Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

• Jürgen Krauß,
• Monika Klimt,
• Markus Luber,
• Peter Mayer and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

• hydroxylactone 2 (55% yield). This outcome was confirmed by comparison with published NMR data [18][19]. At elevated temperature (reflux, 4 h; Table 1, entry 2) a mixture of lactone 2 and known unsaturated lactone 3 [15] (arising from acid-catalyzed dehydration of 2) was obtained. Under even more drastic acidic

• , no signal was observed which could be attributed to a C–H group at the pyrrole ring. The 13C NMR data showed one carbonyl resonance at 170.3 ppm, assignable to a lactone moiety. The HMBC experiment showed a cross peak between the proposed lactone carbonyl carbon and a neighboring CH-O group

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• 1,2,3,4-tetrahydro isomer has been assigned considering only indirect evidences so that the structure corresponding to the 1,2,6,7-tetrahydro isomer cannot be excluded (no NMR data have been reported so far). A well related known example involves the correct structure of fluorindine (5,14-dihydro

Genome mining in Trichoderma viride J1-030: discovery and identification of novel sesquiterpene synthase and its products

• Xiang Sun,
• You-Sheng Cai,
• Yujie Yuan,
• Guangkai Bian,
• Ziling Ye,
• Zixin Deng and
• Tiangang Liu

Beilstein J. Org. Chem. 2019, 15, 2052–2058, doi:10.3762/bjoc.15.202

• and 2D NMR spectroscopy (Table 1, Table S4, and Figures S4–S15, Supporting Information File 1). Compound 1 was a new compound with a known skeleton [35], isolated as a white powder. 1H and 13C NMR data showed four methyl groups at δH 1.87 (t, J = 1.2 Hz, 3H,), δH 0.96 (s, 3H), δH 0.83 (s, 3H), and δH

• 0.80 (d, J = 7.0 Hz, 3H). Five methylenes were detected, including an oxygenated one at δH 4.18 (d, J = 11.6 Hz, 1H), 3.97 (d, J = 9.8 Hz, 1H), as well as three methines and three quaternary carbons including a double bond at δC 137.4 (C-5), 126.5 (C-10). The 2D NMR data indicated that compound 1 is a

• and 13C NMR data showed chemical shifts of five methyl groups at δH 1.83 (t, J = 1.2 Hz, 3H), δH 0.96 (s, 3H), δH 0.82 (s, 3H), δH 0.80 (d, J = 7.0 Hz, 3H), and δH 2.06 (s, 3H). Five methylenes were identified, including an esterified group at C-11 with a resonance of δH 4.64 (d, J = 11.6 Hz 1H), 4.46

Synthesis of 1-azaspiro[4.4]nonan-1-oxyls via intramolecular 1,3-dipolar cycloaddition

• Yulia V. Khoroshunova,
• Denis A. Morozov,
• Andrey I. Taratayko,
• Polina D. Gladkikh,
• Yuri I. Glazachev and
• Igor A. Kirilyuk

Beilstein J. Org. Chem. 2019, 15, 2036–2042, doi:10.3762/bjoc.15.200

• enabled the assignment of these signals to the 1,2-disubstituted alkene moiety. Thus, the NMR data presented above indicate the presence of an isolated spin system, O–CH2–CH–CH2–CH=CH. A similar analysis of the remaining complex multiplets at 1.56, 1.77, and 1.93 ppm as well as their correlation with the

Bipolenins K–N: New sesquiterpenoids from the fungal plant pathogen Bipolaris sorokiniana

• Chin-Soon Phan,
• Hang Li,
• Simon Kessler,
• Peter S. Solomon,
• Andrew M. Piggott and
• Yit-Heng Chooi

Beilstein J. Org. Chem. 2019, 15, 2020–2028, doi:10.3762/bjoc.15.198

• ) showed 15 distinct carbon signals, while 13C and 1H NMR data (Table 1) indicated an isopropyl unit (δC 28.3, 29.2 and 73.1; δH 1.20 and 1.24), one tertiary methyl (δC 20.1; δH 1.25), a disubstituted olefin (δC 105.7 and 155.2; δH 5.12 and 4.89) and four methines (δC 39.6, 51.1, 51.6 and 54.0; δH 1.73

• , 1.88, 2.65 and 3.77), which are typical resonances for sativene-type sesquiterpenoids. The NMR data for 1 were very similar to those for prehelminthosporol lactone (5) except for the replacement of a methine group (δC 32.1; δH 1.42) at C-9 in 5 with a hydroxylated quaternary carbon (δC 73.1) in 1. This

• ). Bipolenin L (2) was isolated as a colourless oil. The HRESIMS [M + H]+ ion at m/z 251.1649 corresponded to a molecular formula C15H22O3 (calcd for C15H23O3+, 251.1642), which is isomeric with 1. The 1H and 13C NMR data for 2 (Table 1) were also very similar to those for 5, with the only significant

Isolation and characterisation of irinans, androstane-type withanolides from Physalis peruviana L.

