(Bio)isosteres of ortho- and meta-substituted benzenes

• H. Erik Diepers and
• Johannes C. L. Walker

Beilstein J. Org. Chem. 2024, 20, 859–890, doi:10.3762/bjoc.20.78

• of physicochemical data showed that the experimentally determined distribution coefficient (logD) and calculated partition coefficient (clogP) are slightly higher for the bioisosteres and the aqueous solubility at pH 7.4 was also increased (Figure 8) [45]. Fluxapyroxad bioisostere (±)-64 had a higher

• fibrosis drug orkambi [67], to its 1,3-cubane bioisostere 183 (Figure 25) [51]. This comparison showed that while the distribution coefficient (logD) did not significantly change upon bioisosteric replacement, the solubility at neutral and low pH as well as the intrinsic clearance rate in human liver

• microsomes (CLint) improved significantly. The increase in solubility is particularly marked at low pH. A related observation was made by Poole and co-workers for quinoline-substituted 1,2,3-BCPs, where larger increases in the lipophilicity of the bioisosteric compound were also found at low pH [68]. One

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• deoxygenated 30 mM tricine buffer at pH 7.5 were incubated for one hour at 21 °C in an anaerobic glove box. The samples were analyzed by LC–MS to measure final glyoxylate and NNG concentrations. The extracted ion chromatograms (EICs) showed that NNG was completely consumed and glyoxylate accumulated within the

• degradation was unrelated to E. coli being unable to uptake 2-NAE, in vitro experiments with purified, reduced Vs NnlA incubated with 2 mM 2-NAE at pH 7.5 were performed. The LC–MS EICs monitoring 2-NAE (m/z 105.03 ± 100 ppm) show the prominent peak characteristic for 2-NAE. The intensity of this peak does

• portion of NNG would be expected to exist as the inhibitory nitronate form at physiological pH, suggesting another potential role for nitramine groups as potent warheads in antibiotics. This antibiotic activity may also require further modification of NNG or its incorporation into a larger natural product

Synthesis and characterization of water-soluble C₆₀–peptide conjugates

• Yue Ma,
• Lorenzo Persi and
• Yoko Yamakoshi

Beilstein J. Org. Chem. 2024, 20, 777–786, doi:10.3762/bjoc.20.71

• successfully provide C60–peptide conjugates with one C60 and two peptide anchors as water-soluble moieties. Among three C60–peptide conjugates prepared, C60–oligo-Lys was soluble in water at neutral pH, and C60–oligo-Glu was soluble in buffer with a higher pH value, but C60–oligo-Arg was insoluble in water and

• purified. Solubility in water The water solubility of C60–peptide conjugates 5a–c was tested after the removal of any remaining solvent traces by lyophilization. Upon addition of Milli-Q® water (pH 7.0), C60–oligo-Lys (5a) was immediately and thoroughly solubilized. In contrast, the other conjugates, C60

• –oligo-Glu (5b, purified) and C60–oligo-Arg (5c, crude), did not produce transparent solutions in water at neutral pH value even by sonication (Figure 2). While C60–oligo-Glu (5b) was soluble in buffer with a higher pH value (>8.3), C60–oligo-Arg (5c) was not soluble in most polar and nonpolar solvents

Methodology for awakening the potential secondary metabolic capacity in actinomycetes

• Shun Saito and
• Midori A. Arai

Beilstein J. Org. Chem. 2024, 20, 753–766, doi:10.3762/bjoc.20.69

• carbonate and terminal olefin functionalities [50]. Thus, artificial methods of genetic engineering and chemistry also play an important role in the identification of novel secondary metabolites. Culture conditions Medium composition, pH, oxygen supply, light Simply modifying the culture conditions is an

• Zeeck and co-workers in the early 2000s, is a method in which the target bacteria are cultured under various conditions (medium composition, temperature, pH, oxygen supply, light quality and quantity, addition of precursors and enzyme inhibitors, etc.) and all metabolites obtained from them are analyzed

• to 12-fold increase) the expression of nine secondary metabolite biosynthetic gene clusters in Streptomyces coelicolor A3(2) [65]. Furthermore, it has been reported that changing the pH of the culture medium can also result in the production of new substances (Figure 3d). Jiang et al. achieved a

Research progress on the pharmacological activity, biosynthetic pathways, and biosynthesis of crocins

