New sesquiterpenoids from the South China Sea soft corals Clavularia viridis and Lemnalia flava

• Qihao Wu,
• Yuan Gao,
• Meng-Meng Zhang,
• Li Sheng,
• Jia Li,
• Xu-Wen Li,
• Hong Wang and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2019, 15, 695–702, doi:10.3762/bjoc.15.64

• molecular weight (Figure 1). In fact, the main difference between 1 and 1a happened only at the tetrasubstituted benzene ring with the substituents exchange between C-7 and C-10 (Figure 1). The assignment of the planar structure of 1 has been further confirmed by 2D NMR experiments, including 1H,1H COSY

• the same laurane skeleton. In fact, compound 2 differed from 1 only by the debromonation at the C-15 position, which was in agree with the lack of 78/80 units in its mass compared to that of 1. The planar structure of 2 was further confirmed by its 2D NMR data (Figure 2). The relative configurations

• 220.1824 [M]+ (calcd for C15H24O, 220.1825). A detailed analysis of 2D NMR experiments (Figure 2), revealed that compound 6 had the same planar structure as 6a and co-occurring 7 differing only in the stereochemistry. The relative configuration of 6 was established by NOESY correlations (Figure 3) in which

Catalyst-free assembly of giant tris(heteroaryl)methanes: synthesis of novel pharmacophoric triads and model sterically crowded tris(heteroaryl/aryl)methyl cation salts

• Rodrigo Abonia,
• Luisa F. Gutiérrez,
• Braulio Insuasty,
• Jairo Quiroga,
• Kenneth K. Laali,
• Chunqing Zhao,
• Gabriela L. Borosky,
• Samantha M. Horwitz and
• Scott D. Bunge

Beilstein J. Org. Chem. 2019, 15, 642–654, doi:10.3762/bjoc.15.60

• 1D and 2D NMR spectroscopy and by EIMS, elemental analysis, and HRMS (see experimental section and Supporting Information File 1). Additionally, single crystals of compound 9{4,7,1} suitable for X-ray analysis were grown from ACN at room temperature. Compound 9{4,7,1} crystallizes in the triclinic

Polyaminoazide mixtures for the synthesis of pH-responsive calixarene nanosponges

• Antonella Di Vincenzo,
• Antonio Palumbo Piccionello,
• Alberto Spinella,
• Delia Chillura Martino,
• Marco Russo and
• Paolo Lo Meo

Beilstein J. Org. Chem. 2019, 15, 633–641, doi:10.3762/bjoc.15.59

• work we verified the feasibility of synthesizing new pH-responsive calixarene nanosponges by using two different polyaminoazide mixtures as the reticulating agent. Full characterization (HR-ESIMS, FTIR, 1D and 2D NMR) of the mixtures has been provided. It is particularly important to stress that the

Chemical structure of cichorinotoxin, a cyclic lipodepsipeptide that is produced by Pseudomonas cichorii and causes varnish spots on lettuce

• Hidekazu Komatsu,
• Takashi Shirakawa,
• Takeo Uchiyama and
• Tsutomu Hoshino

Beilstein J. Org. Chem. 2019, 15, 299–309, doi:10.3762/bjoc.15.27

• summer season in the highland areas of Japan (e.g., Nagano and Iwate prefectures) was isolated. The structure of a toxin produced by this organism was analyzed based on the detailed evaluation of its 2D NMR and FABMS spectra, and this compound has not been reported previously. We propose the name

• ]. Herein, we report the structural determination of the toxin produced by P. cichorii YM8705, which was determined mainly from detailed analyses of its 2D NMR spectra. Although the structure is similar to that of syringopeptin 22A, composed of 22 amino acids, it is not identical, and this new phytotoxic

• , the 1H NMR signals of the monoacetate were well separated (600 MHz, acetone-d6, Supporting Information File 1, Figure S7). Therefore, the 1D and 2D NMR spectra of the monoacetate were analyzed to determine the overall structure. The 1H,1H COSY, TOCSY, NOESY, HMQC and HMBC spectra are shown in

A simple and effective preparation of quercetin pentamethyl ether from quercetin

• Jin Tatsuzaki,
• Tomohiko Ohwada,
• Yuko Otani,
• Reiko Inagi and
• Tsutomu Ishikawa

