The preparation and properties of 1,1-difluorocyclopropane derivatives

• Kymbat S. Adekenova,
• Peter B. Wyatt and
• Sergazy M. Adekenov

Beilstein J. Org. Chem. 2021, 17, 245–272, doi:10.3762/bjoc.17.25

• dibromo derivatives 135 when KBr was employed in a DCM/H2O 1:1 (v/v) mixed solvent. Alternatively, the bromohydroxylation and bromoamidation were also achieved simply by changing the solvent system [108]. Stereodivergent sets of conditions were devised to produce stereodefined (E,E)- and (E,Z

The B & B approach: Ball-milling conjugation of dextran with phenylboronic acid (PBA)-functionalized BODIPY

• Patrizia Andreozzi,
• Lorenza Tamberi,
• Elisamaria Tasca,
• Gina Elena Giacomazzo,
• Marta Martinez,
• Mirko Severi,
• Marco Marradi,
• Stefano Cicchi,
• Sergio Moya,
• Giacomo Biagiotti and
• Barbara Richichi

Beilstein J. Org. Chem. 2020, 16, 2272–2281, doi:10.3762/bjoc.16.188

• recorded on an Inova 400 instrument. Fourier transform infra red absorption spectroscopy (FTIR) was carried out with a Shimadzu IRAffinity-1S spectrometer. Potassium bromide (KBr) pellets were prepared using 100 mg of potassium bromide and 1.0 mg of sample. The spectra were recorded under inert atmosphere

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

• solvent mixture ratio of 2:1 and 1:1, respectively. Muyocopronone A (1) Yellow amorphous solid; [α]D22 +41 (c 0.1, MeOH); UV (MeOH) λmax (log ε) 221 (4.34), 329 (4.25) nm; ECD (0.02 mg/mL, MeOH) λext (Δε) 219 (−2.48), 236 (−4.29), 255 (+1.10), 276 (−1.37), 326 (+2.05), 358 (+2.25) nm; IR (KBr) νmax: 3468

• (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

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

• procedures, and 8a, 23a) or in Supporting Information File 1 (1d, 1e, 2b, 3b, 8b, 23b). All melting points were determined on a Büchi B-540 (Flawil, Switzerland) capillary melting point apparatus and are uncorrected. IR spectra were obtained on a Bruker ALPHA FT-IR spectrometer (Billerica, MA, USA) in KBr

• ). 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

One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• nitrogen atom. Experimental General Melting points were taken on an automated melting point apparatus SRS EZ-Melt MPA120 at a ramp rate of 1 °C/min and are uncorrected. IR spectra were recorded on a Thermo Fischer Nicolet iS50 FT-IR instrument. Spectroscopic grade KBr was used in the sample preparation

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• Systems MPA 100 or a Yanako MP-500P apparatus and were uncorrected. Infrared (IR) spectra were recorded on a JASCO FT IR-4100 spectrometer using dispersed KBr pellets. 1H and 13C NMR spectra were measured at 23 °C on a JEOL RESONANCE JNM-ECZ400S spectrometer at 400 MHz and 100 MHz, respectively. CDCl3 was

• % (98.3 mg (0.19 mmol) from 52.8 mg (0.20 mmol) of 2). mp 133 °C; IR (KBr) ν: 3438, 3003, 2922, 2841, 1502, 1398, 1257, 1213, 1159, 1032, 798 cm−1; 1H NMR (CDCl3) δ (ppm) 7.29 (s, 1H), 7.08 (s, 2H), 7.05 (s, 1H), 7.04 (d, J = 8.0 Hz, 1H), 7.00 (d, J = 8.0 Hz, 1H), 6.81 (d, J = 7.6 Hz, 1H), 6.68 (d, J