• Zhongwei Hua,
• Nan Liu and
• Xiaohui Yan

Beilstein J. Org. Chem. 2024, 20, 741–752, doi:10.3762/bjoc.20.68

• are highly soluble in hot water but slightly soluble in anhydrous ethanol and ether. The presence of multiple conjugated double bonds in crocins makes them susceptible to degradation when exposed to certain conditions, such as high temperature, the presence of metal ions or light, certain pH values

SOMOphilic alkyne vs radical-polar crossover approaches: The full story of the azido-alkynylation of alkenes

• Julien Borrel and
• Jerome Waser

Beilstein J. Org. Chem. 2024, 20, 701–713, doi:10.3762/bjoc.20.64

• source. Upon light irradiation, it can release an azide radical by homolysis of the I−N3 bond [46]. We were pleased to see that irradiation of a mixture of styrene (1a), Ph-EBX (2) and Ts-ABZ (3) afforded 17% isolated yield of the desired homopropargylic azide 4a (Table 1, entry 1). Heating the reaction

• to 80 °C instead of using light to form the radical only afforded traces of the product (Table 1, entry 2). Changing the solvent to DCE slightly increased the yield (Table 1, entry 3). Blue light with an emission spectrum centered around 467 nm was initially selected since Ph-EBX is known to absorb

• generate a large quantity of iodanyl radical from Ts-ABZ (3) homolysis and from the addition–elimination on Ph-EBX (2). Since no quencher is present in the mixture, we wondered if the accumulation of those radicals could be responsible for the low yields obtained. Addition of (TMS)3SiH, a H• donor

Regioselective quinazoline C2 modifications through the azide–tetrazole tautomeric equilibrium

• Dāgs Dāvis Līpiņš,
• Andris Jeminejs,
• Una Ušacka,
• Anatoly Mishnev,
• Māris Turks and
• Irina Novosjolova

Beilstein J. Org. Chem. 2024, 20, 675–683, doi:10.3762/bjoc.20.61

• was washed with pH 7.4 phosphate buffer to reach 96% purity [26]) yielded the regioisomers 15 of the sulfonyl group dance products at a lower yield than the previously mentioned oxidation step, which was most likely caused by the high reactivity of product 14, but the reaction conditions were not

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• optimal pH of Hyg17. We observed increased activity as the pH increased, with the greatest activity observed at pH 10.5–11 (Figure 2c and Supporting Information File 1, Figure S2). Similarly, LcIDH1 and LcIDH2 have an optimum pH of 9.3 and 9.5, respectively, while the myo-inositol dehydrogenase from

• Bacillus subtilis, BsIDH, has an optimal pH between 9.5–10 [12][13]. We also compared product formation between reactions with Hyg17 or BsIDH and myo-inositol using thin-layer chromatography (Supporting Information File 1, Figure S3). We found that both enzymes generated a ketone product with identical

• aminocyclitol [8]. However, none of the enzymes in the pathway have been characterized in vitro. In this study, we show that Hyg17 is an NAD+-dependent myo-inositol dehydrogenase with an optimal pH of 10.5–11. When tested on a range of inositol substrate, we show that Hyg17 has reduced activity on scyllo

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

• thiazole moiety into a thiazoline unit had a measurable impact on several physicochemical parameters, such as LogP and water solubility. Whilst thiazolo[4,5-b]pyridine 5 afforded a moderate water solubility of 49 mg/L, paired with a LogP of 2.28 (pH 2.3), the corresponding 2,3-dihydro[1,3]thiazolo[4,5-b

• ]pyridine 7b had a higher water solubility of 173 mg/L and a lower LogP of 1.59 (pH 2.3). However, the lipophilicity of the new 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines was highly dependent on the substituents. For example, the brominated analogs 13b and 13c showed considerably higher LogP values of 2.88

• . Active fractions were pooled together, and the buffer was exchanged into 25 mM potassium phosphate buffer pH 7.3 containing 10% glycerol with PD10 columns (GE Healthcare). Aliquots of the protein solution were frozen in liquid nitrogen and stored at −80 °C. LpFAT A fluorescence polarization assay

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• first part will be devoted to chemically responsive tweezers, including stimuli such as pH, metal coordination, and anion binding. Then, redox-active and photochemical tweezers will be presented. Keywords: coordination; molecular recognition; molecular switches; photoswitch; redox; supramolecular

• , enabling multilevel switches. The stimuli applied to trigger these conformational changes can be categorized into three principal types: chemical, photochemical, and electrochemical. Chemical stimuli involve the introduction of small reactive molecules, such as reagents, ions, or pH changes, and are