Beilstein J. Org. Chem. 2018, 14, 3112–3121, doi:10.3762/bjoc.14.291

• to a C-methyl group in the 1H NMR spectrum (see Supporting Information File 2). C-Methylation apparently occurred at the 6- or 8-position, since the meta-coupled aromatic signals of 1 at 6.33 and 6.49 ppm were replaced by a singlet signal at 6.69 ppm. Inspection of 2D NMR spectra data (COSY, NOESY

Reactions of 3-(p-substituted-phenyl)-5-chloromethyl-1,2,4-oxadiazoles with KCN leading to acetonitriles and alkanes via a non-reductive decyanation pathway

• Akın Sağırlı and
• Yaşar Dürüst

Beilstein J. Org. Chem. 2018, 14, 3011–3017, doi:10.3762/bjoc.14.280

• compounds were identified by means of IR, 1H NMR, 13C NMR, 2D NMR spectra, TOF–MS and X-ray measurements. Keywords: decyanation; KCN; 1,2,4-oxadiazole; Introduction Heterocyclic scaffolds bearing 1,2,4-oxadiazole rings have been the subject of an increasing and remarkable attention due to their various

Nucleoside macrocycles formed by intramolecular click reaction: efficient cyclization of pyrimidine nucleosides decorated with 5'-azido residues and 5-octadiynyl side chains

• Jiang Liu,
• Peter Leonard,
• Sebastian L. Müller,
• Constantin Daniliuc and
• Frank Seela

Beilstein J. Org. Chem. 2018, 14, 2404–2410, doi:10.3762/bjoc.14.217

• by ESI–TOF mass spectra, 1H and 13C NMR spectroscopy as well as 2D NMR spectra (Supporting Information File 1). The NMR data gave evidence of the structural assignment of the 5’-azido compounds and the macrocycles. A strong upfield shift (≈10 ppm) for the C5’-carbon signal as well as a moderate

Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

• Hendrik V. Schröder and
• Christoph A. Schalley

Beilstein J. Org. Chem. 2018, 14, 2163–2185, doi:10.3762/bjoc.14.190

• site. Chemical oxidation to the dication TTF2+ triggers a translational motion of the wheel towards the 1,5-dihydroxynaphthalene station (green) as shown by UV–vis and 2D NMR experiments. Chemical reduction with zinc powder restored the spectroscopic properties of the starting state and back-shuttling

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• higher (25% on average) than that of N-hydroxysuccinimide (2b). Structures of the iodo-oxyimides 3aa–ka, 3ab–db, 3fb, 3hb and 3kb were confirmed by 1D and 2D NMR spectroscopy, IR spectroscopy, high-resolution mass spectrometry and elemental analysis. An additional confirmation of the structure of 3ca was

Calix[6]arene-based atropoisomeric pseudo[2]rotaxanes

• Carmine Gaeta,
• Carmen Talotta and
• Placido Neri

Beilstein J. Org. Chem. 2018, 14, 2112–2124, doi:10.3762/bjoc.14.186

• the 1,2,3-alternate conformation of 1 is the presence of the broad singlet at 3.71 ppm which correlates in the HSQC spectrum with a carbon resonance at 34.1 ppm [30], related to anti-oriented Ar rings. A close inspection of the 1D and 2D NMR spectrum of 1 in CDCl3 at 233 K clearly evidenced the

• pseudorotaxane could be detected by 1D and 2D NMR studies (Figure 6). In fact, a 2D COSY spectrum of the 1:1 mixture of 1 and 2+ in CDCl3, after 18 h at 298 K, showed the presence of an ArCH2Ar AX system at 3.47/4.62 ppm which correlates in the HSQC spectrum with a carbon resonance at 28.4 ppm related to syn

• thermodynamic one [35]. At this point we turned our attention to the threading properties of bis(4-trifluoromethylbenzyl)ammonium axle 3+. When 1 and 3+·TFPB− were mixed in CDCl3 two atropoisomeric pseudo[2]rotaxane, 3+1cone and 3+11,2,3-alt (Figure 10), were formed in a 1/10 ratio, as revealed by 1D and 2D NMR

Synthesis of new p-tert-butylcalix[4]arene-based polyammonium triazolyl amphiphiles and their binding with nucleoside phosphates

