Hydrogen-bond activation enables aziridination of unactivated olefins with simple iminoiodinanes

• Phong Thai,
• Lauv Patel,
• Diyasha Manna and
• David C. Powers

Beilstein J. Org. Chem. 2024, 20, 2305–2312, doi:10.3762/bjoc.20.197

• aliphatic olefins in the absence of transition metal catalysts, the addition of HFIP enables direct aziridination to be observed. The enhanced reactivity is rationalized as resulting from H-bonding between HFIP and the nitrogen center of the iminoiodinane reagents. 1H NMR data are consistent with such an

Natural resorcylic lactones derived from alternariol

• Joachim Podlech

Beilstein J. Org. Chem. 2024, 20, 2171–2207, doi:10.3762/bjoc.20.187

• on NMR-spectroscopic investigations but turned out to be wrong, when the spectroscopic data were compared with those of synthesized material. Re-evaluation of the NMR data and total synthesis of assumed correct structures revealed revised constitutions, which are given in Figure 10 [44]. No

• . alternata) [42][54]. Its structure was proposed based on NMR-spectroscopic investigations [222] and unambiguously confirmed after total syntheses and comparison of NMR data [217][223][224]. Altenusin was further isolated from A. longipes [60] and further non-specified A. spp. [147][216][225][226], from

Allostreptopyrroles A–E, β-alkylpyrrole derivatives from an actinomycete Allostreptomyces sp. RD068384

• Marwa Elsbaey,
• Naoya Oku,
• Mohamed S. A. Abdel-Mottaleb and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2024, 20, 1981–1987, doi:10.3762/bjoc.20.174

• total 6.5 mg of 1, 3.1 mg of 2, 2.6 mg of 3, 7.2 mg of 4, and 5.6 mg of 5 from 12 L culture. Allostreptopyrrole A (1): greenish yellow amorphous solid; UV (MeOH) λmax nm (log ε) 234 (3.86), 273 sh (3.44); IR (ATR) νmax: 3275, 2964, 2928, 2855, 1658, 1554, 1418 cm−1; 1H and 13C NMR data, see Table 1

• ; HRESITOFMS (m/z): [M – H]– calcd for C15H22NO4, 280.1554; found, 280.1550. Allostreptopyrrole B (2): greenish yellow amorphous solid; +15 (c 0.10, MeOH); UV (MeOH) λmax, nm (log ε): 235 (3.87), 273 sh (3.49); IR (ATR) νmax: 3263, 2964, 2925, 2854, 1658, 1556, 1417 cm−1; 1H and 13C NMR data, see Table 2

• ; HRESITOFMS (m/z): [M – H]– calcd for C15H22NO4, 280.1554; found, 280.1554. Allostreptopyrrole C (3): greenish yellow amorphous solid; −6.1 (c 0.10, MeOH); UV (MeOH) λmax, nm (log ε): 235 (3.82), 276 sh (3.46); IR (ATR) νmax: 3265, 2925, 2856, 1657, 1555, 1417 cm−1; 1H and 13C NMR data, see Table 2

1,2-Difluoroethylene (HFO-1132): synthesis and chemistry

• Liubov V. Sokolenko,
• Taras M. Sokolenko and
• Yurii L. Yagupolskii

Beilstein J. Org. Chem. 2024, 20, 1955–1966, doi:10.3762/bjoc.20.171

• ], respectively, while reference [68] provides UV-spectral data of both isomers. 1H, 19F, and 13C NMR data [69][70] are given in Table 2. Chemistry of HFO-1132 Isomerization Iodine-catalyzed cis–trans isomerization of 1,2-difluoroethylene and corresponding equilibrium measurements were described in the 1960s [47

Novel oxidative routes to N-arylpyridoindazolium salts

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

Beilstein J. Org. Chem. 2024, 20, 1906–1913, doi:10.3762/bjoc.20.166

• -arylpyridoindazolium salts S1–S3 was confirmed with HRMS and 1H, 13C and 19F NMR data; the complete assignment of the signals was performed using 2D NMR methods. The N–N bond formation was additionally confirmed via comparison of the 1H spectra for the salts and their diarylamine precursors. The absence of the signals

Towards an asymmetric β-selective addition of azlactones to allenoates

• Behzad Nasiri,
• Ghaffar Pasdar,
• Paul Zebrowski,
• Katharina Röser,
• David Naderer and
• Mario Waser

Beilstein J. Org. Chem. 2024, 20, 1504–1509, doi:10.3762/bjoc.20.134

• NMR and δ 77.16 ppm for 13C NMR). NMR data are reported as follows: chemical shift (δ ppm), multiplicity (s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, dd = doublet of doublet), coupling constants (Hz), relative integration value. High-resolution mass spectra were obtained using a

