Spin and charge interactions between nanographene host and ferrocene

• Akira Suzuki,
• Yuya Miyake,
• Ryoga Shibata and
• Kazuyuki Takai

Beilstein J. Org. Chem. 2024, 20, 1011–1019, doi:10.3762/bjoc.20.89

• , resulting in the total curve (green). The base lines of the spectra are shifted vertically from each other for clarify. The raw infrared spectrum for FeCp2 (black) and differential absorbance spectra for FeCp2-ACFs-55 (red) and FeCp2-ACFs-150 (green) after subtracting the ACFs spectrum as a background

Carbonylative synthesis and functionalization of indoles

• Alex De Salvo,
• Raffaella Mancuso and
• Xiao-Feng Wu

Beilstein J. Org. Chem. 2024, 20, 973–1000, doi:10.3762/bjoc.20.87

• that kind of chemicals [74]. The reaction was cheap because it took place by irradiation with green light (5 W) in the presence of eosin Y as photocatalyst, under 70 bar of CO, in CH3CN at room temperature (Scheme 41). In 2018, Wu et al. published two papers about the functionalization of indoles. In

• functionalize indole scaffolds. We have seen different approaches in which high catalyst efficiencies, mild conditions and the use of low-toxic chemicals as CO source, that do not require the use of autoclaves, have been successfully applied. Furthermore, in some cases, “green” oxidants such as air were used

• making the process more environmentally friendly especially if we think about them in the industrial field. Clearly, the research in this field is ongoing and it will continue, and more active catalysts and new “green” synthetic approaches will be developed. Pd(0)-catalyzed domino C,N-coupling

Innovative synthesis of drug-like molecules using tetrazole as core building blocks

• Jingyao Li,
• Ajay L. Chandgude,
• Qiang Zheng and
• Alexander Dömling

Beilstein J. Org. Chem. 2024, 20, 950–958, doi:10.3762/bjoc.20.85

• . It aims to meet the growing demand for tetrazole-based compound libraries and novel scaffolds, which are challenging to synthesize through other methods. Keywords: building blocks; green chemistry; multicomponent reaction; Passerini tetrazole reaction; tetrazole; Ugi reaction; Introduction The

One-pot Ugi-azide and Heck reactions for the synthesis of heterocyclic systems containing tetrazole and 1,2,3,4-tetrahydroisoquinoline

• Jiawei Niu,
• Yuhui Wang,
• Shenghu Yan,
• Yue Zhang,
• Xiaoming Ma,
• Qiang Zhang and
• Wei Zhang

Beilstein J. Org. Chem. 2024, 20, 912–920, doi:10.3762/bjoc.20.81

• Chemistry and Center for Green Chemistry, University of Massachusetts Boston, 100 Morrissey Blvd, Boston, MA 02125, USA 10.3762/bjoc.20.81 Abstract A new method for the synthesis of heterocyclic systems containing tetrazole and tetrahydroisoquinoline is developed via the performance of one-pot Ugi-azide

• , and Cs2CO3 (Table 1, entries 12–14). Investigating other Pd catalysts, suche as PdCl2 and Pd(dba)2 also gave low yields (Table 1, entries 15 and 16). Since CH3CN is a more favorable solvent than DMF in green chemistry consideration [52][53], the optimal reaction conditions for the Heck reaction were

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

• ) revealed an extremely small hydrodynamic diameter (<10 nm) by DLS, 5b (green line) and 5c (purple line) revealed the presence of larger aggregates in water (pH 7.0), with a hydrodynamic diameters larger than 1 µm (Figure 3). In buffer at a higher pH value (e.g., pH 9, TRIS buffer), C60–oligo-Glu (5b

• ) showed much smaller aggregation (dotted green line, ≈12 nm), providing a transparent solution, while C60–oligo-Arg (5c) remained insoluble over the tested pH value range (4.0–9.2). This was presumably due to the strong cation–π interactions between the cationic Arg moieties and the aromatic C60, which is

• measured by the ESR spin trapping method under irradiation of visible light (527 nm green LED). 4-Oxo-TEMP was used as a spin trapping reagent to form an adduct with 1O2, i.e., 4-oxo-TEMPO, which was observed by ESR (Figure 7b). As shown in Figure 7a, upon visible light irradiation, three peaks

