Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• reduced pressure. The remaining residue was purified via column chromatography (gradient ethyl acetate/hexane) to afford 6-(2-fluorophenyl)pyridin-2-ylamine (9b, 9.98 g, 93%). 1H NMR (400 MHz, CDCl3, δ) 7.92–7.88 (m, 1H), 7.53–7.49 (m, 1H), 7.36–7.31 (m, 1H), 7.25–7.20 (m, 1H), 7.16–7.10 (m, 1H), 6.50

• was added, followed by thorough extraction. The combined organic layer was dried over magnesium sulfate, filtered, and dried under reduced pressure. The remaining residue was purified via column chromatography (gradient ethyl acetate/hexane) to afford 6-bromo-5-(2-fluorophenyl)[1,3]thiazolo[4,5-b

• acetonitrile, formic acid was added, and the reaction mixture was stirred at room temperature for 2 h. The phases were separated via phase separator, and the organic layer was concentrated under reduced pressure. The remaining crude product was purified via column chromatography (gradient ethyl acetate/hexane

A new analog of dihydroxybenzoic acid from Saccharopolyspora sp. KR21-0001

• Rattiya Janthanom,
• Yuta Kikuchi,
• Hiroki Kanto,
• Tomoyasu Hirose,
• Arisu Tahara,
• Takahiro Ishii,
• Arinthip Thamchaipenet and
• Yuki Inahashi

Beilstein J. Org. Chem. 2024, 20, 497–503, doi:10.3762/bjoc.20.44

• (Scheme 1). KR21-0001A (1) was purified from the culture broth guided by the ion peak (m/z 316) using LC–MS. The supernatant of the culture broth underwent HP20 column chromatography, but 1 was not retained in the resin and eluted in the flowthrough fraction. Since 1 was an acidic compound, the pH of the

• flowthrough fraction was adjusted to 3 with formic acid (FA) and chromatographed again on HP20 column. Now, 1 was retained in the resin and eluted by 50% MeOH with 0.05% FA. Then 1 was purified by silica gel and ODS column chromatography, and ethyl acetate extraction under acidic conditions. As the result of

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• Discussion For chemical investigation, the solvent EtOAc was used to extract the fermentation culture of the fungus P. boydii CS-793 to afford an organic extract. Isolation and purification of the crude extract with a combination of column chromatography (CC) by Lobar LiChroprep RP-18, silica gel, Sephadex

• by Chromeleon software (version 6.80). LC–MS were obtained with a Bruker maXis plus Q-TOF. Column chromatography was carried out using commercially available silica gel (200–300 mesh, Qingdao Haiyang Chemical Co.), Lobar LiChroprep RP-18 (40–63 μm, Merck), and Sephadex LH-20 (Pharmacia). Thin-layer

• chromatography (TLC) was performed with precoated Si gel GF254 plates (Merck, Darmstadt, Germany). Solvents used for extraction and purification were distilled prior to use. Peptone from yeast extract was purchased from Sigma-Aldrich. Rice, monosodium glutamate, and corn steep liquor were purchased from China

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• Supporting Information File 1). To isolate the main difluorinated product 3a, the reaction vessel was purged with nitrogen and the product mixture was partitioned between water and DCM to remove HF and salt by-products. Purification of 3a by column chromatography gave 3a as a white crystalline solid in 65

• . Again, purification by column chromatography gave the products 3 as white crystalline solids and the structures of compounds 3f and 3i were confirmed by X-ray crystallography (Figure 2 and Supporting Information File 1). Molecules 3a, f, and i all exist in the solid state with the dicarbonyl moiety

• , a range of ethyl benzoylacetate derivatives was prepared (see Supporting Information File 1) [45][46] and successfully subjected to difluorination conditions (Table 3). Purification by column chromatography using the minimum amount of silica gel with chloroform as the eluent yielded 5c–g in high

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• 11 had an allene structure. It was also important to note that the reaction proceeded more selectively in ether, which significantly reduced the amount of byproducts. Pure final alcohol 10 was isolated by column chromatography on SiO2 in 46% yield and 1H, 19F and 13C NMR spectra were in full

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• III 400 MHz and Bruker Avance neo 500 MHz spectrometers. High-resolution mass spectra were measured on a Bruker MaXis 4G spectrometer. Melting points were determined with a Kofler hot bench system. Chromatography purifications were performed using a CombiFlash NextGen 300 with Buchi FlashPure

