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

• carbonyl carbon (δC 174.6). Its NMR profile is similar to brocaeloid C [24], with the distinction of an added succinimide substructure at N-15, where the ketone carbonyl carbon at C-16 is replaced by a hydroxy carbon. The isoprene group is consistent with that in compound 1. HMBC cross-peaks from H-10 to C

• sixteen-carbon fatty acid. Notably, two methylene carbons overlapped in the 13C NMR spectrum. The COSY correlations facilitated the determination of the carbon chain fragments from C-11 to C-16 and C-2 to C-10, despite two methylene signals overlapping. The carboxyl group's position at C-1 was confirmed

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

• to carbon materials [2][3]. The properties and characteristics of these linker molecules are keys not only to the purpose of protein immobilization, but also to the behavior of the entire biosensor system. In oscillator-based biosensors, further adsorption on the sensor, such as viruses using antigen

• sensor chips and specifically binds to the antibody. The antigen is then detected by observing the change in the vibrational frequency before and after the injection of the antigen. The immobilization of a protein using a PASE linker on carbon nanotube [1], graphite [4], and graphene [5] has been

• reported. The adsorption of PASE has been considered to mainly come from the pyrene fragment, which forms π–π stacking on these graphitic carbon materials [6][7][8]. The sensitivity of the oscillator-based sensor depends on the structure of the linker molecule. Therefore, understanding the adsorption

Entry to new spiroheterocycles via tandem Rh(II)-catalyzed O–H insertion/base-promoted cyclization involving diazoarylidene succinimides

• Alexander Yanovich,
• Anastasia Vepreva,
• Ksenia Malkova,
• Grigory Kantin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2024, 20, 561–569, doi:10.3762/bjoc.20.48

• consequence, the significantly greater nucleophilicity of the nearest α-carbon atom. When an attempt was made to generate an anion from compound 25 under the action of a stronger base (t-BuOK/THF, 0 °C) in order to effect spirocyclization, only the formation of a complex multicomponent mixture was observed

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

• ) that is labile. By default, the complex is in a closed form with the functional units on each ligand facing each other due to the square planar geometry of the complex. By adding a first ancillary ligand (carbon monoxide, chloride,…) that strongly binds to the metal center, one weak binding site 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

• sp2 methines, one sp3 methine, one sp3 methylene, and one methyl group. The 13C NMR data showed the resonances of twelve carbons, which were classified into six olefinic carbons (including two oxygenated carbons: δC 151.0 and 145.2), three carbonyl carbons, one sp3 methine carbon, one sp3 methylene

• carbon, and one methyl carbon. A spin system H-6 (δH 6.85)/H-7 (δH 7.33) with an ortho-coupling constant (8.5 Hz) was observed using homonuclear correlation spectrometry (COSY). The heteronuclear multiple bond correlation (HMBC) cross-peaks from H-6 to C-2 (δC 112.4) and C-4 (δC 145.2), and from H-7 to C

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

• involvement in proton transfer at the transition state [78]. In systems where protodemetalation is rate determining, a metal-carbon bonded intermediate is allegedly characterized, as in the case of a related palladium-catalyzed hydroamination [47], and a propargylamide cyclization [44]. In our studies, the

• cross-hatched spheres, and carbon and hydrogen atoms are represented by medium and small open spheres, respectively and all nonhydrogen atoms are labeled [43]. (c) 31P NMR spectrum (161.98 MHz, CDCl3). (a) kobs for reaction of urea 1a (0.05 M) in DCM with catalyst 5 and titrated CH3OH/CH3OD. Data for

Pseudallenes A and B, new sulfur-containing ovalicin sesquiterpenoid derivatives with antimicrobial activity from the deep-sea cold seep sediment-derived fungus Pseudallescheria boydii CS-793

• Zhen Ying,
• Xiao-Ming Li,
• Sui-Qun Yang,
• Hong-Lei Li,
• Xin Li,
• Bin-Gui Wang and
• Ling-Hong Meng

Beilstein J. Org. Chem. 2024, 20, 470–478, doi:10.3762/bjoc.20.42

• H-12 and H-13 to C-10 and C-11 constructed the isopentenyl group. Further HMBC correlations from H-15 to C-1, C-7, and C-8 connected the cyclohexane ring and isopentenyl from C-1 and C-8 via the non-protonated carbon C-7. The assignment of the thio-ether bond between C-8 and C-14 was supported by

Synthesis of 2,2-difluoro-1,3-diketone and 2,2-difluoro-1,3-ketoester derivatives using fluorine gas