• , 147.30, 133.58, 125.81, 124.18, 123.54, 123.46, 123.38, 115.10, 112.33, 111.05, 74.39, 61.75, 56.26, 41.85, 41.84; FAB MS m/z: [M+] calcd for C30H21BrO3, 508.0674; found, 508.0665. 3b: yellow solid; yield: >99% (148 mg (0.30 mmol) from 79.2 mg (0.30 mmol) of 2). mp 133 ºC; IR (KBr) ν: 3546, 3041, 3014

KOt-Bu-promoted selective ring-opening N-alkylation of 2-oxazolines to access 2-aminoethyl acetates and N-substituted thiazolidinones

• Qiao Lin,
• Shiling Zhang and
• Bin Li

Beilstein J. Org. Chem. 2020, 16, 492–501, doi:10.3762/bjoc.16.44

• ring-opening N-alkylation is illustrated in Scheme 9. The reaction is proposed to begin with the generation of iminium ether A [27][28], generated from the reaction of 2-metyl-2-oxazoline with benzyl bromide in the presence of KOt-Bu with release KBr. A subsequent second nucleophilic substitution of

Oligomeric ricinoleic acid preparation promoted by an efficient and recoverable Brønsted acidic ionic liquid

• Fei You,
• Xing He,
• Song Gao,
• Hong-Ru Li and
• Liang-Nian He

Beilstein J. Org. Chem. 2020, 16, 351–361, doi:10.3762/bjoc.16.34

• ppm; FTIR (KBr) νmax/cm−1: 3317.18, 2939.11, 2867.62, 1621.52, 1527.51, 1452.10, 1328.75, 1201.00, 998.74, 726.90, 600.28; ESIMS (+) m/z: 100.1, 102.1, 153.2, 289.3, 390.1. For the preparation of other ILs in this paper and for full experimental data see Supporting Information File 1. Catalytic

• , 33.62, 34.65, 73.69, 124.30, 132.51, 173.58 ppm; FTIR (KBr) νmax/cm−1: 3416.44, 3010.55, 2927.89, 2855.81, 1733.38, 1711.66, 1464.22, 1245.41, 1183.74, 725.11; ESIMS (+) m/z: 579.3, 876.6, 1139.7, 1437.8, 1716.9, 1997.1. Acid value determination The acid value of product was determined using a modified

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• nm (4.35); IR (KBr) νmax: 3408, 1737, 1709, 1657, 1620, 1599, 1498, 1452, 1352, 1288 cm−1; HRESIMS (m/z): [M + Na]+ calcd for C16H14O7Na, 341.0637; found, 341.0624. Talaromycone B (2) Colorless gum. [α]D25 +18.0 (c 0.1, MeOH); 1H and 13C NMR see Table 1; UV (MeOH) λmax (log ε) 328 (3.61), 263 (4.07

• ), 239 (4.32), 228 nm (4.26); IR (KBr) νmax: 3437, 1751, 1734, 1654, 1620, 1491, 1448, 1290, 1271, 1205 cm−1; HRESIMS (m/z): [M + Na]+ calcd for C16H14O7Na, 357.0586; found, 357.0572. α-Diversonolic ester (3) Colorless plates (acetone/n-hexane). mp 206–209 °C; [α]D25 +23.2 (c 0.1, MeOH). Aspergillusone

Extension of the 5-alkynyluridine side chain via C–C-bond formation in modified organometallic nucleosides using the Nicholas reaction

• Renata Kaczmarek,
• Dariusz Korczyński,
• James R. Green and
• Roman Dembinski

Beilstein J. Org. Chem. 2020, 16, 1–8, doi:10.3762/bjoc.16.1

• , 78.52, 73.66, 63.53, 52.20, 36.17, 20.76, 20.54, 20.46; IR (cm–1, KBr) 3442 m, 3389 m, 2987 m, 2823 m, 1701 s, 1627 s, 1467 m, 1288 m, 1052 m; TOF–ESI+–MS (m/z): [M + Na]+ calcd for C18H20N2NaO9, 431.1061; found, 431.1064. 2',3',5'-Tri-O-acetyl-5-(3-methoxyprop-1-yn-1-yl)uridine (3). A round-bottom