• and drug delivery systems [12]. pH-Responsive molecular tweezers A particular case of coordination-responsive systems is when a proton is used as a stimulus leading to pH-responsive systems with the protonation/deprotonation of the switchable moiety. The conformational switch in these systems is

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

• ; pH 7.0) as the starter and incubated at 180 rpm in a rotary shaker at 27 °C for 4 days. The 1% portion of the starter was transferred into 20 L of production medium (2% glycerol, 2% soybean meal, and 0.3% NaCl) in a jar fermenter and further incubated at 150 rpm, 27 °C, 0.5 VVM (volume per volume per

• analyzed by LC–MS. The flow-through and 0% fractions were mixed and adjusted to pH 3 by adding formic acid (FA). Then, the mixture was purified by eluting with MeOH/H2O (0%, 50%, and 100%) with 0.05% of FA through a HP20 column (55 i.d. × 500 mm). The 50% fraction was concentrated in vacuo to remove MeOH

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• recently developed series of bisbiphenylphosphine ligands, RP(o-biphenyl)2 (R = OPh, Ph, t-Bu) [36][37]. When urea alkene 1a (0.1 M, CD2Cl2) was treated with 1 mol % LAuOTf, where L = PhOP(o-biphenyl)2 (4a), PhP(o-biphenyl)2 (4b), t-BuP(o-biphenyl)2 (4c), the fastest rate to form 3a was observed with the

• ; there are similarities and differences in the way a sulfonamide or carbonyl impacts a neighboring nitrogen. Sulfonamides have different steric profiles from carbonyls [51]. According to Roush et al. the electron-withdrawing capability of the S(O2)Ph group is in between that of the C(O)Me and CO2Me

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

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

• ), did not give rise to any diffraction. Multiple layer plate or needles clusters were obtained in the presence of PEGs, but only showed weak diffraction (≈3.5 Å). Finally, in the presence of 20% PEG 8K, 0.2 M MgCl2, and 0.1 M Tris HCl pH 8.5, single diamond-shaped crystals were obtained after 1–2 days

• -ᴅ-thiogalactoside (IPTG) [Euromedex, #EU0008-C]. After 20 h, the cells were harvested by centrifugation at 5,000g for 10 min at 4 °C. For purification of bacterial recombinant CMA1, each gram of cell pellet was resuspended with 5 mL of buffer A (20 mM Tris-HCl pH 7.5, 500 mM NaCl). After addition of

• mL HisTrap column, where pure CMA1 protein was collected in the flowthrough and column wash. Full-length CMA1 (6-291) was purified from remaining E. coli contaminants using a 1 mL HiTrap™ SP Sepharose FF column (Cytiva) preequilibrated with 50 mM sodium acetate pH 5.5. After loading, the column was

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

• = 11.7, J4,5 = 10.3, J4,3e = 4.8, 1H, H-4), 7.27 (d, JNH,5 = 9.9, 1H, NH), 7.33–7.49 (m, 5H, Ph); 13C NMR (75 MHz, CDCl3, δ, ppm, J, Hz) 37.0 (C-3), 40.1 (CH2Cl), 40.3 (CH2Cl), 49.8 (C-5), 53.1 (OMe), 62.5 (C-9), 70.1 (C-4), 71.5, 71.8 (C-6, C-7), 75.5 (C-8), 88.2 (C-2), 114.1 (q, JC,F = 285, CF3), 114.2

• (q, JC,F = 285, CF3), 115.2 (q, JC,F = 288, CF3), 127.6, 129.6, 130.6, 136.0 (Ph), 156.4 (q, JC,F = 45, COCF3), 156.9 (q, JC,F = 44, COCF3), 158.0 (q, JC,F = 39, COCF3), 166.2, 167.5, 168.4 (COCH2Cl, CO2Me); 19F NMR (282 MHz, CDCl3, δ, ppm) −76.8 (NHCOCF3), −75.7, −75.2 (OCOCF3); HRESIMS (m/z): [M

• , J5,4 = 10.6, J5,NH = 10.3, J5,6 = 10.3, 1H, H-5), 4.13 (ABq, ΔδAB = 0.03, JAB = 14.7, 2H, CH2Cl), 4.76 (dd, J6,5 = 10.3, J6,7 = 2.2, 1H, H-6), 5.45 (dd, J7,8 = 4.4, J7,6 = 2.2, 1H, H-7), 5.77 (ddd, J4,3a = 11.4, J4,5 = 10.6, J4,3e = 4.8, 1H, H-4), 6.99 (d, JNH,5 = 10.3, 1H, NH), 7.33–7.50 (m, 5H, Ph

