Supramolecular approaches to mediate chemical reactivity

• Pablo Ballester,
• Qi-Qiang Wang and
• Carmine Gaeta

Beilstein J. Org. Chem. 2022, 18, 1463–1465, doi:10.3762/bjoc.18.152

• and sometimes even unachievable separation and purification procedures. Rui Wang and Yang Yu [16] reported an interesting review in which they summarized various site-selective reactions mediated by molecular containers. They focused their attention on reactions that give different product

Naphthalimide-phenothiazine dyads: effect of conformational flexibility and matching of the energy of the charge-transfer state and the localized triplet excited state on the thermally activated delayed fluorescence

• Kaiyue Ye,
• Liyuan Cao,
• Davita M. E. van Raamsdonk,
• Zhijia Wang,
• Jianzhang Zhao,
• Daniel Escudero and
• Denis Jacquemin

Beilstein J. Org. Chem. 2022, 18, 1435–1453, doi:10.3762/bjoc.18.149

• , confirming that the CT absorption band strongly depends on the electron-donating ability of the donor. In both NI-Ph-PTZ and NI-PhMe2-PTZ, the CT band is negligible, due to the large separation between the NI and PTZ moieties. Note that in NI-Ph-PTZ, the electronic coupling between the NI and the phenyl

• , ΦΔ are much larger, up to 100% in dichloromethane (DCM) and ACN, likely due to the heavy-atom effect. Electrochemistry study The redox potentials of the dyads were studied with cyclovoltammetry (Figure 6, Table 3), and the Gibbs free energy changes of the charge separation (ΔGCS) and charge

• separation states energy levels (ECS) of the compounds were calculated (Table 4). A reversible oxidation wave at +0.36 V (vs Fc/Fc+) was observed for NI-PTZ, which is attributed to the oxidation of the PTZ units. A reversible reduction wave at −1.75 V (vs Fc/Fc+) was observed, which is attributed to the

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

• –97%). This method allows for easy recovery of the unreacted aldehyde as well as separation of the product (just by extraction by hexane and drying under reduced pressure) without its decomposition. The structure of the final imines was confirmed by 1H NMR, 13C NMR, ESI–MS, and the release of the VOCs

Thermally activated delayed fluorescence (TADF) emitters: sensing and boosting spin-flipping by aggregation

• Ashish Kumar Mazumdar,
• Gyana Prakash Nanda,
• Nisha Yadav,
• Upasana Deori,
• Upasha Acharyya,
• Bahadur Sk and
• Pachaiyappan Rajamalli

Beilstein J. Org. Chem. 2022, 18, 1177–1187, doi:10.3762/bjoc.18.122

• ) interactions [15]. Several molecular designs were proposed to adjust the ICT interactions through covalent D–A linking. The separation of the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) of the donor and acceptor molecules leads to a reduction of the singlet

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

• is minimal, about 0.1 kcal·mol−1). In this case, the kinetic factor mainly determines the predominant product. With a difference of potential barrier of ca. 4.4 kcal·mol−1 in the first stage (to form intermediate), or 7.8 kcal·mol−1 in the final stage (for H2O separation) (IS5 isomerization to yield

• remaining two reaction routes are to form the intermediates IS9, IS10 with the separation of a H2O molecule from the O–H and N–H bonds resulting in 10ab and 10ab-v2, respectively, which are evaluated lower than the above two pathways in releasing H2O molecule from two –OH groups. Hence, from the calculated

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

• (catalyst) separation in one step. The use of a packed bed simplifies the translation of optimized batch reaction conditions to continuous flow, as the only components present in the reaction mixture are the substrate and a base. The metallaphotoredox cross-coupling of sulfinates with aryl halides was used

• processes [5] (Figure 1d): The heterogeneous catalyst remains located in a specific part of the reactor through which the reaction mixture is pumped, which reduces material damage through attrition and the confinement of the catalysts in the packed bed lifts the need for solid separation. If the catalyst is

