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

• stable configuration (conformation 1) in a straight form on graphene. There is at least one metastable bent configuration (conformation 2) on the potential energy surface. Besides, the reaction barrier of the conformational change of the PASE was determined. In this paper, we further examine a reaction

• PASE on graphene [3][4]. The protein and pyrene are connected via an alkyl chain. The atomic configuration of this alkyl chain is believed not to be largely affected by the substitution of the succinimidyl group with an amino group. On the other hand, proteins alone do not readily form adsorbed

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

• vibrations of the thiophene and amide carbonyl groups were observed at 1663–1678 and 1705–1713 cm−1, respectively. The 1H NMR spectra contained signals of methine protons (=CH–) in the region 7.92–9.02 ppm, which corresponded to the Z-configuration of the C=C bond. According to data previously obtained [14

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

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

• 129.4) and C-10 through a sulfur atom. Based on these results, the structure of 1 was elucidated as 4-((2-acetamido-2-carboxyethyl)thio)-2,3-dihydroxybenzoic acid. The absolute configuration of 1 was determined by advanced Marfey’s analysis. 1 was de-sulfurized with skeletal Ni and then hydrolyzed with

• HCl. The obtained amino acid (alanine) and authentic amino acids were modified using Nα-(5-fluoro-2,4-dinitrophenyl)-ᴅ-leucinamide (ᴅ-FDLA). The LC–MS analysis of ᴅ-FDLA derivatives revealed that the chiral center of the amino acid in 1 had ʟ configuration (Figure S7, Supporting Information File 1

• Saccharopolyspora. Only bootstrap values above 50% (percentages of 1000 replications) are shown. Structure of KR21-0001A (1). (a) 1H,1H COSY and HMBC correlations and (b) absolute configuration. Fermentation of Saccharopolyspora sp. KR21-0001 and isolation procedure of KR21-0001A (1). NMR spectroscopic data of KR21

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

• the HMBC correlation from H-14 to C-8, as well as the molecular formula combined with chemical shifts (δC 35.9, CH2-14, and δC 45.8, CH-8) [12]. Furthermore, HMBC correlations from the protons of methoxy to C-2 attached the methoxy group to C-2. The relative configuration of compound 1 was determined

• verified by the COSY and HMBC correlations (Figure 2). The structure and relative configuration of compound 2 were deduced the same as for 1 by NOE correlations (Figure 3). Moreover, the absolute configurations of compound 2 were unambiguous determined by X-ray diffraction with the refined Flack parameter

• should be mentioned that compound 3 was the first sulfur-containing ovalicin sesquiterpenoid, which was previously isolated from Sporothrix sp. FO-4649, but its absolute configuration was not explicitly represented, and their 1H and 13C NMR data were incomplete [10]. Thus, a full assignment of the NMR

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• all cases, except the reaction in diglyme (Table 1, entry 5), a mixture of (E)- and (Z)-2-bromo-1,1,1,4,4,4-hexafluorobut-2-enes (3a,b) in a ratio of 2:1 was formed. The configuration of the isomers was determined by the 5JFFcis coupling constant in the 19F{H} NMR spectrum (ca. 0 Hz for (Z)-isomer and

• distillation in 52% yield for 6a,b and 34% yield for 7a,b. NMR analysis showed the mixtures of (E)- and (Z)-isomers in both cases with the ratio E/Z = ≈4:5 for 6a,b and E/Z = ≈1:2 for 7a,b. The configuration of the isomers was determined by the 5JFFcis coupling constant in the 19F{H} NMR spectrum (ca. 0 Hz for

• column 7a was isolated in 67% yield. The 19F{1H} NMR spectra of 7a, showed the coupling constant of CF3 and CF3 to be 11.3 Hz, suggesting strongly that product 7a like the original silane 8 has (E)-configuration. Although some olefins presented above were obtained several decades ago, there was almost no

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

• 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

Discovery of unguisin J, a new cyclic peptide from Aspergillus heteromorphus CBS 117.55, and phylogeny-based bioinformatic analysis of UngA NRPS domains