• Annika Stein,
• Dave Compera,
• Bianka Karge,
• Mark Brönstrup and
• Jakob Franke

Beilstein J. Org. Chem. 2019, 15, 2003–2012, doi:10.3762/bjoc.15.196

• C19H24O5 for the first compound, which was supported by the 13C spectrum (Table 1). By comparing the spectrum to NMR data of other withanolides, we quickly identified the Michael system in ring A based on two olefinic protons (δH 6.94 and 6.22 ppm), a secondary alcohol at C-4 (δH 3.79 ppm), a 5,6-epoxide

• –7.6 min, 6 mg), perulactone H (6) (tR = 7.6–7.8 min, 9 mg) and withanolide F (5) (tR = 7.8–8.5 min, 9 mg) which were identified by NMR [20]. Analytical data 4β-Hydroxywithanolide E (1) was isolated as a white crystalline powder. NMR data of 1 is listed in Table 1. All spectroscopic properties matched

• NaIO4 reaction was confirmed by NMR analysis. See also Figure S21 in Supporting Information File 1 for extracted ion chromatograms (EICs). 13C and 1H NMR data (CDCl3, 500 MHz, 298 K) of irinans A (2) and B (3) in comparison to the known compound 4β-hydroxywithanolide E (1, CDCl3, 400 MHz, 298 K, δ in

Reactions of 2-carbonyl- and 2-hydroxy(or methoxy)alkyl-substituted benzimidazoles with arenes in the superacid CF₃SO₃H. NMR and DFT studies of dicationic electrophilic species

• Dmitry S. Ryabukhin,
• Alexey N. Turdakov,
• Natalia S. Soldatova,
• Mikhail O. Kompanets,
• Alexander Yu. Ivanov,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1962–1973, doi:10.3762/bjoc.15.191

• benzimidazole system. The same applies to the reactivity of the carbon C2 in dications I and II. Then we studied the protonation of benzimidazoles in the superacid TfOH by means of NMR. Selected 1H, 13C and 15N NMR data for starting neutral benzimidazoles 1, 3a, and 7 (in CDCl3, (CD3)2CO, CD3OD) and their

• Information File 1). However, the signals of the proton bound to the oxygen of the formyl or the hydroxy groups is not observed due to the fast proton exchange for these groups in TfOH at room temperature. The obtained NMR data demonstrate the formation of N-protonated-O-protosolvated species I', III', and

• –11. Reaction mechanism of the formation of compounds 12. Selected calculated [DFT, 6-311+G(2d,2p) basis set] electronic characteristics of the protonated forms of benzimidazoles. 1H, 13C and 15N NMR data of benzimidazoles 1, 3a, 7 in the corresponding deuterated solvent and species I', III', VIII' in

An azobenzene container showing a definite folding – synthesis and structural investigation

• Abdulselam Adam,
• Saber Mehrparvar and
• Gebhard Haberhauer

Beilstein J. Org. Chem. 2019, 15, 1534–1544, doi:10.3762/bjoc.15.156

• solution, the larger are the changes caused by the LED lamps. This effect is already known for this kind of switches [49][50]. The trans,trans/cis,trans/cis,cis ratio of the solution after synthesis amounts to 63:35:2 and resemble the 1H NMR data (68:31:<1). After irradiation with light of the wavelength λ

Different reactivity of phosphorylallenes under the action of Brønsted or Lewis acids: a crucial role of involvement of the P=O group in intra- or intermolecular interactions at the formation of cationic intermediates

• Stanislav V. Lozovskiy,
• Alexander Yu. Ivanov and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2019, 15, 1491–1504, doi:10.3762/bjoc.15.151

• –H (Table 1). These species are formed by protonation of the central carbon atom of the allene system that gives the corresponding allyl cations, which undergo cyclization onto the oxygen of the P=O group. These ions have similar NMR data: the signal of the new proton H4 is located in the range 6.30

• compounds 9, 10, 11, 12 from aillene 1a involving AlCl3 attack on the central atom of allenic complex 13. Plausible reaction mechanism B of formation of compounds 11, 12 from allene 1a involving HCl–AlCl3 attack on the central atom of allenic complex 13. Selected 1H, 13C and 31P NMR data for cations A–H

Genomics-inspired discovery of massiliachelin, an agrochelin epimer from Massilia sp. NR 4-1

