Naphthalene diimide bis-guanidinio-carbonyl-pyrrole as a pH-switchable threading DNA intercalator

• Poulami Jana,
• Filip Šupljika,
• Carsten Schmuck and
• Ivo Piantanida

Beilstein J. Org. Chem. 2020, 16, 2201–2211, doi:10.3762/bjoc.16.185

• : s, singlet; d, doublet, m, multiplet; br, broad. MALDI–TOF mass spectra were recorded on a Bruker BioTOF III. The UV–vis spectra were recorded on a Varian Cary 100 Bio spectrophotometer and CD spectra on JASCO J815 spectrophotometer at 25 °C using appropriate 1 cm path quartz cuvettes. The

• ZetasizerNano ZS from Malvern equipped with a 4 mW He-Ne laser (633 nm wavelength) at a fixed detector angle of 173° with an avalanche photodiode detector in sodium cacodylate buffer (I = 0.05 M, pH 5.0) at 25 °C in UV-transparent microcuvettes (1 cm) equipped with a stopper. Mixtures of DNA (50 μM) and

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

• (ε = 270 M−1⋅cm−1 at 383 nm) [209][210] reveals a path length of l = 0.74 cm at which distance (from the surface) 90% of the light is absorbed. In comparison, a PRC reaction at the same concentration (c = 5.0 mM) involving the prototypical catalyst [Ru(bpy)3]Cl2 (ε = 11280 M−1⋅cm−1 at 452 nm) gives a

Access to highly substituted oxazoles by the reaction of α-azidochalcone with potassium thiocyanate

• Mysore Bhyrappa Harisha,
• Pandi Dhanalakshmi,
• Rajendran Suresh,
• Raju Ranjith Kumar and
• Shanmugam Muthusubramanian

Beilstein J. Org. Chem. 2020, 16, 2108–2118, doi:10.3762/bjoc.16.178

• points reported in the work are uncorrected. Unless stated otherwise, solvents and chemicals were obtained from commercial sources and used without further purification. Infrared spectra were recorded on a Perkin Elmer instrument with neat sample and only major peaks are reported in cm−1. The 1H and 13C

Muyocopronones A and B: azaphilones from the endophytic fungus Muyocopron laterale

• Ken-ichi Nakashima,
• Junko Tomida,
• Tomoe Tsuboi,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 2100–2107, doi:10.3762/bjoc.16.177

• with a molecular formula of C25H30O7, as confirmed by a protonated molecular ion at m/z 443.2073 in the HRESIMS. The IR spectrum exhibited absorptions corresponding to the hydroxy (νmax 3468 cm−1) and carbonyl (νmax 1717, 1674, and 1633 cm−1) groups. In addition, in the 1H NMR spectrum (Table 1

• , 2963, 2934, 2876, 1717, 1674, 1634, 1553, 1456, 1387, 1335, 1314, 1231, 1177, 1121, 1086, 972, 914, 878 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS (m/z): [M + H]+ calcd for C25H31O7, 443.2064; found, 443.2073. Muyocopronone B (2) Yellow amorphous solid; [α]D22 +73 (c 0.1, MeOH); UV (MeOH) λmax

• (log ε) 218 (4.14), 331 (4.28) nm; ECD (0.02 mg/mL, MeOH) λext (Δε) 219 (−2.80), 253 (+2.10), 275 (−1.99), 351 (+4.19) nm; IR (KBr) νmax: 3480, 2963, 2936, 2876, 1717, 1669, 1634, 1551, 1456, 1373, 1332, 1267, 1231, 1184, 1123, 1088, 970, 914, 878, 735 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS (m

Clustering and curation of electropherograms: an efficient method for analyzing large cohorts of capillary electrophoresis glycomic profiles for bioprocessing operations

• Ian Walsh,
• Matthew S. F. Choo,
• Sim Lyn Chiin,
• Amelia Mak,
• Shi Jie Tay,
• Pauline M. Rudd,
• Yang Yuansheng,
• Andre Choo,
• Ho Ying Swan and
• Terry Nguyen-Khuong

Beilstein J. Org. Chem. 2020, 16, 2087–2099, doi:10.3762/bjoc.16.176

• capillary electrophoresis. The N-glycans were separated using a 5 minute separation across a 30 cm capillary. N-Glycan peaks in the electropherograms were annotated for all 391 electropherograms separately demonstrating that varying culture conditions resulted in significant differences in the