• Sharmila Neupane,
• Marcelo Rodrigues de Amorim and
• Elizabeth Skellam

Beilstein J. Org. Chem. 2024, 20, 321–330, doi:10.3762/bjoc.20.32

• ) and from δH 2.93 and 3.01 (H2-β) to C=O (δC 171.1) (Figure 3), together with key NOESY interactions between the NH signals at δH 7.98↔8.44↔8.14. The absolute configuration of 1 was assigned by Marfey’s method [14]. Comparison of the retention time by LC–MS between the derivatized 1 as well as the

• visualized using Web Logo [22] and compared to literature motifs (Figures S3 and S4, Supporting Information File 1). Marfey’s method to determine the absolute configuration of 1 and 2 Samples 1 and 2 (0.3 mg each) were hydrolyzed in 0.5 mL of 6 N HCl at 115 °C for 20 h. After cooling, the reaction mixture

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• steric clashes or density effects). Another supporting finding can be seen in the fact that CSB (exhibiting iduronic acid in α-configuration, rather than its epimer, glucuronic acid, in β-configuration) showed virtually no binding to CMA1, further arguing for contacts of the GAG chain with the binding

• galactose that is preferentially presented in a β-configuration, enables it to bind to a range of biologically relevant epitopes, such as LacdiNAc, Sda, blood group H, and chondroitin sulfate motifs. Further, the inhibition of binding by the presence of Lewis antigen motifs additionally narrows it binding

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

• spiropyridazine-benzosultams. The electronic effects of substituents and the influence of steric hindrance on the reaction were explored. The configuration of the product was determined by X-ray single crystal diffraction. This method has the advantages of mild reaction conditions, wide substrate scope, and high

Synthesis of the 3’-O-sulfated TF antigen with a TEG-N₃ linker for glycodendrimersomes preparation to study lectin binding

• Mark Reihill,
• Hanyue Ma,
• Dennis Bengtsson and
• Stefan Oscarson

Beilstein J. Org. Chem. 2024, 20, 173–180, doi:10.3762/bjoc.20.17

• 4.95 ppm with a J value of 3.6 Hz in the 1H NMR spectrum proving the anomeric α-configuration. The presence of Troc-rotamers was also apparent, with a ratio of 19:6 being observed by 1H NMR in CDCl3 at 25 °C. Catalytic amounts of NaOMe (0.005 M) in MeOH were used to remove the acetate from compound 4

Photoinduced in situ generation of DNA-targeting ligands: DNA-binding and DNA-photodamaging properties of benzo[c]quinolizinium ions

• Julika Schlosser,
• Olga Fedorova,
• Yuri Fedorov and
• Heiko Ihmels

Beilstein J. Org. Chem. 2024, 20, 101–117, doi:10.3762/bjoc.20.11

• spectrometry. In all cases, the E-configuration of the alkene double bonds was indicated by characteristic coupling constants of the alkene protons (3JH–H = 16 Hz). Absorption properties and photoreactions of styrylpyridine derivatives In acetonitrile solution, the styrylpyridines 2a–g exhibited long

Biphenylene-containing polycyclic conjugated compounds

• Cagatay Dengiz

Beilstein J. Org. Chem. 2023, 19, 1895–1911, doi:10.3762/bjoc.19.141

• benzene rings connected with a four-membered ring, is a highly intriguing compound in terms of its structure. It possesses a planar configuration and consists of 4n π-electrons, rendering it antiaromatic. However, despite being antiaromatic, biphenylene is more stable than other known antiaromatic

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• configuration comprising indium–tin oxide (ITO) as the bottom electrode, a few μm thick organic layer as the active medium, and aluminum as the top electrode. The entire deposition process was carried out under a vacuum exceeding 2 × 10−6 mbar to ensure the integrity and purity of the layers. In our TOF setup

• × ttr), where d represents the thickness of the organic layer, and U corresponds to the applied voltage over the sample. Cyclic voltammetry (CV) measurements were conducted using a mAUTOLAB type III galvanostat, employing a glassy carbon working electrode in a three-electrode cell configuration. The