Synthesis of 2-benzyl N-substituted anilines via imine condensation–isoaromatization of (E)-2-arylidene-3-cyclohexenones and primary amines

• Lu Li,
• Na Li,
• Xiao-Tian Mo,
• Ming-Wei Yuan,
• Lin Jiang and
• Ming-Long Yuan

Beilstein J. Org. Chem. 2024, 20, 1468–1475, doi:10.3762/bjoc.20.130

• -cyclohexenone. This is further supported by the 13C NMR spectrum, which contains two peaks at δ = 38.4 and 47.7 indicating the two types of benzylic carbons. The NMR data of known compound 4ab were also in good correlation with previously reported data [19]. The synthetic practicability of the protocol was

Synthesis of cyclic β-1,6-oligosaccharides from glucosamine monomers by electrochemical polyglycosylation

• Md Azadur Rahman,
• Hirofumi Endo,
• Takashi Yamamoto,
• Shoma Okushiba,
• Norihiko Sasaki and
• Toshiki Nokami

Beilstein J. Org. Chem. 2024, 20, 1421–1427, doi:10.3762/bjoc.20.124

• linear trisaccharide 20b were produced with monomer 17b with a 3,4-di-O-benzyl group (Table 2, entry 2). Although the 3-hydroxy protecting group R3 also affected the product distribution, formation of the corresponding 1,6-anhydrosugars was not observed in both cases. NMR data suggested that cyclic

Computation-guided scaffold exploration of 2E,6E-1,10-trans/cis-eunicellanes

• Zining Li,
• Sana Jindani,
• Volga Kojasoy,
• Teresa Ortega,
• Erin M. Marshall,
• Khalil A. Abboud,
• Sandra Loesgen,
• Dean J. Tantillo and
• Jeffrey D. Rudolf

Beilstein J. Org. Chem. 2024, 20, 1320–1326, doi:10.3762/bjoc.20.115

• collected NMR data of 1 in chloroform [5], but when we dissolved 2 in chloroform for NMR, it cyclized into two 6/6/6-tricyclic diterpenes (5 and 6) [7]. We discovered that 2 was much more sensitive to acid than 1 and eventually took advantage of its reactivity to determine its absolute configuration [7

Competing electrophilic substitution and oxidative polymerization of arylamines with selenium dioxide

• Vishnu Selladurai and
• Selvakumar Karuthapandi

Beilstein J. Org. Chem. 2024, 20, 1221–1235, doi:10.3762/bjoc.20.105

• based on HRMS data. To test whether the isolated black solid was a single compound or an isomeric mixture of compounds 1 and 2, 77Se NMR spectroscopy could be a convenient tool. Unfortunately, 77Se NMR data was not reported in the work of Bhat et al. [37]. With this question in mind, the reaction was

Three-component N-alkenylation of azoles with alkynes and iodine(III) electrophile: synthesis of multisubstituted N-vinylazoles

• Jun Kikuchi,
• Roi Nakajima and
• Naohiko Yoshikai

Beilstein J. Org. Chem. 2024, 20, 891–897, doi:10.3762/bjoc.20.79

• oxazolidinone-substituted ynamide also proved to undergo iodo(III)azolation in a regio- and stereoselective fashion to give the product 4ai in a moderate yield. Note that terminal alkynes such as phenylacetylene also took part in the reaction, albeit in a much-diminished yield (7% by 1H NMR; data not shown

Discovery and biosynthesis of bacterial drimane-type sesquiterpenoids from Streptomyces clavuligerus

• Dongxu Zhang,
• Wenyu Du,
• Xingming Pan,
• Xiaoxu Lin,
• Fang-Ru Li,
• Qingling Wang,
• Qian Yang,
• Hui-Min Xu and
• Liao-Bin Dong

Beilstein J. Org. Chem. 2024, 20, 815–822, doi:10.3762/bjoc.20.73

• that the only difference between compounds 3 and 2 is the position of the hydroxy group [28]. Analyses of the NMR data of compound 4 concluded that it is an analogue of 2. In comparison with 2, compound 4 has a ketone carbonyl signal at δC 219.1 and we finally confirmed its structure by comparing it

• comparing the 1H and 13C NMR data with the literature (Figures S11 and S12 in Supporting Information File 1) [41]. Although the chemical structure of compound 8 has been documented, its 1H and 13C NMR data were not fully reported [42]. Therefore, we conducted comprehensive 1D and 2D NMR experiments on it

Isolation and structure determination of a new analog of polycavernosides from marine Okeania sp. cyanobacterium

