Synthesis of 5-arylidenerhodanines in L-proline-based deep eutectic solvent

• Stéphanie Hesse

Beilstein J. Org. Chem. 2023, 19, 1537–1544, doi:10.3762/bjoc.19.110

• , volatile solvents, hard conditions, and/or difficult purifications. However, green chemistry has become a crucial sub-discipline in the field of chemistry and the chemical industry is giving major priority to sustainable processes. Since a few years, deep eutectic solvents (DES) are considered as a

• promising emerging class of green solvents as they offer numerous advantages, such as low volatility, non-flammability, chemical and thermal stability, recyclability, and above all a good biodegradability [10]. Moreover, their synthesis is usually easy and cheap as DES are formed by simply mixing an H-bond

• derivative synthesis. In accordance with the principles of green chemistry, we envisaged a procedure with temperatures not too high and reaction times not too long. We also wanted to isolate pure compounds by a simple filtration after precipitation in aqueous media without the need for extraction or

Complexes of resorcin[4]arene with secondary amines: synthesis, solvent influence on “in-out” structure, and theoretical calculations of non-covalent interactions

• Waldemar Iwanek

Beilstein J. Org. Chem. 2023, 19, 1525–1536, doi:10.3762/bjoc.19.109

• and the pyrrolidine molecule are marked in green, 1.478 Å in DMSO and 1.565 Å in CHCl3. Additionally, the lengths of hydrogen bonds between the protons of the hydroxy groups and the oxygen atoms in the upper ring of R[4]A are marked in purple. It is worth noting the significantly shorter length of the

• (PBE0-D4/def2-mTZVPP/CPCM(DMSO) structures of these complexes. The lengths of intermolecular hydrogen bonds between R[4]A and amines are marked in green, while the intramolecular hydrogen bonds between the oxygen anion and the hydrogen atom of the adjacent hydroxy group in R[4]A are marked in violet

• highlighted in blue. Theoretically calculated (PBE0-D4/def2-mTZVPP/CPCM) structures of the R[4]A:pyrrolidine complex in DMSO and CHCl3. The lengths of hydrogen bonds between the R[4]A molecule and the pyrrolidine molecule are marked in green, while the lengths of hydrogen bonds in the upper ring of R[4]A

N-Sulfenylsuccinimide/phthalimide: an alternative sulfenylating reagent in organic transformations

• Fatemeh Doraghi,
• Seyedeh Pegah Aledavoud,
• Mehdi Ghanbarlou,
• Bagher Larijani and
• Mohammad Mahdavi

Beilstein J. Org. Chem. 2023, 19, 1471–1502, doi:10.3762/bjoc.19.106

• -catalyzed sulfenylation by N-(sulfenyl)succinimides/phthalimides In 2012, Chen and co-workers found that in the reaction of N-(organothio)succinimides 1 and sodium sulfinates 2 using a Lewis acid in ionic liquids (ILs) and water as a green solvent system leads to the formation of thiosulfonates 3 (Scheme 2

• by Guo and Wu et al. (Scheme 19) [56]. Employment of a reusable heterogeneous nanomaterial, mild reaction conditions, avoiding the use of any additive, or base, and water/EtOH as a green solvent system were the advantages of this new method. N-Sulfenyl sulfoximines 45 were synthesized as coupling

• stereogenic carbon centers bearing a sulfur atom. Although, significant efforts have been made to form enantioselective C–S bonds, the direct sulfenylation with more green, economical, and environmentally friendly sulfenylating reagents remains a challenge for organic chemists. N-(Sulfenyl)succinimides

Functional characterisation of twelve terpene synthases from actinobacteria

• Anuj K. Chhalodia,
• Houchao Xu,
• Georges B. Tabekoueng,
• Binbin Gu,
• Kizerbo A. Taizoumbe,
• Lukas Lauterbach and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 1386–1398, doi:10.3762/bjoc.19.100

• branches indicate groups of homologous sesquiterpene synthases, green branches indicate groups of homologous diterpene synthases, and purple branches indicate groups of homologous sesterterpene synthases from which at least one representative was functionally characterised. The red arrows highlight enzymes

