohexane carboxaldehyde and pivaldehyde were applied, consistent with the stability of the generated acyl

Synthesis and investigation on optical and electrochemical properties of 2,4-diaryl-9-chloro-5,6,7,8-tetrahydroacridines

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 2450–2461, doi:10.3762/bjoc.17.162

• and, as expected, the cyclohexane ring is not involved. In all cases, the electron densities of HOMO were localized in the π-bonding orbitals between the carbon backbone of the quinoline ring and its two external phenyls. The LUMO electron densities were mainly located in the π* antibonding orbitals

• visualize the region of the attractive and repulsive potential, respectively. For the phenyl-substituted derivative 4a, the blue-colored surface, located mainly at the cyclohexane ring, visualizes the electron deficiency (high electrostatic potential). The red regions, localized essentially at the nitrogen

Synthesis of 5-arylacetylenyl-1,2,4-oxadiazoles and their transformations under superelectrophilic activation conditions

• Andrey I. Puzanov,
• Dmitry S. Ryabukhin,
• Anna S. Zalivatskaya,
• Dmitriy N. Zakusilo,
• Darya S. Mikson,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2021, 17, 2417–2424, doi:10.3762/bjoc.17.158

• in the same reaction in TfOH (compare entry 3 in Table 2 with data shown in Scheme 5). Thus, among the tested acidic reagents, TfOH showed better results for the hydroarylation of compounds 3. Additionally, the reaction of oxadiazole 3a with benzene in TfOH (rt, 1 h) in the presence of cyclohexane

Synthesis of O⁶-alkylated preQ₁ derivatives

• Laurin Flemmich,
• Sarah Moreno and
• Ronald Micura

Beilstein J. Org. Chem. 2021, 17, 2295–2301, doi:10.3762/bjoc.17.147

• combined organic layers were washed with brine and dried over magnesium sulfate. The solvents were removed and the remaining crude product was purified by flash column chromatography on silica gel (10–30% ethyl acetate in cyclohexane) to give 1.00 g of compound 4 (79%) as a white foam. TLC: 40% ethyl

• acetate in cyclohexane, Rf = 0.68; 1H NMR (300 MHz, CDCl3) δ 7.32–6.94 (m, 19H, HC(aromatic, DMTr) & HC(8)), 6.83–6.65 (m, 8H, HC(arom, DMTr)), 5.54 (s, 1H, HN(2)), 3.80 & 3.77 (s, 12H, H3CO(DMTr), 3.37 (s, 1H, H3CO(O6) ppm; 13C NMR (101 MHz, CDCl3) δ 162.4 (C(6)), 158.7 & 158.4 & 158.0 (C(aromatic, DMTr

• column chromatography on silica gel (10–25 % ethyl acetate in cyclohexane) to give 823 mg of compound 5 (82%) as a white foam. TLC: 30% ethyl acetate in cyclohexane Rf 0.51; 1H NMR (CDCl3, 400 MHz) δ 9.91 (s, 1H, CHO), 7.49 (s, 1H, HC(8)), 7.29–7.23 (m, 2H, HC(aromatic, DMTr), 7.20–7.11 (m, 6H, HC

Photoredox catalysis in nickel-catalyzed C–H functionalization

• Lusina Mantry,
• Rajaram Maayuri,
• Vikash Kumar and
• Parthasarathy Gandeepan

Beilstein J. Org. Chem. 2021, 17, 2209–2259, doi:10.3762/bjoc.17.143

• . Notably, the photocatalytic conditions proved suitable for the benzylic C(sp3)−H and unactivated alkane cyclohexane C‒H arylations. The catalytic cycle is proposed to involve the oxidative addition of nickel(0) 4-IV into an aryl chloride 8a to form nickel(II) intermediate 4-V (Figure 4) [56]. The SET

• xanthone as the photocatalyst and NiCl2·6H2O as the nickel catalyst can efficiently catalyze the transformation of methylarenes 25 into arylacetic acids 91 under UV light irradiation (Scheme 47). Furthermore, the authors also applied this methodology to functionalize unactivated alkanes such as cyclohexane