• Vladimir A. Burilov,
• Guzaliya A. Fatikhova,
• Mariya N. Dokuchaeva,
• Ramil I. Nugmanov,
• Diana A. Mironova,
• Pavel V. Dorovatovskii,
• Victor N. Khrustalev,
• Svetlana E. Solovieva and
• Igor S. Antipin

Beilstein J. Org. Chem. 2018, 14, 1980–1993, doi:10.3762/bjoc.14.173

• observation of cross-peaks between hydroxy protons 4 and the methylene bridge protons 5 and 5’, on the one hand, and the methylene protons 6–8 in the octyl chain (δ = 3.98, 3.18 and 2.04 ppm), on the other hand, is also in line with this conclusion. Thus, the 2D NMR data are completely consistent with the

Synthesis and photophysical studies of a multivalent photoreactive Ru^II-calix[4]arene complex bearing RGD-containing cyclopentapeptides

• Sofia Kajouj,
• Lionel Marcelis,
• Alice Mattiuzzi,
• Adrien Grassin,
• Damien Dufour,
• Pierre Van Antwerpen,
• Didier Boturyn,
• Eric Defrancq,
• Mathieu Surin,
• Julien De Winter,
• Pascal Gerbaux,
• Ivan Jabin and
• Cécile Moucheron

Beilstein J. Org. Chem. 2018, 14, 1758–1768, doi:10.3762/bjoc.14.150

• silica gel column chromatographic purification. Complex 7 was fully characterized by 1D and 2D NMR spectroscopy in CD3CN at 600 MHz. In accordance with the presence for the chiral Ru(TAP)2phen moiety, the 1H NMR spectrum of 7 is characteristic of a C1 symmetrical compound as all the protons belonging to

• , t = triplet, q = quartet, br = broad, m = massif, mult = multiplet). 2D NMR spectra (COSY, HSQC, HMBC, HSQC) were recorded to complete signal assignments. Melting points were recorded on a Stuart Scientific Analogue SMP11 or Büchi Melting Point B-545. Infrared spectra were recorded on a Bruker Alpha

Lanyamycin, a macrolide antibiotic from Sorangium cellulosum, strain Soce 481 (Myxobacteria)

• Lucky S. Mulwa,
• Rolf Jansen,
• Dimas F. Praditya,
• Kathrin I. Mohr,
• Patrick W. Okanya,
• Joachim Wink,
• Eike Steinmann and
• Marc Stadler

Beilstein J. Org. Chem. 2018, 14, 1554–1562, doi:10.3762/bjoc.14.132

• Bochum, Germany 10.3762/bjoc.14.132 Abstract Lanyamycin (1/2), a secondary metabolite occurring as two epimers, was isolated from the myxobacterium Sorangium cellulosum, strain Soce 481. The structures of both epimers were elucidated from HRESIMS and 1D and 2D NMR data and the relative configuration of

• ). Careful handling of the samples 1 and 2 allowed measuring 1D and 2D NMR data sets in methanol-d4 of both before a rearrangement finally restored the original mixture. Comparative NMR analyses showed that the spectra of 1 and 2 were very similar (Table 1, and Supporting Information File 1, Tables S1 and S2

Synthetic avenues towards a tetrasaccharide related to Streptococcus pneumonia of serotype 6A

• Aritra Chaudhury,
• Mana Mohan Mukherjee and
• Rina Ghosh

Beilstein J. Org. Chem. 2018, 14, 1095–1102, doi:10.3762/bjoc.14.95

• corresponding characterization data. Supporting Information File 146: 1H and 13C NMR of compounds 1, 3a, 4, 5, 6a, 6b, 7, 12a, 19, 20, 21, and 23 and 2D NMR (COSY, HSQC and HMBC) of compound 23. Acknowledgements RG acknowledges the SERB, DST (Scheme No. SR/S1/OC-61/2012), India for financial support. AC and

Diels–Alder cycloadditions of N-arylpyrroles via aryne intermediates using diaryliodonium salts

• Huangguan Chen,
• Jianwei Han and
• Limin Wang

Beilstein J. Org. Chem. 2018, 14, 354–363, doi:10.3762/bjoc.14.23

• synthesized in 75% yield (Scheme 2b), whose structure was determined by 2D-NMR analyses (see Supporting Information File 1). Furthermore, as a unique electron donor, the novel compound 5 may have potential applications in photosensitive dyes and OLEDs [28][29]. Interestingly, the bridged-ring compound 6 could

