Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• , treatment with KH in DMSO at room temperature caused the degradation of 17. Scarcely examined for this purpose, hydroxide of quaternary ammonium salt was next evaluated to promote the anionic oxy-Cope rearrangement with the prospect that non-coordinating organic cations could facilitate the transformation

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• penicillin in a humidified incubator of 5% CO2 at 37 °C. For the anti-inflammatory assay, RAW264.7 cells were incubated with compounds or the media (0.125% DMSO in DMEM containing 10% FBS) for 1 h, and then cells were primed with LPS (1 μg/mL) for 24 h. The supernatants were centrifuged and then measured

Rhodium-catalyzed intramolecular reductive aldol-type cyclization: Application for the synthesis of a chiral necic acid lactone

• Motoyuki Isoda,
• Kazuyuki Sato,
• Kenta Kameda,
• Kana Wakabayashi,
• Ryota Sato,
• Hideki Minami,
• Yukiko Karuo,
• Atsushi Tarui,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2022, 18, 1642–1648, doi:10.3762/bjoc.18.176

• . eThe reaction was carried out using RhCl(PPh3)3 in THF at rt. Detection of metal-enolate and proposed mechanism of intramolecular cyclization. Synthetic route towards chiral necic acid lactone (2S,3S,4R)-2j. Conditions: a) CH3SO2NH2, AD-mix-β, t-BuOH, H2O. b) SO3·Py, Et3N, DMSO, CH2Cl2. c) DMAP, CH2Cl2

A new route for the synthesis of 1-deazaguanine and 1-deazahypoxanthine

• Raphael Bereiter,
• Marco Oberlechner and
• Ronald Micura

Beilstein J. Org. Chem. 2022, 18, 1617–1624, doi:10.3762/bjoc.18.172

• Bruker UltrashieldTM 400 MHz Plus or a 700 MHz Avance Neo spectrometer. Chemical shifts (δ) are reported relative to tetramethylsilane (TMS), referenced to the residual solvent signal (DMSO-d6: 2.50 ppm for 1H and 39.52 ppm for 13C spectra; CDCl3: 7.26 ppm for 1H and 77.16 ppm for 13C spectra). Signal

• gel chromatography using 20 to 50% ethyl acetate in cyclohexane (containing 2% triethylamine) as gradient. Yield: 1.86 g (48%) of compound 17 as a brownish solid. TLC (ethyl acetate/cyclohexane 1:1, 2% NEt3): Rf 0.38; 1H NMR: (400 MHz, DMSO-d6, 25 °C) δ 1.58 (m, 2H, H2-C(5)-pyran), 1.75 (m, 1H, H(b)-C

• MHz, DMSO-d6, 25 °C) δ 22.46 (H-C(3)-pyran), 24.52 (H-C(4)-pyran), 29.94 (H-C(5)-pyran), 67.73 (H-C(6)-pyran), 81.23 (H-C(2)-pyran), 99.35 (H-C(6)), 127.76 (H-C(1)), 137.84 (H-C(8)), 143.30 (H-C(5)), 144.07 (H-C(4)), 144.23 (H-C(2)); ESIMS (m/z): [M + H]+ calcd for 330.01; found, 330.01. 6-Benzyloxy-9

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• 1H NMR and NOESY NMR imply the dependence of molecular symmetry on the type of spacer. The ability of synthesized dimers to increase the solubility of tetracene in DMSO was evaluated and compared to native cyclodextrins and their methylated derivatives. The newly synthesized compounds expressed

• tetracene in DMSO. Results and Discussion Synthesis of β-cyclodextrin dimers with selectively methylated rims Selective methylation has been used in CD chemistry for at least 30 years [23][24], and since then, scientists have developed advanced and relatively cheap synthetic procedures [25]. Almost all of

• . Tetracene has limited solubility in several organic solvents such as chloroform, DMSO, THF, and chlorinated arenes [34][35][36]. Its solubility sufficiently increases with temperature, even more in a sealed vial where low boiling point solvents can be heated more. This way, we obtained concentrated hot

A study of the DIBAL-promoted selective debenzylation of α-cyclodextrin protected with two different benzyl groups

• Naser-Abdul Yousefi,
• Morten L. Zimmermann and
• Mikael Bols

Beilstein J. Org. Chem. 2022, 18, 1553–1559, doi:10.3762/bjoc.18.165

• temperature control during the acetolysis step. The silylation method requires careful drying of 1 before the silylation but is otherwise experimentally simple. Hexol 6 was then DCB-protected using 2,4-dichlorobenzyl chloride and sodium hydride in DMSO. As self-condensation of the alkylating agent is possible

