Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• ). To clarify whether the mechanism of the DNA photodamage proceeds through the formation of radicals, experiments with commmonly employed radical scavengers were conducted (Table 3, Supporting Information File 1, Figure S17). In the presence of hydroxyl-radical scavengers DMSO, t-BuOH, and 2-propanol

• to the residual proton signal of the solvent [CD3CN: δ(1H) = 1.94 ppm, δ(13C) = 118.36 ppm or DMSO-d5: δ(1H) = 2.50 ppm, δ(13C) = 39.52 ppm] or to an internal standard in CDCl3 [TMS: δ(1H) = 0.00 ppm, δ(13C) = 0.00 ppm]. Structural assignments were made with additional information from gCOSY, gHSQC

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• CH2Cl2 (CD2Cl2, 1H = 5.32 ppm, 13C = 54.00 ppm), deuterated DMSO ((CD3)2SO, 1H = 2.50 ppm, 13C = 39.53 ppm), deuterated acetone ((CD3)2CO, 1H = 2.05 ppm, 13C = 29.84 ppm), or deuterated benzene (C6D6, 1H = 7.16 ppm, 13C = 128.39 ppm) were used as solvents and internal references. Chemical shift values

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• phosphorus signal for 2d). Stability tests were also performed in two different deuterated solvents, CDCl3 and DMSO-d6. No air or moisture exclusion was applied. The tests were performed at room temperature and at 60 °C. 1H and 31P NMR spectra of the solutions were taken after 24, 48 and 72 h. At room

• temperature the observable decomposition after 72 h is very low in both solvents. NMR spectra (1H and 31P) show trace amounts of the phosphine oxide of 1. The total amount of phosphine oxide is somewhat lower in DMSO-d6 when compared to CDCl3. Additionally, in CDCl3 further unknown decomposition products were

Cycloaddition reactions of heterocyclic azides with 2-cyanoacetamidines as a new route to C,N-diheteroarylcarbamidines

• Pavel S. Silaichev,
• Tetyana V. Beryozkina,
• Vsevolod V. Melekhin,
• Valeriy O. Filimonov,
• Andrey N. Maslivets,
• Vladimir G. Ilkin,
• Wim Dehaen and
• Vasiliy A. Bakulev

Beilstein J. Org. Chem. 2024, 20, 17–24, doi:10.3762/bjoc.20.3

• , 0.5 mmol; 1,4-dioxane (2 mL)) as a colorless powder; mp 225–226 °C; 1H NMR (400 MHz, DMSO-d6) δ 3.16 (s, 3H), 3.21 (s, 3H), 5.08 (s, 1H), 5.46 (s, 2H), 6.52 (s, 1H), 6.53 (s, 1H), 7.19 (br. s, 2H), 7.25–7.39 (m, 5H); 13C NMR (101 MHz, DMSO-d6) δ 27.1, 29.8, 48.4, 87.4, 120.9, 127.4, 127.6, 128.5

• NMR (400 MHz, DMSO-d6) δ 5.48 (s, 2H), 6.68 (s, 1H), 6.69 (s, 1H), 7.10 (d, J = 3.9 Hz, 1H), 7.24 (d, J = 6.9 Hz, 2H), 7.28–7.38 (m, 3H), 7.43 (d, J = 3.9 Hz, 1H), 8.42 (br. s, 1H), 9.15 (br. s, 1H); 13C NMR (101 MHz, DMSO-d6) δ 48.5, 112.6, 121.2, 127.2, 127.6, 128.5, 135.7, 138.8, 143.6, 153.5

Identification of the p-coumaric acid biosynthetic gene cluster in Kutzneria albida: insights into the diazotization-dependent deamination pathway

• Seiji Kawai,
• Akito Yamada,
• Yohei Katsuyama and
• Yasuo Ohnishi

Beilstein J. Org. Chem. 2024, 20, 1–11, doi:10.3762/bjoc.20.1

• a linear gradient of chloroform/methanol. Fractions containing compound 6 were concentrated by evaporation. The residual materials were desorbed in 1 mL DMSO and applied to a reversed-phase high-performance liquid chromatography (HPLC, Shimadzu Corp.) equipped with a COSMOCORE Packed column 5C18-AR