• these heterogeneous catalysts, using a packed-bed reactor. The use of a packed-bed reactor for these solid–liquid reactions is attractive as reaction and separation can be combined in one step. This is particularly notable in our case since, after complexing poly-czbpy with nickel (Ni@poly-czbpy), 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

• range of m/z 50–1600. For MS–MS analysis, the collision-induced dissociation (CID) energy was set to 15–40 eV or 30–50 eV depending on the compounds. The HPLC–UV analysis of the chiral separation was conducted with a CHIRALCEL OX-3R column (150 mm × 4.6 mm, 3 μm, DAICEL) with isocratic 35% B at a flow

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

• reactions and usually the product separation is easy [4][5]. Among ILs, imidazolium derivatives are the most studied, in part due to their ease of synthesis, low cost and diverse applications from solvents and reagents in synthesis, to supporting electrolytes in electrochemistry [6]. The imidazolium cation

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• triethylamine to the eluent [44]. Also, using a solvent mixture with a low polarity, which is necessary to receive a good separation from the side products, led to a precipitation of the compound on the column, and many attempts were necessary to find an ideal solvent mixture. Additionally, the reaction was

On Reuben G. Jones synthesis of 2-hydroxypyrazines

• Pierre Legrand and
• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 935–943, doi:10.3762/bjoc.18.93

• previously reported [13], the separation (by any mean) of the 2-hydroxypyrazine isomers 3 and 4 is challenging. To overcome this, we used water-heated columns and preheated eluent mixtures (see the experimental part) which allowed to run chromatography over silica gel at 60 °C. At this temperature and using

Anti-inflammatory aromadendrane- and cadinane-type sesquiterpenoids from the South China Sea sponge Acanthella cavernosa

• Shou-Mao Shen,
• Qing Yang,
• Yi Zang,
• Jia Li,
• Xueting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 916–925, doi:10.3762/bjoc.18.91

• anti-inflammatory activity by the inhibition of LPS-induced TNF-α and CCL2 release in RAW 264.7 macrophages. Keywords: Acanthella cavernosa; anti-inflammatory; biosynthetic pathway; chiral separation; marine sponge; sesquiterpenoid; Introduction Marine sponges of the genus Acanthella (class

• with five related known ones [2, 3, (−)-4, 6, and 7] (Figure 1), were obtained. Herein, we report the isolation, chiral separation of racemic mixtures of 4 and 5, structural elucidation, plausible biosynthetic pathway, and biological evaluation of these isolated compounds. Results and Discussion By the

• equipped with a DAD G1315D detector and an Agilent Eclipse XDB-C18 column (5 μm, 9.4 × 250 mm). In contrast, chiral HPLC separation was operated on the chromatography equipped with CHIRALPAK IB N-3 column (5 μm, 4.6 × 250 mm). All solvents used for CC and HPLC were analytical grade (Shanghai Chemical

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• Sharpless epoxidation as a key step and purification of enantiomerically enriched intermediates through HPLC separation on a chiral stationary phase. Their enzymatic conversion with 2-methylisoborneol synthase (2MIBS) demonstrates that (R)-2-Me-LPP is the on-pathway intermediate, while a minor formation of

• Supporting Information File 56: Experimental. Acknowledgements We thank Andreas Schneider for HPLC separation of the enantiomers of 2-methyllinalool. Funding This work was supported by the German Research Foundation (DI1536/11-1) and the International Postdoctoral Exchange Fellowship Program (No. 2020038).

Synthesis of α-(perfluoroalkylsulfonyl)propiophenones: a new set of reagents for the light-mediated perfluoroalkylation of aromatics

• Durbis J. Castillo-Pazos,
• Juan D. Lasso and
• Chao-Jun Li

Beilstein J. Org. Chem. 2022, 18, 788–795, doi:10.3762/bjoc.18.79

• as N-phenylpyrrole and 2-phenylindole were found to produce large quantities of the desired perfluorohexyl and perfluorooctyl analogues as observed by both 1H NMR and GC–MS analysis. However, these molecules generated large concentrations of fluorinated byproducts which rendered separation of the