N-Boc-α-diazo glutarimide as efficient reagent for assembling N-heterocycle-glutarimide diads via Rh(II)-catalyzed N–H insertion reaction

• Grigory Kantin,
• Pavel Golubev,
• Alexander Sapegin,
• Alexander Bunev and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2023, 19, 1841–1848, doi:10.3762/bjoc.19.136

• ][10], potentially opening a path for its use in treating KRAS-induced cancers. A common characteristic of the degraders elaborated in the literature involves the compulsory integration of an E3-ligase ligand motif into the PROTAC configuration [11]. The E3-ligase most frequently utilized in TPD

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• product was purified by preparative thin-layer chromatography (SiO2, hexane/ethyl acetate 2:1, Rf 0.36) to obtain the product (S)-14 as pale-yellow crystals. The products had the same spectroscopic data than those of reported (the absolute configuration was determined by the optical rotation of the

Quinoxaline derivatives as attractive electron-transporting materials

• Zeeshan Abid,
• Liaqat Ali,
• Sughra Gulzar,
• Faiza Wahad,
• Raja Shahid Ashraf and
• Christian B. Nielsen

Beilstein J. Org. Chem. 2023, 19, 1694–1712, doi:10.3762/bjoc.19.124

• recent study by Eedugurala et al., a terachlorobenzene ring were fused to the [1,2,5]thiadiazolo[3,4-g]quinoxaline unit in the polymer backbone of Qx6 which enhanced the stability of the polymer and led to its high-spin configuration compared to the analogous material Qx5 featuring 6,7-dimethyl-[1,2,5

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

• -(1,2,2-triphenylvinyl)phenyl)-9H-carbazol-3-yl)naphtho[2,3-c][1,2,5]thiadiazole (TPECNz), built on a D–A–D type structure was designed and synthesized (Scheme 1). The D–A–D configuration was constructed by incorporating a second symmetrical donor in the D–A framework, which could further reduce the

• configuration with dihedral angles of 54–56° between the planes of the terminal carbazole donors and the Nz acceptor that are beneficial for the state mixing between the LE and CT states. The lowest unoccupied molecular orbital (LUMO) was mainly localized on the Nz ring, while the highest occupied molecular

• of the twisted configuration between them as observed in the optimized structure (Figure 1a) [47]. In solution, TPECNz exhibits a strong deep-red emission with the PL spectrum (λem = 648 nm) described by a broad PL band (FWHM = 120 nm) that reflects the corresponding ICT absorption band well

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

• ) in 1D and 2D ROE spectroscopy (ROESY) suggested that the relative configuration of the aglycone in 1 is identical to that in breynin B (6). The remaining NMR resonances (Table 2) were attributed to a tetrasaccharide based on the observation of four anomeric methine signals at δC 103.2 (C-1′), 104.5

• reduce computational costs (Figure 3a). The calculated ECD curve for 1′ agreed well with the experimental ECD spectra of 1 and 6, indicating that the aglycones of these compounds had an absolute configuration of 1R,3R,4R,6S,7R,9S,11S,12R,16S,17S (Figure 3b). Similarly, the absolute configurations of

• substituent at C-17 and the same relative configuration as 5 otherwise, as supported by the SSCC and NOE observed in the 1H NMR, NOESY, and J-resolved spectra. As the computed and experimental ECD curves of 3 were in good agreement, the absolute configuration of compound 3 was established as 4R,6S,7R,9S,11S

α-(Aminomethyl)acrylates as acceptors in radical–polar crossover 1,4-additions of dialkylzincs: insights into enolate formation and trapping

• Angel Palillero-Cisneros,
• Paola G. Gordillo-Guerra,
• Fernando García-Alvarez,
• Olivier Jackowski,
• Franck Ferreira,
• Fabrice Chemla,
• Joel L. Terán and
• Alejandro Perez-Luna