• Capillary electrophoresis of the released and APTS-labelled antibody N-glycans was performed on a CESI8000 CE instrument (Sciex) equipped with a solid state laser-induced fluorescent detector (excitation 488 nm, emission 520 nm). Separations were made across a 20 cm effective length (30 cm total length), 50

• µm i.d. uncoated bare fused capillary, HR-NCHO separation gel buffer (Sciex). The applied electric field strength was 1500 V/cm with the cathode at the injection side and the anode at the detection side (reversed polarity). Samples were electrokinetically injected using 1kV for 5 s. For migration

Naphthalene diimide–amino acid conjugates as novel fluorimetric and CD probes for differentiation between ds-DNA and ds-RNA

• Annike Weißenstein,
• Myroslav O. Vysotsky,
• Ivo Piantanida and
• Frank Würthner

Beilstein J. Org. Chem. 2020, 16, 2032–2045, doi:10.3762/bjoc.16.170

• stability of similar NDI compounds is greater in weakly acidic buffer solution over a longer period of time [24]. Compounds 3a,b, and 5 revealed absorption maxima of 518–540 nm with molar extinction coefficients of nearly 10000 M−1 cm−1 (Figure 2). Further, 3a,b, and 5 show strong fluorescence at 573–602 nm

• , 18H), 2.14 (m, 4H); 13C NMR (DMSO-d6, 101 MHz) 161.1, 160.7, 137.6, 134.1, 127.0, 126.3, 122.5, 63.2, 52.2, 37.7, 21.4; HRMS-ESI+ (methanol, m/z): [M]2+ calcd for C26H32Cl2N4O4, 267.0900; found, 267.0900; UV–vis (MeOH) λ [nm] (ε [M−1 cm−1]) 397 (10300), 377 (10900), 357 (16000). Synthesis of (S)-N,N

• , 53.7, 53.7, 53.6, 53.5, 43.6, 39.0, 38.4, 23.2, 23.1; HRMS-ESI+ (methanol, m/z): [M]2+ calcd for C29H39ClN6O6, 301.1310; found, 301.1317; UV–vis (cacodylate buffer, pH 5.0) λ [nm] (ε [M−1 cm−1]) 519 (9100), 369 (9400), 351 (7500), 333 (5000); fluorescence (cacodylate buffer, pH 5.0, λex = 470 nm): λmax

pH- and concentration-dependent supramolecular self-assembly of a naturally occurring octapeptide

• Goutam Ghosh and
• Gustavo Fernández

Beilstein J. Org. Chem. 2020, 16, 2017–2025, doi:10.3762/bjoc.16.168

• structure (Figure 1a) [54][55][56]. To support the results obtained from CD spectroscopy, FTIR spectroscopy was performed in D2O (pH 7.4). The appearance of two intense peaks at 1629 and 1678 cm−1 in the amide I region (Figure 1b) suggested an intermolecular antiparallel β-sheet arrangement [57][58][59][60

• ]. The band at 1678 cm−1 was the characteristic feature of an antiparallel conformation of the sheet structure or the β-turn structure [61]. To further confirm the β-sheet formation, we performed a ThT fluorescence spectroscopy assay. ThT is a widely used fluorescent dye that is amyloid-specific and can

• between 1800 and 1500 cm−1, with 200 accumulations at a resolution of 0.4 cm−1. CD spectroscopy CD experiments were performed on a JASCO J-1500 spectropolarimeter equipped with a Peltier module as a temperature controller. The experiments were carried out in buffer solutions at different pH values. The

Natural dolomitic limestone-catalyzed synthesis of benzimidazoles, dihydropyrimidinones, and highly substituted pyridines under ultrasound irradiation

• Kumar Godugu,
• Venkata Divya Sri Yadala,
• Mohammad Khaja Mohinuddin Pinjari,
• Trivikram Reddy Gundala,
• Lakshmi Reddy Sanapareddy and
• Chinna Gangi Reddy Nallagondu

Beilstein J. Org. Chem. 2020, 16, 1881–1900, doi:10.3762/bjoc.16.156

• in Figure 3. In the IR spectrum, two distinct vibrational modes of the carbonates, i.e., out-of-plane bending and in-plane bending, were observed at 875 cm−1 (ν2) and 720 cm−1 (ν4), respectively. The bands at 1086 cm−1 and 1424 cm−1 were ascribed to a symmetric stretching vibration (ν1) and an