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

• benzoguanidine donor and compare it with the benchmark carbazole-based material (4CzIPN). Extended π-conjugation in 4BGIPN material results in yellow-green luminescence at 512 nm with a fast radiative rate of 5.5 × 10−5 s−1 and a photoluminescence quantum yield of 46% in methylcyclohexane solution. Such a

• is up to 0.4 eV higher in energy than the singlet 1CT state. The high quantum yields of up to 46% indicate that the yellow-green 4BGIPN emitter shows a high promise as a platform for developing bright 4BGIPN-TADF class III type compounds with unity PLQY. Future works may benefit in isolating a

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• are widespread as essential building blocks in various drugs, natural products, agrochemicals, and materials. Modern economy requires developing green strategies with improved efficiency and reduction of waste. Due to its atom and step-economy, the cross-dehydrogenative coupling (CDC) reaction has

• synthetic strategy for the construction of C–C bonds in organic synthesis (Scheme 1b). Compared with traditional coupling reactions, the CDC strategy has the following advantages: 1) atom economy, 2) green and efficient reaction, 3) a wide range of substrate sources. Therefore, organic chemists consider the

• source played a key role, with lower yields or no product obtained when the reaction was performed without water or under other light source conditions such as 19 W CFL or irradiation with blue or green LEDs. This method is applicable to various heteroatom-containing compounds such as quinolines

Unravelling a trichloroacetic acid-catalyzed cascade access to benzo[f]chromeno[2,3-h]quinoxalinoporphyrins

• Chandra Sekhar Tekuri,
• Pargat Singh and
• Mahendra Nath

Beilstein J. Org. Chem. 2023, 19, 1216–1224, doi:10.3762/bjoc.19.89

• visible and near IR regions [11][12][13][14]. Similarly, simple quinoxaline-based heterocycles have shown their potential as photosensitizers to induce toxicity in a single cell green algae such as Chlamydomonas reinhardtii [15] and also displayed efficacy against Mycobacterium tuberculosis and other

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

• resulted in a significant reduction in kinetics and selectivity (Table 1, entry 3). Other more green and biobased solvent alternatives, such as ethanol [36], can effectively replace the acetonitrile (for the complete scope of solvents, please consult Supporting Information File 1, Table S2), but reaction

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

• enabling controlled bond activations [45]. Regarding the reductive C–C arylation, the application of the xanthene dye rhodamine 6G (Rh-6G) as a catalyst for the reduction of heteroarenes bearing two or three bromine atoms (e.g., 6) under irradiation with green light (λ = 530 nm) gave monosubstituted

• products (e.g., 7) whereas irradiation with blue light (λ = 455 nm) provided disubstituted products 8 (Figure 5A). Additionally, adding a different trapping reagent before switching from green to blue light allows for a sequential and controlled substitution in a one-pot reaction (Figure 5B). 2,4,6

• -Tribromopyrimidine (6a), whose core pyrimidine structure can be found in many biologically active compounds, could be sequentially substituted with 1,3,5-trimethoxybenzene and N-methylpyrrole to give 8a. The protocol also enabled the selective reductive dehalogenation at the benzylic position of 9a with green light

The effect of dark states on the intersystem crossing and thermally activated delayed fluorescence of naphthalimide-phenothiazine dyads

• Liyuan Cao,
• Xi Liu,
• Xue Zhang,
• Jianzhang Zhao,
• Fabiao Yu and
• Yan Wan

Beilstein J. Org. Chem. 2023, 19, 1028–1046, doi:10.3762/bjoc.19.79

• 3LE appear with a characteristic absorption peak of 3NI* at 463 nm and this process can be ascribed to SOCT-ISC (green line in Figure 7d). This postulation is supported by the nanosecond transient spectra (see below). Nanosecond transient absorption (ns-TA) spectra In order to study the lowest-lying

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• (40 μM) and 1 (2 mM) in citrate phospate buffer pH 3 (right) from 350–400 nm with 0 (blue), 2 (red), 4 (green), 6 (orange) and 8 (grey) bar of CO2. Binding of CO2 to 1 as a function of pressure. The results of crystallization of α-cyclodextrin from water in an atmosphere of CO2 carried out in a