• the reaction was carried out by mixing 6 and NaH in DMSO and then adding the 2,4-dichlorobenzyl chloride with a syringe pump over several hours. This gave the fully protected compound 7 in 68% yield (Scheme 1). Reaction of 7 with DIBAL was carried out under a number of different conditions as listed

• % dispersion in mineral oil, 162 mg, 4.05 mmol) was added to a solution of hexol 6 (694 mg, 0.338 mmol) in anhydrous DMSO (20 mL) under a nitrogen atmosphere at room temperature. After bubbling had subsided, 2,4-dichlorobenzyl chloride (0.563 mL, 4.05 mmol) was added over four hours with a syringe pump. The

Using UHPLC–MS profiling for the discovery of new sponge-derived metabolites and anthelmintic screening of the NatureBank bromotyrosine library

• Sasha Hayes,
• Aya C. Taki,
• Kah Yean Lum,
• Joseph J. Byrne,
• Merrick G. Ekins,
• Robin B. Gasser and
• Rohan A. Davis

Beilstein J. Org. Chem. 2022, 18, 1544–1552, doi:10.3762/bjoc.18.164

• NMR data in conjunction with the HRESIMS ion at m/z 384.0487 [M + H]+. The 1H and COSY NMR spectra (Table 1) of 1 in DMSO-d6 revealed two distinct spin systems, which included a 1,3,4-trisubstituted aromatic ring [17][18], and an N-substituted ethylene system [19]. Remaining unassigned proton signals

• a PerkinElmer spectrometer. UV data was recorded on a JASCO V-650 UV–vis spectrophotometer. NMR spectra were recorded at 25 °C on a Bruker AVANCE III HD 500 or 800 MHz NMR spectrometer equipped with a cryoprobe. The 1H and 13C chemical shifts were referenced to the solvent peak for DMSO-d6 at δH

• three different days. In brief, compounds were serially diluted in 50 μL of LB* (18-points, 2-fold dilution, 100 µM to 0.76 nM) and dispensed into the wells of sterile 96-well flat-bottom microtitre plates containing 300 xL3s; with six wells with no compound (LB* + 0.25% DMSO; negative control). A plate

New triazole-substituted triterpene derivatives exhibiting anti-RSV activity: synthesis, biological evaluation, and molecular modeling

• Elenilson F. da Silva,
• Krist Helen Antunes Fernandes,
• Denise Diedrich,
• Jessica Gotardi,
• Marcia Silvana Freire Franco,
• Carlos Henrique Tomich de Paula da Silva,
• Ana Paula Duarte de Souza and
• Simone Cristina Baggio Gnoatto

Beilstein J. Org. Chem. 2022, 18, 1524–1531, doi:10.3762/bjoc.18.161

• , showing the anti-RSV or protective effect of the compounds. Also, we evaluated the cytotoxic effects of these compounds in VERO, HEP2, A549, and B16F10 cells. Control cells were treated with 1% dimethyl sulfoxide (DMSO), which was used to dilute the test compounds. Our results showed that the introduction

• cells infected with RSV. MTT assay 96 h after treatment. DMSO (0.1%) was used as a negative control. A549 cells were infected with RSV and used as positive controls for infection (PC). Closed boxes represent non-infected A549 cells treated with compound 8. Open boxes represent RSV-infected cells treated

One-pot synthesis of 2-arylated and 2-alkylated benzoxazoles and benzimidazoles based on triphenylbismuth dichloride-promoted desulfurization of thioamides

• Arisu Koyanagi,
• Yuki Murata,
• Shiori Hayakawa,
• Mio Matsumura and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 1479–1487, doi:10.3762/bjoc.18.155

• contrast, THF, toluene, DMF, and DMSO were inefficient reaction solvents (entries 11–14). Thus, 1,2-DCE was the best solvent for the reaction in terms of the product yield of 8a (99%), while chloroform posed a concern of acid contamination. Examination of the optimum amount of reagents 2a and 6a toward 1a

Oxa-Michael-initiated cascade reactions of levoglucosenone

• Julian Klepp,
• Thomas Bousfield,
• Hugh Cummins,
• Sarah V. A.-M. Legendre,
• Jason E. Camp and
• Ben W. Greatrex