Synthesis and spectroscopic properties of β-meso directly linked porphyrin–corrole hybrid compounds

• Baris Temelli and
• Hilal Kalkan

Beilstein J. Org. Chem. 2018, 14, 187–193, doi:10.3762/bjoc.14.13

• -5,10,15,20-tetraphenylporphyrins with meso-substituted dipyrromethanes. Hybrid compounds have been characterized by 1H NMR, 13C NMR, 2D NMR, UV–vis absorption and fluorescence spectroscopy. Keywords: corrole; hybrid compounds; indium(III) chloride; porphyrin; porphyrinoids; Introduction Porphyrins and

An efficient synthesis of 1,6-anhydro-N-acetylmuramic acid from N-acetylglucosamine

• Matthew B. Calvert,
• Christoph Mayer and
• Alexander Titz

Beilstein J. Org. Chem. 2017, 13, 2631–2636, doi:10.3762/bjoc.13.261

• reported vs 2.00 observed) and one of the H6 protons (4.350 reported vs 4.03 observed) [12]. However, when 2D NMR studies were carried out in acetone-d6, in which 12 is significantly more stable, we were able to unequivocally prove the reported structure by identifying key HMBC correlations between H-1 and

• ), 170.91 (C=O, Ac), 101.81 (CH, C-1), 80.20 (CH, C-3), 77.16 (CH, C-5), 74.58 (CH, α-Lac), 70.94 (CH, C-4), 65.97 (CH2, C-6), 50.97 (CH, C-2), 23.05 (Me, Ac), 19.23 (Me, Lac-Me); HRMS (ESI–TOF) m/z: [M + H]+ calcd for C11H18NO7, 276.10833; found, 276.10713. AnhydroMurNAc and derivatives. 2D NMR

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

• Xinli Pan,
• Nicole Domin,
• Sebastian Schieferdecker,
• Hirokazu Kage,
• Martin Roth and
• Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

• singlets in the 1H NMR spectrum. They were positioned next to the quaternary carbon C-2 on the basis of HMBC interactions. Interpretation of 2D NMR data allowed an extension of this residue with CH-4 and CH2-5. Ultimately, a heteronuclear long-range correlation from H-4 to C-6 linked the two fragments to

Fluorination of some highly functionalized cycloalkanes: chemoselectivity and substrate dependence

• Attila Márió Remete,
• Melinda Nonn,
• Santos Fustero,
• Matti Haukka,
• Ferenc Fülöp and
• Loránd Kiss

Beilstein J. Org. Chem. 2017, 13, 2364–2371, doi:10.3762/bjoc.13.233

• treatment of dihydroxylated amino acid ester (±)-1 with 1.5 equiv of Deoxofluor after 70 min afforded through intramolecular cyclization a compound which was identified on the basis of 2D NMR analysis as oxazoline derivative (±)-2 as the sole product in 71% yield. When the same reaction was carried out in

• 2D NMR and X-ray data fluorohydrine derivative (±)-5 through chemodifferentiation in a moderate yield (Scheme 2, Figure 1). This result indicated that in the case of compound (±)-4, the C-4 hydroxy group is transformed into a leaving group on interaction with Deoxofluor, followed by a fluoride attack

Structural diversity in the host–guest complexes of the antifolate pemetrexed with native cyclodextrins: gas phase, solution and solid state studies

• Magdalena Ceborska,
• Magdalena Zimnicka,
• Aneta Aniela Kowalska,
• Kajetan Dąbrowa and
• Barbara Repeć

Beilstein J. Org. Chem. 2017, 13, 2252–2263, doi:10.3762/bjoc.13.222

• gas phase, in solution and in the solid state. Mass spectrometry was employed for the investigation of the architecture and relative gas-phase stabilities of these supramolecular complexes. The mode of complexation was further tracked by 1D and 2D NMR proving the formation of the exclusion-type

• the free PTX molecule is engaged in strong H-bonds between the carboxylate donor –NH group, which are gradually broken. Overall all the data obtained from 1D and 2D NMR experiments suggests formation of exclusion-type associate of two equally probable conformations depicted in Figure 3a. Moreover

