Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• of the solid samples in spectroscopic grade potassium bromide (KBr). Thermogravimetric analyses were performed using a Pyris 1 TGA thermoanalyzer (Perkin-Elmer), at 10 °C min−1 heating rate, under nitrogen flow (20 mL min−1), from 25 to 350 °C. Melting points were determined in triplicate using a

A deep-red fluorophore based on naphthothiadiazole as emitter with hybridized local and charge transfer and ambipolar transporting properties for electroluminescent devices

• Suangsiri Arunlimsawat,
• Patteera Funchien,
• Pongsakorn Chasing,
• Atthapon Saenubol,
• Taweesak Sudyoadsuk and
• Vinich Promarak

Beilstein J. Org. Chem. 2023, 19, 1664–1676, doi:10.3762/bjoc.19.122

• illumination). a) DSC and TGA thermograms measured at a heating rate of 10 °C min−1 under N2 flow. b) Cyclic voltammogram (CV) and differential pulse voltammogram (DPV) analyzed in dry CH2Cl2 at a scan rate of 50 mV s−1 under an argon atmosphere (insert: HOMO/HOMO−1/LUMO orbitals). a) Schematic structure of

Sulfur-containing spiroketals from Breynia disticha and evaluations of their anti-inflammatory effect

• Ken-ichi Nakashima,
• Naohito Abe,
• Masayoshi Oyama,
• Hiroko Murata and
• Makoto Inoue

Beilstein J. Org. Chem. 2023, 19, 1604–1614, doi:10.3762/bjoc.19.117

• filtered and analyzed by HPLC without dilution. HPLC separation was performed on a 150 × 4.6 mm i.d. CAPCELL PAK C18 UG120 column (Osaka Soda) at 35 °C with isocratic elution using 20% CH3CN in 50 mM H3PO4 for 30 min and subsequent column washing with 90% CH3CN at a flow rate 0.8 mL/min. Detection at 250

C–H bond functionalization: recent discoveries and future directions

• Indranil Chatterjee

Beilstein J. Org. Chem. 2023, 19, 1568–1569, doi:10.3762/bjoc.19.114

• techniques. Some energy-economic reactors such as ball mill, microwave, ultrasound and, most importantly, flow reactors have also evolved towards a more sustainable future. To showcase the modern approaches in this domain, this thematic issue in the Beilstein Journal of Organic Chemistry gathers recent

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• % B in 19.5 min and then maintaining 100% B for 5 min, flow rate 0.6 mL/min, UV–vis detection 200–640 nm) connected to a MaXis ESI-TOF mass spectrometer (Bruker) (scan range 100–2500 m/z, capillary voltage 4500 V, dry temperature 200 °C). NMR spectra were recorded at 25 °C on a Bruker (Billerica, MA

• with CH2Cl2/MeOH 97.5:2.5 (v/v) was subjected to a flash chromatography system (PLC 2020, Gilson) equipped with a VP Nucleodur C18 HTec column (10 µm, 250 × 40 mm). The chromatographic separation was performed by using a constant flow rate of 10 mL/min with the mobile phases made with solvent A

• the stationary phase and the solvent mixture CH2CH2/MeOH 92:8 (v/v) as the mobile phase. The elution was performed for 25 min each with a flow rate of 2 mL/min, an automatic pressure in the range of 1–10 bar and the UV absorptions were set at 210, 254, and 366 nm to yield compounds 15 (3.2 mg, yellow

Organic thermally activated delayed fluorescence material with strained benzoguanidine donor

• Alexander C. Brannan,
• Elvie F. P. Beaumont,
• Nguyen Le Phuoc,
• George F. S. Whitehead,
• Mikko Linnolahti and
• Alexander S. Romanov

Beilstein J. Org. Chem. 2023, 19, 1289–1298, doi:10.3762/bjoc.19.95

• , equipped with an AFC-11 4-circle kappa goniometer, VariMAXTM microfocus optics, a Hypix-6000HE detector and an Oxford Cryosystems 800 plus nitrogen flow gas system, at a temperature of 100 K. Data were collected and reduced using CrysAlisPro v42 [21][22]. Absorption correction was performed using empirical