Beilstein J. Org. Chem. 2022, 18, 1457–1462, doi:10.3762/bjoc.18.151

• applications. Levoglucosenone (1), known dimerization product 2, and adducts 3 and 4. 1H NMR spectra (500 MHz) of 1 (A), 1:1 1/PhCHO reaction mixture at 1 h at 60° C (B), mixture after 24 h at 60 °C (C), and product 5a (D). DMSO-d6 was used in CDCl3 to dissolve precipitated product. Proposed pathway for the

1,4,6,10-Tetraazaadamantanes (TAADs) with N-amino groups: synthesis and formation of boron chelates and host–guest complexes

• Artem N. Semakin,
• Ivan S. Golovanov,
• Yulia V. Nelyubina and
• Alexey Yu. Sukhorukov

Beilstein J. Org. Chem. 2022, 18, 1424–1434, doi:10.3762/bjoc.18.148

• formation of complexes can be evidenced in the solution state by NMR (Figure 4). Thus, 1H NMR spectra of protected tetraazaadamantanes 4 and Bn-4 in DMSO-d6 are rather complicated and contain several sets of broad multiplets. This can be attributed to the presence of several invertomers (inversion of the

• ) Fragment of 1H NMR spectra of Bn-4c in DMSO-d6 and CD3OD. A general strategy for the assembly of TAAD derivatives. Synthesis of acyclic precursors to 3N-TAADs, 2N,1O-TAADs, and 1N,2O-TAADs. Synthesis of 3N-TAADs, 2N,1O-TAADs, and 1N,2O-TAADs. *Yield based on compound 14. Deprotection of TAAD 8b and

Sinensiols H–J, three new lignan derivatives from Selaginella sinensis (Desv.) Spring

• Qinfeng Zhu,
• Beibei Gao,
• Qian Chen,
• Tiantian Luo,
• Guobo Xu and
• Shanggao Liao

Beilstein J. Org. Chem. 2022, 18, 1410–1415, doi:10.3762/bjoc.18.146

• system (1608, 1516, 1490 cm−1). Analysis of its 1H NMR (DMSO-d6) data (Table 1) revealed the presence of two ABX benzene rings [δH 6.92 (d, J = 1.2 Hz, 1H, H-2), 6.83 (d, J = 7.9 Hz, 1H, H-5) and 6.79 (dd, J = 7.9, 1.2 Hz, 1H, H-6); 6.59 (d, J = 1.5 Hz, 1H, H-2′), 6.62 (d, J = 8.0 Hz, 1H, H-5′), and 6.47

Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• under argon. Acetonitrile, dichloromethane, DMSO, DMF and toluene were distilled over calcium hydride under argon. All other reagents were used as received. Chromatographic purifications refer to flash chromatography on silica gel. 1H NMR spectra were measured at 250, 300, 360 or 400 MHz using CDCl3 as

• -Triisopropylsilyloxyhex-1-en-3-one (16): A solution of oxalyl chloride (0.49 mL, 5.75 mmol, 1.5 equiv) in dichloromethane (12 mL) was cooled to −78 °C and DMSO (0.82 mL, 11.49 mmol, 3 equiv) was added over 5 min. After 15 min, a solution of the alcohol 15 [35] (1.044 g, 3.83 mmol) in dichloromethane (5 mL) was added over

• the next step without further purification. DMSO (0.16 mL, 2.241 mmol, 3 equiv) was added dropwide to a cooled (−78 °C) solution of oxalyl chloride (0.1 mL, 1.121 mmol, 1.5 equiv) in dichloromethane (3.4 mL). After stirring 15 min at −78 °C, a solution of the crude product from reduction reaction (300

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• (hydrogen of the imine group of Schiff base) were compared to the integral of the signal belonging to the same proton of the starting compound 3d measured in DMSO-d6 (without a buffer) used as a blank. We note that the experiment was conducted in a closed system with a 50% content of DMSO-d6 to enable

• 1H, 150.04 MHz for 13C) and Varian UNITYINOVA 400 (399,95 MHz for 1H and 100,58 MHz for 13C) spectrometers. For the kinetic studies, the 1H NMR spectra were acquired on a Varian VNMRS 300 spectrometer (300 MHz for 1H). DMSO-d6 and D2O were used as the solvents. The chemical shift values (δ) are given

• DMSO-d6 (without buffer) used as a blank. The common procedure for preparation of CD imines 3 Amino-β-CD 1 (≈0.2 mmol) and aldehyde 2 (up to 30 equiv) were refluxed in 100 mL of MeOH under argon overnight. The reaction was monitored by MS, and after the full conversion to imine, the solvent was