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• . Results and Discussion We found that a convenient way toward 6,8-di-tert-butyl-2-(arylamino)-3H-phenoxazin-3-ones 4 involves the short-term heating (30 min) of a molten mixture of 1 and an arylamine at 250 °C, followed by purification of the products by column chromatography. No preliminary grinding of

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• compounds was performed on a Shimadzu LC-20AD liquid chromatography (CBM-20A Communication Bus Module, CTO-20A column oven, DGU-20A Degassing Unit and SIL-20A AutoSampler) coupled to a Shimadzu SPD-20A UV–vis Detector system using a RP-18 column (Shimadzu, Premier 250 × 10 mm i.d., 5 µm, flow rate of 3.0 mL

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• in bacteria as well as the oxidative environment of the secretory pathway, as CMA1 exhibits predicted disulfide bridges. A single step of His-tag affinity chromatography was sufficient to yield protein of adequate purity and good yield (≈15 mg of eluted protein from 800 mL of cell culture, Figure 1c

• hexa-His tag, cleavable by TEV (Tobacco etch virus) protease. Despite the presence of the DsbC signal peptide, we did not observe periplasmic localization, and all proteins were instead purified from the cytoplasm. Ni-NTA affinity chromatography followed by TEV protease cleavage of the fusion construct

• and subsequent reverse Ni-NTA affinity chromatography resulted in significant co-purification of E. coli contaminants, necessitating an extra purification step, where cation exchange chromatography allowed us to obtain pure fractions of CMA16–291. Of note, this additional purification step was not

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• purification by column chromatography prior to their on-surface deposition. By way of example, the synthesis of decacene precursor 59 was achieved in three synthetic steps by iterative [4 + 2] cycloadditions with an overall yield of 4.7% (Scheme 17). The synthesis of epoxyacene 59 started with the mono-Diels

Unveiling the regioselectivity of rhodium(I)-catalyzed [2 + 2 + 2] cycloaddition reactions for open-cage C₇₀ production

• Cristina Castanyer,
• Anna Pla-Quintana,
• Anna Roglans,
• Albert Artigas and
• Miquel Solà

Beilstein J. Org. Chem. 2024, 20, 272–279, doi:10.3762/bjoc.20.28

• heating at 90 °C for 4 hours. The crude reaction mass obtained with these conditions was then purified by column chromatography (toluene). After eluting unreacted pristine C70, a dark reddish fraction was isolated and analyzed by HPLC. A major peak was observed at a retention time of 17.5 minutes, which

• has Cs symmetry [50], we can conclude that the major product formed was the α-isomer, as previously anticipated. All attempts to separate the two isomers by column chromatography and preparative TLC were unsuccessful. Malonate-tethered compound 2b had the same spectroscopic behavior as 2a though in

• column chromatography, giving an inseparable mixture of different isomers. The oxygenation process was confirmed by HRMS, which gave a single peak at m/z = 1170.0756 corresponding to [3a + Na]+. On analyzing carefully the mixture by 1H NMR spectroscopy, we observed three different sets of three methyl

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• in vacuo and the resulting residue was subjected to 1H NMR spectroscopy or column chromatography. A divided-cell experiment was performed using an H-type cell (4G glass filter). Compound 1 (0.2 mmol), Bu4NPF6 (387 mg, 1 mmol), phosphate base (90 mg, 0.2 mmol), CH2Cl2 (10 mL), and methyl vinyl ketone

• was removed by filtration through a short silica gel pad under reduced pressure. The filtrate was concentrated in vacuo and the resulting residue was subjected to 1H NMR spectroscopy or column chromatography. Application of amidyl radical species generated by PCET. (A) Effect of phosphate base on the

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• results of 1H NMR spectra and TLC analysis, the second component was still present. This “permanent impurity” cannot be separated by chromatography or recrystallization, but it can be eliminated to some extent by washing the nitration products with hot chloroform, in which the impurity is slightly better

• with a potassium hydroxide solution, and the oxidation product was isolated by chromatography. Nitroacenaphthylene 13 can also be obtained similarly (Scheme 5). Thus, although nitro groups usually hinder the dehydrogenation of acenaphthenes, in our case, the opposite trend is observed. We believe that

Chiral phosphoric acid-catalyzed transfer hydrogenation of 3,3-difluoro-3H-indoles

• Yumei Wang,
• Guangzhu Wang,
• Yanping Zhu and
• Kaiwu Dong

Beilstein J. Org. Chem. 2024, 20, 205–211, doi:10.3762/bjoc.20.20

• and the reaction mixture was stirred at room temperature for 3 h. After concentrating the mixture, the residue was purified by column chromatography on silica gel using a mixture of petroleum ether/ethyl acetate 30:1 (v/v) as the eluent to afford products 2. The yields were determined by 19F NMR