• -II (10 mm ID × 250 mm, Nacalai Tesque), and the metabolites were eluted with a linear gradient of water/acetonitrile containing 0.1% formic acid. Fractions containing compound 6 were concentrated by evaporation. Compound 6 was then desorbed in DMSO-d6, and the structure was determined by the JNM-A600

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• volume and after cooling the precipitate was filtered. The crude product was washed with cold MeOH and EtOAc and dried under reduced pressure yielding 2 (7.40 g, 35%) as white powder, which was used in the next reaction without further purification. 1H NMR (400 MHz, DMSO-d6) 7.67–7.66 (m, 2H), 7.37–7.33

• for 1 h. After cooling, the reaction was quenched by the addition of ice and the precipitate was filtered off. The crude product was purified by flash chromatography on silica gel using chloroform as eluent yielding compound 3 (1.0 g, 78%) as white powder. Mp > 200 °C; 1H NMR (400 MHz, DMSO-d6) 7.91

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• further purifications. TLC (SiO2; DCM/MeOH/25% NH4OH(aq) 10:1:0.01, Rf 0.22); mp 158–160 °C; −51.8 (c 1.00, DMSO); IR (cm−1) νmax: 2957, 2923, 2853, 1664, 1620, 1609, 1560, 1508, 1437, 1378, 1331, 1277, 1201, 1175, 1126, 1021, 930, 884, 832, 799, 719, 700, 679, 620, 550, 521, 414; 1H NMR (500 MHz, MeOH

Synthetic approach to 2-alkyl-4-quinolones and 2-alkyl-4-quinolone-3-carboxamides based on common β-keto amide precursors

• Yordanka Mollova-Sapundzhieva,
• Plamen Angelov,
• Danail Georgiev and
• Pavel Yanev

Beilstein J. Org. Chem. 2023, 19, 1804–1810, doi:10.3762/bjoc.19.132

• additional decarbamoylative step (Scheme 2). The decarbamoylation of compounds 3a–d was carried out by heating at 60 °C in neat H3PO4 for 90 minutes [62] and gave the corresponding β-enaminoketones 6a–d in good yields (Table 2). The NMR spectra of compounds 6 in DMSO-d6 in all cases indicated a mixture of Z

• . coli, using the hole-plate method in Mueller–Hinton agar, with 100 µg loading of each compound in 100 µL DMSO (Table 6). Interestingly, at this concentration most of the compounds showed weak to moderate activity against E. coli, while S. aureus was inhibited only by C5 and C7-substituted analogs

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• NMR spectrum in DMSO-d6 shows the presence of two methylpyrazole moieties (singlet signals of two methyl groups at 3.63 and 3.70 ppm, singlet signals of two CH protons of pyrazole rings at 7.81 and 7.84 ppm), a H–N–C–H fragment with trans-orientation of protons (two doublets at 9.87 and 7.50 ppm, 3J

• the 1H,13C-HSQC and 1H,13C-HMBС spectra, as well as by comparing the experimental carbon chemical shifts in DMSO-d6 with those calculated for 6 by the GIAO method at the PBE1PBE/6-311+G(2d,p) level of theory using the DFT B3LYP/6-311++G(d,p) optimized geometries (DMSO solution) and applying a multi

• the 1H and 13C{1H} NMR spectra of compound 5 in DMSO-d6 show only a half-number set of proton or carbon signals (five and six signals, respectively), thus indicating its C2-symmetric dimeric structure. The analysis of 2D NMR spectroscopic data provided additional evidence for the macrocycle 5

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• intensity bands, respectively, at 1519 and 1336 cm−1. These modes were calculated at 1608 and 1379 cm−1 in the gas phase. Although N-acylhydrazones are usually prone to undergo speciation in DMSO-d6 solution [47], 1H NMR measurements showed the existence of only one set of signals in the spectra of hdz-CH3

• stability in aqueous medium. Thus, the electronic absorption spectra of hdz-CH3 and hdz-NO2 were recorded in a 10% DMSO/buffer solution (pH 7.4) immediately after preparation and at regular time intervals. The UV–vis spectrum of hdz-CH3 between 250 and 450 nm (Figure 6A) shows two multicomponent absorptions