• asymmetric stretching vibration (ν3) of the carbonate group, respectively. The combined bands of the carbonate group, i.e., ν1 + ν4 and ν1 + ν3 were observed at 1798 and 2524 cm−1, respectively [76][77][81]. The IR bands at 3446 cm−1 (broad) and 1674 cm−1 (sharp) indicated the presence of stretching and

• bending vibrations of water [82]. The impurities aluminium silicate and iron oxides in the NDL were confirmed by IR spectroscopy. The peaks located at 446, 551, 817, 952, 1247, and 1383 cm−1 were attributed to the Si–O bending, Fe–O stretching, Al–O–Si stretching, Si–OH bending, Si–O stretching, and Al–O

One-pot and metal-free synthesis of 3-arylated-4-nitrophenols via polyfunctionalized cyclohexanones from β-nitrostyrenes

• Haruyasu Asahara,
• Minami Hiraishi and
• Nagatoshi Nishiwaki

Beilstein J. Org. Chem. 2020, 16, 1830–1836, doi:10.3762/bjoc.16.150

• , CDCl3, δ) 21.0 (CH3), 42.8 (CH), 44.3 (CH2), 46.0 (CH2), 57.6 (CH3), 78.6 (CH), 93.6 (CH), 126.8 (CH), 130.0 (CH), 133.6 (C), 138.4 (C), 203.1 (C); IR (ATR) vmax: 536, 821, 1091, 1340, 1550, 1718 cm−1; HRESIMS-TOF (m/z): [M + Na]+ calcd for C14H17NO4Na, 286.1050; found, 286.1040. Minor isomer: 1H NMR

One-pot synthesis of oxazolidinones and five-membered cyclic carbonates from epoxides and chlorosulfonyl isocyanate: theoretical evidence for an asynchronous concerted pathway

• Esra Demir,
• Ozlem Sari,
• Yasin Çetinkaya,
• Ufuk Atmaca,
• Safiye Sağ Erdem and
• Murat Çelik

Beilstein J. Org. Chem. 2020, 16, 1805–1819, doi:10.3762/bjoc.16.148

• :5); mp 91–93 °C; (268 mg, yield 40%); 1H NMR (400 MHz, CDCl3, ppm) δ 4.70–4.65 (m, 1H, CH-O), 4.57–4.53 (m, 1H, CH-N), 2.28–0.95 (m, 12H, 6×CH2); 13C NMR (100 MHz, CDCl3, ppm) δ 148.9 (C=O), 80.7 (C-O), 65.7 (C-N), 26.9 (CH2), 25.3 (CH2), 28.4 (CH2), 25.3 (CH2), 24.9 (CH2), 24.2 (CH2); IR (CHCl3, cm

• , cm−1): 2932, 1804, 1460, 1160, 1066, 976; anal. calcd for: C, 71.28; H, 4.98; found: C, 71.43; H, 4.73; HRMS–ESI (m/z): [M + H]+ calcd for C12H10O3+, 202,0624; found, 202,0637. 3a,4,9,9a-Tetrahydro-4,9-methanonaphtho[2,3-d]oxazol-2(3H)-one (9i): Colourless solid, Rf = 0.3 (EtOAc/hexanes, 1:5); mp 133

• (CH2); IR (CHCl3, cm−1): 3340, 2918, 1802, 1647, 1461, 1368, 1166, 1001; anal. calcd for: C, 71.63; H, 5.51; N, 6.96; found: C, 71.48; H, 5.72; N, 6.79; HRMS–ESI (m/z): [M + H]+ calcd for C12H11NO2+, 201,0784; found, 201,0796. 3a-Phenylhexahydrobenzo[d][1,3]dioxol-2-one (8j): Colourless solid, Rf = 0.4

Rearrangement of o-(pivaloylaminomethyl)benzaldehydes: an experimental and computational study

• Csilla Hargitai,
• Györgyi Koványi-Lax,
• Tamás Nagy,
• Péter Ábrányi-Balogh,
• András Dancsó,
• Gábor Tóth,
• Judit Halász,
• Angéla Pandur,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2020, 16, 1636–1648, doi:10.3762/bjoc.16.136