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• filtered through a celite pad to remove the residual catalyst and base. The solvent was then evaportated under reduced pressure and the crude was purified by flash chromatography (hexane/AcOEt 9:1), to yield o-(2-bromophenyl)aminoaniline (3) compound as a purple oil (0.057 g, 47% yield). Via Chan–Lam

• then evaporated under reduced pressure and the crude was purified by flash chromatography (hexane/AcOEt 9:1), to yield o-(2-bromophenyl)aminoaniline (3a) as a purple oil (0.07 g, 59% yield).1H NMR (CDCl3, 400 MHz) δ 4.00 (s, NH2, 2H), 5.76 (s, NH, 1H), 6.59–6.61 (d, J = 8 Hz, Ar, 1H), 6.65–6.69 (t, J

• celite and washed with DCM, then, the solvent was evaporated under reduced pressure to give a crude mixture. Further purification by flash chromatography (hexane/AcOEt 1:1), gave the desired compound 5,10-dihydro-11H-dibenzo[b,e][1,4]diazepin-11-one (4a) as a yellow solid yield (0.032 g, 80%). Mp 249–251

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• the stereoselectivity of sialylation, it is important to analyze anomeric ratio values (α/β) for the disaccharide fraction separated by size-exclusion chromatography since the retention values of different disaccharide anomers on silica gel may be surprisingly large and a minor isomer may be lost

• during purification by silica gel chromatography. On the other hand, NMR analysis of the crude reaction mixtures may be misleading due to possible overlap of the signals of H-3eq belonging both to disaccharide and monosaccharide derivatives sometimes present in such glycosylation mixtures. At low

• glycosylation reactions was distilled under argon over P2O5 and then over CaH2 and stored over molecular sieves (MS) 3 Å. Powdered MS 3 Å (Fluka) were activated before the reactions by heating at ≈220 °C in high vacuum for 6 h. Column chromatography was performed on silica gel 60 (40–63 μm, Merck). Gel

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• removed from the reaction mixture in vacuo. Sulfation was then performed through addition of SO3·NMe3 to the DMF solution. Consumption of 1 was observed by TLC after 72 hours and stirring with Dowex® 50WX4 (Na+ form) resin resulted in formation of target 2. Purification by flash chromatography, however

• , led to isolation of a mixture of 2 and a tin-related impurity (n-butyl chain evident by NMR). Acetylation of this material followed by flash chromatography proved ineffective in removing the unwanted entity. To overcome this problem, flash chromatography was performed before stirring with the ion

• were carried out under an inert atmosphere of nitrogen in oven-dried glassware with magnetic stirring. N2-flushed plastic syringes were used to transfer air- and moisture-sensitive reagents. All reactions were monitored by thin-layer chromatography (TLC) on Merck® DC-Alufolien plates precoated with

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• diluted with ethyl acetate (20 mL) and washed with saturated sodium bicarbonate and brine successively. The organic layer was dried over anhydrous sodium sulfate and concentrated in vacuo. The residue was purified on preparative thin-layer chromatography (PTLC) to afford the desired product 3. Methods for

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• ) affords 7 with 16% yield, 8 with 25% yield, and 9 with 46% yield. Furthermore, 7 and 8 are efficiently converted into 10 and 11, respectively, with high yields (80% and 95%, respectively) via column chromatography employing silica gel in acetonitrile, thereby instigating further molecular transformation

• in TCBDs and DCNQs and their optical resolutions were first realized in 2010 through their conjugation with methylated fullerenes, as shown in Figure 2 [130]. The optical resolution was realized using a chiral high-performance liquid chromatography (HPLC) system equipped with an (S,S)-WHELK-O1 column

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• room temperature for 12 hours under visible light irradiation (450 nm). After completion, the reaction mixture was concentrated, and the crude product was purified by column chromatography to afford the desired dihydropyrido[1,2-a]indolone product. Representative dihydropyrido[1,2-a]indolone

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

• residue was purified by washing with n-pentane, n-hexane or n-hexane and EtOAc and subsequently by column chromatography or recrystallization from MeOH with addition of HClO4. 2-Methoxycarbonyl-8,9-dimethoxybenzo[c]quinolizinium perchlorate (3c) According to GP, a solution (c = 0.80 mM) of 2c (100 mg, 334