• while the chemical shift of amidic proton PTX#H2 does not change. 2D ROESY NMR of β-CD/PTX (Figure 4) closely resembles 2D NMR spectrum of β-CD/FA [20] suggesting that for both guests a similar mode of complexation is taking place. Comparable changes are also observed in 1H NMR after complexation of the

The chemistry and biology of mycolactones

• Matthias Gehringer and
• Karl-Heinz Altmann

Beilstein J. Org. Chem. 2017, 13, 1596–1660, doi:10.3762/bjoc.13.159

• family known to date. A structure was proposed by the Small group based on mass fragmentation and 1H/2D NMR spectroscopic data. This structure, which features a tetraenoate (lower) side chain with a terminal 1,3-diol motif was once again confirmed by total synthesis in the Kishi laboratory; the relative

A new member of the fusaricidin family – structure elucidation and synthesis of fusaricidin E

• Marcel Reimann,
• Louis P. Sandjo,
• Luis Antelo,
• Eckhard Thines,
• Isabella Siepe and
• Till Opatz

Beilstein J. Org. Chem. 2017, 13, 1430–1438, doi:10.3762/bjoc.13.140

• optical rotation of [α]D25 +20.9 (c 0.6, DMSO-d6). The mass difference between both metabolites is 14 amu. This observation was supported by two ion peaks observed in the ESIMS spectrum at m/z 961.6 and m/z 975.6, respectively. Through extensive analysis of the 1 and 2D NMR data of the major component 1

Switchable highly regioselective synthesis of 3,4-dihydroquinoxalin-2(1H)ones from o-phenylenediamines and aroylpyruvates

• Juraj Dobiaš,
• Marek Ondruš,
• Gabriela Addová and
• Andrej Boháč

Beilstein J. Org. Chem. 2017, 13, 1350–1360, doi:10.3762/bjoc.13.132

• % yield after crystallisation from DMSO. To prove the exact structure of 17d (ANTI) was not easy and we had to combine the more complex 2D NMR techniques (HSQC, NOESY and HMBC). At first, we assigned hydrogens and carbons in the main regioisomer. Next, we proved for 17d its ANTI isomerism by HMBC analysis

• -dihydroquinoxaline-2(1H)-ones. Their ANTI (17) or SYN (16) structures were assigned by complex 2D NMR techniques (HSQC, NOESY and HMBC) or by a proposed simplified method (NOE interaction between higher 1H NMR (DMSO-d6) shifted H-N(4), bonded by intramolecular hydrogen bond, and H-C(5) or interaction of lower

An eco-compatible strategy for the diversity-oriented synthesis of macrocycles exploiting carbohydrate-derived building blocks

• Sushil K. Maurya and
• Rohit Rana

Beilstein J. Org. Chem. 2017, 13, 1106–1118, doi:10.3762/bjoc.13.110

• starting material) and appearance of multiplet near δ 5.65 ppm for the alkenyl protons. Moreover, the complete structural assignment was done with the help of 2D NMR. It is worth mentioning here that the reaction proceeded with excellent selectivity for the trans product (confirmed by 2D NMR). Next we

Cycloheximide congeners produced by Streptomyces sp. SC0581 and photoinduced interconversion between (E)- and (Z)-2,3-dehydroanhydrocycloheximides

• Li Yang,
• Ping Wu,
• Jinghua Xue,
• Huitong Tan,
• Zheng Zhang and
• Xiaoyi Wei

Beilstein J. Org. Chem. 2017, 13, 1039–1049, doi:10.3762/bjoc.13.103

• ) using MeOH as solvent. 1H NMR, 13C NMR, and 2D NMR data were recorded on a Bruker Avance III 500 MHz spectrometer with TMS as internal standard. HRESIMS data were recorded on a Bruker maXis Q-TOF spectrometer. Preparative HPLC were carried out with a Shimadzu Shim-packed Pro-ODS column (20 mm × 25 cm

• energies and selected geometrical parameters of key stationary points in S0, S1, and T1 potential energy surfaces of 2a/3a and 4a. Antifungal activity and cytotoxicity of 1–6a. Supporting Information Supporting Information File 176: HRESIMS, 1D and 2D NMR spectra of compounds 1–3; energies, populations