Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• superposition of the spectra recorded for Q[8] (a) and CPE (b), and there was no interaction. When comparing (c) and (d), the C–H stretching vibration peak was observed at 3100 cm−1 and the C=C skeleton vibration peaks of the benzene ring of CPE were observed at 1603, 1520 and 1413 cm−1; the bending vibration

• peaks of the O–H bonds were observed at 1106 and 1066 cm−1. The nitro-symmetric tensile vibration peak observed at 1503 cm−1 and the nitro-asymmetric tensile vibration peak at 1320 cm−1 disappeared in the spectrum (d). At the same time, the fingerprint region peak of the benzene ring observed from 500

• to 900 cm−1 disappeared or weakened. Therefore, it can be inferred that CPE interacts with Q[8]. The effect of Q[8] on the properties of CPE Stability analysis The stability of CPE and CPE@Q[8] in artificial gastrointestinal juice was investigated using UV–is spectroscopy. Figure 7A shows the

Biological properties and conformational studies of amphiphilic Pd(II) and Ni(II) complexes bearing functionalized aroylaminocarbo-N-thioylpyrrolinate units

• Samet Poyraz,
• Samet Belveren,
• Sabriye Aydınoğlu,
• Mahmut Ulger,
• Abel de Cózar,
• Maria de Gracia Retamosa,
• Jose M. Sansano and
• H. Ali Döndaş

Beilstein J. Org. Chem. 2021, 17, 2812–2821, doi:10.3762/bjoc.17.192

• the IR spectra (recorded using a Nicolet 510 P-FT) are listed and wave numbers are given in cm−1. Nuclear magnetic resonance spectra and decoupling experiments were determined at 250 MHz on a Q.E 300 instrument, at 300 MHz on a Bruker Avance AC-300 and at 500 MHz on a Bruker AM500 spectrometer as

• ), 129.4 (2C), 129,2 (4C), 128.8 (2C), 128.2 (4C), 127.7 (2C), 127.5 (2C), 73.1 (2C), 63.1 (2C), 52.9 (2C), 51.5 (2C), 45.5 (2C), 40.2 (2C), 36.4 (2C); IR (cm−1) νmax: 3027, 2948, 1738, 1587, 1492, 1398, 1359, 1244, 1101, 1023, 704; ESIMS m/z: 1234 (21), 1233 (30), 1232 (47), 1231 (M+, 64), 1230 (100

• ), 72.8 (2C), 60.6 (2C), 55.8 (2C), 55.1 (2C), 52.7 (2C), 51.5 (2C), 45.8 (2C), 40.4 (2C), 36.8 (2C); IR (cm−1) νmax: 3023, 2947, 1735, 1587, 1496, 1396, 1361, 1268, 1205, 1122, 1024, 703; ESIMS m/z: 1216 (5), 1215 (25), 1214 (M+, 38), 1213 (67), 1212 (100); anal. calcd for C62H66N4NiO14S2: C, 61.3; H

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• VERTEX 70 spectrophotometer with Platinum ATR accessory (diamond crystal) in the 4000–400 cm−1 region. High-resolution mass spectra (HRMS) were obtained for all compounds on a hybrid high-resolution and high-accuracy (5 μL/L) micro Q-TOF mass spectrometer (Bruker Scientific®, Billerica, MA, USA) at the

• 660 nm red light diode laser positioned 2.0 cm from the sample (TheraLase DMC, São Carlos, SP, Brazil) with an average power of 100 mW, during 10 min (irradiation intervals every 30 s). All spectra are provided in Supporting Information File 1 (Figures S8–S17). Synthetic procedures General procedure

• ), 123.36 (q, J = 274.0 Hz, CF3), 121.85 (C-4a), 119.64 (q, J = 5.3 Hz, C-3), 119.29 (C6H4OH), 119.01 (C6H4OH), 117.37 (C6H4OH), 114.75 (t, J = 2.2 Hz, C-5), 25.34 (CH3) ppm; 19F NMR (565 MHz, CDCl3) δ −61,71 (CF3) ppm; FTIR (ATR) ν: 3061 (ν OH), 1627 (ν CH=N), 1118 (ν C-O) cm−1; HRMS–ESI (m/z): [M + H