Substrate specificity of a ketosynthase domain involved in bacillaene biosynthesis

• Zhiyong Yin and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2024, 20, 734–740, doi:10.3762/bjoc.20.67

• followed by buffer exchange and then digestion with proteinase K; F) (R)-11 is not bound to BaeJ-KS2-C222A after incubation and buffer exchange (5 centrifugations); G) the filtrate obtained from the incubation of (R)-11 BaeJ-KS2-C222A containing free (R)-11 (first centrifugation). Green dots represent 13C

• = thioesterase. The black dot indicates a methyl branch introduced by the β-branching cassette. Synthesis of the BaeJ-KS2 substrate surrogates (S)-11 and (R)-11. Green dots represent 13C-labelled carbons. Supporting Information Supporting Information File 76: Experimental part and NMR spectra. Acknowledgements

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 such as green LEDs or a compact fluorescent lamp (CFL) were used only a small decrease in yield could be observed, although 4 hours of irradiation were needed to reach full conversion using CFL (Table 5, entries 8 and 9). The concentration, a factor expected to play an important role in a three

Organic electron transport materials

• Joseph Cameron and
• Peter J. Skabara

Beilstein J. Org. Chem. 2024, 20, 672–674, doi:10.3762/bjoc.20.60

• soluble in ethyl acetate, a green solvent, and solution-processed for PM6:Y6 bulk-heterojunction solar cells with power conversion efficiency > 13% [6]. In addition to orthogonal processing, it has been shown that treatment with base [7] or photo-crosslinking [8] can insolubilise solution-processed layers

HPW-Catalyzed environmentally benign approach to imidazo[1,2-a]pyridines

• Luan A. Martinho and
• Carlos Kleber Z. Andrade

Beilstein J. Org. Chem. 2024, 20, 628–637, doi:10.3762/bjoc.20.55

• expensive, extremely dangerous, strong oxidizing, and even explosive. In this scenario, heteropolyacids emerge as greener and safer alternatives due to their very strong Brønsted acidity. In particular, phosphotungstic acid (HPW) is an economical and green attractive catalyst for being cheap, non-toxic, and

• green catalyst with greater chemical and thermal stability in comparison to other heteropolyacids [43]. HPW has been shown to catalyze MCRs in the synthesis of heterocyclic compounds with high efficiency and chemoselectivity (Figure 2), including functionalized benzo[c]chromeno[2,3-a]phenazine [44

• -Aminopyridine (1a), 4-nitrobenzaldehyde (2a), and tert-butyl isocyanide (3a) were chosen as model substrates and different conditions were screened (Table 1). Glycerol, a green and sustainable solvent, was tried first, but unfortunately, the expected intense orange solid product 4a was obtained in low yields

Chemical and biosynthetic potential of Penicillium shentong XL-F41

• Ran Zou,
• Xin Li,
• Xiaochen Chen,
• Yue-Wei Guo and
• Baofu Xu

Beilstein J. Org. Chem. 2024, 20, 597–606, doi:10.3762/bjoc.20.52

• , compound 7, corresponding to the major peak in our optimized fermentation (Figure 1), was obtained at the gram level. Compound 1 (shentonin A) was obtained as a light green solid with a chemical formula of C20H26N2O3, as determined by HRMS m/z 365.1828 [M + Na]+ (calcd for C20H26N2O3Na+, 365.1835) and HRMS

• calculated spectrum of 2R,3R,16R-1 matched better with the experimental one, so the absolute configuration of 1 was tentatively determined to be 2R,3R,16R, namely shentonin A. Compound 2 (shentonin B) was isolated as a light green solid. Its chemical formula, C19H24N2O2, was confirmed by HRMS with m/z

• isolation of compound 3 (2.19 mg). Physical and spectroscopic data of compounds 1–3 Shentonin A (1): light green solid; [α]D20 +40.0 (c 0.17, CH3OH); UV (CH3OH) λmax, nm (log ε): 400 (3.45), 240 (4.24) nm; IR (KBr) νmax: 3347, 2960, 2926, 1688, 1654, 1612, 1260, 1078, 1021, 797 cm−1; for 1H NMR (CDCl3, 600