• Alexander S. Hampton,
• David R. W. Hodgson,
• Graham McDougald,
• Linhua Wang and
• Graham Sandford

Beilstein J. Org. Chem. 2024, 20, 460–469, doi:10.3762/bjoc.20.41

• difluoromethylphenyl sulfoxide offer the possibility of transferring difluoromethylene groups directly into organic systems [19][20][21][22][23][24][25] and there is now a very extensive literature on carbon–carbon bond-forming reactions using these and other difluoromethylated building blocks [3][26][27][28][29][30

• , or N-fluoroammonium ion 6, to form difluoroketones 3a–i. Quinuclidine hydrofluoride has independently been shown to be an effective form of soluble fluoride ion in a variety of carbon–fluorine bond-forming processes [57][58]. Enols are, in general, significantly more acidic than their isomeric keto

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

• Eiichi Kayahara Yoshiyuki Mizuhata Shigeru Yamago Institute for Chemical Research, Kyoto University, Uji 611-0011, Japan 10.3762/bjoc.20.38 Abstract A dication of [5]cycloparaphenylene ([5]CPP2+) was selectively encapsulated by neutral [10]CPP to form the shortest double-layer carbon nanotube

• chemistry; Introduction Since the first bottom-up organic synthesis of cycloparaphenylenes (CPPs) [1][2][3][4][5][6][7], which are the carbon nanorings with the shortest possible structural constituent of armchair carbon nanotubes (CNTs), a new science of cyclic nanocarbons has emerged through synthesizing

• . Furthermore, Isobe and co-workers also showed that the carbon nanorings with the simplest structural unit of chiral CNTs, such as cyclochrysenylene [34], cyclonaphthylenes [35], and cycloanthanthrenylene [36], are also excellent hosts of fullerenes with exceptionally high binding constants. These results open

Mono or double Pd-catalyzed C–H bond functionalization for the annulative π-extension of 1,8-dibromonaphthalene: a one pot access to fluoranthene derivatives

• Nahed Ketata,
• Linhao Liu,
• Ridha Ben Salem and
• Henri Doucet

Beilstein J. Org. Chem. 2024, 20, 427–435, doi:10.3762/bjoc.20.37

• , carbon 2 should be more reactive than carbon 4 in the Pd-catalyzed direct arylation, but we previously observed that the main product of the reaction was C4-arylated 1,3-dichlorobenzene [32]. This selectivity could be due to the steric hindrance of the chloro substituents. As a result, in the presence of

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

• counterparts, due to their recyclability, ease of handling, and low cost [40]. Carbon-based solid acid catalysts especially are an interesting catalyst class, because they display low corrosiveness, toxicity, and higher catalytic activity, while also being insoluble in most organic solvents. The large amount

• of strong acidic sites that are on the carbon-based solid acids enhance their catalytic ability, compared to traditional Lewis and protic acids [41][42][43]. The most common examples in literature for the reaction of the synthesis of BIMs under solvent-free conditions utilize either protic acids

• . immobilized carbon nanotubes on sulfonated polyacrylamide creating polymer/carbon nanotube composites, which could also be employed in the synthesis of BIMs [115][116]. This methodology used a catalyst loading of 5 mol % under reflux conditions (85 °C) in acetonitrile for 30–40 minutes with product yields

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

• irradiation, EDA complex 74 triggered a radical chain process initiated by B–B bond cleavage, forming boryl-NHPI ester radical 75 and boryl radical 76. Subsequent decarboxylation of 75 yields carbon-centered radical 9 and boryl-phthalimide byproduct 77. Meanwhile DMA-ligated B2cat2 78 is formed upon

• significant advantages compared to other methods. It allows for single electron reduction to be facilitated by cost-effective carbon-based cathodes, eliminating the requirement for precious metal photocatalysts or exogeneous reductants such as Zn0. In the final section of this perspective, we explore examples

• ] (Scheme 32A). Under these conditions, activation of NHPI ester 160 by SET occurs at the cathode’s surface affording the corresponding radical anion 161 (Scheme 32B). Subsequent fragmentation leads to the cyclohexyl radical (162) which then adds to the terminal carbon of radical acceptor 163, leading to

Facile approach to N,O,S-heteropentacycles via condensation of sterically crowded 3H-phenoxazin-3-one with ortho-substituted anilines

• Eugeny Ivakhnenko,
• Vasily Malay,
• Pavel Knyazev,
• Nikita Merezhko,
• Nadezhda Makarova,
• Oleg Demidov,
• Gennady Borodkin,
• Andrey Starikov and
• Vladimir Minkin