• -up study in solution (Figure 6B), indicating that the compound is stable in a water-rich medium. The spectrum of hdz-CH3 in DMSO, a solvent in which N-acylhydrazones are usually considered long-lived species, is included in the figure for the sake of comparison. Thus, the presence of the methyl

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• appropriate concentrations by dissolving in DMSO and diluting 1000-fold in medium. RAW 264.7 cells were preincubated with fresh medium containing test samples or vehicle (DMSO) for 24 h. After preincubation, LPS was added at a final concentration of 50 ng/mL. qRT-PCR analysis Total RNA was extracted using

Lewis acid-promoted direct synthesis of isoxazole derivatives

• Dengxu Qiu,
• Chenhui Jiang,
• Pan Gao and
• Yu Yuan

Beilstein J. Org. Chem. 2023, 19, 1562–1567, doi:10.3762/bjoc.19.113

• compared with DMSO and DMF (Table 1, entries 8 and 9). The reaction yield was decreased to 21% when increasing the temperature to 140 °C under standard conditions (Table 1, entry 10). Finally, the nitrogen atmosphere was essential since the yield substantially decreased under air atmosphere (Table 1, entry

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• min), and 15 (1.23 mg, white oil). 5,7-Dimethylpseudopithonone (1): yellow oil, 0 (c 0.27, MeOH); UV (MeOH): λmax (PDA): 218, 290, 342 nm; 1H NMR (500 MHz, CD3OD) and 13C NMR (125 MHz, DMSO-d6) are shown in Table 1; (+)-HRESIMS (m/z): [M + H]+ calcd for C12H15O4, 223.0965; found, 223.0961. 3,9

• -Diacetylalternariol (2): white amorphous powder, UV (MeOH): λmax (PDA): 222, 258, 330 nm; 1H NMR (500 MHz, DMSO-d6) and 13C NMR (125 MHz, DMSO-d6) are shown in Table 1; (+)-HRESIMS (m/z): [M + H]+ calcd for C18H15O7, 343.0812; found, 343.0809. Chemical structures of compounds 1 and 2. Key COSY and HMBC correlations

• of compounds 1 and 2. 1H (500 MHz) and 13C (125 MHz) NMR data of compounds 1 and 2 in DMSO-d6. Supporting Information Supporting Information File 2: HRESIMS data and 1H, 13C, COSY, HSQC, and HMBC NMR spectra of compounds 1 and 2. Acknowledgements We thank C. Kakoschke for the measurement of NMR

Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• same protocol as described by Molnar et al. [43] where DPPH and the synthesized compounds were tested in a solution at 0.2 mM concentration in DMSO as solvent. Because phenolic compounds can be easily oxidized to quinones, it is well known that most hydroxylated compounds have antioxidant properties

• -Hydroxymethylfurfurylidene)-2-thioxothiazolidin-4-one (3j). ochre yellow solid obtained after 1 h at 60 °C in 36% yield (two-step yield). Mp 149 °C; 1H NMR (400 MHz, DMSO-d6) δ (ppm) 4.49 (s, 2H), 5.52 (br s, 1H, OH), 6.58 (d, J = 3.6 Hz, 1H), 7.11 (d, J = 3.6 Hz, 1H), 7.44 (s, 1H, =CH), 13.62 (br s, 1H, NH); 13C NMR (100

• MHz, DMSO-d6) δ (ppm) 196.8, 169.1, 161.2, 148.8, 121.8, 121.0, 117.8, 110.9, 56.0. HRMS–ESI− (m/z): [M]− calcd for C9H6NO3S2: 240.982814; found, 240.982805. DPPH-scavenging activity Determination of antioxidant activity was performed according to the procedure described in the literature [21]. A DMSO

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• exchange and dispersion interactions in CHCl3 in relation to DMSO are the driving forces behind the placement of sec-amine molecules into the R[4]A cavity and the formation of “in” type complexes. Keywords: complexes; DFT calculations; hydrogen bond; resorcin[4]arene; supramolecular chemistry

• stoichiometry complexes recorded in DMSO-d6 and CDCl3 solution are very different. On the other hand, complexes with a 1:2 stoichiometry are insoluble in CDCl3, hence their further analysis is limited to the solution in DMSO. Figure 1 shows the 1H NMR spectra of the 1:1 complex of R[4]A with pyrrolidine in DMSO