• ). The title compound (517 mg, 51%) was isolated as white solid. Mp 125–126 °C (EtOAc/hexane); IR (KBr): νNH 3344, νCH 3082, νHC=O 1682, νC=O (amide) 1641, νC=C (Ar) 1596, 1494, νasC−O−C 1268, νsC−O−C 1064 cm−1; HRMS (m/z): [M + H]+ calcd for C14H18NO4+ 264.1230; found: 264.1229; anal. calcd for

• according to general procedure I using 1a [2] (1.02 g, 3.88 mmol) and TFA (30 µL, 44 mg, 0.39 mmol). The title compound (135 mg, 13%) was isolated as a white solid. Mp 248–250 °C (EtOAc/hexane); IR (KBr): νNH 3336, νCH 3088, νHC=O 1680, νC=O (amide) 1659, νC=C (Ar) 1614, 1474, νasC−O−C 1257, νsC−O−C 1052 cm

• , νHC=O 1695, νC=O (amide) 1663, νC=C (Ar) 1612, 1527, νasC−O−C 1276, νsC−O−C 1074 cm−1; HRMS (m/z): [M+H]+ calcd for C28H37N2O5+ 481.2697; found: 481.2681; anal. calcd for C28H36N2O5 (480.61): N, 5.83; H, 7.55; C, 69.98%; found: N, 5.87; H, 7.36; C, 69.83%. 1H and 13C spectra are shown on page S19 of

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

• ), 123.5 (s), 126.2 (d), 128.2 (d), 128.9 (d), 136.5 (s), 137.0 (s), 143.6 (s), 147.1 (s), 151.5 (s), 152.6 (s), 154.3 (s), 164.0 (s), 172.1 (s); IR (nujol): νmax = 3196, 3039, 1738, 1727, 1700 cm−1; ESIMS (m/z): [M − Br]+ 570; anal. calcd. for C33H36BrN3O6 (650.56): C, 60.92; H, 5.58; N, 6.46; found: C

• ), 108.1 (d), 110.2 (d), 125.2 (d), 126.0 (d), 127.4 (d), 127.8 (s), 128.0 (d), 128.4 (s), 128.7 (s), 129.1 (s), 138.2 (s), 143.8 (s), 145.7 (s), 146.3 (s), 148.9 (s), 150.1 (s), 152.3 (s); IR (nujol): νmax = 3288, 3129, 1742 cm−1; HRMS–ESI (m/z): [M + H]+: calcd. for C33H38N3O6, 572.2761; found, 572.2814

Antibacterial scalarane from Doriprismatica stellata nudibranchs (Gastropoda, Nudibranchia), egg ribbons, and their dietary sponge Spongia cf. agaricina (Demospongiae, Dictyoceratida)

• Cora Hertzer,
• Stefan Kehraus,
• Nils Böhringer,
• Fontje Kaligis,
• Robert Bara,
• Dirk Erpenbeck,
• Gert Wörheide,
• Till F. Schäberle,
• Heike Wägele and
• Gabriele M. König

Beilstein J. Org. Chem. 2020, 16, 1596–1605, doi:10.3762/bjoc.16.132

• together with the 13C NMR data, giving evidence for one C–C and two C–O double bonds, thus suggested a structure with six rings. The presence of a hydroxy group and ester functionalities was deduced from characteristic IR absorptions at 3416, 1732 and 1234 cm−1 (Supporting Information File 1) [39][40][53

• ) vmax: 3416, 2922, 2861, 1732, 1234 cm−1; 1H and 13C NMR (Table 1); HRAPCIMS (m/z): [M + H]+ calcd. for C29H43O6, 487.3060; found, 487.3054. Doriprismatica stellata nudibranch, egg ribbon, and Spongia cf. agaricina specimen. The structurally new 12-deacetoxy-4-demethyl-11,24-diacetoxy-3,4

Mechanochemical green synthesis of hyper-crosslinked cyclodextrin polymers

• Alberto Rubin Pedrazzo,
• Fabrizio Caldera,
• Marco Zanetti,
• Silvia Lucia Appleton,
• Nilesh Kumar Dhakar and
• Francesco Trotta

Beilstein J. Org. Chem. 2020, 16, 1554–1563, doi:10.3762/bjoc.16.127

• comparison of the FTIR spectra after 4 h treatment in water at 40 °C. The FTIR spectra of βNS-CDI 1:4 obtained through different synthetic approaches, with and without solvent, exhibited a band at around 1750 cm−1 due to the carbonyl group of the carbonate bond. Even after hours of treatment in H2O at 40 °C