Continuous flow synthesis of azobenzenes via Baeyer–Mills reaction

• Jan H. Griwatz,
• Anne Kunz and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2022, 18, 781–787, doi:10.3762/bjoc.18.78

• cyclohexane to the reaction mixture after the tube reactor (Figure 3). The reaction solution with cyclohexane was continuously fed into a separating funnel containing brine. After phase separation, drying of the organic phase with MgSO4, and evaporation of the solvent, AB (1a) could be obtained in 98% yield

Synthesis of odorants in flow and their applications in perfumery

• Merlin Kleoff,
• Paul Kiler and
• Philipp Heretsch

Beilstein J. Org. Chem. 2022, 18, 754–768, doi:10.3762/bjoc.18.76

• formation of hydrazone 28. As one equivalent of water is formed in this condensation process, which is detrimental for the subsequent Shapiro reaction, water is continuously removed by in-line separation of the reaction mixture using a PTFE-membrane separator. The organic layer is then mixed with a solution

• conducting both generation and pyrolysis of triperoxide 55 in flow reactors, while phase separation of the biphasic mixture containing triperoxide 55 is realized in a PTFE membrane reactor [50]. Since many macrocyclic musks (or their precursors) contain internal olefins, they are frequently prepared by ring

• at low temperatures or instable intermediates, e.g., endoperoxide (55), benefit from the superior reaction control and safety profile of flow reactors. Many of the transformations in this review demonstrate the utilization of solid-supported reagents in cartridges that allow to avoid separation of

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• of the enzymatic products: UHPLC-HESI-HRMS measurement was performed on a Dionex Ultimate3000 system combined with a Q-Exactive Plus mass spectrometer (Thermo Scientific) with a heated electrospray ion source (HESI). Metabolite separation was carried out by reversed-phase liquid chromatography at 40

New synthesis of a late-stage tetracyclic key intermediate of lumateperone

• Mátyás Milen,
• Bálint Nyulasi,
• Tamás Nagy,
• Gyula Simig and
• Balázs Volk

Beilstein J. Org. Chem. 2022, 18, 653–659, doi:10.3762/bjoc.18.66

• recently described in a patent application [24] by a direct trifluoroacetylation of tetrahydroquinoxaline (37) with 0.92 equiv of TFAA, followed by chromatographic product separation. We carried out the same reaction (Scheme 6) and in addition to the expected compound 31 (39%), a significant amount of bis

Heteroleptic metallosupramolecular aggregates/complexation for supramolecular catalysis

• Prodip Howlader and
• Michael Schmittel

Beilstein J. Org. Chem. 2022, 18, 597–630, doi:10.3762/bjoc.18.62

• , introduced by Lehn, uses maximum site occupancy to afford heteroleptic aggregates [35]. While this principle is limited, the charge-separation approach by Stang is of much wider use [36]. Probably, most contributions in the literature, though, are based on using steric constraints in heteroleptic aggregation

• (73%) and 109b (82%) in high yield (Figure 23b) [110], although the relevant distances in the pseudo-rotaxane 110a,b (prior to the second click reaction) are 14.3 and 21.1 Å. Actually, the yield with [FeCu2(104)2]4+ was far better than with a dicopper reference catalyst, where the separation of the

Shift of the reaction equilibrium at high pressure in the continuous synthesis of neuraminic acid

• Jannis A. Reich,
• Miriam Aßmann,
• Kristin Hölting,
• Paul Bubenheim,
• Jürgen Kuballa and
• Andreas Liese

Beilstein J. Org. Chem. 2022, 18, 567–579, doi:10.3762/bjoc.18.59

• initial activity was analyzed using a standard activity assay. High-performance liquid chromatography (HPLC) For quantification of the product N-acetylneuraminic acid, an Agilent HPLC system connected with a variable wavelength detector at 210 nm was used. Separation was realized with a Nucleogel Sugar

• , and as the mean residence time. The RDT was measured by placing the reactor into an HPLC, replacing the regular separation column. Hereby, the mean residence time of the reactor was calculated to be 66% of the quotient of reactor volume and flow rate. When kinetic parameters were calculated by