• , 90.35, 87.46, 80.19, 75.44, 73.20, 70.01, 62.91, 60.30, 57.88, 51.08, 20.83, 20.54, 20.45; IR (cm–1, KBr) 3208 br w, 3082 br w, 2938 br w, 2823 br w, 1743 s, 1692 vs, 1628 m, 1453 m, 1214 vs, 1092 s; TOF–ESI+–MS (m/z): [M + Na]+ calcd for C19H22N2NaO10, 461.1167; found, 461.1171. General procedure for

• NMR (150 MHz, CDCl3) δ 198.71, 170.73, 170.29, 170.26, 160.23, 149.43, 138.26, 113.71, 94.82, 85.91, 82.58, 79.29, 74.03, 65.45, 63.65, 37.93, 20.90, 20.60, 20.54; IR (cm–1, KBr) 3356 br m, 3089 br w, 2960 br w, 2093 m, 2056 s, 2024 br s, 1736 vs, 1638 m, 1561 m, 1406 m, 1228 vs, 1024 s; TOF–ESI+–MS

Unexpected one-pot formation of the 1H-6a,8a-epiminotricyclopenta[a,c,e][8]annulene system from cyclopentanone, ammonia and dimethyl fumarate. Synthesis of highly strained polycyclic nitroxide and EPR study

• Sergey A. Dobrynin,
• Igor A. Kirilyuk,
• Yuri V. Gatilov,
• Andrey A. Kuzhelev,
• Olesya A. Krumkacheva,
• Matvey V. Fedin,
• Michael K. Bowman and
• Elena G. Bagryanskaya

Beilstein J. Org. Chem. 2019, 15, 2664–2670, doi:10.3762/bjoc.15.259

• internally referenced to the residual solvent peak. IR spectra were acquired on an FTIR spectrometer in KBr and are reported in wavenumbers (cm−1). Reactions were monitored by TLC using UV light 254 nm, 1% aqueous permanganate and Dragendorff reagent as visualizing agents. Column chromatography was performed

• 4:1). 1: 70 mg (5%); colorless crystals; mp 146.8–148.4 °C; IR (KBr): 3298 (N-H), 1734, 1718 (C=O); 1H NMR (400 MHz, CDCl3, δ) 1.08–1.16 (m, 1H), 1.35–1.48 (m, 3H), 1.49–1.57 (m, 1H), 1.60–1.69 (m, 3H), 1.70–1.76 (m, 1H), 1.84–1.90 (m,1H), 1.91–1.98 (m, 2H), 1.99–2.08 (m, 3H), 2.14–2.20 (m, 1H

• silica gel (hexane/ethyl acetate 4:1). 2: 56 mg (48%); red crystals; mp 127.0 °C dec, IR (KBr): 3438 (O-H) 1730 (C=O); X-ray: triclinic system, P-1, a = 8.2240(5), b = 10.9423(6), c = 11.4515(8) Å, α = 83.440(3), β = 75.611(3), γ = 83.119(2)º, V = 987.17(11) Å3, Z = 2, 2θmax = 27.292°, 4388 independent

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• used for the preparations of the agar plates. The stock solution containing 23.48 g NaCl, 10.61 g MgCl2·6H2O, 3.92 g Na2SO4, 1.47 g CaCl2·2H2O, 0.66 g KCl, 0.19 g NaHCO3, 0.1 g KBr, 0.04 g SrCl2, 0.03 g H3BO3 per litre deionized water equals 35‰ salinity. Dilutions with 7, 14, 21 and 28‰ water were

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• ) and 12 (tR 6.88 min). Bipolenin K (1): Colourless oil; [α]D20 −59 (c 0.15, MeOH); IR (KBr) λmax 3445, 2926 and 1729 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS m/z: [M + H]+ calcd for C15H23O3+, 251.1642; found, 251.1646, and [M + H − H2O]+ calcd for C15H21O2+, 233.1536; found, 233.1531. Bipolenin