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

• large excess of HF·Py (40 equiv) proved to be necessary to remove the bulky silyl group. After concentration, the crude product was acetylated (Ac2O/Py, 1:2, v/v), furnishing per-acetylated compound 8 in a 53% yield over the 3 steps. Deacetylation of 8 with freshly prepared 1 M NaOMe/MeOH in MeOH at pH

• -300 4 Å molecular sieves (5.45 g) were added, and the resulting suspension was stirred at room temperature for 23 hours. NIS (5.23 g, 23.2 mmol) and AgOTf (577 mg, 2.25 mmol) were added, and the reaction was stirred at room temperature for 1 hour. Et3N was then added until the pH became neutral, and

• (100 mL) and freshly prepared 1 M NaOMe/MeOH was added until the solution reached pH 10. The reaction was stirred at room temperature for 1 hour, then neutralised with Amberlite® IR120 (H+ form) resin. The resin was filtered off, washed with MeOH and the filtrate was concentrated in vacuo. After

Tandem Hock and Friedel–Crafts reactions allowing an expedient synthesis of a cyclolignan-type scaffold

• Viktoria A. Ikonnikova,
• Cristina Cheibas,
• Oscar Gayraud,
• Alexandra E. Bosnidou,
• Nicolas Casaretto,
• Gilles Frison and
• Bastien Nay

Beilstein J. Org. Chem. 2024, 20, 162–169, doi:10.3762/bjoc.20.15

• to a complex mixture of products, the transformation of phenylmalonate substrate 16 (n = 0, Ar1 = Ph) in the presence of nucleophile 5 allowed the formation of cyclized indanyl product 17 in a decent 54% yield. Conclusion During this work, we demonstrated that the prenyl motif can be used as a

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

• : spectrum at the end of the irradiation. Photometric titration of ct DNA to 3c (A) 3e (B) 3f (C) and 3g (D) (c = 20 µM) in Na phosphate buffer (pH 7.0, T = 20 °C, cNa+ = 16 mM). The arrows indicate the development of the absorption bands during titration. Inset: plot of absorption versus cDNA. Fluorimetric

• titration of ct DNA to 3c (A), 3e (B), 3f (C), and 3g (D) (c = 20 µM) in Na phosphate buffer (pH 7.0, T = 20 °C, cNa+ = 16 mM). The arrows indicate the development of the emission bands during titration. Inset: plot of relative emission intensity versus cDNA. CD (A) and LD (B) spectra of 3f and ct DNA (cDNA

• = 20 µM) in Na phosphate buffer (pH 7.0, T = 20 °C, cNa+ = 16 mM) at LDR = 0 (black), 0.2 (red), 0.5 (green), 1.0 (blue), 1.5 (orange), and 2.0 (magenta). Changes of the absorption (A) and CD (B) spectra during the irradiation of 2e (1) and 2f (2) (c = 20 μM) in the presence of ct DNA (cDNA = 0.1 mM

Optimizing reaction conditions for the light-driven hydrogen evolution in a loop photoreactor

• Pengcheng Li,
• Daniel Kowalczyk,
• Johannes Liessem,
• Mohamed M. Elnagar,
• Dariusz Mitoraj,
• Radim Beranek and
• Dirk Ziegenbalg

Beilstein J. Org. Chem. 2024, 20, 74–91, doi:10.3762/bjoc.20.9

• ) processes, and photocatalysis. Upon upscaling, both PV-E and PEC reactors exhibit pH gradients at electrodes and elevated solution electrical resistivity. These challenges arise from the substantial separation between reduction and oxidation sites, alongside mass transport restrictions in the liquid phase

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

• , 4JP-C = 2.2 Hz, CCH3), 96.6 (d, 1JP-C = 99.0 Hz, C6), 124.6 (d, 1JP-C = 86.0 Hz, Ci-Ph), 127.3 (d, 2JP-C = 12.5 Hz, C5), 129.4 (d, 3JP-C = 11.9 Hz, C4), 131.3 (d, 4JP-C = 1.4 Hz, C3), 132.6 (d, 3JP-C = 9.3 Hz, C2), 132.9 (d, 3JP-C = 2.7 Hz, Cm-Ph), 133.4 (d, 2JP-C = 14.8 Hz, Co-Ph), 140.5 (d, 4JP-C