• chromatography (SiO2, CHCl3/MeOH 95:5 → 90:10). The crude product was filtered through celite, washed with n-pentane (3 × 10 mL), suspended in CHCl3 (1 mL) and filtered to give the product as brown amorphous solid, containing small amounts of impurities according to 1H NMR-spectroscopic analysis (4.0 mg, 11 µmol

• . H2O (5 mL). A saturated aq solution of NaBF4 (3 mL) was added to the solution. A brown precipitate was removed by filtration. The filtrate was extracted with MeNO2 (3 × 10 mL) and the solvent was evaporated to give a brown solid, which was purified by column chromatography (SiO2, CHCl3/MeOH, 95:5, Rf

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

• molecular sieves, or by drying over 3 Å molecular sieves. All remaining anhydrous solvents were obtained from a solvent drying tower (IT model PS-MD-05). HPLC grade solvents were used unless otherwise specified. Purification by chromatography was performed using silica gel (flash: 40–63 μm, Sepacore® Flash

• by flash column chromatography (SiO2, 20% EtOAc/heptane), and recrystallization from CH2Cl2/MeOH followed by centrifugation yielded 9 (136 mg, 57%) as an orange solid. Rf = 0.18 (70% CH2Cl2/heptane); mp 178–181 °C; 1H NMR (500 MHz, CDCl3) δ 7.99 (s, 1H), 7.80 (d, J = 8.4 Hz, 2H), 7.76 (s, 1H), 7.72

• MgSO4 and concentrated under reduced pressure. The residue was purified by flash column chromatography (SiO2, 20% EtOAc/heptane), yielding 13 (15.5 mg, 26%) as a purple solid. Rf = 0.23 (20% EtOAc/heptane); 1H NMR (500 MHz, CDCl3) δ 8.64 (s, 2H), 8.50 (s, 2H), 8.12 (s, 2H), 7.96 (s, 2H), 7.83 (d, J

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

• regulator (cmaR), under the control of tipA promoter (Figure 2A). When we cultured S. albus-cma and analyzed its metabolites by liquid chromatography–mass spectrometry (LC–MS), formation of avenalumic acid was not observed. Instead, production of p-coumaric acid (5) was detected (Figure 2B and Figure S3A,D

• and evaporated completely in vacuo. The residual materials were dissolved in 200 µL of methanol. The obtained samples were analyzed by liquid chromatography–electrospray ionization mass spectrometry (LC–ESIMS) using an LC-2040C 3D Plus system (Shimazu Corp., Kyoto, Japan) equipped with a COSMOCORE

• 2.6C18 Packed column (2.1 mm ID × 100 mm, Nacalai Tesque) coupled with a model LCMS-8040 liquid chromatography–mass spectrometer (LC–MS) (Shimazu Corp.). The compounds were eluted with a linear gradient of water/acetonitrile containing 0.1% formic acid. Isolation and structural determination of compound

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• Spinsolve 60 spectrometer operating at 62.5 MHz (1H NMR), 15.7 MHz (13C{1H} NMR) and 58.8 MHz (19F NMR) using the solvent as internal standard. All the NMR spectra of neat IL were performed on Spinsolve 60 spectrometer. The chemical shifts (δ) are given in ppm relative to TMS. Flash chromatography was

• removed under reduced pressure. The crude was analysed by 1H NMR and 13C NMR and then the products were purified by column chromatography. General procedure for the electrochemical generation of BF3 in BMIm-BF4 All the experiments were carried out in a home-made divided glass cell separated through a

• phase was washed with water (3 × 20 mL), dried on Na2SO4, filtered and then the solvent was removed under reduced pressure. The crude was analysed by 1H NMR and 13C NMR and then the products were purified by column chromatography. Procedure for the evaluation of the current efficiency in the

Aldiminium and 1,2,3-triazolium dithiocarboxylate zwitterions derived from cyclic (alkyl)(amino) and mesoionic carbenes

• Nedra Touj,
• François Mazars,
• Guillermo Zaragoza and
• Lionel Delaude

Beilstein J. Org. Chem. 2023, 19, 1947–1956, doi:10.3762/bjoc.19.145

• acetonitrile (Scheme 4). However, all our attempts to purify compounds 6c–f by recrystallization or column chromatography remained unsuccessful. Several studies have shown that metal alkoxides, such as potassium tert-butoxide (pKa = 22), were basic enough to deprotonate 1,2,3-triazolium salts (pKa ≈ 22–23