• Kairi Umeda,
• Naoaki Kurisawa,
• Ghulam Jeelani,
• Tomoyoshi Nozaki,
• Kiyotake Suenaga and
• Arihiro Iwasaki

Beilstein J. Org. Chem. 2024, 20, 645–652, doi:10.3762/bjoc.20.57

• from a marine Okeania sp. cyanobacterium. The relative configuration was elucidated primarily by analyzing the two dimensional nuclear magnetism resonance (2D NMR) data. The absolute configuration was clarified by comparing the electronic circular dichroism (ECD) data of 1 with those of known analogs

• characteristic UV absorption around 270 nm. The molecular formula of 1 was determined to be C44H66O15 based on the HRESIMS data. The NMR data for 1 are summarized in Table 1. The 1H NMR spectrum of compound 1 was similar to those of known polycavernosides but matched none of them, suggesting that 1 was a new

• analog of polycavernosides [1][3][4][5]. A detailed analysis of the NMR data revealed the planar structure of 1, as shown in Figure 2. COSY and HMQC spectral analyses revealed several partial structures, indicated by the bold bonds in Figure 2. Four HMBC were observed from singlet methyl signals: δH 0.85

Production of non-natural 5-methylorsellinate-derived meroterpenoids in Aspergillus oryzae

• Jia Tang,
• Yixiang Zhang and
• Yudai Matsuda

Beilstein J. Org. Chem. 2024, 20, 638–644, doi:10.3762/bjoc.20.56

• structures, the biosynthetic pathway, and NMR data and spectra. Acknowledgements We thank Prof. Katsuya Gomi (Tohoku University), Prof. Katsuhiko Kitamoto (University of Tokyo), and Prof. Jun-ichi Maruyama (University of Tokyo) for providing the expression vectors and fungal strain. We are grateful to Dr

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

• 175.94, δC 194.36). Its NMR data closely resemble those of brocaeloid D [23], with the notable addition of a methoxy group (δH 3.20/δC 53.92). HMBC correlations confirmed the presence of a reversed prenyl group and differentiated compound 1 from brocaeloid D by the substitution of a succinimide

• substructure at C-14 with a methine at C-16, indicated by the methoxy group. The position of the methoxy substituent was established by HMBC correlations, and the 13C NMR data suggested that compound 1 includes a 4-oxo-2,3-dihydro-(1H)-quinolin-3-yl fragment. The planar structure was established from HMBC

• structure of compound 1. 1H and 13C data of compound 1 (recorded in CDCl3). 1H and 13C NMR data of compound 2 (recorded in CDCl3). 1H and 13C NMR data of compound 3 (recorded in CDCl3). Antimicrobial activity of compounds 1–12. Minimum inhibitory concentrations were shown in µg/mL. Biosynthetic gene

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

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

• 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

• –6.10). Then, compound 2 (13.7 mg) was isolated by CC on Si gel (CH2Cl2/MeOH, 250:1 to 50:1) and preparative TLC (plate: 20 × 20 cm, developing solvent: ether/acetone 2:1) from Fr. 6.3 (578 mg). Pseudallene A (1): colorless crystals (MeOH); mp 115–117 °C; [α]D25 +20.0 (c 0.4, MeOH); 1H and 13C NMR data

• , see Table 2; HRESIMS (m/z): [M + H]+ calcd for C16H29O5S, 333.1730; found: 333.1733). Pseudallene B (2): colorless crystals (MeOH); mp 171–175 °C; [α]D25 +53.3 (c 0.3, MeOH); 1H and 13C NMR data, see Table 2; HRESIMS (m/z): [M + H]+ calcd for C15H27O5S, 319.1573; found: 319.1568.. X-ray

(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

• . Nevertheless, it was tentatively identified in the mixture, based on 1H, 19F and 13C NMR data. The 19F NMR spectrum showed three signals with the integrated intensity ratio 3:1:1, a doublet for a CF3 group at δ −71.5 ppm with a coupling constant of 3JFH = 6 Hz and two highly characteristic signals of geminal

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

• compound 1 was elucidated by 1D and 2D NMR and HRESIMS/MS. Unguisin B was identified by the 1H and 13C NMR data with the reported data [1][5]. Compound 1 was obtained as a white amorphous solid optically active, with +23.4 (c 0.1, MeOH). Its molecular formula was established as C41H56N8O7 by HRMS ([M + H

• ]+ at m/z 773.4338, calculated for C41H57N8O7+, m/z 773.4345, Δ 0.9 ppm; [M + Na]+ at m/z 795.4162, calculated for C41H56N8O7Na+, m/z 795.4164, Δ 0.3 ppm) and NMR data analysis, corresponding to eighteen indices of hydrogen deficiency. Its UV spectrum exhibited absorption maxima at λmax 219 and 279 nm

