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

Icilio Guareschi and his amazing “1897 reaction”

• Gian Cesare Tron,
• Alberto Minassi,
• Giovanni Sorba,
• Mara Fausone and
• Giovanni Appendino

Beilstein J. Org. Chem. 2021, 17, 1335–1351, doi:10.3762/bjoc.17.93

Photoinduced post-modification of graphitic carbon nitride-embedded hydrogels: synthesis of 'hydrophobic hydrogels' and pore substructuring

• Cansu Esen and
• Baris Kumru

Beilstein J. Org. Chem. 2021, 17, 1323–1334, doi:10.3762/bjoc.17.92

• of this study, which is divided into two parts, the hydrogel denoted as HGCM was utilized as the main substrate for both sections. To prepare HGCM, firstly graphitic carbon nitride was synthesized from the thermal treatment of a cyanuric acid–melamine supramolecular complex (CM) [42]. The resulting

• yellow powder was ultrasonicated in water to obtain a g-CN aqueous colloidal dispersion. The freshly prepared CM/water colloidal dispersion was mixed with water-soluble monomer (N,N-dimethylacrylamide, DMA) and crosslinker (N,N’-methylenebisacrylamide, MBA) followed by the addition of the redox couple

• were characterized via FTIR analysis to elucidate structural footprints of CM embedding and vTA photographing. The broad peak in the range from 3639 cm−1 to 3136 cm−1 corresponds to the hydrogen bonding between carboxyl and hydroxy groups with amide functionality of the hydrogel backbone. Significant

A new glance at the chemosphere of macroalgal–bacterial interactions: In situ profiling of metabolites in symbiosis by mass spectrometry

• Marine Vallet,
• Filip Kaftan,
• Veit Grabe,
• Fatemeh Ghaderiardakani,
• Simona Fenizia,
• Aleš Svatoš,
• Georg Pohnert and
• Thomas Wichard

Beilstein J. Org. Chem. 2021, 17, 1313–1322, doi:10.3762/bjoc.17.91

• following the procedure for in situ MS imaging described by Kessler et al. [19]. Briefly, algal gametes were inoculated to 10 mL medium in 9 cm diameter sterile Petri dishes with a clean and autoclaved glass slide (25 mm × 75 mm) with cavities (Paul Marienfeld, Germany) on the bottom; samples were incubated

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

• , valuable precursors of chiral amines. Experimental Experimental procedure for the reduction in glycerol The desired nitroolefin (0.4 mmol) was suspended in glycerol (4 mL) in a 7 mL vial equipped with a 3.5 cm-long magnetic stir bar. Ammonia borane (12 mg, 0.4 mmol) was added to the suspension at room

• ), dried over Na2SO4, filtered, and the solvent was evaporated under reduced pressure. The crude product was purified by column chromatography (silica as stationary phase; eluent: n-hexane/ethyl acetate). Experimental procedure for the reduction in DES In a 7 mL vial with a 3.5 cm-long magnetic stir bar

• 7 mL vial with a 3.5 cm-long magnetic stir bar, 2.5 g of DES were freshly prepared, ChCl and glycerol (1:2 molar ratio) were mixed, and the mixture was heated at 70 °C for 15 min until it became a colorless liquid. Then, the DES was slowly cooled to room temperature in 15 min. trans-β-Methyl-β

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• * transition, with a shift of the peak to 210 nm when biguanide is protonated. Infrared spectra present three characteristic absorption bands: a sharp absorption peak of medium intensity in the 1150–1170 cm−1 range, a strong band between 1480–1660 cm−1 corresponding to the C=N vibration, and a strong band at

• 3100–3400 cm−1 for the N–H bonds vibrations. NMR spectra record specific signals at 6.8–7.5 ppm for the shifts of the protons and 158–165 ppm for the 13C. Biguanides are good nucleophiles and easily carbonated under ambient conditions. They are stable over a wide range of pH. Often, heating in the

Synthesis of 10-O-aryl-substituted berberine derivatives by Chan–Evans–Lam coupling and investigation of their DNA-binding properties

• Peter Jonas Wickhorst,
• Mathilda Blachnik,
• Denisa Lagumdzija and
• Heiko Ihmels