Radical ligand transfer: a general strategy for radical functionalization

• David T. Nemoto Jr,
• Kang-Jie Bian,
• Shih-Chieh Kao and
• Julian G. West

Beilstein J. Org. Chem. 2023, 19, 1225–1233, doi:10.3762/bjoc.19.90

• . Further, we demonstrated that diazidation could be rendered catalytic using Fe(III) nitrate hydrate III as the iron source and performing the reaction under continuous flow conditions. Interestingly, this mechanism bears some similarity to Lin’s electrocatalytic diazidation, where azido radical generation

• is required for this process, implicating the nitrate counterion functioning as an internal oxidant to regenerate the active Fe(III) species capable of LMCT and RLT. This result is consistent with our finding that iron nitrate can catalytically diazidate alkenes in flow with no additional oxidant and

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• highlights photo- and electrochemical methods for recycling amines and NADH analogues that can be used as electron donors in artificial photosynthesis. Important properties of sacrificial donors and recycling strategies are also discussed. Compounds from other fields, such as redox flow batteries and

• sacrificial donor. However, it is likely that high steady-state concentrations of a donor will be needed and using the costs targets set for redox flow battery electrolytes is probably a sensible starting point. In an ideal system, the only inputs needed would be carbon dioxide, water, and light. This implies

• sources. Following the example of ‘decoupled water splitting’ and redox flow batteries (RFBs) by recycling the electron donor ex-situ offers several potential advantages [8][57][58]. For example, decoupling carbon dioxide reduction and water oxidation in two separate reactors would allow the development

Two new lanostanoid glycosides isolated from a Kenyan polypore Fomitopsis carnea

• Winnie Chemutai Sum,
• Sherif S. Ebada,
• Didsanutda Gonkhom,
• Cony Decock,
• Rémy Bertrand Teponno,
• Josphat Clement Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2023, 19, 1161–1169, doi:10.3762/bjoc.19.84

• , Milford, MA, USA). The solvent system was as follows; deionized H2O + 0.1% formic acid (FA, v/v) (solvent A) and acetonitrile (ACN) + 0.1% FA (v/v) (solvent B). The separation gradient was operated as follows; 5% B for 0.5 min, 5% B to 100% B for 20 min, and 100% B for 10 min. The flow rate was maintained

• min, 5% B to 100% B within 19.5 min and at 100% B for 5 min. The flow rate was maintained at 0.6 mL/min and UV–vis detection made at 200–600 nm. The calculation of the compounds’ molecular formulas was performed using the Smart Formula algorithm of the Compass DataAnalysis software (Bruker Daltonics

• were performed as follows: isocratic conditions at 5% solvent B for 10 min, followed by an increase to 20% in 3 min, 20% to 90% within 50 min, 90% to 100% in 5 min and finally isocratic conditions of solvent B at 100% for 30 min. The flow rate in each case was 40 mL/min and UV detections were carried

Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• Damiano Diprima Hannes Gemoets Stefano Bonciolini Koen Van Aken Ecosynth, Industrielaan 12, 9800 Deinze, Belgium Flow Chemistry Group, Van ’t Hoff Institute for Molecular Sciences (HIMS), University of Amsterdam, Science Park 904, 1098 XH, Amsterdam, The Netherlands Creaflow, Industrielaan 12

• flow using the HANU flow reactor, indicating scalability and improving safety. Keywords: catalyst-free; flow chemistry; oxygen; photochemistry; sustainable oxidation; Introduction Oxidation reactions are widely used in the chemical industry, but are often problematic due to challenges with

• running the process in continuous flow [5][6][7][8]. Moreover, flow reactors that provide intense mixing can overcome the gas–liquid mass transfer limitations typical of batch reactions and improve productivity. Several studies have demonstrated the scalability and safety of such methods for the oxidation

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

• feedstocks, and scalability up to gram scales in continuous flow. This review provides comparisons between the two techniques (multi-photon photoredox catalysis and PEC) to help the reader to fully understand their similarities, differences and potential applications and to therefore choose which method is

• standardization but also thanks to developments in technology (flow, alternating polarity) and understanding that fundamentally improve selectivity. Among these is its innovative merger with PRC (synthetic PEC) in a fashion that tackles the issues of both parent techniques and has risen to the forefront of