• L (2): Colourless oil; [α]D20 −63 (c 0.04, MeOH); IR (KBr) λmax 3419, 2920 and 1730 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS m/z: [M + H]+ calcd for C15H23O3+, 251.1642; found, 251.1649, and [M + H − H2O]+ calcd for C15H21O2+, 233.1536; found, 233.1535. Bipolenin M (3): Colourless oil; [α]D20

• −57 (c 0.04, MeOH); IR (KBr) λmax 3418, 2927 and 1720 cm−1; 1H and 13C NMR data, see Table 1; HRESIMS m/z: [M + H]+ calcd for C15H23O3+, 251.1642; found, 251.1647, and [M + H − H2O]+ calcd for C15H21O2+, 233.1536; found, 233.1545. Bipolenin N (4): Colourless oil; [α]D20 +38 (c 0.04, MeOH); IR (KBr

Synthesis and anion binding properties of phthalimide-containing corona[6]arenes

• Meng-Di Gu,
• Yao Lu and
• Mei-Xiang Wang

Beilstein J. Org. Chem. 2019, 15, 1976–1983, doi:10.3762/bjoc.15.193

• NMR (101 MHz, acetone-d6, 25 °C) δ 168.8, 164.4, 147.1, 132.2, 132.1, 129.6, 128.8, 127.5, 125.6; IR (KBr, cm−1) ν: 3078, 1777, 1724, 1494, 1384, 1230, 1115, 955; HRMS-APCI: [M + H]+ calcd for C48H22N15O12, 1000.1567; found, 1000.1553; anal. calcd for C48H21N15O12: C, 57.66; H, 2.12; N, 21.01; found

• , 25.8; IR (KBr, cm−1) ν: 2934, 2858, 1772, 1715, 1382, 1228, 955; HRMS-APCI: [M + H]+ calcd for C48H40N15O12, 1018.2975; found, 1018.2954; anal. calcd for C48H39N15O12: C, 56.64; H, 3.86; N, 20.64; found: C, 56.51; H, 3.83; N, 20.24. 3c: 215 mg, yield 63%, red solid, mp 275 °C (decomp.); 1H NMR (400 MHz

• , CDCl3, 25 °C) δ 7.63 (s, 6H), 3.38 (t, J = 6.8 Hz, 6H), 1.54–1.48 (m, 6H), 1.23–1.19 (m, 18H), 0.82 (t, J = 6.8 Hz, 9H); 13C NMR (101 MHz, CDCl3, 25 °C) δ 167.4, 164.4, 145.5, 130.1, 124.7, 38.6, 31.2, 29.7, 28.1, 26.4, 22.4, 13.9; IR (KBr, cm−1) ν: 3081, 2931, 2859, 1774, 1717, 1494, 1440, 1417, 1379

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• -assisted oxidation reactions and, we have gained valuable experience in handling this reagent in several mechanochemical applications [45][46]. N-Chlorosuccinimide (1.1 mmol) and 3-pheny-1-propanol (1.0 mmol) were milled together in the presence of TEMPO (5 mol %), K2CO3 (4.0 mmol) and KBr (3.0 mol %) for

• a catalytic amount of KBr promotes the in situ generation of HOBr, which is a stronger oxidant than HOCl [57]. The results improved remarkably by using as oxidant a 6% aqueous solution of NaOCl (1.14 mL, 1.1 mmol) adsorbed on NaHCO3 (6.5 g) in the presence of a catalytic amount of TEMPO (5.0 mol

• %) and KBr (3.0 mol %) (Table 1, entry 6). Within 20 minutes, the alcohol was completely and selectively oxidized into the corresponding aldehyde (as assessed by GC–MS analyses). The use of NaCl, alone or in combination with NaHCO3, as an adsorbent [58] (Table 1, entries 1–5, 7) or bases (Na2CO3, Table 1

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

• Alexander F. de la Torre,
• Gabriel S. Scatena,
• Oscar Valdés,
• Daniel G. Rivera and
• Márcio W. Paixão