• biosynthesis of unguisins B and J in A. heteromorphus CBS 117.55. 1D and 2D NMR data for 1 (1H: 500 MHz, 13C: 125 MHz; DMSO-d6). Supporting Information Supporting Information File 36: Spectroscopic and spectrometric data of 1 and 2. Bioinformatic data of the biosynthetic gene clusters. Acknowledgements We

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

• (CDCl3, δ = 77.16 ppm; CD3OD, δ = 49.00 ppm; (CD3)2SO δ = 39.52 ppm and 13C NMR spectra recorded in D2O are unreferenced. All 13C NMR spectra are 1H decoupled. All NMR data are represented as follows: chemical shift (δ ppm), multiplicity (s = singlet, br s = broad singlet, d = doublet, app d = apparent

• literature were recorded in CDCl3 [3], NMR data are not comparable. HRESIMS m/z: [M + Na]+ calcd for C32H48N4O19; 815.2810; found; 815.2806. 2-[2-(2-Azidoethoxy)ethoxy]ethyl β-ᴅ-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-α-ᴅ-galactopyranoside [3][4] (1): Compound 8 (1.47 g, 1.85 mmol) was dissolved in MeOH

• -6), 60.9 (C-6), 50.1 (CH2(Linker)), 48.5 (C-2GalNAc), 22.0 (CH3(NHAc)). NMR data match those reported in the literature [3][4]. HRESIMS m/z: [M + H]+ calcd for C20H36N4O13, 541.2357; found, 541.2354. 2-[2-(2-Azidoethoxy)ethoxy]ethyl 3-O-sulfo-β-ᴅ-galactopyranosyl-(1→3)-2-acetamido-2-deoxy-α-ᴅ

Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• molecules were determined by single-crystal X-ray crystallography. The bonding situation in the solid state together with NMR data suggests an important contribution of an ylidic resonance structure in these molecules. The phosphonium phenolates are characterized by UV–vis absorptions peaking around 360 nm

NMRium: Teaching nuclear magnetic resonance spectra interpretation in an online platform

• Luc Patiny,
• Hamed Musallam,
• Alejandro Bolaños,
• Michaël Zasso,
• Julien Wist,
• Metin Karayilan,
• Eva Ziegler,
• Johannes C. Liermann and
• Nils E. Schlörer

Beilstein J. Org. Chem. 2024, 20, 25–31, doi:10.3762/bjoc.20.4

• ), Cleveland, Ohio 44106, United States, Department of Chemistry, Johannes Gutenberg University Mainz, 55099 Mainz, Germany 10.3762/bjoc.20.4 Abstract NMRium is the first web-based software that allows displaying, processing, interpretation, and teaching of 1D and 2D NMR data in a user-friendly interface. It

• of NMR data. While initially intended for small molecules data repositories and databases [34][35], NMRium provides unique functionalities that make it particularly well-suited for educational application. Teaching the interpretation of NMR spectra Nowadays, the interpretation of NMR experiments is

• and storing entire NMRium projects in their current state, whether partially or fully analyzed. Features of NMRium What differentiates NMRium from most other NMR data processing software, specifically with respect to its educational application, is the ability to handle NMR data (proprietary format of

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• with the formation of B2F7− or with the DBU-BF3 adduct (a direct comparison with literature data is not possible in this case, as the NMR data reported in previous papers were obtained in molecular solvents, while we carried out the experiments in pure ionic liquid) [115]. To our surprise, the addition

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

• product 6b in high yield. The reaction with methyl pyrrole-2-carboxylate resulted in the isolation of only the C–H insertion product 9c in low yield. Similar reaction progress was observed in the case with imidazole, the product N–H insertion was observed only in trace amounts (according to NMR data of

• yield. As a side process, а carbenoid's repeated attack at the 6-position of the tetrahydroquinoline ring of compound 6x was observed according to NMR data. Introducing a bromine atom to block the 6-position led to a significant increase in the target product 6y yield. The decomposition of diazo reagent

• suppressed the targeted reaction. Merely traces of the N–H insertion product were detectable in NMR data, with insignificant conversion of the initial heterocycle. Examples of N–H insertion reactions with azoles containing non-equivalent nitrogen atoms deserve separate discussion. As the only product of the

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• of N2H4·H2O (2.9–3.0 equiv) with a catalytic amount of TsOH·H2O (0.05 equiv) in refluxing EtOH or 1,4-dioxane resulted in the formation of mixtures of macrocycle 5, pyrazolyl-1,2,4-triazole 10, and a very small amount of bis-pyrazole 6 according to NMR data (Table 1, entries 22 and 23). It is