Nomimicins B–D, new tetronate-class polyketides from a marine-derived actinomycete of the genus Actinomadura

• Zhiwei Zhang,
• Tao Zhou,
• Taehui Yang,
• Keisuke Fukaya,
• Enjuro Harunari,
• Shun Saito,
• Katsuhisa Yamada,
• Chiaki Imada,
• Daisuke Urabe and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2021, 17, 2194–2202, doi:10.3762/bjoc.17.141

• ). Placement of the oxygenated carbon atom C8 between C7 and C9 and the attachment of the oxygenated methylene carbon atom C26 to C8 were deduced from the HMBC correlations from H7 and H9 to C8 and C26 and from H26 to C7, C8, and C9, thereby establishing a highly oxygenated cyclohexane ring. This six-membered

• (Table 2). A sequence of COSY correlations from the doublet methyl proton H26 to an oxymethine proton H7 via an oxymethine proton H9, together with HMBC correlations from H26 and H8 to C7 and H8 to C6, gave an oxygenated cyclohexane ring with a methyl substitution (Figure 6). COSY correlations were

• extended from H10 to a methylene proton H17, providing a carbon chain containing double bonds at C11/C12 and C15/C16. HMBC correlations from a singlet methyl hydrogen atom H25 to C4, C5, and C13 indicated closure of another cyclohexane ring, and thus a dehydrodecalin core with a side chain at C13 was

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

• the chains on a surface and the intermolecular interaction that occurs, vertical phase separation is suppressed in systems such as polystyrene in cyclohexane, in contrast to free dissolved chains [128]. However, at vanishingly small concentrations, classical brushes always exhibit a behavior

• (like polystyrene in cyclohexane), which always show an UCST. This critical point is usually located in the semi-dilute regime and the brush can contract discontinuously or continuously [114][131]. The more complex dependencies on χ leads to a bilayer-type profile, as has been shown for PNIPAAm [132

Natural products in the predatory defence of the filamentous fungal pathogen Aspergillus fumigatus

• Jana M. Boysen,
• Nauman Saeed and
• Falk Hillmann

Beilstein J. Org. Chem. 2021, 17, 1814–1827, doi:10.3762/bjoc.17.124

• . In A. fumigatus, the fma cluster is located on the sub-telomeric region on chromosome 8 and is comprised of 15 genes. At the cellular level fumagillin is regulated by both cluster specific regulator FumR (FapR) and global regulator LaeA [95]. Fumagillin consists of a cyclohexane ring and

• decatetraenedioic acid connected via an ester bond. There is also a methoxy group, an epoxide and a terpene derived aliphatic chain that contains another epoxide, linked to cyclohexane. These unstable di-epoxides are responsible for the biological activity of fumagillin, which targets the active site of the

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

• ketones, as is illustrated with representative in Scheme 65. In addition, the Takeuchi group reported a spiro-type analogue, (2'S,3R,5'R)-2-fluoro-2'-methylethyl-5'-methyl-2H,4H-spiro[benzo[e][1,2]thiazine-3,1'-cyclohexane]-1,1-dione (28-7a) [94], as their third chiral reagent in this sultam series. As

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• co-workers [50] were the first to test restricting PNA backbone conformation by locking the backbone in a fused cyclohexane ring of either S,S or R,R configuration (chPNA, Figure 4). Both S,S or R,R chPNAs formed weaker complexes with complementary DNA and RNA than unmodified PNA [50]. Later, Kumar

• -derived acbcPNA and cyclopentane-derived acpcPNA formed stable duplexes with matching DNA and RNA, while cyclohexane-derived achcPNA did not form complexes with either DNA or RNA, which was explained by unfavorable torsional angles and conformational rigidity of the cyclohexane backbone [62

2,4-Bis(arylethynyl)-9-chloro-5,6,7,8-tetrahydroacridines: synthesis and photophysical properties