• -d6 and CDCl3, respectively. In DMSO, the resonances of the triplet and multiplet protons of the pyrrolidine molecule are located at 2.77 ppm and 1.62 ppm, respectively. On the other hand, in CDCl3, the protons of the pyrrolidine molecule are located at the following ppm: 3.59 (t), 3.51(t), 1.96 (m

Synthesis and biological evaluation of Argemone mexicana-inspired antimicrobials

• Jessica Villegas,
• Bryce C. Ball,
• Katelyn M. Shouse,
• Caleb W. VanArragon,
• Ashley N. Wasserman,
• Hannah E. Bhakta,
• Allen G. Oliver,
• Danielle A. Orozco-Nunnelly and
• Jeffrey M. Pruet

Beilstein J. Org. Chem. 2023, 19, 1511–1524, doi:10.3762/bjoc.19.108

• original berberine used a DMSO solution [11]. Thus, we reevaluated a number of variants and berberine itself using DMSO solutions at the same concentrations. Several results showed comparable zones of inhibition to those collected with methanol solutions, with one significant exception. When tested against

• S. aureus, the DMSO solutions were roughly 1.4 times more potent than results with the methanol solution (see Supporting Information File 1). This improved potency was seen for original berberine as well as the variants tested. Variants that were inactive as methanol solutions remained inactive when

• their DMSO solutions were tested. While this was a notable improvement against S. aureus, the general trends in potency were in agreement with those presented in Table 1. Furthermore, some organisms showed a weak zone of inhibition with the DMSO blank. This fact, coupled with the general trends in

Application of N-heterocyclic carbene–Cu(I) complexes as catalysts in organic synthesis: a review

• Nosheen Beig,
• Varsha Goyal and
• Raj K. Bansal

Beilstein J. Org. Chem. 2023, 19, 1408–1442, doi:10.3762/bjoc.19.102

• DMSO. However, the Cu(I) complex 54 was obtained in trace amounts only (Scheme 18) [31]. This complex could be obtained in good yield through transmetallation of the corresponding Ag complex as discussed later in Scheme 24. Douthwaite and co-workers reported the synthesis of Cu(I) bromide complexes 56a

Consecutive four-component synthesis of trisubstituted 3-iodoindoles by an alkynylation–cyclization–iodination–alkylation sequence

• Nadia Ledermann,
• Alae-Eddine Moubsit and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2023, 19, 1379–1385, doi:10.3762/bjoc.19.99

• nitrogen protection or activation using KOt-Bu in DMSO as a base. Under these conditions, the formation of the terminal (aza)indole anion is the driving force (Scheme 1) [34]. As a consequence, the electrophilic trapping of this intermediate with alkyl halides provides as concise access to N-substituted

• , 122 mg, 1.20 mmol), DBU (457 mg, 3.00 mmol), and DMSO (1.50 mL) were added under nitrogen. The reaction mixture was heated at 100 °C (oil bath) for 2 h. After cooling to room temperature, potassium tert-butoxide (505 mg, 4.50 mmol) and DMSO (1.50 mL) were added to the reaction mixture and heated to

• 100 °C (oil bath) for 15 min. After cooling to room temperature, N-iodosuccinimide (3, 338 mg, 1.50 mmol) and DMSO (1.00 mL) were added and the mixture stirred at room temperature for a further 2 to 5 h (monitored by TLC). Then, methyl iodide (4a, 639 mg, 4.50 mmol) was added and the reaction mixture

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• chromatography. Because 4.6 was obtained in better yields and in only 3 steps, the epimerization of 4.6 to 4.10 was also reported (Figure 4B). This epimerization is achieved in three-step sequence that starts with the double tosylation of 4.6 to produce 4.11. Then, the SN2 reaction with potassium acetate in DMSO

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• deprotonation the latter with sodium hydride base. The compound shows poor solubility in most common organic solvents with moderate solubility in dichloromethane, 1,2-dichlorobenzene and dimethyl sulfoxide (DMSO). Compound 4BGIPN was characterized by high-resolution mass spectrometry (HRMS), elemental analysis

• Supporting Information File 1 for NMR). In DMSO-d6 solution, 4BGIPN isomers do not show interconversion even upon warming to 120 °C, resulting in a similar set of signals. Excellent fit between HRMS and elemental analysis further supports the formation of the isomeric mixture of 4BGIPN as evidenced by the