Copper-catalyzed N-arylation of amines with aryliodonium ylides in water

• Kasturi U. Nabar,
• Bhalchandra M. Bhanage and
• Sudam G. Dawande

Beilstein J. Org. Chem. 2023, 19, 1008–1014, doi:10.3762/bjoc.19.76

• .19.76 Abstract Copper sulfate catalyzed an efficient, inexpensive, and environment-friendly protocol that has been developed for N-arylation of amines with 1,3-cyclohexadione-derived aryliodonium ylides in water as a green solvent. Aromatic primary amines substituted with electron-donating as well as

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• -dimethoxytetrahydrofuran; green synthesis; microwave-assisted reaction; N-substituted pyrrole; Introduction Heterocyclic compounds are the most explored molecules in organic chemistry in terms of their synthesis and various applications. Among the diverse heterocyclic compounds, N-containing heterocycles are found in

• . This methodology has been applied to diverse areas of chemistry, including natural product synthesis [45][46], medicinal chemistry [47][48], polymer chemistry [49][50] and porphyrin chemistry [51][52][53]. In recent years, green chemistry has become a widely used method for organic synthesis in order

• to reduce energy consumption and the carbon footprint. The traditional heating techniques used to synthesize compounds are being replaced by contemporary green alternative energy systems, such as photocatalysis, microwave irradiation, ultrasonic irradiation, grinding, and ball milling processes

Photoredox catalysis enabling decarboxylative radical cyclization of γ,γ-dimethylallyltryptophan (DMAT) derivatives: formal synthesis of 6,7-secoagroclavine

• Alessio Regni,
• Francesca Bartoccini and
• Giovanni Piersanti

Beilstein J. Org. Chem. 2023, 19, 918–927, doi:10.3762/bjoc.19.70

• -dimethylallyltryptophan (DMAT) derivatives containing unactivated alkene moieties has been developed, providing green and efficient access to various six-, seven-, and eight-membered ring 3,4-fused tricyclic indoles. This type of cyclization, which was hitherto very difficult to comprehend in ergot biosynthesis and to

Cyclodextrins as building blocks for new materials

• Miriana Kfoury and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2023, 19, 889–891, doi:10.3762/bjoc.19.66

• use of CDs and further stimulate their market. The exploration of the potential of inclusion complexation is not limited to the biomedical field. CDs are renewable and biodegradable materials that enable green and environmental biotechnologies for all applications [11]. The ability of CDs to act as

Light-responsive rotaxane-based materials: inducing motion in the solid state

• Adrian Saura-Sanmartin

Beilstein J. Org. Chem. 2023, 19, 873–880, doi:10.3762/bjoc.19.64

• direction, one potential strategy is the approach followed by Feringa and co-workers [72], in which palladium-porphyrin photosensitizer-based struts were employed within a metal-organic material, allowing the use of green light as irradiation source because of the effective energy transfer between these

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky,
• Mikhail E. Minyaev and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• systems which are unavailable by other methods. Wherein, usually UV-promoted reactions are environmentally friendly due to the absence of toxic reagents, which is especially perspective in context of green chemistry [9][10]. Thus, studies of the photochemical behavior of organic compounds play an

Sulfate radical anion-induced benzylic oxidation of N-(arylsulfonyl)benzylamines to N-arylsulfonylimines

• Joydev K. Laha,
• Pankaj Gupta and
• Amitava Hazra

Beilstein J. Org. Chem. 2023, 19, 771–777, doi:10.3762/bjoc.19.57

• with ortho-substituted anilines is also reported. The key features of the protocol include the use of a green oxidant, a short reaction time (30 min), chromatography-free isolation, scalability, and economical, delivering N-arylsulfonylimines in excellent yields of up to 96%. While the oxidation of N

• -substituted anilines. The key features including the use of a green oxidant, a short reaction time, chromatography-free isolation, and scalability mark a distinction from the contemporary methods. Although we propose a dual role for SO4·− involving both hydrogen atom abstraction (HAT) and single electron