• Najeh Tka,
• Mohamed Adnene Hadj Ayed,
• Mourad Ben Braiek,
• Mahjoub Jabli,
• Noureddine Chaaben,
• Kamel Alimi,
• Stefan Jopp and
• Peter Langer

Beilstein J. Org. Chem. 2021, 17, 1629–1640, doi:10.3762/bjoc.17.115

• prepared products are given in Table 4. For phenylethynyl-substituted product 4a, the blue colored surface, located mainly at the cyclohexane ring, visualizes the electron deficiency. While the red region, localized essentially at the nitrogen atom and its closer ethynyl group, show the electron abundance

Methodologies for the synthesis of quaternary carbon centers via hydroalkylation of unactivated olefins: twenty years of advances

• Thiago S. Silva and
• Fernando Coelho

Beilstein J. Org. Chem. 2021, 17, 1565–1590, doi:10.3762/bjoc.17.112

• carried out between 96 and completely deuterated cyclohexane 96-d12. A considerable decrease in the reaction yield was observed when the reaction was carried out in the presence of radical trapping reagents (Scheme 37B). Based on these observations, the C(sp3)–H homolytic bond cleavage appears to be the

Nitroalkene reduction in deep eutectic solvents promoted by BH₃NH₃

• Chiara Faverio,
• Monica Fiorenza Boselli,
• Patricia Camarero Gonzalez,
• Alessandra Puglisi and
• Maurizio Benaglia

Beilstein J. Org. Chem. 2021, 17, 1041–1047, doi:10.3762/bjoc.17.83

• . Ammonia borane also proved to be an efficient reagent for the reduction of both linear and branched aliphatic nitroolefins, affording the expected products in fair to good yield (Scheme 3). The reduction of (2-nitrovinyl)cyclohexane (5a) afforded product 6a in 60% yield in DES B. Analogously

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

• Dat Phuc Tran,
• Yuki Sato,
• Yuki Yamamoto,
• Shin-ichi Kawaguchi,
• Shintaro Kodama,
• Akihiro Nomoto and
• Akiya Ogawa

Beilstein J. Org. Chem. 2021, 17, 866–872, doi:10.3762/bjoc.17.72

• using a radical initiator such as 1,1'-azobis(cyclohexane-1-carbonitrile) (V-40) (Scheme 1a) [45] or upon photoirradiation (Scheme 1b) [38] yields vic-bis(diphenylphosphino)alkenes in good yields. Unfortunately, this photoinduced reaction of Ph2PPPh2 was not applicable to alkenes [42]. To change the

• (X)PPh2 to unsaturated C–C bonds. The addition of Ph2P(O)PPh2 (1) to 1-octyne (2a). Phosphinylphosphination of various terminal alkynes 2 with 1. aIsolated yields. V-40 = 1,1’-azobis(cyclohexane-1-carbonitrile). bRepeated 2 times. Attempted radical addition to internal alkynes and insight into the

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• the scope of cyclohexane-1,3-dione 2a is limited. On the contrary, dimedone (2d) did not react with N-tosyl-1,2,3-triazole, but reacted with N-mesyl-1,2,3-triazole to form the 5,5-dimethyl-3-oxo-cyclohex-1-en-1-yl methanesulfonate intermediate 4a. The highly substrate-dependent nature of the reaction

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• conformation in radical 20, in which the interactions of the carbonyl group and the cyclohexane ring are minimized, the β-face at the radical center is significantly blocked by the silyloxy group hindering the approach of TEMPO (3), whereas the α-face is free for radical coupling resulting in the formation of

• mmol) was added to a round-bottomed flask containing a stirring bar, which was sealed with a septum, and dried under vacuum by a heat gun. Dry THF (8 mL) and amide 8 (1.0 mmol) were added under argon. The mixture was cooled to 0 °C in an ice/water bath, sec-butyllithium (1.4 M solution in cyclohexane

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

• Anuj Kumar Chhalodia and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

• treated for 24 h at 40 °C. The reaction was quenched by the addition of water and the aqueous phase extracted with ethyl acetate. The extract was dried with MgSO4 and then concentrated in vacuo. The residue was purified by silica column chromatography (cyclohexane/EtOAc 5:1) to give compound 40 (1.80 g