• . The band of interest at around 1750 cm−1 assignable to the carbonyl group of the carbonate bond, was visible in all samples, even after treating for hours in H2O at 40 °C. Thermogravimetric analysis of β-CD-based carbonate nanosponges, obtained through solution (DMF) and mechanochemical (ball mill

4-Hydroxy-3-methyl-2(1H)-quinolone, originally discovered from a Brassicaceae plant, produced by a soil bacterium of the genus Burkholderia sp.: determination of a preferred tautomer and antioxidant activity

• Dandan Li,
• Naoya Oku,
• Yukiko Shinozaki,
• Yoichi Kurokawa and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1489–1494, doi:10.3762/bjoc.16.124

• (5.2 mg) with sufficient purity for structure characterization. The molecular formula of 1 was determined to be C10H9NO2 based on a sodium adduct molecular ion peak at m/z 198.0525 observed by a HRESITOFMS measurement (calcd 198.0526). The broad IR absorption band around 3100 cm−1 and an intense peak

• at 1600 cm−1 indicated the existence of hydroxy and aromatic groups, respectively. The 1H and 13C NMR spectra in DMSO-d6 displayed 6 and 10 resonances, respectively, and by combining with the results of 1H,1H coupling constants and COSY and HSQC spectroscopic analysis, following 8 molecular pieces

• MeCN/0.1% HCOOH mixed in ratios of 2:8, 3:7, 4:6, 5:5, 6:4, 7:3, and 8:2, respectively. A fraction eluted by 30% MeCN was evaporated to provide 69.4 mg of a solid, which was purified by HPLC on an ODS column (Cosmosil AR-II, 1 × 25 cm) eluted with 16% MeCN containing 0.1% HCO2H at a flow rate of 4 mL

Disposable cartridge concept for the on-demand synthesis of turbo Grignards, Knochel–Hauser amides, and magnesium alkoxides

• Mateo Berton,
• Kevin Sheehan,
• Andrea Adamo and
• D. Tyler McQuade

Beilstein J. Org. Chem. 2020, 16, 1343–1356, doi:10.3762/bjoc.16.115

• solution of starting material and LiCl, a bicomponent packed-bed column was assembled. First, ≈4.5 cm of the Omnifit column was filled with magnesium (chips/powder, 1:1) and the upper ≈4.5 cm with anhydrous lithium chloride (Figure 5). The two components were separated by fiberglass previously dried at 120

Synthesis of 3-substituted isoxazolidin-4-ols using hydroboration–oxidation reactions of 4,5-unsubstituted 2,3-dihydroisoxazoles

• Lívia Dikošová,
• Júlia Laceková,
• Ondrej Záborský and
• Róbert Fischer

Beilstein J. Org. Chem. 2020, 16, 1313–1319, doi:10.3762/bjoc.16.112

• , 527 cm−1; 1H NMR (600 MHz, CDCl3) δ 2.44 (bs, 1H, OH), 3.66 (d, J = 4.7 Hz, 1H, H-3), 3.81 (dd, J = 2.6, 9.3 Hz, 1H, H-5a), 3.82 (d, J = 14.2 Hz, 1H, PhCH2), 3.98 (d, J = 14.2 Hz, 1H, PhCH2), 4.11 (dd, J = 6.1, 9.3 Hz, 1H, H-5b), 4.48 (ddd, J = 2.6, 4.8, 6.1 Hz, 1H, H-4), 7.21–7.43 (m, 10H, H-Ph); 13C

• isoxazolidin-4-one 9a (305 mg, 1.20 mmol, 68%) as yellowish waxy solid that gradually decomposed over time. mp 35–38 °C; Rf 0.61 (n-hexane/EtOAc, 1:1); IR (ATR) νmax: 3032, 2871, 2814, 1770, 1495, 1454, 1123, 1048, 737, 695, 615, 545, 470 cm−1; 1H NMR (300 MHz, CDCl3) δ 3.97 (s, 1H, H-3), 3.98 (d, J = 14.3 Hz