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

• -oxyl (TEMPO) oxidation [8]. TEMPO oxidation, in particular, has been successfully applied on a manufacturing scale as a low-cost and green oxidation method [9]. However, these oxidation processes generally require stoichiometric oxidants, and reduced byproducts must be purged in a purification step

Palladium-catalyzed enantioselective three-component synthesis of α-arylglycine derivatives from glyoxylic acid, sulfonamides and aryltrifluoroborates

• Bastian Jakob,
• Nico Schneider,
• Luca Gengenbach and
• Georg Manolikakes

Beilstein J. Org. Chem. 2023, 19, 719–726, doi:10.3762/bjoc.19.52

• α-arylglycine motifs (highlighted in green and blue). The Petasis reaction – fundamental reactivities and recent developments. Observations from previous studies and mechanistic rationale. Initial experiments. Reaction scope – aryltrifluoroborates (yields and enantiomeric ratios in parentheses refer

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• (highlighted in green). In comparison to linearly conjugated materials, oligomeric and polymeric compounds with a fully cross-conjugated carbon backbone are relatively unexplored [17][18][19][20]. Molecules of this type serve not only as objects of fundamental research into the phenomena of cross-conjugation

• nitro group. There are two types of independent non-equivalent dications, marked in blue and green, and two types of BF4− anions, marked in red and yellow, in the crystal structure of salt 11c (Figure S68 in Supporting Information File 1). Monomer fragments in both are identical (Table 2, Figure 5). The

• directions of electron density transfer are possible (Figure 7): between two DMAN fragments through the butadiyne linker (highlighted in green) and between the DMAN and aryl rings through the acetylene bridge (highlighted in blue). Obviously, the “butadiyne path” includes a longer conjugation chain

pH-Responsive fluorescent supramolecular nanoparticles based on tetraphenylethylene-labelled chitosan and a six-fold carboxylated tribenzotriquinacene

• Nan Yang,
• Yi-Yan Zhu,
• Wei-Xiu Lin,
• Yi-Long Lu and
• Wen-Rong Xu

Beilstein J. Org. Chem. 2023, 19, 635–645, doi:10.3762/bjoc.19.45

• powders of CS-TPE exhibit a pale-yellow appearance under normal daylight conditions and emit intense green-blue light when exposed to UV irradiation (365 nm). This phenomenon differs greatly from the fluorescence properties of conventional ACQ fluorophores, which are typically nonfluorescent under UV

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

• 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

Direct C2–H alkylation of indoles driven by the photochemical activity of halogen-bonded complexes

• Martina Mamone,
• Giuseppe Gentile,
• Jacopo Dosso,
• Maurizio Prato and
• Giacomo Filippini

Beilstein J. Org. Chem. 2023, 19, 575–581, doi:10.3762/bjoc.19.42

• both UV–vis and nuclear magnetic resonance (NMR) spectroscopy [29]. In particular, the optical absorption spectra of substrate 2a (green dotted line), DABCO (red dotted line), and the solution containing both 2a and DABCO (blue line) were recorded in acetonitrile (Figure 2). Specifically, it was

A new oxidatively stable ligand for the chiral functionalization of amino acids in Ni(II)–Schiff base complexes

• Alena V. Dmitrieva,
• Oleg A. Levitskiy,
• Yuri K. Grishin and
• Tatiana V. Magdesieva

Beilstein J. Org. Chem. 2023, 19, 566–574, doi:10.3762/bjoc.19.41

• are presented in different colors: the hydrogen bonding are labeled in blue color of the reduced density gradient isosurface; green color corresponds to the dispersion interactions (van der Waals interactions, the π-stacking); red color represents steric clashes. The interplay of these through-space

• protons. Low-gradient isosurfaces with low densities (blue color of the isosurface corresponds to the hydrogen bonding; the dispersion interactions (van der Waals interactions, the π-stacking) are marked in green color; red color indicates steric clashes) obtained for the ʟ- (left image) and ᴅ-alanine