Comparative study of thermally activated delayed fluorescent properties of donor–acceptor and donor–acceptor–donor architectures based on phenoxazine and dibenzo[a,j]phenazine

• Saika Izumi,
• Prasannamani Govindharaj,
• Anna Drewniak,
• Paola Zimmermann Crocomo,
• Satoshi Minakata,
• Leonardo Evaristo de Sousa,
• Piotr de Silva,
• Przemyslaw Data and
• Youhei Takeda

Beilstein J. Org. Chem. 2022, 18, 459–468, doi:10.3762/bjoc.18.48

• the efficacy of introducing two electronic donors on the acceptor unit. The calculations employed density functional theory (DFT) with the long-range corrected ωPBE functional and the 6-31G(d,p) basis set. Tuning of the range separation parameter was performed for both molecules [20] with the results

The asymmetric Henry reaction as synthetic tool for the preparation of the drugs linezolid and rivaroxaban

• Martin Vrbický,
• Karel Macek,
• Jaroslav Pochobradský,
• Jan Svoboda,
• Miloš Sedlák and
• Pavel Drabina

Beilstein J. Org. Chem. 2022, 18, 438–445, doi:10.3762/bjoc.18.46

• the starting aldehydes on the enantioselectivity of the Henry reaction was examined. Moreover, the resulting nitroaldols 22, 24, and 26 were formed as a pair of epimers, and therefore, a possible separation of the individual stereoisomers of these compounds was assumed. Hence, it should be noted that

• of stereoisomers that are easier to separate by standard techniques than enantiomers. In particular, an exploration of convenient chromatographic conditions was performed. Unfortunately, none of the conditions was successful even though all derivatives were tested. Subsequently, the separation of the

• experiments with de values of 84% and 88%, respectively. Hence, the higher temperature led to a slight drop of the de, nevertheless, the higher amount of the undesired diastereomer was considered as convenient here, in terms of the study of its separation. The nitroaldols 24 and 26 were isolated as an oil

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• steps whose main difficulties are the separation of pyridine byproducts and inorganic phosphate (Scheme 20). Kulkarni and co-workers reported a method for menadione reduction mediated by 5,6-O-isopropylidene-ʟ-ascorbic acid (70, R = H) under UV light irradiation [120]. Initial studies were carried out

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• there is more than one potential reactive site in a certain substrate, because poor site-selectivity would result in complicated and sometimes even unachievable separation and purification procedures. Hence, in order to drive reactions economically and efficiently, organic chemists have made great

Recent developments and trends in the iron- and cobalt-catalyzed Sonogashira reactions

• Surendran Amrutha,
• Sankaran Radhika and
• Gopinathan Anilkumar

Beilstein J. Org. Chem. 2022, 18, 262–285, doi:10.3762/bjoc.18.31

• nanorods was found to increase with respect to Fe3+ ions-to-ligand ratio and vice versa. The reusability and separation of the ferromagnetic α-Fe2O3 nanoparticle catalyst were very effective, simple and economical due to its magnetic nature. The in situ-generated α-Fe2O3 nanoparticles showed better

Flow synthesis of oxadiazoles coupled with sequential in-line extraction and chromatography

• Kian Donnelly and
• Marcus Baumann

Beilstein J. Org. Chem. 2022, 18, 232–239, doi:10.3762/bjoc.18.27

• using sodium thiosulphate solution. To avoid the hazards associated with handling of iodine on multi-gram scale, in addition to eliminating unit operations, an in-line quench and separation was developed. The in-line quench consisted of employing a 4-way mixer, through which sodium thiosulphate solution

• ], however, many of them involve the use of expensive and complex membrane filters. To reduce cost and increase simplicity we opted to use a ‘home-made’ setup to achieve continuous separation which consisted of a laboratory separating funnel, into which we collect the biphasic reaction output following

• aqueous workup (Scheme 5). Dichloromethane (DCM) was selected as the organic solvent of choice due to its increased density compared to DMSO and water. Separation in a continuous manner could then be simply achieved by adjusting the outlet tap of the separating funnel such that a constant volume is