Beilstein J. Org. Chem. 2021, 17, 991–1000, doi:10.3762/bjoc.17.81

• according to the published protocol [66]. Calf thymus DNA (ct DNA, type I; highly polymerized sodium salt; ε = 12824 cm−1 M−1) [67] was purchased from Sigma-Aldrich (St. Louis, USA) and used without further purification. Concentration of ct DNA is given in base pairs (bp). The ct DNA was dissolved in BPE

• : 6.0 mM Na2HPO4, 2.0 mM NaH2PO4, 1.0 mM Na2EDTA; pH 7.0. All buffer solutions were prepared from purified water (resistivity 18 MΩ cm) and biochemistry-grade chemicals. The buffer solutions were filtered through a PVDF membrane filter (pore size 0.45 μm) prior to use. Structures and numbering of

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• (698 mg, 72%) as a yellow solid substance. 2a: −26.4 (c 1.0, CHCl3); IR (KBr): 2999, 2952, 2837, 1696, 1606, 1509, 1451, 1410, 1297, 1251, 1177, 1155, 1074, 1035 cm−1; 1H NMR (CDCl3) δ 2.00 (s, 3H), 2.80 (s, 3H), 3.48, 3.57 (AB, J = 10.7 Hz, 2H), 3.67 (s, 2H), 3.74 (s, 3H), 3.74 (s, 3H), 4.37 (s, 1H

• 1.0, CHCl3); IR (KBr): 3350, 2971, 2837, 1750, 1712, 1587, 1509, 1444, 1411, 1335, 1284, 1249, 1226, 1176, 1116, 1068, 1035 cm−1; 1H NMR (CDCl3) δ 1.23 (d, J = 6.5 Hz, 3H), 1.25 (d, J = 6.2 Hz, 3H), 2.05 (s, 3H), 2.55–2.66 (m, 1H), 3.05 (d, J = 4.2 Hz, 3H), 3.48, 3.53 (AB, J = 10.8 Hz, 2H), 3.59, 3.74

• were recorded at 10 °C in a quartz cuvette of 1 cm optical path length. The samples were prepared in the same manner as described in the UV melting experiments. The molar ellipticity was calculated from the equation [θ] = θ/cl, where θ, c, and l indicate the relative intensity, sample concentration

Valorisation of plastic waste via metal-catalysed depolymerisation

• Francesca Liguori,
• Carmen Moreno-Marrodán and
• Pierluigi Barbaro

Beilstein J. Org. Chem. 2021, 17, 589–621, doi:10.3762/bjoc.17.53

• –0.97 g⋅cm−3, Tm 130 °C) is a highly crystalline material with a low degree of short chain branching. Owing to the high stiffness, tensile strength, resistance to moisture and gas permeability, it is mainly used in the manufacture of water pipes, toys, beverage bottles, outdoor furniture, housewares and

• electrical cables [138][139]. LDPE (0.91–0.94 g⋅cm−3, Tm 120 °C) is a poorly crystalline material having a high degree of short chain and long chain branching. It is featured by a good flexibility, transparency and high impact strength, which make it suitable for short-term applications, such as films, food

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

• , 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

• : 3082 (w), 2950 (w), 2845 (w), 1736 (s), 1634 (w), 1435 (w), 1354 (w), 1277 (w), 1240 (w), 1216 (w), 1172 (w), 1144 (w), 1017 (w), 985 (w), 922 (w), 859 (w), 820 (w), 756 (w), 722 (w), 669 (w), 582 (w), 478 (w), 435 (w) cm−1; 1H NMR (CDCl3, 500 MHz) δ 5.83 (ddt, J = 17.1, 9.9, 7.3, 1H), 5.19 (ddt, J

• ), 1418 (w), 1375 (w), 1331 (w), 1306 (m), 1373 (m), 1259 (m), 1203 (w), 1180 (w), 1131 (m), 1056 (w), 1004 (w), 988 (w), 971 (w), 956 (w), 898 (w), 786 (w), 774 (w), 749 (w), 601 (w), 514 (w), 505 (w), 441 (w) cm−1; 1H NMR (d6-DMSO, 500 MHz) δ 3.63 (s, 3H), 3.37 (t, J = 7.5, 2H), 3.01 (s, 3H), 2.78 (t, J