• efficiency and selectivity of the reactions (vide infra, conPET section). Electrolytes have the potential to be i) aqueous-separated and recovered in batch, or ii) decreased, even ultimately eliminated by flow reactors as an engineering control. Regarding purely the chemical reactivity and scope of

Five new sesquiterpenoids from agarwood of Aquilaria sinensis

• Hong Zhou,
• Xu-Yang Li,
• Hong-Bin Fang,
• He-Zhong Jiang and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 998–1007, doi:10.3762/bjoc.19.75

• purified by preparative HPLC on YMC-Pack-ODS-A with aqueous MeCN (63%), and then purified by semi-preparative HPLC on YMC-Pack-ODS-A with aqueous MeOH (82%) to afford 7 (36.1 mg, tR = 21.3 min; flow rate: 3 mL/min). Fr.6.5 (9.3 g) was further fractionated into ten parts (Fr.6.5.1–Fr.6.5.10) by a silica gel

• min, flow rate: 3 mL/min). Fr.6.5.8 (787.3 mg) was separated by VLC on silica gel eluted with petroleum ether/acetone (25:1–1:1) to provide six portions (Fr.6.5.8.1–Fr.6.5.8.6). Fr.6.5.8.4 (91.0 mg) was further purified by semi-preparative HPLC on SEP Basic 120 C18 with aqueous MeCN (46%) to afford 10

• (4.5 mg, tR = 24.9 min; flow rate: 3 mL/min). Fr.6.6 (9.1 g) was further divided into fifteen parts (Fr.6.6.1–Fr.6.6.15) by a YMC-ODS column (MeOH, 45–80%). Fr.6.6.10 (747.8 g) was separated a by silica gel column washed with petroleum ether/acetone (1:9–6:4) to yield thirteen portions (Fr.6.6.10.1–Fr

Intermediates and shunt products of massiliachelin biosynthesis in Massilia sp. NR 4-1

• Till Steinmetz,
• Blaise Kimbadi Lombe and
• Markus Nett

Beilstein J. Org. Chem. 2023, 19, 909–917, doi:10.3762/bjoc.19.69

• , Macherey-Nagel) and a gradient of acetonitrile in water supplemented with 0.1% (v/v) trifluoroacetic acid. The gradient conditions were as follows: from 20% acetonitrile to 90% in 30 minutes and kept at 90% for 10 minutes. The flow rate was set to 5 mL/min. The elution of compounds was monitored with a

Non-peptide compounds from Kronopolites svenhedini (Verhoeff) and their antitumor and iNOS inhibitory activities

• Yuan-Nan Yuan,
• Jin-Qiang Li,
• Hong-Bin Fang,
• Shao-Jun Xing,
• Yong-Ming Yan and
• Yong-Xian Cheng

Beilstein J. Org. Chem. 2023, 19, 789–799, doi:10.3762/bjoc.19.59

• /H2O, 70%). Fr. E25 (248.6 mg) was subjected to preparative HPLC (MeOH/H2O (0.04% TFA), 50–100%, flow rate: 10 mL min−1) to obtain six fractions (Fr. E251–Fr. E256). Fr. E254 was concentrated under reduced pressure to yield compound 9 (20.00 mg). Additionally, Fr. E255 (51.8 mg) was further purified

• using semi-preparative HPLC (C30, MeOH/H2O, 25%, flow rate: 3 mL min−1) to yield compound 8 (16.23 mg, tR = 25.04 min). Fr. E5 (9.0 g) was separated into eleven parts (Fr. E51–Fr. E59, Fr. E5A–B) by Sephadex LH-20 (MeOH/H2O, 70%). Fr. E53 (4.26 g) was divided into eleven portions (Fr. E531–Fr. E539, Fr

• :1–1:1), and Fr. E53732 (63.8 mg) was further purified using semi-preparative HPLC (ODS-A, MeCN/H2O (0.04% TFA), 55%, flow rate: 3 mL min−1) to afford compound 7 (15.70 mg, tR = 14.05 min). Fr. E54 (415.3 mg) was separated into twelve fractions (Fr. E541–Fr.E549, Fr. E54A–Fr.E54C) using an MCI gel

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• 10.3762/bjoc.19.55 Abstract We report on the high potential of a honeycomb reactor for the use in aerobic oxidation under continuous-flow conditions. The honeycomb reactor is made of porous material with narrow channels separated by porous walls allowing for high density accumulation in the reactor. This