The ethoxycarbonyl group as both activating and protective group in N-acyl-Pictet–Spengler reactions using methoxystyrenes. A short approach to racemic 1-benzyltetrahydroisoquinoline alkaloids

• Marco Keller,
• Karl Sauvageot-Witzku,
• Franz Geisslinger,
• Nicole Urban,
• Michael Schaefer,
• Karin Bartel and
• Franz Bracher

Beilstein J. Org. Chem. 2021, 17, 2716–2725, doi:10.3762/bjoc.17.183

• Finnigan LTQ FT Ultra Fourier Transform Ion Cyclotron Resonance device at 250 °C for ESI. IR spectra were recorded on a Perkin Elmer FT-IR Paragon 1000 instrument as neat materials. Absorption bands were reported in wave numbers (cm−1), obtained on a ATR PRO450-S accessory (Jasco). Melting points were

N-Sulfinylpyrrolidine-containing ureas and thioureas as bifunctional organocatalysts

• Viera Poláčková,
• Dominika Krištofíková,
• Boglárka Némethová,
• Renata Górová,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2021, 17, 2629–2641, doi:10.3762/bjoc.17.176

• , 1700, 1162 cm−1. 1H NMR (300 MHz, CDCl3) δ 3.98–3.84 (m, 2H); 3.68–3.57 (m, 1H), 3.53–3.35 (m, 2H), 2.13–2.03 (m, 1H), 1.99–1.81 (m, 3H), 1,47 (s, 9H) ppm. (S)-tert-Butyl 2-(isocyanatomethyl)pyrrolidine-1-carboxylate (3b) BTC (0.33 g, 1.11 mmol) was dissolved in dry THF (10 mL) and the solution was

• , 2973, 1685, 1161, 1107, 1038 cm−1; HRMS (m/z): [M + H]+ calcd for C15H29N3O3S2, 364.1723; found, 364.1725; [M + Na]+ calcd, 386.1543; found, 386.1544. (S)-tert-Butyl 2-((3-((S)-tert-butylsulfinyl)thioureido)methyl)pyrrolidine-1-carboxylate ((S,S)-5a) +30.5 (c 0.5, MeOH); 1H NMR (600 MHz, CDCl3) δ 9.22

• , 2973, 1653, 1159, 1237, 1058 cm−1; HRMS (m/z): [M + Na]+ calcd for C15H29N3O3S2, 386.1543; found, 386.1543; [M + H]+ calcd, 364.1729; found, 364.1722. General procedure for the preparation of N-sulfinylurea pre-catalysts (S,R)-5b and ((S,S)-5b) A stirred solution of (R)-tert-butanesulfinamide or (S

In-depth characterization of self-healing polymers based on π–π interactions

• Josefine Meurer,
• Julian Hniopek,
• Johannes Ahner,
• Michael Schmitt,
• Jürgen Popp,
• Stefan Zechel,
• Kalina Peneva and
• Martin D. Hager

Beilstein J. Org. Chem. 2021, 17, 2496–2504, doi:10.3762/bjoc.17.166

• =C (1570–1605 cm−1) and C=O stretching (1640–1710 cm−1) region of the infrared spectra of P1 recorded during heating. These regions are specific to the perylene moieties in the polymers and, therefore, allow a direct observation of the π–π interactions in the polymer. Both the C=C and C=O vibrations

• are sensitive to the electron density in the perylene systems, which changes depending on the strength of π–π interactions [28][29][30]. During heating, the C=C stretching vibrations located at 1578 and 1594 cm−1 show opposite behavior regarding their wavenumber position: While the band at 1578 cm−1

• shifts to slightly higher wavenumbers (indicating more electron density in the perylene rings), the band at 1594 cm−1 shifts to slightly lower frequencies (indicating less electron density in the perylene rings). This seemingly counterintuitive behavior can be explained by the fact that the perylene

Exfoliated black phosphorous-mediated CuAAC chemistry for organic and macromolecular synthesis under white LED and near-IR irradiation

• Azra Kocaarslan,
• Zafer Eroglu,
• Önder Metin and
• Yusuf Yagci

Beilstein J. Org. Chem. 2021, 17, 2477–2487, doi:10.3762/bjoc.17.164

• azide groups decomposed at higher temperature. The IR spectrum of the cross-linked polymer further demonstrates the formation of a triazole ring by the decrease of the azide peak at 2100 cm−1 (Figure 6b). Representative TEM images recorded at different magnifications of the resulting cross-linked