Beilstein J. Org. Chem. 2019, 15, 1210–1216, doi:10.3762/bjoc.15.118

• (KBr, cm−1): 3500, 3120, 2930, 2860, 1720, 1680, 1540, 1420, 1320, 1180, 1080, 790. 740, 600; microanalysis: N (2.68%), C (58.29%), H (5.12%), S (0%); loading = 0.64 mmol·g−1. PFA-supported catalyst 4. Compound 2 (545 mg, 1 mmol, 1.0 equiv), furfuryl alcohol (860 µL, 10 mmol, 10 equiv) and TFA (38 µL

• , 0.5 mmol) were reacted in CHCl3 (5 mL) according to the general procedure B. After precipitation in petroleum ether, polymer 4 was obtained as a black amorphous solid. IR (KBr, cm−1): 3500, 3120, 2930, 1720, 1680, 1610, 1550, 1420, 1350, 1200, 1160, 1110, 1038, 780, 740, 600; microanalysis: N (1.36

• %), C (50.52%), H (3.77%), S (0%); loading = 0.33 mmol·g−1. PFA. Furfuryl alcohol (860 µL, 10 mmol) and TFA (38 µL, 0.5 mmol) were reacted in CHCl3 (5 mL) according to the general procedure B. After precipitation in petroleum ether, PFA was afforded as a black amorphous solid. IR (KBr, cm−1): 3480, 2930

Novel (2-amino-4-arylimidazolyl)propanoic acids and pyrrolo[1,2-c]imidazoles via the domino reactions of 2-amino-4-arylimidazoles with carbonyl and methylene active compounds

• Victoria V. Lipson,
• Tetiana L. Pavlovska,
• Nataliya V. Svetlichnaya,
• Anna A. Poryvai,
• Nikolay Yu. Gorobets,
• Erik V. Van der Eycken,
• Irina S. Konovalova,
• Svetlana V. Shiskina,
• Alexander V. Borisov,
• Vladimir I. Musatov and
• Alexander V. Mazepa

Beilstein J. Org. Chem. 2019, 15, 1032–1045, doi:10.3762/bjoc.15.101

• [1,2-c]imidazol and 3,3’-spiroxindole fragments in the core structure. Experimental Reagents and analytics: Starting materials were purchased from commercial suppliers. Melting points were determined on a Kofler apparatus and temperatures were not corrected. The IR spectra were recorded in KBr on a

• 243–245 °C; IR (KBr, cm−1) ν: 3404–2800 (NH2, NH, OH), 1684 (C=O); 1H NMR (200 MHz, DMSO-d6) δ 12.27 (br s, 2H, NH, OH), 7.61–7.49 (m, 2H, Harom), 7.48–7.31 (m, 5H, Harom), 7.27–7.01 (m, 5H, NH2,, Harom), 5.48 (s, 1H, CH), 1.51 (s, 6H, CH3); 13C NMR (125 MHz, CDCl3) δ 166.8 (C=O), 146.6 (C-OH), 144.0

• added to the reaction mixture and the solid product 9 was filtered off, washed with iPrOH and dried on air. 9b: colourless solid, 52%; mp 222–224 °C; IR (KBr, cm−1) ν: 3432–3160 (NH3+, COO−), 1782 (C=O); 1H NMR (400 MHz, DMSO-d6) δ 8.54 (br s, 2H, NH3+), 7.29–7.16 (m, 6H, Harom), 7.15–7.03 (m, 3H, Harom

Photochemical generation of the 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) radical from caged nitroxides by near-infrared two-photon irradiation and its cytocidal effect on lung cancer cells

• Ayato Yamada,
• Manabu Abe,
• Yoshinobu Nishimura,
• Shoji Ishizaka,
• Masashi Namba,
• Taku Nakashima,
• Kiyofumi Shimoji and
• Noboru Hattori