• give the isoxazolidinol 10a (215 mg, 0.84 mmol, 76%) as colorless oil. Rf 0.41 (n-hexane/EtOAc, 1:1); IR (ATR) νmax: 3421, 3028, 2924, 2868, 1495, 1454, 1107, 1028, 749, 696, 599, 531 cm−1; 1H NMR (600 MHz, CDCl3) δ 1.65 (bs, 1H, OH), 3.70 (d, J = 14.4 Hz, 1H, PhCH2), 3.79 (d, J = 5.5 Hz, 1H, H-3

Ferrocenyl-substituted tetrahydrothiophenes via formal [3 + 2]-cycloaddition reactions of ferrocenyl thioketones with donor–acceptor cyclopropanes

• Grzegorz Mlostoń,
• Mateusz Kowalczyk,
• André U. Augustin,
• Peter G. Jones and
• Daniel B. Werz

Beilstein J. Org. Chem. 2020, 16, 1288–1295, doi:10.3762/bjoc.16.109

• , 73.7 (for 9 HC(Fc)), 97.0 (C(Fc)), 126.6, 127.1, 127.9, 128.0, 128.8, 129.0 (for 10 arom. HC), 138.9, 144.2 (2 arom. C), 169.0, 170.3 (2 C=O); IR (cm−1) ν: 1737 brs (2C=O), 1492 m, 1444 m, 1429 m, 1258 m, 1239 s, 1073 m, 814 m, 760 m, 697 vs, 497 vs; Anal. calcd for C30H28FeO4S (540.45): C, 66.67; H

• C=O); IR (cm−1) ν: 1727 brs (2C=O), 1431 m, 1259 s, 1164 s, 1107 m, 1000 m, 818 s, 760 m, 696 s, 479 vs; anal. calcd for C34H32Fe2O4S (648.37): C, 62.98; H, 4.97; S, 4.94; found: C, 62.68; H, 4.93; S, 4.88. Dimethyl 2-ferrocenyl-5-phenyl-2-(naphth-2-yl)tetrahydrothiophene-3,3-di-carboxylate (cis-9c

• arom. HC), 132.1, 132.8, 138.8, 141.8 (4 arom. C), 168.9, 170.3 (2 C=O); IR (cm−1) ν: 1738 brs (2C=O), 1429 m, 1239 s, 1215 s, 1170 m, 1053 m, 810 s, 758 m, 704 s, 480 vs; anal. calcd for C34H30FeO4S (590.51): C, 69.15; H, 5.12; S, 5.43; found: C, 67.16; H, 5.01; S, 5.47. Dimethyl 2-ferrocenyl-2-phenyl

Activated carbon as catalyst support: precursors, preparation, modification and characterization

• Melanie Iwanow,
• Tobias Gärtner,
• Volker Sieber and
• Burkhard König

Beilstein J. Org. Chem. 2020, 16, 1188–1202, doi:10.3762/bjoc.16.104

• structures [65]. The spectra are usually recorded between 4000 cm−1 and 400 cm−1. The most characteristic bands of functional groups on the surface of the activated carbons are ≈3500, 1700, 1610, 1420 and 1140 cm−1 which indicate free or intermolecular bonded OH groups, carbonyl (C=O) stretching vibrations

• N-containing functional groups on the surface of ammonia treated activated carbon samples such as bands of N–H stretching vibrations (3376–3294 cm−1), cyclic amides (1665–1641 cm−1), nitriles (2251–2265 cm−1) and pyridine-like functionalities (1334–1330 cm−1). Simultaneously, a diminished band at

• about 1700 cm−1 was found due to the decomposition of the oxygen-containing surface groups at higher treatment temperatures [115]. The group of Moreno-Castilla investigated the treatment with oxidizing agents (H2O2 or HNO3) or activating reagents by FTIR. They found that the amount of oxygen fixed on

Development of fluorinated benzils and bisbenzils as room-temperature phosphorescent molecules

• Shigeyuki Yamada,
• Takuya Higashida,
• Yizhou Wang,
• Masato Morita,
• Takuya Hosokai,
• Kaveendra Maduwantha,
• Kaveenga Rasika Koswattage and
• Tsutomu Konno

Beilstein J. Org. Chem. 2020, 16, 1154–1162, doi:10.3762/bjoc.16.102

• benzil 2a in toluene absorbs UV light at 315 and 295 nm with molar extinction coefficients (ε) of 36500 and 28700 M−1·cm−1, respectively (Figure 4A). Similarly, the toluene solution of the fluorinated benzil with a hexyloxy chain (2b) absorbs UV light at 314 (ε: 30400 M−1·cm−1) and 293 nm (ε: 40500 M−1