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

• inositols with NAD+, (b) myo-inositol with NAD+ or NADP, and (c) myo-inositol at different pH values (orange is HEPEs, green is Tris, blue is CHES, and red is CAPS). NAD(P)H concentrations were measured after 20 minutes. Michaelis–Menten plots for Hyg17 using varying concentrations of (d) myo-inositol, (e

Possible bi-stable structures of pyrenebutanoic acid-linked protein molecules adsorbed on graphene: theoretical study

• Yasuhiro Oishi,
• Motoharu Kitatani and
• Koichi Kusakabe

Beilstein J. Org. Chem. 2024, 20, 570–577, doi:10.3762/bjoc.20.49

• activation barrier in detail. Figure 3 shows the structure at the activation barrier top. Two hydrogen atoms connected by the green line are characteristically close to each other. One hydrogen is on the pyrene skeleton and the other is on the alkyl chain. The distance between these hydrogens is close, with

• of the torsion angle and the distance between hydrogen atoms reveal appearance of a steric hindrance effect. The dihedral angles formed by the four carbon atoms connected by the red line in Figure 3, and the distance between hydrogen atoms connected by the green line in Figure 3, for conformation 1

Synthesis of photo- and ionochromic N-acylated 2-(aminomethylene)benzo[b]thiophene-3(2Н)-ones with a terminal phenanthroline group

• Vladimir P. Rybalkin,
• Sofiya Yu. Zmeeva,
• Lidiya L. Popova,
• Irina V. Dubonosova,
• Olga Yu. Karlutova,
• Oleg P. Demidov,
• Alexander D. Dubonosov and
• Vladimir A. Bren

Beilstein J. Org. Chem. 2024, 20, 552–560, doi:10.3762/bjoc.20.47

• the phenanthroline unit was also involved in a π–π-stacking interaction (blue plane–green plane in Figure 4), with the plane centroid–plane centroid distance being 3.6998(8) Å (plane shift 1.4919(17) Å, twist and fold angles 1.54° and 1.92°, respectively). Cation-induced transformations of the

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

• ’ assessment of green mass, i.e., 5 = ≥90% inhibition, 4 = 70–89% inhibition, 3 = 50–69% inhibition, 2 = 40–49% inhibition, 1 = 21–39% inhibition, and — = <20% inhibition. Advanced screening was carried out with or as emulsifiable concentrate formulations, three replicate pots, and a standardized number of

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

• ) to produce a chiral nematic phase, whose reflected color can change from green to purple under cross-polarized view upon protonation. This system serves as an elegant example of a macroscopic effect induced by a conformational change at the molecular level. In a different approach where the stimuli

• was easily detected by a large charge transfer absorption band (λmax = 725 nm) and a noticeable emission change (brown to green solution). This complexation happened only in the presence of Cl− and not with the tweezers in alternate conformation, demonstrating the allosteric regulation of the

Enhanced host–guest interaction between [10]cycloparaphenylene ([10]CPP) and [5]CPP by cationic charges

• Eiichi Kayahara,
• Yoshiyuki Mizuhata and
• Shigeru Yamago

Beilstein J. Org. Chem. 2024, 20, 436–444, doi:10.3762/bjoc.20.38

• between the Hirshfeld surface and the contacting atoms, most sp2-hybridzed carbon atoms of the [10]CPP host have short contact with the Hirshfeld surface, as shown in green, despite the tilting of [10]CPP and [5]CPP. In the crystal packing, there were two orientations, as highlighted in blue and red in

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

• reaction between aldehydes with indoles, while focusing on the more environmentally friendly methods developed over the years. Keywords: aldehyde; BIMs; Friedel–Crafts reaction; green chemistry; indole; Review Medicinal properties In recent years, diindolylmethane (DIM, 1) and its derivatives known as

• , lowering its LUMO energy, by withdrawing electron-density through a variety of covalent interactions. Green and sustainable approaches Solvent-free processes Alternative processes, that limit environmental pollution and toxic byproducts, came to the forefront of research for the introduction of novel

• of green chemistry. Organocatalysis is the acceleration of chemical reactions with the use of small organic compounds, which do not contain any amounts of enzyme or inorganic elements [37][38][39]. The benefits of solid acid catalysis render them as an appealing choice, compared to their liquid