• , 7.56 mmol, 30%) as pale yellow oil. TLC Rf 0.44 (cyclohexane/EtOAc 10:3); IR (diamond-ATR) ν̃: 2998 (w), 2952 (w), 2845 (w), 2256 (w), 1730 (m), 1436 (w), 1354 (w), 1240 (w), 1215(w), 1195 (w), 1171 (w), 1139 (w), 1046 (w), 1017 (w), 979 (w), 907 (w), 822 (w), 726 (m), 648 (w), 435 (w) cm−1; 1H NMR

• water and extracted with ethyl acetate. The extracts were dried with MgSO4 and concentrated in vacuo. The obtained residue was purified by silica gel column chromatography (cyclohexane/EtOAc 5:1) to give compound 26 (0.23 g, 1.20 mmol, 57%). TLC Rf = 0.72 (cyclohexane/EtOAc = 1:1); IR (diamond-ATR) ν̃

Identification of volatiles from six marine Celeribacter strains

• Anuj Kumar Chhalodia,
• Jan Rinkel,
• Dorota Konvalinkova,
• Jörn Petersen and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

• chromatography (cyclohexane/ethyl acetate 1:1) to give 41 as a colorless solid (0.82 g, 3.85 mmol, 64%). Rf 0.60 (cyclohexane/ethyl acetate 5:1; TLC visualized with UV illumination at 366 nm); GC (HP-5MS): I = 1854; IR (diamond-ATR) ν̃: 3060 (s), 2916 (s), 1425 (w), 1310 (s), 1236 (s), 1005 (w), 756 (w), 431 (s

• chromatography (cyclohexane/ethyl acetate 99:1) gave a mixture of stereoisomers (Z)-42 and (E)-42 as pale yellow oil (96 mg, 0.65 mmol, 92%, dr 94:6 by 1H NMR). The product mixture was separated by preparative HPLC to give pure (Z)-42 (73 mg, 0.50 mmol, 70%) and (E)-42 (6 mg, 0.04 mmol, 6%). (Z)-42. Rf 0.74

• (cyclohexane/ethyl acetate 1:1); GC (HP-5MS): I = 1200; IR (diamond-ATR) ν̃: 2982 (w), 2927 (w),1695 (m), 1569 (m), 1434 (w), 1374 (w), 1300 (w), 1266 (w), 1213 (m), 1166 (s), 1095 (w), 1033 (w), 986 (w), 961 (w), 800 (w), 727 (w), 687 (w) cm−1; 1H NMR (700 MHz, CDCl3, 298 K) δ 7.04 (d, J = 10.14 Hz, 1H, CH

Au(III) complexes with tetradentate-cyclam-based ligands

• Ann Christin Reiersølmoen,
• Thomas N. Solvi and
• Anne Fiksdahl

Beilstein J. Org. Chem. 2021, 17, 186–192, doi:10.3762/bjoc.17.18

• in two model reactions. Results and Discussion Synthesis of potential ligands Chiral cyclam derivatives have previously been directly synthesized from (1R,2R)-cyclohexane-1,2-diamine (A) and malonyl dichloride [36], giving 36% yield of the wanted cyclam tetraamide product 2a. Additionally, a

A novel and robust heterogeneous Cu catalyst using modified lignosulfonate as support for the synthesis of nitrogen-containing heterocycles

• Bingbing Lai,
• Meng Ye,
• Ping Liu,
• Minghao Li,
• Rongxian Bai and
• Yanlong Gu

Beilstein J. Org. Chem. 2020, 16, 2888–2902, doi:10.3762/bjoc.16.238

• , the substrate scope of the reaction was subsequently investigated, and it was found that the reaction could tolerate a wide range of functionalities, including fluoro, chloro, iodo, cyclohexane and benzyloxy moieties. Acetophenones with an electron-donating group in the para-position of the aromatic