• system equipped with an auto sampler system, a temperature-controlled pump, a column oven, a refractive index (RI) detector, a purge and degasser unit and a TSKgel superhZ2000, 4.6 mm ID × 15 cm × 2cm column. Tetrahydrofuran was used as an eluent at a flow rate of 1.0 mL/min at 40 °C. The refractive index

• ][42][43]. For the synthesis, 500 mg of red phosphorus, 20 mg of Sn and 10 mg of SnI4 were placed into a quartz ampoule with the dimensions of 20 cm length and 1.5 cm width. The air was evacuated by vacuum, and the ampoule was left to dry at least for 30 min under vacuum. The sealed ampoule was placed

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

• methoxy substituent in para-position, gave the highest value of 5770 cm−1. The fluorescence quantum yields of 4a–d were calculated with a comparative method, where quinine sulfate (SQ) in 0.1 M H2SO4 was used as standard [66]. The fluorescence and absorbance spectra for quinine sulfate and product 4b are

• PC spectrophotometer in quartz cuvettes with a path length of 1 cm. Emission spectra were recorded on a Perkin-Elmer LS 50B spectrofluorimeter. Cyclic voltammetry was performed in anhydrous acetonitrile solution containing 0.1 M of tetrabutylammonium tetrafluoroborate (n-Bu4NBF4) as a supporting

Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction

• Ren-Jie Fang,
• Chen Yan,
• Jing Sun,
• Ying Han and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159

• , 125.6, 121.7, 120.7, 120.3, 119.2, 111.3, 21.1; IR (KBr) ν: 2988, 1786, 1734, 1611, 1485, 1456, 1357, 1314, 1185, 1021, 988, 786, 734 cm−1; HRMS–ESI-TOF (m/z): [M + Na]+ calcd for C34H22NaN2O3, 529.1523; found, 529.1512. 2. General procedure for the preparation of carbazoles 6a–n: To a round-bottomed

• , 127.0, 126.9, 126.4, 122.4, 122.0, 121.8, 121.6, 119.6, 108.7, 32.1; IR (KBr) ν: 3057, 3023, 2907, 2360, 2339, 1720, 1605, 1482, 1320, 1267, 1172, 1009, 936, 805, 743, 612, 447 cm−1; HRMS–ESI (m/z): [M + Na]+ calcd for C39H27NO2, 564.1934; found, 564.1926. The crystallographic data of the compounds 3a

Isolation and characterization of new phenolic siderophores with antimicrobial properties from Pseudomonas sp. UIAU-6B

• Emmanuel T. Oluwabusola,
• Olusoji O. Adebisi,
• Fernando Reyes,
• Kojo S. Acquah,
• Mercedes De La Cruz,
• Larry L. Mweetwa,
• Joy E. Rajakulendran,
• Digby F. Warner,
• Deng Hai,
• Rainer Ebel and
• Marcel Jaspars

Beilstein J. Org. Chem. 2021, 17, 2390–2398, doi:10.3762/bjoc.17.156

• −9.5 (c 0.02, MeOH); UV (MeOH) λmax, nm (log ε): 276 (3.23); IR (cm−1) νmax: 3333, 1677 1660, 1538, 1493, 1203, 1138; NMR data, see Table 1; HRESIMS (m/z): [M − 1]− calcd for C11H13N2O4, 237.0880; found, 237.0874, Δ = −2.53 ppm. Pseudomonin B (2): yellowish oil; [α]D25 −13.3 (c 0.05, MeOH); UV (MeOH

• ) λmax, nm (log ε): 297 (3.64); IR (cm−1) νmax: 3137, 1673, 1660; NMR data, see Table 1; HRESIMS (m/z): [M + H]+ calcd for C16H21O4N4, 333.1557; found 333.1561, Δ = 1.20 ppm. Pseudomonin C (3): white amorphous solid; [α]D25 −45.6 (c 0.02, MeOH); UV (MeOH) λmax, nm (log ε): 299 (3.85); IR (cm−1) νmax