• structure raised the mixing efficiency of a gas–liquid reaction system, and it effectively accelerated the aerobic oxidation of benzyl alcohols to benzaldehydes under continuous-flow conditions. This reactor is a promising device for streamlining aerobic oxidation with high process safety because it is a

• from operators or the equipment can have disastrous consequences. Because the large headspace of batch reactor aggravates these safety risks, the use of O2 in batch manufacturing is very limited [14]. Recently, continuous flow synthesis has recently been studied as a way to mitigate the safety risks

Enolates ambushed – asymmetric tandem conjugate addition and subsequent enolate trapping with conventional and less traditional electrophiles

• Péter Kisszékelyi and
• Radovan Šebesta

Beilstein J. Org. Chem. 2023, 19, 593–634, doi:10.3762/bjoc.19.44

C3-Alkylation of furfural derivatives by continuous flow homogeneous catalysis

• Grédy Kiala Kinkutu,
• Catherine Louis,
• Myriam Roy,
• Juliette Blanchard and
• Julie Oble

Beilstein J. Org. Chem. 2023, 19, 582–592, doi:10.3762/bjoc.19.43

• develop a continuous flow process specifically for the C3-alkylation of furfural (Murai reaction). The transposition of a batch process to a continuous flow process is often costly in terms of time and reagents. Therefore, we chose to proceed in two steps: the reaction conditions were first optimized

• using a laboratory-built pulsed-flow system to save reagents. The optimized conditions in this pulsed-flow mode were then successfully transferred to a continuous flow reactor. In addition, the versatility of this continuous flow device allowed both steps of the reaction to be carried out, namely the

• formation of the imine directing group and the C3-functionalization with some vinylsilanes and norbonene. Keywords: biomass; C–H activation; flow; furfural; homogeneous catalysis; Introduction The conversion of biomass derivatives into value-added products is one of the key branches of green chemistry and

Transition-metal-catalyzed C–H bond activation as a sustainable strategy for the synthesis of fluorinated molecules: an overview

• Louis Monsigny,
• Floriane Doche and
• Tatiana Besset

Beilstein J. Org. Chem. 2023, 19, 448–473, doi:10.3762/bjoc.19.35

• . Note that in 2018, Besset and Lebel developed a more efficient process for the palladium-catalyzed trifluoromethylthiolation by C–H bond activation under continuous flow conditions [127]. I.4) Difluoromethylthiolation of aromatic and vinylic C(sp2)–H bonds (C–SCF2H and C–SCF2CO2Et bonds) More recently

Discrimination of β-cyclodextrin/hazelnut (Corylus avellana L.) oil/flavonoid glycoside and flavonolignan ternary complexes by Fourier-transform infrared spectroscopy coupled with principal component analysis

• Nicoleta G. Hădărugă,
• Gabriela Popescu,
• Dina Gligor (Pane),
• Cristina L. Mitroi,
• Sorin M. Stanciu and
• Daniel Ioan Hădărugă

Beilstein J. Org. Chem. 2023, 19, 380–398, doi:10.3762/bjoc.19.30

• a Netzsch 204 F1 Phoenix apparatus (both from Netzsch Group, Selb, Germany). The TG–DTG and DSC conditions were similar: temperature program of 25–500 °C, with a heating rate of 10 °C/min, nitrogen purge and protection flow of 40 mL/min, the data acquisition and handling by Netzsch Proteus-Thermal

Continuous flow synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin

• János Máté Orosz,
• Dóra Ujj,
• Petr Kasal,
• Gábor Benkovics and
• Erika Bálint

Beilstein J. Org. Chem. 2023, 19, 294–302, doi:10.3762/bjoc.19.25

• of Science, Charles University, 128 43 Prague 2, Czech Republic 10.3762/bjoc.19.25 Abstract The first continuous flow method was developed for the synthesis of 6-monoamino-6-monodeoxy-β-cyclodextrin starting from native β-cyclodextrin through three reaction steps, such as monotosylation, azidation

• and reduction. All reaction steps were studied separately and optimized under continuous flow conditions. After the optimization, the reaction steps were coupled in a semi-continuous flow system, since a solvent exchange had to be performed after the tosylation. However, the azidation and the