• ·cm−1) (Figure 4B). Both 2a and 2b exhibit weak absorption at around 400 nm (ε: ≈170 M−1·cm−1). As shown in Figure 4C–E, on the other hand, the bisbenzil derivatives 3a–c show an absorption band at 290 nm (ε: 29600–51200 M−1·cm−1) as the major signal, together with a quite weak absorption band at 402

• –405 nm (ε: 180–260 M−1·cm−1). To gain more information about the slight difference between the absorption behaviors of the benzil and bisbenzil derivatives, DFT and time-dependent DFT (TD-DFT) calculations at the CAM-B3LYP/6-31+G(d) level of theory were performed for fluorinated benzil 2a and

Synthesis and properties of quinazoline-based versatile exciplex-forming compounds

• Rasa Keruckiene,
• Simona Vekteryte,
• Ervinas Urbonas,
• Matas Guzauskas,
• Eigirdas Skuodis,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 1142–1153, doi:10.3762/bjoc.16.101

• (in parentheses: multiplicity, coupling constant, and integration). IR spectra were recorded with a Vertex 70 Bruker spectrometer equipped with an ATR attachment with a diamond crystal over frequencies of 600–3500 cm−1 with a resolution of 5 cm−1 over 32 scans. The IR spectra were presented as a

• function of transparency (T) expressed in percent (%) against the wavenumber (v) expressed in cm−1. Elemental analysis was performed with an Exeter Analytical CE-440 elemental analyzer. Mass spectra were obtained with a Waters ZQ 2000 mass spectrometer. The introduction of the sample into the ion source

• , CDCl3) δ 8.28–8.22 (m, 2H), 8.16 (d, J = 9.1 Hz, 2H), 7.96–7.84 (m, 3H), 7.61 (dd, J = 9.5, 6.6 Hz, 4H), 6.94 (tt, J = 8.6, 2.4 Hz, 1H); 13C NMR (101 MHz, CDCl3) δ 165.01, 161.01, 156.01, 149.40, 134.00, 133.90, 133.10, 129.24, 128.8, 128.66, 127.76, 127.4, 127.14, 104.70; ATR-IR (solid state on ATR, cm

Synthesis of esters of diaminotruxillic bis-amino acids by Pd-mediated photocycloaddition of analogs of the Kaede protein chromophore

• Esteban P. Urriolabeitia,
• Pablo Sánchez,
• Alexandra Pop,
• Cristian Silvestru,
• Eduardo Laga,
• Ana I. Jiménez and
• Carlos Cativiela

Beilstein J. Org. Chem. 2020, 16, 1111–1123, doi:10.3762/bjoc.16.98

• (PM100D, Thorlabs) was 1 W. The PCB (dimensions: 7 × 6 cm) and the flask were placed inside a custom-built set-up for fixing the light source and the sample container, and dissipating the excess heat. A concave mirror was placed in front of the PCB to maximize the light that irradiated the balloon. Light

• ), 130.1 (d, 4JCF = 3.4 Hz, C, C6H4F), 129.9 (d, 5JCF = 1.6 Hz, =CH, Cvin), 129.3 (s, CH, Cm, C6H5), 128.3 (s, CH, Co, C6H5), 116.3 (d, 2JCF = 22.3 Hz, CH, C6H4F), 113.4 (s, CH, =Cα); 19F NMR (282.40 MHz, CDCl3) δ −106.71 (tt, J = 8.5, 5.6 Hz); HRMS (ESI+) m/z: [M + Na]+: calcd for C18H12FNNaO2, 316.0750

• ; found, 316.0719; IR (ν, cm−1): 1782 (νC=O), 1655 (νC=N). General synthesis of the ortho-palladated derivatives 3a–f, 3h–j In a similar manner as described in [30], to a solution of the oxazolones 2a–j in CF3CO2H (8 mL), the stoichiometric amount of Pd(OAc)2 (1:1 molar ratio) was added. The resulting

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• strain 3-44-a(19)T (AB302183). Fermentation Strain RD062863 growing on double-diluted ISP2 agar medium consisting of yeast extract 0.2%, malt extract 0.5%, glucose 0.2%, and agar 2% (pH 7.3) was inoculated into test tubes (inner diameter, 15 mm; length 16.5 cm) each containing 5 mL of YG seed medium