Beilstein J. Org. Chem. 2024, 20, 336–345, doi:10.3762/bjoc.20.34

• amines, the direction of which is controlled by the large positive charge at the C(2) center of the p-quinone imine moiety of the heterocycle. With this in mind, we turned our attention to solid-state organic reactions. Numerous examples of nucleophilic substitutions at carbon centers are discussed in

• Maxis™ Impact (resolving power (FWHM) of 40,000 at m/z 1222, electrospray ionization). The cyclic voltammograms of 4a–h, 5a–c, 6a,b, and 10c were measured with the use of three-electrode configuration (glassy carbon working electrode, Pt counter electrode, Ag/Ag+ reference electrode using 0.01 M AgNO3

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

• modelling and solid-state X-ray analysis, provides a detailed description of the spatial arrangement of cyclodextrin host–guest complexes in solution. The chiral cavity of the cyclodextrin molecule creates an anisotropic environment for the guest molecule resulting in a splitting of its prochiral carbon

• signals in 13C NMR spectra. This signal split can be correlated to the distance of the guest atoms from the wall of the host cavity and to the spatial separation of binding sites preferred by pairs of prochiral carbon atoms. These measurements complement traditional solid-state analyses, which rely on the

• 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

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• conversion in situ, triggered by thermal activation, photoirradiation or redox control. Beside well-established reactions involving the elimination of carbon-based small molecules, i.e., retro-Diels–Alder and decarbonylation processes, the late-stage extrusion of chalcogen fragments has emerged as a highly

• π-CPCs relies on the extrusion of carbon monoxide (CO) from soluble precursors incorporating bridging ketone fragment(s). In contrast with the thermal activation required in retro-Diels–Alder reactions, photoirradiation of α-diketones triggers a Strating–Zwanenburg decarbonylation leading to the

• in-solution organic chemistry techniques, ii) for their improved processing, as well as iii) for their in situ structural characterization and electronic investigation both at the material and single-molecule scales. Reactions involving the elimination of carbon-based small molecules, i.e., retro

Synthesis of spiropyridazine-benzosultams by the [4 + 2] annulation reaction of 3-substituted benzoisothiazole 1,1-dioxides with 1,2-diaza-1,3-dienes

• Wenqing Hao,
• Long Wang,
• Jinlei Zhang,
• Dawei Teng and
• Guorui Cao

Beilstein J. Org. Chem. 2024, 20, 280–286, doi:10.3762/bjoc.20.29

• ketimines as suitable three-carbon synthons in [3 + 2] and [3 + 3] annulations [11][12][13][14][15]. However, methods using N-sulfonyl ketimines as dienophiles in [4 + 2] annulation reactions to afford biologically important spiro compounds are still limited to date [16]. 1,2-Diaza-1,3-dienes [17][18][19

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

• opening. Keywords: cycloadditions; DFT calculations; [70]fullerene; open-cage fullerenes; rhodium; Introduction The discovery of C60 (buckminsterfullerene) in 1985 [1] initiated the search for possible technological applications of fullerenes. Nowadays, applications for these carbon-based molecules have

• applications are still in various stages of research and development. The functionalization of fullerenes makes them versatile materials, broadening the range of potential applications [17][18]. It allows the properties of these carbon cages to be tuned, making them more soluble (especially in water for

• medical applications) and improving their stability, among other desirable properties. The most common reactions used to functionalize fullerenes are Diels–Alder and 1,3-dipolar cycloadditions and Bingel–Hirsch cyclopropanations [19][20]. In most cases, functionalization occurs while preserving the carbon

Additive-controlled chemoselective inter-/intramolecular hydroamination via electrochemical PCET process

• Kazuhiro Okamoto,
• Naoki Shida and
• Mahito Atobe

Beilstein J. Org. Chem. 2024, 20, 264–271, doi:10.3762/bjoc.20.27

• radical acceptor moieties. Therefore, we investigated the origin of this selectivity under electrochemical conditions. Results and Discussion Anodic oxidation of uridine derivative 1 was performed in a CH2Cl2/Bu4NPF6 (0.1 M) electrolyte system using a carbon felt (CF) anode and a Pt cathode in the

• was 0.01 M. A glassy carbon anode (φ 3 mm) and Pt cathode (φ 3 mm) were used. Scan rate = 100 mV/s. Plausible models illustrating the size effect of the hydrogen bond complex on the interaction efficiency with electrode surfaces. Plausible mechanism for the inter-/intramolecular hydroamination of 1