• benzonitrile acceptor core. We found that the material is formed as a mixture of the rotational isomers that do not experience interconversion upon heating the 4BGIPN solution in DMSO to 120 °C. Two rotational isomers were successfully crystallized to show different up and down orientations of the

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

• Vladislav Yu. Shuvalov,
• Ekaterina Yu. Vlasova,
• Tatyana Yu. Zheleznova and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

• ) under solvent-free conditions, through subsequent elimination of a benzamide molecule in a superbasic medium (t-BuOK/DMSO). The fluorescent properties of the synthesized compounds were studied. 4-Arylpyrazolo[3,4-b]pyridin-6-ones luminesce in the region of 409–440 nm with a quantum yield of 0.09–0.23

• (Table 1). For compound 3a, the possibility of benzamide elimination was studied. The benzamide fragment is a poor leaving group; however, in a superbasic medium, we were able to eliminate this group in compound 3a. In order to select optimal synthesis conditions, we heated compound 3a in DMSO at

• temperatures from 90 to 150 °C for 1.5, 3.5 and 6 h in the presence of KOH or t-BuOK (Table 1). The best yield of 4-phenylpyrazolo[3,4-b]pyridin-6-one 4а (81%) was achieved at 150 °C in DMSO containing 1.5 equiv of t-BuOK for 1.5 h. Obviously, the preparation of 4-phenylpyrazolo[3,4-b]pyridin-6-one 4а could be

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• halides and the coupling products were obtained in good yields (52–74%) (Figure 4B). To suppress the rapid HAT with solvent DMF that yields the dehalogenated product, DMSO was chosen as solvent for the C–H arylation. When applying the catalytic protocol to 2-allyloxy-1,3,5-tribromobenzene, the 5-exo-trig

• a two-photon process. DBU was found to quench the steady-state fluorescence of *PC1 with a quenching rate constant two orders of magnitude smaller than the diffusion rate constant in DMSO at 298 K and one order of magnitude greater under the borylation reaction conditions (i.e., 0.20 M DBU) than the

• obtained by transient absorption spectroscopy with femtosecond pulsed laser excitation and were 2–3 orders of magnitude greater (e.g., keT (*PC1•−) = 6.8 × 1010 s−1) than the diffusion rate in DMSO (kdiff = 4.0 × 108 s−1 of 0.12 M 1d) confirming a preassociation of PC1•− and the substrate prior to PET

Synthesis of imidazo[4,5-e][1,3]thiazino[2,3-c][1,2,4]triazines via a base-induced rearrangement of functionalized imidazo[4,5-e]thiazolo[2,3-c][1,2,4]triazines

• Dmitry B. Vinogradov,
• Alexei N. Izmest’ev,
• Angelina N. Kravchenko,
• Yuri A. Strelenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2023, 19, 1047–1054, doi:10.3762/bjoc.19.80

• synthetic bioactive 1,3-thiazine and imidazothiazolotriazine derivatives with high antiproliferative activity. 1H NMR spectra of the starting compound 1d (a) and the reaction mixture after 1.5 (b) and 4 (c) hours in DMSO-d6 (the colored signals correspond to the protons shown in red in Scheme 4). 1H NMR

• spectra of compounds 4a and 5a in DMSO-d6 in the region of 4.3–9.0 ppm. 13C NMR GATED spectra of compounds 4a and 5a in DMSO-d6 in the region of 156.0–168.0 ppm. General view of 5a in the crystal in thermal ellipsoid representation (p = 80%). Base-induced transformations and rearrangements of

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• such as 2 and 3 and did not. Recently the solid complex of CO2 and 1 have been studied as a food product additive [9][10][11]. Anions of 1 in DMSO have been found to have a high capacity for capturing of CO2 [12]. Being cheap, biodegradable and eco-friendly these carbohydrates might form the basis in

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• -free and greener synthesis of various N-substituted pyrroles 43 under solvent-free conditions (Scheme 20a). For the optimizations of the reaction conditions, various catalysts (Ca(NO3)2∙4H2O, UO2(NO3)2∙6H2O, Bi(NO3)2∙5H2O) and solvents (H2O, CH3CN, EtOH, DMSO, DMF, MeOH, CH2Cl2, no solvent) were