• : 3341, 2927, 1670, 1633, 1205; NMR data, see Table 1; HRESIMS (m/z): [M + H]+ calcd for C19H23N2O4, 343.1652; found, 343.1653, Δ = 2.01 ppm. Pseudomobactin A (4): yellow amorphous solid; [α]D25 −17.7 (c 0.05, MeOH); UV (MeOH) λmax, nm (log ε): 260 (3.59), 302 (4.12); IR (cm−1) νmax: 3320, 2930, 1675

Synthesis and antimicrobial activity of 1H-1,2,3-triazole and carboxylate analogues of metronidazole

• Satya Kumar Avula,
• Syed Raza Shah,
• Khdija Al-Hosni,
• Muhammad U. Anwar,
• Rene Csuk,
• Biswanath Das and
• Ahmed Al-Harrasi

Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154

• antifungal activity of all compounds were evaluated by inhibiting the growth of Didymella sp. (Figure 7 and Table 3). The fungal colony after 7 days of control treatment was noted to be 8.6 cm in diameter. Whereas, the growth of the fungal colony was detected maximum, i.e., 8.8 ± 0.2 and 9.0 ± 0.3 cm against

• compound 2 and 3, respectively. However, compound 5e and 7c efficiently inhibited the fungal growth by limiting the colony diameter to 3 ± 0.3 and 3.1 ± 0.2 cm followed equally by compound 7b and compound 5b with 4.1 ± 0.3 and 4.6 ± 0.2 cm, respectively. Compared to control and metronidazole treatments

• , room temperature, 4–5 h, 86–93%. Synthesis of 1H-1,2,3-triazole compounds 5a–i. Synthesis of carboxylate compounds 7a–e. Antifungal zone (cm) of metronidazole derivatives 5a–i and 7a–e. Antibacterial activities (OD 600 nm) of metronidazole derivatives 5a–i and 7a–e.a Supporting Information Supporting

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• -tetrahydrodehydrodiconiferyl alcohol 4-O-α-ʟ-rhamnopyranoside and was named aleuritiside C. Compound 15 was obtained as a yellow gum. The [M + Na]+ ion peak at m/z 411.1260 (calcd for 411.1267) in the HRESIMS corresponded to the molecular formula C17H24O10. The IR spectrum exhibited signals at 3321 cm−1 and 1675 cm−1

• semipreparative HPLC (30% aq. CH3CN) to yield compound 9 (10 mg). Aleuritiside A (1). Colorless gum; [α]D25 −12.1 (c 0.05, MeOH); IR (KBr) νmax: 3360, 2943, 2830, 1448, 1033 cm−1; UV (MeOH) λmax, nm (log ε): 282 (1.40), 228 (3.61); ECD (MeOH) λmax, nm (Δε): 292 (5.3), 248 (3.3), 221 (−2.1); 1H and 13C NMR data

• , see Table 1; positive HRMS–FAB (m/z): [M + Na]+ calcd for C25H32O11Na, 531.1837; found, 531.1844. Aleuritiside B (2). Colorless gum; [α]D25 −15.4 (c 0.05, MeOH); IR (KBr) νmax: 3355, 2945, 2832, 1453, 1033 cm−1; UV (MeOH) λmax, nm (log ε): 283 (1.31), 230 (3.53); ECD (MeOH) λmax, nm (Δε): 276 (−3.3

(Phenylamino)pyrimidine-1,2,3-triazole derivatives as analogs of imatinib: searching for novel compounds against chronic myeloid leukemia

• Luiz Claudio Ferreira Pimentel,
• Lucas Villas Boas Hoelz,
• Henayle Fernandes Canzian,
• Frederico Silva Castelo Branco,
• Andressa Paula de Oliveira,
• Vinicius Rangel Campos,
• Floriano Paes Silva Júnior,
• Rafael Ferreira Dantas,
• Jackson Antônio Lamounier Camargos Resende,
• Anna Claudia Cunha,
• Nubia Boechat and
• Mônica Macedo Bastos

Beilstein J. Org. Chem. 2021, 17, 2260–2269, doi:10.3762/bjoc.17.144

• obtained from the nucleophilic substitution reaction of intermediate 8 in 85% yield. The 1H and 13C NMR spectra of compounds 8 and 9 were similar, but in the IR spectrum of intermediate 9, it was possible to observe the characteristic stretching of the azide group at 2103 cm−1. The 1,3-dipolar