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

• , the scope of sulfonium salts was examined, as summarized in Scheme 2a. Alkylsulfonium salts substituted with a halide (F, Cl, or Br) or isocyano group at the para-position of the aryl ring (1b–e) were successfully converted into the carbon–sulfur bond formation products (3ba–fa) in moderate to good

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

• in chloroform and carbon tetrachloride upon exposure to orange light. The lifetime of Z-11a in CCl4 was significant and the thermal backward reaction occurred in darkness with the restoration of the initial absorption of the E-isomer for 57% after 5 h and for 100% in 18 h. N,N'-Diethylindigo (11b

• the isomerization of 9a. In 2015, Głowacki and co-workers successfully synthesized N,N'-di(tert-butoxycarbonyl)indigos 17a–c for the first time [64]. The incorporation of bulky tert-butoxycarbonyl (Boc) substituents induced a notable strain on the central ethylenic carbon that in combination with the

Metal-catalyzed coupling/carbonylative cyclizations for accessing dibenzodiazepinones: an expedient route to clozapine and other drugs

• Amina Moutayakine and
• Anthony J. Burke

Beilstein J. Org. Chem. 2024, 20, 193–204, doi:10.3762/bjoc.20.19

• was disclosed that DMF, the reaction solvent, could act as a potential carbon monoxide surrogate under certain circumstances, notably, in metal-catalyzed aminocarbonylation procedures [19][20]. Unfortunately, no DBDAP was obtained and we only observed the formation of intermediate 3a in 25% yield

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

• substituent in meta position (R2 = F, Cl, Br, OMe) was present (12f–i), as expected from the increased nucleophilicity of the carbon involved in the intramolecular Friedel–Crafts reaction. In the para position, R3 = Br and CO2Me were tested and showed good results, to give 12j and 12k with more than 70

Copper-promoted C5-selective bromination of 8-aminoquinoline amides with alkyl bromides

• Changdong Shao,
• Chen Ma,
• Li Li,
• Jingyi Liu,
• Yanan Shen,
• Chen Chen,
• Qionglin Yang,
• Tianyi Xu,
• Zhengsong Hu,
• Yuhe Kan and
• Tingting Zhang

Beilstein J. Org. Chem. 2024, 20, 155–161, doi:10.3762/bjoc.20.14

• selective C5-bromination of 8-aminoquinoline amides using carbon tetrabromide and dibromomethane under photo- and electrocatalysis conditions [27][28]. In 2017, Xia and co-workers reported a novel, mild, metal-free, and regioselective bromination of amides, wherein the organic dye eosin Y acted as the

Perspectives on push–pull chromophores derived from click-type [2 + 2] cycloaddition–retroelectrocyclization reactions of electron-rich alkynes and electron-deficient alkenes

• Michio Yamada

Beilstein J. Org. Chem. 2024, 20, 125–154, doi:10.3762/bjoc.20.13

• process. The [2 + 2] CA–RE sequence proceeds successively, as depicted in Scheme 1, where electron-donating groups are denoted as EDGs. During the [2 + 2] CA process, the nucleophilic attack by the terminal alkyne carbon of an electron-rich alkyne on an electron-deficient alkene, such as TCNE and 7,7,8,8

• TCNQ with electron-rich alkynes, the alkyne terminal carbon executes a nucleophilic attack on the exocyclic carbon of the dicyanovinyl (DCV) group of TCNQ, affording dicyanoquinodimetanes (DCNQs) [12][13]. Intense ICT bands of TCBD and DCNQ are observed at around 450–470 nm and 680–710 nm, respectively

• equivalents of TCNEO relative to the alkyne substrate for the generation of the TCBD products [100]. For the reaction, the formal [3 + 2] cycloaddition reaction is postulated to initiate through the initial nucleophilic attack of the alkyne carbon on the electrophilic TCNEO carbon, yielding a zwitterionic

Visible-light-induced radical cascade cyclization: a catalyst-free synthetic approach to trifluoromethylated heterocycles

• Chuan Yang,
• Wei Shi,
• Jian Tian,
• Lin Guo,
• Yating Zhao and
• Wujiong Xia

Beilstein J. Org. Chem. 2024, 20, 118–124, doi:10.3762/bjoc.20.12

• indole ring (3m and 3n) furnished the products in moderate yields. The structure of compound 3m (4-Br) was confirmed by X-ray single crystal diffraction (CCDC: 2304916). Reactions of substrates with a longer carbon chain and a branched chain also proceeded well and afforded the products in 43% (3o) and