Beilstein J. Org. Chem. 2019, 15, 863–873, doi:10.3762/bjoc.15.84

• was removed by rotary evaporation and the crude product was purified by silica gel column chromatography (hexane/EtOAc 10:1, v/v) to give 6-ethyl-2-(4-nitrophenyl)benzofuran (5a, 10.0 g, 57.3%). mp 114 °C; IR (KBr, cm−1): 3429, 2968, 1601, 1520, 1344, 1108, 828, 825, 754, 692; 1H NMR (400 MHz, CDCl3

• gel column chromatography (hexane/ether 15:1, v/v) to give 2a (236 mg, 37.8%). mp 109 °C; IR (KBr, cm−1): 3429, 2934, 1600, 1521, 1345, 1062, 825; 1H NMR (400 MHz, CDCl3) δ (ppm) 8.31 (d, J = 9.0 Hz, 2H), 7.99 (d, J = 9.0 Hz, 2H), 7.57 (d, J = 8.1 Hz, 1H), 7.54 (s, 1H), 7.25 (dd, J = 8.1, 1.2 Hz, 1H

• ; IR (KBr, cm−1): 2922, 1601, 1514, 1340, 1194, 853, 811, 754, 690; 1H NMR (400 MHz, CDCl3) δ (ppm) 8.30 (d, J = 9.0 Hz, 2H), 7.99 (d, J = 9.0 Hz, 2H), 7.46 (d, J = 9.2 Hz, 1H), 7.44 (s, 1H), 7.21 (dd, J = 8.4, 1.8 Hz, 1H), 7.19 (d, J = 0.8 Hz, 1H), 2.76 (q, J = 7.6 Hz, 2H) 1.30 (t, J = 7.6 Hz, 3H

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• -oxymethylcarboxylic acid [31][32][33] were prepared as described in the literature. All other reagents were purchased from commercial vendors and used without further purification. Melting points were determined in open glass capillaries and are uncorrected. The IR spectra were recorded as KBr disks using a Bruker

Synthesis and selected transformations of 2-unsubstituted 1-(adamantyloxy)imidazole 3-oxides: straightforward access to non-symmetric 1,3-dialkoxyimidazolium salts

• Grzegorz Mlostoń,
• Małgorzata Celeda,
• Katarzyna Urbaniak,
• Marcin Jasiński,
• Vladyslav Bakhonsky,
• Peter R. Schreiner and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2019, 15, 497–505, doi:10.3762/bjoc.15.43

• (1H NMR: 600 MHz; 13C NMR: 151 MHz). Chemical shifts are reported relative to solvent residual peaks (1H NMR: δ = 7.26 ppm [CHCl3]; 13C NMR: δ = 77.0 ppm [CDCl3]). IR spectra were registered with a FTIR NEXUS spectrometer (as film or KBr pellets). Melting points were determined in capillaries with a

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• yellow oil; reaction time (method A) – 1 h; yield 5.0 g, 66%. IR (KBr) ν (cm−1): 2933, 1802, 1733; 1H NMR (300 MHz, CDCl3) δ 8.09 (s, 1H, H-C(8)), 4.23 (t, 3J = 7.2 Hz, 2H, -CH2-), 1.88 (quintet, 3J = 7.2 Hz, 2H, -CH2-), 1.36–1.13 (m, 8H, 4 × -CH2-), 0.82 (t, 3J = 6.8 Hz, 3H, -CH3) ppm; 13C NMR (75.5 MHz

• (KBr) ν (cm−1): 2932, 2858, 2170, 2123; 1H NMR (300 MHz, CDCl3) δ 7.87 (s, 1H, H-C(8)), 4.15 (t, 3J = 7.2 Hz, 2H, -CH2-), 1.93–1.77 (m, 2H, -CH2-), 1.39–1.15 (m, 8H, 4 × -CH2-), 0.84 (t, 3J = 6.8 Hz, 3H, -CH3) ppm; 13C NMR (75.5 MHz, CDCl3) δ 155.9, 154.1, 153.7, 143.7, 121.5, 44.2, 31.6, 29.8, 28.7