• products 1a,b, and 2a–j, respectively, with 30–84% yields. This last step was adapted from a method already described in the literature [31]. The formation of compounds 1a,b and 2a–j was observed by the disappearance of the characteristic stretching of the azide groups at 2107 and 2103 cm−1 in the IR

• spectra, which are present in intermediates 5 and 9, respectively, and compounds 2a–j showed carbonyl absorption at 1671–1660 cm−1 (amide). 1H NMR spectrum analysis showed the appearance of a single signal at 8.52 ppm and between 8.61–7.79 ppm referring to the hydrogen of the 1,2,3-triazole (C-5) for

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

• ). Nomimicin B (1) Colorless amorphous solid; [α]D23 −29 (c 0.10, MeOH); UV (MeOH) λmax (log ε) 246 (3.83), 293 nm (3.71); ECD (c 9.5 × 10−5, MeOH) λext (Δε) 208 (−5.27), 247 (+3.72), 294 nm (−1.24); IR νmax: 3360, 2965, 1755, 1619, 1408, 1088, 998 cm−1; see Table 1 for 1H and 13C NMR data; HRESITOFMS (m/z

• , 1007 cm−1; see Table 1 for 1H and 13C NMR data; HRESITOFMS (m/z): [M + Na]+ calcd for C30H40O7Na, 535.2666; found, 535.2665. Nomimicin D (3) Colorless amorphous solid; [α]D23 −70 (c 0.10. MeOH); UV (MeOH) λmax (log ε) 243 (3.99), 302 nm (3.54); IR νmax: 3380, 2963, 1723, 1619, 1413, 1258, 1010 cm−1

• (Δε) 208 (−4.98), 244 (+3.85), 298 nm (−1.09); IR νmax: 3348, 2938, 1735, 1620, 1435, 997 cm−1; HRESITOFMS (m/z): [M + Na]+ calcd for C30H40O6Na, 519.2717; found, 519.2722. ECD calculations The conformational sampling of structure 4a was performed by applying 100,000 steps of the Monte Carlo Multiple

Facile and innovative catalytic protocol for intramolecular Friedel–Crafts cyclization of Morita–Baylis–Hillman adducts: Synergistic combination of chiral (salen)chromium(III)/BF₃·OEt₂ catalysis

• Karthikeyan Soundararajan,
• Helen Ratna Monica Jeyarajan,
• Raju Subimol Kamarajapurathu and
• Karthik Krishna Kumar Ayyanoth

Beilstein J. Org. Chem. 2021, 17, 2186–2193, doi:10.3762/bjoc.17.140

• filtration, the solvent was removed under reduced pressure and the crude product was purified on silica gel (using hexane/EtOAc) to afford the desired product 6a as a white solid (81%). Methyl 1H-indene-2-carboxylate (6a): Yield: 160 mg (81%); white solid; mp 85–87 °C; IR (cm−1): 3062, 2953, 2884, 1947, 1735

• mg (67%); off-white solid; mp 194–196 °C; IR (cm−1): 1674, 1652, 1582, 1568, 1454, 1278, 1117; 1H NMR (CDCl3, 400 MHz) δH 8.31–7.46 (m, 5H, Aro-H), 7.14 (s, 1H, N=CH), 4.56–4.50 (t, J = 8 Hz, 2H, CO-CH2), 2.84–2.79 (t, J = 8 Hz, 2H, N-CH2); 13C NMR (CDCl3, 100 MHz) δC 185.12 (1C, C=O), 133.02–128.83

• purified by column chromatography to afford the corresponding [3 + 2] cycloaddition product 8a in 61% yield. Compound (8a): Yield: 192 mg (61%); yellowish oil; IR (cm−1): 2972, 2254, 1954, 1562, 1671, 1455, 1245; 1H NMR (CDCl3, 400 MHz) δH 7.80–7.06 (m, 9H, Aro-H), 5.90 (s, 1H, HC-N-CO), 4.36–4.21 (m, 2H

Chemical syntheses and salient features of azulene-containing homo- and copolymers

• Vijayendra S. Shetti

Beilstein J. Org. Chem. 2021, 17, 2164–2185, doi:10.3762/bjoc.17.139

• ) resulting in a relatively small electron repulsion energy in the first singlet excited state and thus, a small HOMO–LUMO (S0–S1) gap compared to naphthalene. The large energy gap between its S2 and S1 states (up to 15000 cm−1) makes internal conversion less probable, making azulene emit from the S2 state