Beilstein J. Org. Chem. 2023, 19, 1443–1451, doi:10.3762/bjoc.19.103

• ZnMe2 (entries 9 and 10). This difference can be ascribed to a less favorable homolytic substitution reaction of ZnMe2 in relation to its higher analogues and is in line with previous literature observations [11]. The configuration of the major diastereomer was determined by chemical correlation (Scheme

• concomitant deprotection of the nitrogen and the ester groups. The sample was found to have a negative optical rotation, thereby indicating that the major enantiomer present had S configuration [26]. This allowed to establish that the configuration of the major diastereomer present in (RS)-14b was (RS,S), and

• 5 and 8a in 77–88% yields, albeit as poorly selective mixtures of diastereoisomers. This lack of stereocontrol is not surprising, given the well-known difficulty to control the relative configuration between the two adjacent stereocenters created during aldol condensations with zinc enolates

Correction: 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, 1370–1371, doi:10.3762/bjoc.19.97

• theoretical ECD spectra of both enantiomers to determine the absolute configuration. By comparison of the recalculated and the experimental spectra, it became evident that in fact, the (3S,4S)-enantiomer rather than the (3R,4R)-enantiomer was obtained (Figure 2). Consequently, in the first paragraph of the

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• alkenyl compounds, the vinyl ether function is characterized by a (Z)-configuration as shown in Figure 1. In addition, an acyl group is present on the secondary alcohol of the glycerol. This acyl group is constituted by a saturated or unsaturated lipid chain or, in the case of platelet-activating factor

• (PAF), by an acetyl group (R2 = CH3) [1]. The asymmetric carbon of the glycerol (sn-2 position) features a R configuration. The last substituent attached to the glycerol unit is a polar head group mostly constituted by a phosphatidylethanolamine group (PE) or a phosphocholine moiety (PC). ELs with

• produces the diester 4.12 with an inversion of the configuration of the chiral carbon atom. Then, 4.12 was hydrolyzed in the presence of KOH to produce 4.10. The installation of the phosphocholine group was achieved following two schemes: a) Starting from the diol 4.10 (Figure 4C), tritylation and

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

• (CV) was performed using a three-electrode configuration consisting of a glassy carbon macrodisk working electrode (GCE) (diameter of 3 mm; BASi, Indiana, U.S.A.) combined with a Pt wire counter electrode (99.99%; GoodFellow, Cambridge, U.K.) and an Ag wire pseudoreference electrode (99.99

Selective construction of dispiro[indoline-3,2'-quinoline-3',3''-indoline] and dispiro[indoline-3,2'-pyrrole-3',3''-indoline] via three-component reaction

• Ziying Xiao,
• Fengshun Xu,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2023, 19, 1234–1242, doi:10.3762/bjoc.19.91

• effect. The single crystal structure of compound 3a was determined by X-ray crystallographic diffraction (Figure 1). From Figure 1 it can be seen that the two scaffolds of oxindole at neighboring positions are in trans-configuration. The ethoxycarbonyl group is also in trans-position to the carbonyl

• group in the neighboring oxindole scaffold. Therefore, it can be concluded that the obtained dispiro compounds 3a–m have this kind of relative configuration on the basis of 1H NMR spectra and crystal structure determination. It should be pointed out that ammonium acetate was employed as nitrogen source

• is largely general. The 1H NMR spectra of the obtained compounds 4j–p clearly show similar chemical shifts of the characteristic groups as the spiro compounds 4a–i. Therefore, it can be concluded that the spiro compounds 4j–p have the same relative configuration as the spiro compounds 4a–i. In order

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

• positions were notably confirmed to be at C-3 and C-21, respectively. The ᴅ-configuration of the β-glucopyranosyl unit was assumed to be the one found in related fungal lanostanosides namely; ganosinoside A from Ganoderma sinense [26], fomitosides I and J from Fomitopsis pinicola [34]. Concerning the

• configuration at C-3', it was assigned as S by careful comparison of the 1H and 13C NMR data of compound 1 with those of related lanostane derivatives comprising the 3-hydroxy-3-methylglutaryl moiety produced by some fungi including Fomitopsis pinicola [23], Piptoporus betulinus [13], and Pholiota populnea [35