• (0.48) nm; ECD (1 × 10−4 M, MeCN) λext (Δε) 217.0 (+17.3), 235.5 (−10.8) nm; IR (ATR) νmax 3328, 1722 cm−1; for 1H and 13C NMR data, see Table 1; HRESITOFMS (m/z): [M − H]− calcd for C27H27N4O6, 503.1931; found, 503.1936. Pseudosporamicin A (2): white amorphous powder; [α]D25 −23 (c 0.50, MeOH); UV

• (MeOH) λmax (log ε) 218 (4.65) nm; IR (ATR) νmax 3366, 1713, 1635 cm−1; for 1H and 13C NMR data, see Table 2; HRESITOFMS (m/z) [M − H]− calcd for C47H75O12, 831.5259; found, 831.5255. Pseudosporamicin B (3): white amorphous powder; [α]D25 −9.3 (c 0.50, MeOH); UV (MeOH) λmax (log ε) 223 (4.56) nm; IR

Synthesis of novel multifunctional carbazole-based molecules and their thermal, electrochemical and optical properties

• Nuray Altinolcek,
• Ahmet Battal,
• Mustafa Tavasli,
• William J. Peveler,
• Holly A. Yu and
• Peter J. Skabara

Beilstein J. Org. Chem. 2020, 16, 1066–1074, doi:10.3762/bjoc.16.93

• system. The IR spectra were obtained (4000–400 cm−1) using a Shimadzu IRAffinity-1S Fourier transform infrared spectrophotometer. The mass spectra were obtained by Bruker microTOFq mass spectrometers to obtain low- and high-resolution spectra using electron ionisation (EI) or electrospray ionisation (ESI

• , J = 7.7 Hz, 3H), 1.47–1.37 (m, 3H), 1.37–1.19 (m, 6H), 0.87 (t, J = 7.1 Hz, 4H); 13C NMR (600 MHz, CDCI3) δ (ppm) 192.0, 160.0, 150.9, 142.5, 141.5, 141.0, 129.1, 126.1, 124.8, 123.4, 123.1, 120.6, 119.4, 119.3, 119.3, 118.6, 109.0, 108.9, 43.3, 31.6, 29.0, 27.0, 22.5, 14.0; FTIR (cm−1): 2956, 2924

• , 119.9, 119.5, 109.1, 109.1, 43.3, 31.5, 28.9, 26.9, 22.5, 14.0; FTIR (cm−1): 2950, 2924, 2866, 2852, 2822, 2786, 2724, 1696, anal. calcd for: C24H24N2O, C: 80.87, H: 6.79, N: 7.86; found C: 80.88, H: 6.91, N: 7.12; MS (EI+, m/z): 356 (M+, 73%), 285 ([M − C5H11]+, 100%), HRMS (FAB+, m/z): calculated for

Aryl-substituted acridanes as hosts for TADF-based OLEDs

• Naveen Masimukku,
• Dalius Gudeika,
• Oleksandr Bezvikonnyi,
• Ihor Syvorotka,
• Rasa Keruckiene,
• Dmytro Volyniuk and
• Juozas V. Grazulevicius

Beilstein J. Org. Chem. 2020, 16, 989–1000, doi:10.3762/bjoc.16.88

• characterized by triplet energies higher than 2.5 eV. The layer of 10-ethyl-9,9-dimethyl-2,7-di(naphthalen-1-yl)-9,10-dihydroacridine demonstrated hole mobilities reaching10−3 cm2/V·s at electric fields higher then ca. 2.5 × 105 V/cm. The selected compounds were used as hosts in electroluminescent devices which

• according to the Poole–Frenkel model µ = µ0 exp(β·E0.5), where µ and µ0 are respectively hole and field-free mobilities, β is the Poole–Frenkel constant, and E is the electric field [31]. The values of hole mobility in the layers of 4 exceeded 10−3 cm2/V·s at electric fields higher than ca. 2.5 × 105 V/cm

• photoelectron emission spectroscopy. For one compound, the hole mobility exceeded 10−3 cm2/V·s at electric fields higher than 2.5 × 105 V/cm. The selected compounds demonstrated similar host performances in electroluminescent devices with low turn-on voltages of 3.2–3.6 V and maximum external quantum