• peak around 690 nm supporting the oligomeric nature of the soluble fraction. The thermogravimetric analysis (TG) showed that PAZ-I2 was thermally more stable than PAZ-Br2. The electrical conductivity of PAZ-Br2 (5 × 10−3 S/cm) was far too superior compared to PAZ-I2 (10−6 S/cm). In 1997, Kihara

• polyazulene 3 or 3’ was soluble in various organic solvents such as toluene, dichloromethane, tetrahydrofuran (THF), and N,N’-dimethylformamide (DMF). The ‘true polyazulene’ exhibited the conductivity of 5.38 × 10−8 S/cm, which was increased to 8.16 × 10−3 S/cm upon exposure to iodine atmosphere, presumably

An initiator- and catalyst-free hydrogel coating process for 3D printed medical-grade poly(ε-caprolactone)

• Jochen Löblein,
• Thomas Lorson,
• Miriam Komma,
• Tobias Kielholz,
• Maike Windbergs,
• Paul D. Dalton and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2021, 17, 2095–2101, doi:10.3762/bjoc.17.136

• min (Figure 1E) and the intensity of the blue coloration is proportional to reaction time resulting in a complete coating of the PCL fibers after 30 min. The distance between the UV source and the scaffold was varied from 0.5 cm, 1.0 cm, and 1.5 cm (Figure 1F) and, as the intensity decreases inversely

• . However, the authors used UV-C light with an intensity of 0.024 W/cm2 compared to UV-A light with a calculated intensity of 0.079 W/cm2 at a distance of 1.0 cm used in the present study. After SIPGP, a thin, heterogeneous material can be seen spanning large proportion of the pores (Figure 2A and Figure 2B

• spatially resolved polymer identification based on chemical functionalities. A unique peak at 1111 cm−1 was identified and is attributed to backbone stretching of aliphatic chains [ν(C–C)] in PCL. Also, a characteristic band at 829 cm−1 was detected which can be assigned to PHEMA and refers to the

Towards new NIR dyes for free radical photopolymerization processes

• Haifaa Mokbel,
• Guillaume Noirbent,
• Didier Gigmes,
• Frédéric Dumur and
• Jacques Lalevée

Beilstein J. Org. Chem. 2021, 17, 2067–2076, doi:10.3762/bjoc.17.133

• photochemical reactivity of NIR dyes in a three-component PIS. Quantitative estimations of the polymerization time of PETIA monomer using a NIR dye/iod/amine 0.1:3:2, w/w/w system upon exposure to a laser diode at 785 nm (0.9 W/cm²), thickness = 1.4 mm, under air and at room temperature. The irradiation starts

A study on selective transformation of norbornadiene into fluorinated cyclopentane-fused isoxazolines

• Zsanett Benke,
• Attila M. Remete and
• Loránd Kiss

Beilstein J. Org. Chem. 2021, 17, 2051–2066, doi:10.3762/bjoc.17.132

• Abstract This work presents an examination of the selective functionalization of norbornadiene through nitrile oxide 1,3-dipolar cycloaddition/ring-opening metathesis (ROM)/cross-metathesis (CM) protocols. Functionalization of commercially available norbornadiene provided novel bicyclic scaffolds with

• multiple stereogenic centers. The synthesis involved selective cycloadditions, with subsequent ROM of the formed cycloalkene-fused isoxazoline scaffolds and selective CM by chemodifferentiation of the olefin bonds of the resulting alkenylated derivatives. Various experimental conditions were applied for

• the CM transformations with the goal of exploring substrate and steric effects, catalyst influence and chemodifferentiation of the olefin bonds furnishing the corresponding functionalized, fluorine-containing isoxazoline derivatives. Keywords: functionalization; metathesis; nitrile oxide

Volatile emission and biosynthesis in endophytic fungi colonizing black poplar leaves

• Christin Walther,
• Pamela Baumann,
• Katrin Luck,
• Beate Rothe,
• Peter H. W. Biedermann,
• Jonathan Gershenzon,
• Tobias G. Köllner and
• Sybille B. Unsicker