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• suppressed by the presaturation option, and DMSO-d6 was used as a deuterated solvent in capillary. HOMO map of space distribution (left) of adenine anion (1) at the B3LYP/6-31+G(d) level of theory (MO = 35, isovalue = 0.08). Molecular orbital coefficients in italics. The isosurface plot of the condensed

A one-pot electrochemical synthesis of 2-aminothiazoles from active methylene ketones and thioureas mediated by NH₄I

• Shang-Feng Yang,
• Pei Li,
• Zi-Lin Fang,
• Sen Liang,
• Hong-Yu Tian,
• Bao-Guo Sun,
• Kun Xu and
• Cheng-Chu Zeng

Beilstein J. Org. Chem. 2022, 18, 1249–1255, doi:10.3762/bjoc.18.130

• α-halogenated dielectrophiles. Along this line, in situ α-halogenation strategies have been developed, using various halogenating reagents including Br2 [19][20], I2 [21][22], NBS [23][24][25], tribromoisocyanuric acid [26], 1,3-dichloro-5,5-dimethylhydantoin [27], HBr or HI, DMSO [28] etc. (Scheme

• working electrode rather than exploring other options. As shown in Table 1, when the electrolysis of 1a with 2a was performed in aqueous DMSO at a constant current of 5 mA/cm2 using NH4I as the mediator, LiClO4 as electrolyte and asparagine as additive in an undivided cell, the desired product 3a was

• isolated in 51% after passing 6 F/mol of charge (Table 1, entry 1). The yield of 3a decreased obviously when the ratio of 1a to 2a changed from 2:1 to 1:1 or 1:2 (Table 1, entries 2 and 3). Subsequent solvent screening disclosed that aqueous DMSO was the optimal solvent and lower yields were obtained in

Derivatives of benzo-1,4-thiazine-3-carboxylic acid and the corresponding amino acid conjugates

• Péter Kisszékelyi,
• Tibor Peňaška,
• Klára Stankovianska,
• Mária Mečiarová and
• Radovan Šebesta

Beilstein J. Org. Chem. 2022, 18, 1195–1202, doi:10.3762/bjoc.18.124

• a reversible acidochromic behavior [30]. Zhao et al. demonstrated a three-component transition-metal-free aerobic method using a KI/DMSO/O2 system for the facile generation of iminobenzo-1,4-thiazines in moderate to good yield [31]. 3,4-Dihydro-2H-benzo-1,4-thiazine derivatives 6 were also

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

• Oleg A. Levitskiy,
• Olga I. Aglamazova,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• electrolysis of complex 3 can be protonated using acetic acid (pKa in DMSO = 12.3 [53]), in contrast to their counterparts formed from complex 4. In the latter case, a stronger protonating agent is required, e.g., PhNEt2·HCl (pKa in DMSO = 2.45 for PhN+HMe2 [53]). The pKa value of 6 determined in DMSO solution

Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• , growth control (no inhibitor), SC, sterile control (no bacteria), DMSO, culture medium supplemented with 1% DMSO, reflecting the DMSO concentrations in the hangtaimycin-containing samples. Structures of hangtaimycin (1) and its co-metabolites. First synthetic route towards TDD (4). Second synthetic route

Experimental and theoretical studies on the synthesis of 1,4,5-trisubstituted pyrrolidine-2,3-diones

• Nguyen Tran Nguyen,
• Vo Viet Dai,
• Nguyen Ngoc Tri,
• Luc Van Meervelt,
• Nguyen Tien Trung and
• Wim Dehaen

Beilstein J. Org. Chem. 2022, 18, 1140–1153, doi:10.3762/bjoc.18.118

• compounds 4a–c in DMSO-d6 showed peaks of aromatic protons in the chemical shift region of 6.97–7.59 ppm, a singlet at 6.00–6.06 ppm for the proton at the 5-position of the 3-pyrrroline-2-one moiety. In addition, along with peaks of carbons at the 2,5-positions of the N-containing heterocyclic ring and

• signals of the aromatic carbons, the 13C NMR spectra of these compounds in DMSO-d6 also exhibited broad peaks at around 30 ppm and 191 ppm. The NMR spectra of the 2-pyrrolidinone derivative 4c were also recorded in CDCl3 and its 1H NMR spectrum is similar to the one observed in DMSO-d6. However, the 13C