• reduction steps were compatible to be coupled in one flow system obtaining 6-monoamino-6-monodeoxy-β-cyclodextrin in a high yield. Our flow method developed is safer and faster than the batch approaches. Keywords: azidation; continuous flow; β-cyclodextrin; H-cube; 6-monoamino-6-monodeoxy-β-cyclodextrin

Investigation of cationic ring-opening polymerization of 2-oxazolines in the “green” solvent dihydrolevoglucosenone

• Solomiia Borova and
• Robert Luxenhofer

Beilstein J. Org. Chem. 2023, 19, 217–230, doi:10.3762/bjoc.19.21

• K. HFIP was supplemented with 3 g/L potassium triflate, and the flow rate was adjusted to 0.50 mL/min. Calibration was performed using PEG standards with molar masses ranging from 0.1–1,000 kg/mol. Before every measurement, samples were filtered through 0.2 µm PTFE filters, Roth (Karlsruhe, Germany

Insight into oral amphiphilic cyclodextrin nanoparticles for colorectal cancer: comprehensive mathematical model of drug release kinetic studies and antitumoral efficacy in 3D spheroid colon tumors

• Sedat Ünal,
• Gamze Varan,
• Juan M. Benito,
• Yeşim Aktaş and
• Erem Bilensoy

Beilstein J. Org. Chem. 2023, 19, 139–157, doi:10.3762/bjoc.19.14

Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

• Kah Yean Lum,
• Jonathan M. White,
• Daniel J. G. Johnson,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11

• (0.1% TFA) were held for the first 1 min, followed by a linear gradient to 100% MeOH (0.1% TFA) over 59 min, all at a flow rate of 9 mL/min. Sixty fractions (60 × 1 min) were collected from the start of the HPLC run. Fractions containing UV-active material were analysed by 1H NMR spectroscopy and LCMS

• first 1 min, followed by a linear gradient to 80% MeOH/20% H2O (0.1% TFA) over 59 min, all at a flow rate of 9 mL/min. 3-(4-(Difluoromethoxy)phenyl)-5-phenethoxy-8-(trifluoromethyl)-[1,2,4]triazolo[4,3-a]pyrazine (10). White amorphous solid (6 mg, 12%); UV (MeOH) λmax (log ε): 243 (3.94), 324 (3.50) nm

Modern flow chemistry – prospect and advantage

• Philipp Heretsch

Beilstein J. Org. Chem. 2023, 19, 33–35, doi:10.3762/bjoc.19.3

• Philipp Heretsch Institute of Organic Chemistry, Leibniz Universität Hannover, Schneiderberg 1B, 30167 Hannover, Germany 10.3762/bjoc.19.3 Keywords: flow chemistry; method development; reactor design; Organic chemistry has shaped modern society by fulfilling the basic needs for pharmaceuticals

• , agrochemicals, fragrances, and many more. Implementation of new and innovative technologies has played a vital role in this mission and has contributed to the opening of new research areas and to pushing the frontiers of existing ones. Among these new technologies, continuous flow chemistry has stepped on the

• chemicals. This has again led to improved scalability, higher purity of products, and eventually decreased manufacturing costs. From the undisputed role of continuous flow chemistry for process chemists, the advent of this technology in academic research laboratories, especially for method development and

Two-step continuous-flow synthesis of 6-membered cyclic iodonium salts via anodic oxidation

• Julian Spils,
• Thomas Wirth and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 27–32, doi:10.3762/bjoc.19.2

• continuous-flow procedure for the generation of six-membered diaryliodonium salts. The accompanying scalability and atom economy are significant improvements to existing batch methods. Benzyl acetates are submitted to this two-step procedure as highly available and cheap starting materials. An acid-catalyzed

• Friedel–Crafts alkylation followed by an anodic oxidative cyclization yielded a defined set of cyclic iodonium salts in a highly substrate-dependent yield. Keywords: electrochemistry; flow chemistry; hypervalent compounds; iodine; oxidation; Introduction Hypervalent iodine compounds (HVI) are well

• anodic oxidation [37][38][39][40]. Due to the apparent advantages of electrochemical processes, their implementation in flow is simple and straightforward since further dilution or additives are unnecessary [41][42]. One early example of this combination in the field of HVI chemistry is the anodic