Beilstein J. Org. Chem. 2021, 17, 1698–1711, doi:10.3762/bjoc.17.118

• were brought into pure culture on PDA medium using the same culturing conditions as above. Fresh mycelium was harvested from pure cultures for molecular identification of the morphospecies. Molecular identification of endophytic fungi DNA was extracted from fresh mycelium (approximately 5 cm in

• mycelium reached a diameter of 5 cm (± 0.5 cm). For each fungal species, seven replicates were used with fungus-free petri dishes with PDA medium used as blanks. Volatiles were trapped for 1 h by using four polydimethylsiloxane (PDMS) tubes. To prevent PDMS tubes from touching the mycelium, the tubes were

• (approximately 5 cm in diameter) growing on PDA using the RNeasy® Plant Mini Kit (Qiagen) according to the manufacturer’s instructions. The RNA concentration was assessed using a spectrophotometer (NanoDrop 2000c, Thermo Fisher Scientific). RNA was treated with DNase I (Thermo Fisher Scientific) prior to cDNA

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

• methoxy substituent exhibits a larger red shift of around 40 nm. Based on the absorption and emission spectra, the prepared tetrahydroacridine derivatives possess stokes shifts (wavenumber) ranging from 2400 to 4300 cm−1. Their fluorescence quantum yields range from 0.1 to 0.2 as measured according to a

• were recorded on a Shimadzu 2401 PC spectrophotometer in quartz cuvettes with a path length of 1 cm. Emission spectra were recorded on a Perkin-Elmer LS50B spectrofluorimeter. Theoretical calculations Theoretical studies were realized in vacuum with Gaussian 09 program [72]. The geometry of the

Breaking paracyclophane: the unexpected formation of non-symmetric disubstituted nitro[2.2]metaparacyclophanes

• Suraj Patel,
• Tyson N. Dais,
• Paul G. Plieger and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2021, 17, 1518–1526, doi:10.3762/bjoc.17.109

• , J = 7.2, 8.5, 13.3 Hz, 1H, H-1b); 13C NMR (126 MHz, CDCl3) δ (ppm) 149.0, 142.2, 139.9, 139.5, 137.9, 137.5, 136.6, 133.3, 133.3, 132.6, 130.1, 129.7, 36.2, 35.1, 35.0, 34.6; IR: 3009, 2928, 1694, 1531, 1516, 1336, 808 cm−1; mp: 158–160 °C; Rf: 0.43 (10% EtOAc, 90% hexane). Data matches previous

• ; ESIMS (m/z): [M]– 264, 252, 223, 151, 89; IR: 3306, 2917, 2850, 1738, 1534, 1261 cm−1; mp: 152–155 °C; Rf: 0.40, (10% EtOAc, 90% hexane). (4(16)Z)-8-Hydroxy-6-nitrotricyclo[9.2.2.14,8]hexadeca-1(13),4,(16),6,11,14-pentaen-5-one (6) 1H NMR (500 MHz, DMSO-d6) δ (ppm) 7.48 (d, J = 8.1 Hz, 1H, H-13), 7.29

• , 2925, 1665, 1535, 1356, 1010, 729 cm−1; mp: 206–213 °C; Rf: 0.25 (20% EtOAc, 80% hexane). (4(16)Z)-8-Hydroxy-7-methoxy-6-nitrocyclo[9.2.2.14,8]hexadeca-1(13),4(16),11,14-tetraen-5-one (14) and (4(16)Z)-8-hydroxytricyclo[9.2.2.14,8]hexadeca-1(13),4(16),6,11,14-pentaen-5-one) (15): To a solution of 6

A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines

• Greta Utecht-Jarzyńska,
• Karolina Nagła,
• Grzegorz Mlostoń,
• Heinz Heimgartner,
• Marcin Palusiak and
• Marcin Jasiński

Beilstein J. Org. Chem. 2021, 17, 1509–1517, doi:10.3762/bjoc.17.108

• , 1495, 1331, 1279, 1230, 1133, 1100, 921, 716 cm−1; ESIMS (m/z): 365.1 (100, [M + Na]+), 343.1 (12, [M + H]+); Anal. calcd for C18H9F3N2O2: C, 63.16; H, 2.65; N, 8.18; found: C, 63.34; H, 2.63; N, 8.24 (all values are given as percentages). 3a,5,6,7a-Tetramethyl-1-(p-tolyl)-3-(trifluoromethyl)-3a,7a