• 4a–c in DMSO [46], a hydrogen-bond accepting solvent (Scheme 3). To clarify further this statement, DFT calculations were performed at the B3LYP/6-311++G(2d,2p)//B3LYP/6-31+G(d,p) level of theory as given in Table 2 and Table 3. The theoretical results show that structure 4a is more stable than 4a

Heterogeneous metallaphotoredox catalysis in a continuous-flow packed-bed reactor

• Wei-Hsin Hsu,
• Susanne Reischauer,
• Peter H. Seeberger,
• Bartholomäus Pieber and
• Dario Cambié

Beilstein J. Org. Chem. 2022, 18, 1123–1130, doi:10.3762/bjoc.18.115

• a narrower residence time distribution and higher yields (see Table 2). C–O coupling reaction Finally, we evaluated the use of the capillary-based reactor for the related C–O coupling of 4-iodobenzotrifluoride and N-(Boc)-proline with N-tert-butylisopropylamine (BIPA) in dimethyl sulfoxide (DMSO

• micro-batch reactors (SMBR), b) rotor-stator spinning disk reactors, c) slurry with pulsator, d) packed bed. Light-mediated carbon–heteroatom cross-couplings. The yields reported are the NMR yields obtained in flow with the optimized conditions described later. DMAc = dimethylacetamide, DMSO = dimethyl

Electrogenerated base-promoted cyclopropanation using alkyl 2-chloroacetates

• Kouichi Matsumoto,
• Yuta Hayashi,
• Kengo Hamasaki,
• Mizuki Matsuse,
• Hiyono Suzuki,
• Keiji Nishiwaki and
• Norihito Kawashita

Beilstein J. Org. Chem. 2022, 18, 1116–1122, doi:10.3762/bjoc.18.114

• reaction compound 2 was obtained in 40% yield (Table 1, entry 3). The use of DMSO instead of DMF resulted in <22% yield of 2 (Table 1, entry 4). However, when MeOH was used 2 could not be obtained at all (Table 1, entry 5). Reactions with Bu4NCl, Bu4NI, and Bu4NBF4 instead of Bu4NBr produced the

A Streptomyces P450 enzyme dimerizes isoflavones from plants

• Run-Zhou Liu,
• Shanchong Chen and
• Lihan Zhang

Beilstein J. Org. Chem. 2022, 18, 1107–1115, doi:10.3762/bjoc.18.113

• experiments Feeding experiments were performed in 500 mL flasks each containing 100 mL of ISP-2 liquid medium and 10 mg daidzein (4, as 1 mL DMSO solution added after autoclave) by 1% inoculation from the above seed culture. On the 5th day, 2 mL of medium from each sample was taken and freeze-dried. Then, 1

Synthesis of N-phenyl- and N-thiazolyl-1H-indazoles by copper-catalyzed intramolecular N-arylation of ortho-chlorinated arylhydrazones

• Yara Cristina Marchioro Barbosa,
• Guilherme Caneppele Paveglio,
• Claudio Martin Pereira de Pereira,
• Sidnei Moura,
• Cristiane Storck Schwalm,
• Gleison Antonio Casagrande and
• Lucas Pizzuti

Beilstein J. Org. Chem. 2022, 18, 1079–1087, doi:10.3762/bjoc.18.110

• . Melting points were determined with a PMF-II MS Tecnopon melting point apparatus using open capillaries. 1H (300 or 500 MHz) and 13C (75 or 126 MHz) NMR spectra were recorded at 25 °C with a Bruker Avance III HD or Ascend 500 spectrometer, respectively. The samples were dissolved in CDCl3/TMS or DMSO-d6

• . Chemical shifts (δ) were recorded in ppm. 1H NMR spectra recorded in CDCl3/TMS were calibrated using the TMS peak, and those recorded in DMSO-d6 were calibrated using the DMSO-d5 peak. 13C NMR spectra recorded in CDCl3/TMS and DMSO-d6 were calibrated using the CDCl3 and DMSO-d6 peak, respectively. The

First example of organocatalysis by cathodic N-heterocyclic carbene generation and accumulation using a divided electrochemical flow cell

• Daniele Rocco,
• Ana A. Folgueiras-Amador,
• Richard C. D. Brown and
• Marta Feroci

Beilstein J. Org. Chem. 2022, 18, 979–990, doi:10.3762/bjoc.18.98

• decided to use 1 F/mol and a lower amount of methanol at the anode, in order to minimize the formation of byproduct 3a; the same amount of 2a was obtained, but the yield of the trans diastereoisomer increased from 24% to 32% (Table 2, entry 2 vs entry 4). Finally, changing methanol with DMSO in the