• -purine (6a): Slightly brown solid, reaction time – 4 h; yield 0.88 g, 51%. IR (KBr) ν (cm−1): 3062, 2927, 2858, 2148, 2122, 1570, 1254; 1H NMR (300 MHz, CDCl3) δ 7.56 (s, 1H, H-C(8)), 4.03 (t, 3J = 7.0 Hz, 2H, -CH2-), 3.62–3.54 (m, 4H, 2 × -CH2-), 2.00–1.92 (m, 4H, 2 × -CH2-), 1.83 (quintet, 3J = 7.0 Hz

Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce

• Hidekazu Komatsu,
• Takashi Shirakawa,
• Takeo Uchiyama and
• Tsutomu Hoshino

Beilstein J. Org. Chem. 2019, 15, 299–309, doi:10.3762/bjoc.15.27

• white solid. Its IR spectrum (KBr tablet, Supporting Information File 1, Figure S1) showed strong and broad absorption bands at 1535 cm−1 and 1660 cm−1, indicating that cichorinotoxin has amide groups and that it is a peptide. In addition, a band at 1740 cm−1 (medium) was also observed, suggesting that

Synthesis of nonracemic hydroxyglutamic acids

• Dorota G. Piotrowska,
• Iwona E. Głowacka,
• Andrzej E. Wróblewski and
• Liwia Lubowiecka

Beilstein J. Org. Chem. 2019, 15, 236–255, doi:10.3762/bjoc.15.22

• sequence. Reagents and conditions: a) (CF3CH2O)2P(O)CH2COOMe, KHMDS, 18-crown-6, THF; b) PTSA, MeOH; c) NaOCl, TEMPO, KBr, NaHCO3, water/acetone; d) 3 M HCl, 80 °C. Synthesis of the orthogonally protected (2S,3R)-2 from a chiral aziridine. Reagents and conditions: a) LiHMDS, AcOt-Bu, THF; b) NaBH4, iPrOH

Selective ring-opening metathesis polymerization (ROMP) of cyclobutenes. Unsymmetrical ladderphane containing polycyclobutene and polynorbornene strands

• Yuan-Zhen Ke,
• Shou-Ling Huang,
• Guoqiao Lai and
• Tien-Yau Luh

Beilstein J. Org. Chem. 2019, 15, 44–51, doi:10.3762/bjoc.15.4

• was poured into H2O (50 mL) and DCM (50 mL). The organic layer was separated, washed with brine (100 mL) and dried (MgSO4). The solvent was removed in vacuo and the residue was chromatographed on silica gel (DCM/MeOH 20:1) to afford 12 (515 mg, 79%). mp 207–209 °C; IR (KBr): ν 3455, 3306, 3056, 2940

• ) to afford 9 (512 mg, 70%). mp 238–240 °C; IR (KBr): ν 3333, 3051, 2949, 2843, 1699, 1606, 1547, 1511, 1473, 1376, 1274, 1216, 1180, 1106, 1050, 963, 828, 769, 740 cm−1; 1H NMR (400 MHz) δ 1.51 (d, J = 8.2 Hz, 1H), 1.61 (d, J = 8.2 Hz, 1H), 1.72–1.85 (m, 4H), 2.92–2.98 (m, 6H), 3.07–3.09 (m, 2H), 3.25

• afforded 14 as a grayish powder (74.8 mg, 89%). IR (KBr): ν 3350, 3054, 2954, 2847, 1695, 1605, 1512, 1476, 1381, 1275, 1179, 1107, 967, 827, 768, 733, 698 cm−1; 1H NMR (400 MHz) δ 1.51–1.72 (m, 6H), 2.92–3.48 (m, 16H), 4.26 (br, 2H), 5.49 (m, 2H), 6.12 (br, 2H), 6.36 (m, 5H), 7.63 (br, 2H), 7.86 (br, 2H