• , 1379, 1267, 1170, 1118, 1070, 1029, 954, 850, 816, 712 cm−1; ESIMS (m/z): 365.4 (100, [M + H]+); Anal. calcd for C19H19F3N2O2: C, 62.63; H, 5.26; N, 7.69; found: C, 62.76; H, 5.39; N, 7.95. Structures of exemplary benzo- and heteroaromatic fused 1,4-quinone drugs and natural products. X-ray structure

Design, synthesis and photophysical properties of novel star-shaped truxene-based heterocycles utilizing ring-closing metathesis, Clauson–Kaas, Van Leusen and Ullmann-type reactions as key tools

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2021, 17, 1374–1384, doi:10.3762/bjoc.17.96

• 600 to 4000 cm−1. UV–vis spectra were recorded on a UV-1800 Shimadzu spectrophotometer and the fluorescence spectra were recorded on an Agilent Carry Eclipse spectrofluorimeter. Synthesis of 10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene (7): Truxene scaffold 7 was prepared according to a literature

• , 149.65, 147.08, 145.20, 137.48, 124.91, 122.66, 117.60, 56.57, 36.44, 26.54, 22.63, 13.71; IR (KBr): 2957, 2925, 2858, 1742, 1594, 1517, 1458 cm−1; MS (m/z): 814.00. Synthesis of 5,5,10,10,15,15-hexabutyl-10,15-dihydro-5H-diindeno[1,2-a:1',2'-c]fluorene-2,7,12-triamine (4): To a 100 mL round bottom flask

• (d, J = 8.1 Hz, 3H), 3.69 (b–NH, 6H), 2.91–2.81 (m, 6H), 1.96–1.87 (m, 6H), 0.94–0.60 (m, 12H), 0.56–0.42 (m, 30H); 13C NMR (75 MHz, CDCl3) δ 155.72, 144.69, 141.19, 138.07, 132.30, 125.41, 113.23, 109.04, 55.05, 36.85, 26.50, 22.95, 13.91; IR (KBr): 3369, 3012, 2953, 2922, 2855, 1619, 1584, 1485 cm

Fritsch–Buttenberg–Wiechell rearrangement of magnesium alkylidene carbenoids leading to the formation of alkynes

• Tsutomu Kimura,
• Koto Sekiguchi,
• Akane Ando and
• Aki Imafuji

Beilstein J. Org. Chem. 2021, 17, 1352–1359, doi:10.3762/bjoc.17.94

• ) 3558, 3004, 2965, 2932, 2905, 2837, 1606, 1585, 1512, 1461, 1307, 1250, 1178, 1156, 1085, 1055, 1028, 838, 801, 754 cm−1; 1H NMR (301 MHz, CDCl3) δ 2.42 (s, 3H), 3.76 (s, 3H), 3.82 (s, 3H), 4.19 (s, 1H), 5.23 (s, 1H), 6.83 (d, J = 8.9 Hz, 2H), 6.94 (d, J = 8.9 Hz, 2H), 7.29–7.42 (m, 6H), 7.55 (d, J

• (hexane/EtOAc) to give sulfoxide 2a [1.38 g, 3.34 mmol, 87%, Rf = 0.50 (hexane/EtOAc 1:1)]. Colorless solid; mp 140.2–141.0 °C; IR (ATR) 3063, 3032, 3024, 2955, 2932, 2908, 2837, 1603, 1577, 1506, 1462, 1306, 1246, 1172, 1082, 1049, 1031, 829 cm−1; 1H NMR (399 MHz, CDCl3) δ 2.42 (s, 3H), 3.79 (s, 3H

• , 820 cm−1; 1H NMR (301 MHz, CDCl3) δ 3.83 (s, 6H), 6.87 (d, J = 8.8 Hz, 4H), 7.45 (d, J = 8.8 Hz, 4H); 13C NMR (126 MHz, CDCl3) δ 55.3, 88.0, 114.0, 115.7, 132.9, 159.4; EIMS (m/z, %): 238 ([M]+, 100), 223 (55); HRMS–EI (m/z): [M]+ calcd for C16H14O2, 238.0994; found, 238.0997. Optimized geometries of