• = 8.0 Hz, Cp-Ph), 174.1 (d, 2JP-C = 4.4 Hz, C1), 174.8 (d, 3JP-C = 13.9 Hz, CO); 31P{1H} NMR (δ in ppm, 162 MHz, CDCl3, 298 K) 25.1; UV–vis (CHCl3): λmax = 352 nm (ε = 5.53 × 103 L mol−1 cm−1). 1H NMR spectrum of 2a recorded on a 300 MHz spectrometer in CDCl3 at 23 °C; the inset shows a 3D-model based

Facile access to pyridinium-based bent aromatic amphiphiles: nonionic surface modification of nanocarbons in water

• Lorenzo Catti,
• Shinji Aoyama and
• Michito Yoshizawa

Beilstein J. Org. Chem. 2024, 20, 32–40, doi:10.3762/bjoc.20.5

• , and graphene nanoplatelets) are achieved through noncovalent encircling with the bent amphiphiles. The resultant imidazole-modified nanocarbons display a pH-responsive surface charge, as evidenced by NMR and zeta-potential measurements. In addition, solubilization of a nitrogen-doped nanocarbon (i.e

• pyridinium-based amphiphiles (Figure 1c). The noncovalent modification of C60 with multiple imidazole side-chains is found to yield a pH-responsive surface charge, as evidenced by NMR and zeta-potential measurements. A nitrogen-doped nanocarbon, i.e., graphitic carbon nitride (g-C3N4), is likewise

• through the template effect of the hydrophobic nanocarbon guests (Table 2). Moreover, aromatic micelle (PA-Im)n and its host–guest composite (PA-Im)n·(C60)m were anticipated to provide pH-dependent ZPs via imidazole-based protonation/deprotonation. Micelle (PA-Im)n showed a significantly higher ZP (41.7

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

• metabolites were extracted with 5 mL of ethyl acetate after adjusting the pH to approximately 4 by adding 6 M HCl. The ethyl acetate layer was collected, and it was washed with an equal volume of distilled water to remove the compounds that can be dissolved in water. The ethyl acetate layer was then collected

• (15 mg/L) was added to the culture, and the culture was continued for another 1 day. The pH was adjusted to 4 by adding 6 M HCl to the culture, and the metabolites were extracted by ethyl acetate. After the ethyl acetate was evaporated, the metabolites were absorbed for 5.0 g silica gel 60 (0.040

• were harvested by centrifugation and suspended in lysis buffer (20 mM HEPES-NaOH, 10% glycerol, and 200 mM NaCl2; pH 8.0). The cells were disrupted by sonication on ice, and cell debris was removed by centrifugation. The recombinant protein was purified using His60 Ni Superflow Resin (TaKaRa Bio Inc

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

• of MIC precursors [24][25][26][27][28]. By analogy with the archetypical NHCs bearing mesityl (Mes) or 2,6-diisopropylphenyl (Dipp) substituents on their nitrogen atoms, we have prepared three triazole derivatives with mixed Mes/Ph, Mes/Bu, or Dipp/Ph substituents on N1 and C4, respectively (Scheme 3

• ) with thermal ellipsoids drawn at the 50% probability level. ORTEP representations of zwitterions 6b (MIC-Dip-Ph-Me·CS2, top) and 6e (MIC-Mes-Bu-Me·CS2, bottom) with thermal ellipsoids drawn at the 50% probability level. Synthesis of CAAC·CS2 zwitterion 2 from its free carbene parent 1. Synthesis of

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

• acid ester 9 was hydrolyzed under basic conditions in an ethanol/water mixture. After the reaction, the pH of the mixture was adjusted to 4 with hydrochloric acid, which resulted in the precipitation of the product 10 in excellent yield (95%). Next, carboxylic acid 10 was converted into the

• , trifluoroacetic acid (5.74 mL, 75 mmol, 63 equiv) was added dropwise. The reaction mixture was stirred at room temperature for 1 h. Then, it was cooled to 0 °C, and a 40% NaOH(aq) solution was added to set the pH to 13. To this mixture, water (60 mL) was added, and it was extracted with DCM/MeOH 20:1 (60 mL

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• scientifique avec le Brésil) (joint project Ph-C 962/20) for support.