Mechanisms for radical reactions initiating from N-hydroxyphthalimide esters

• Carlos R. Azpilcueta-Nicolas and
• Jean-Philip Lumb

Beilstein J. Org. Chem. 2024, 20, 346–378, doi:10.3762/bjoc.20.35

Spatial arrangements of cyclodextrin host–guest complexes in solution studied by ¹³C NMR and molecular modelling

• Konstantin Lebedinskiy,
• Ivan Barvík,
• Zdeněk Tošner,
• Ivana Císařová,
• Jindřich Jindřich and
• Radim Hrdina

Beilstein J. Org. Chem. 2024, 20, 331–335, doi:10.3762/bjoc.20.33

• peaks of all prochiral carbon signals of the guest upon complexation with α-CD. The biggest split, 22.5 Hz, was observed for prochiral carbons 8 and 10, depicted in Figure 1 in green color, followed by a split of carbons 3 and 9 (in blue color) and the smallest difference in the magnetic field shielding

• α-CD cavity. The NMR splitting is generally larger if the prochiral guest atoms are located closer to the cavity of the α-CD. In other words, the splitting is larger, if the radius of a density is bigger or the density runs deeper into the α-CD cavity. In Figure 3, the green and blue densities with

• well-separated light and dark clouds (belonging to different prochiral carbons from a pair) have larger radii and run deeper into the α-CD cavity than the red density with mixed light and dark clouds. Accordingly, our NMR experiment only showed splitting for the green and blue atoms (see Figure 1

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

• methyl groups in the six-membered ring formed in the cycloaddition and coming from the starting diyne 1a (highlighted in red in Scheme 2). In contrast, for the minor isomer (green dots), which has Cs symmetry, the two methyl groups (highlighted in green in Scheme 2) appear as a single peak at δ = 2.40

• protons marked in red and the ones marked in green might be those of the β-isomer (29%). Unfortunately, NMR experiments did not allow to differentiate between α- and β-3a derivatives. The reaction was carried out also with bis(fulleroid) derivative 2b, exhibiting the same behavior. Conclusion In this

Nucleophilic functionalization of thianthrenium salts under basic conditions

• Xinting Fan,
• Duo Zhang,
• Xiangchuan Xiu,
• Bin Xu,
• Yu Yuan,
• Feng Chen and
• Pan Gao

Beilstein J. Org. Chem. 2024, 20, 257–263, doi:10.3762/bjoc.20.26

• . Therefore, developing a green method to functionalize alkylthianthrenium salts is still highly desirable. Considering the highly polarized C(sp3)–S bond in alkylthianthrenium salts, alkylthianthrenium salts have the potential to serve as alkyl electrophiles to react with nucleophiles directly in the absence

Catalytic multi-step domino and one-pot reactions

• Svetlana B. Tsogoeva

Beilstein J. Org. Chem. 2024, 20, 254–256, doi:10.3762/bjoc.20.25

• triggers the next, which in the end yields a complex product. In contrast to a conventional “stop-and-go” method, only a single workup and purification is needed (Figure 1b), and therefore these reaction cascades can be considered superior to stepwise synthetic approaches in the context of green chemistry

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

• (Scheme 8). In addition to the spectral data confirming the composition and asymmetric structure of compound 16, a clear sign of the emerging acenaphthylene system is its yellow-orange color, which distinguishes the UV-active (yellow-green luminescence) acenaphthylene 16 from the light-beige UV-inactive

Photochromic derivatives of indigo: historical overview of development, challenges and applications

• Gökhan Kaplan,
• Zeynel Seferoğlu and
• Daria V. Berdnikova

Beilstein J. Org. Chem. 2024, 20, 228–242, doi:10.3762/bjoc.20.23

• new level of complexity and promise. The photochromic indigos represent a relatively rare type of visible-light-responsive T-type photoswitches demonstrating negative photochromism. The absorption of the photoswitchable indigos covers the spectral range from green to NIR light (≈550–700 nm) making

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

• , Yantai, 264005, P. R. China Chang-Kung Chuang Institute & Shanghai Key Laboratory of Green Chemistry and Chemical Processes, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, P. R. China 10.3762/bjoc.20.20 Abstract A convenient and efficient method for the