• Jan Diettrich,
• Hirokazu Kage and
• Markus Nett

Beilstein J. Org. Chem. 2019, 15, 1298–1303, doi:10.3762/bjoc.15.128

• H-15, which is only possible if the latter two protons are syn-oriented. We thus propose (14R,15R,17R,19S) configuration for 1. It is noteworthy that the same conclusion can also be drawn from a comparison of the 1H NMR data of the thiazoline-thiazolidine moieties in pyochelin and agrochelin (Table

Synthesis of non-racemic 4-nitro-2-sulfonylbutan-1-ones via Ni(II)-catalyzed asymmetric Michael reaction of β-ketosulfones

• Alexander N. Reznikov,
• Anastasiya E. Sibiryakova,
• Marat R. Baimuratov,
• Eugene V. Golovin,
• Victor B. Rybakov and
• Yuri N. Klimochkin

Beilstein J. Org. Chem. 2019, 15, 1289–1297, doi:10.3762/bjoc.15.127

• in Figure 5. The relative configurations of other Michael adducts 8 and 9 were determined by comparing their NMR data with those of compound 8d. For (2R,3S)-isomers the value of 3JHH for proton at 2-C was 5 Hz, while for (2S,3S)-isomers this value was 11 Hz. It is possible to use the previously

Molecular recognition using tetralactam macrocycles with parallel aromatic sidewalls

• Dong-Hao Li and
• Bradley D. Smith

Beilstein J. Org. Chem. 2019, 15, 1086–1095, doi:10.3762/bjoc.15.105

• conformations is an outward directed NH residue. Solution-state NMR data suggests that the surrounding tetralactam in these [2]rotaxanes undergoes rapid exchange between these different conformations, a dynamic process that has been called macrcocyle breathing, and that there is also simultaneous co

Mechanistic investigations on multiproduct β-himachalene synthase from Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 1008–1019, doi:10.3762/bjoc.15.99

• with (E)- and (Z)-(4-13C,4-2H)IPP, DMAPP, FPPS and HcS targeting the positions C-3 and C-7 (Figure S11, Supporting Information File 1), using published NMR data for 7 [44]. The stereochemical fate for the hydrogens at C-1 was then targeted by the incubation of (1R)- and (1S)-(1-13C,1-2H)FPP [28] with

• situation like a 1,11-cyclisation. Intriguingly, the stereochemical course of the initial cyclisation step can even be substrate dependent. The 1,6-cyclisation towards the monoterpenes 10, 11 and 13 as investigated by the incubation of (1S)- and (1R)-(1-13C,1-2H)GPP with HcS and comparison to the NMR data

• expression, protein purification, incubation experiments with isotopically labelled precursors, preparative scale incubation and synthesis of (2-13C)DMAPP. The amino acid sequence of HcS, a phylogenetic tree of bacterial terpene synthases, SDS-PAGE analysis of the recombinant protein, listed NMR data for 1

New terpenoids from the fermentation broth of the edible mushroom Cyclocybe aegerita

• Frank Surup,
• Florian Hennicke,
• Nadine Sella,
• Maria Stroot,
• Steffen Bernecker,
• Sebastian Pfütze,
• Marc Stadler and
• Martin Rühl

Beilstein J. Org. Chem. 2019, 15, 1000–1007, doi:10.3762/bjoc.15.98

• m/z 519.2718 in the HRESIMS spectrum. 1H and 1H,13C-HSQC NMR data (Table 1) indicated the presence of four methyls and twelve methylenes, three of them oxomethylene groups. A database search with this data within the Chapman & Hall Dictionary of Natural Products on DVD suggested its identity as

• bovistol, which was confirmed by the elucidation of the structure by COSY and HMBC NMR data [5]. In the course of the isolation of 1 the minor metabolites 2 and 3 accrued. Metabolite 2 was analysed for a molecular weight of 478 Da. Its molecular formula C30H38O5, deduced from HRESIMS data, indicated the

• formal loss of one molecule of water. 1H and HSQC NMR data (Table 1) of 2 were very similar to those of 1, with the exception of the replacement of methyl CH3-12 by an exomethylene group. HMBC correlations from both exo-methylene protons 12-H2 to C-2, C-3, C-4, in addition to those from both 1-H2 and 10

Coordination chemistry and photoswitching of dinuclear macrocyclic cadmium-, nickel-, and zinc complexes containing azobenzene carboxylato co-ligands

• Jennifer Klose,
• Tobias Severin,
• Peter Hahn,
• Alexander Jeremies,
• Jens Bergmann,
• Daniel Fuhrmann,
• Jan Griebel,
• Bernd Abel and
• Berthold Kersting

Beilstein J. Org. Chem. 2019, 15, 840–851, doi:10.3762/bjoc.15.81

• protons [C(CH3)3] appear as singlets. The remaining six signals can be assigned to the methylene protons of the linking diethylenetriamine chains (two doublets for the benzylic CH2 and four multiplets for linking CH2 groups). The 1H NMR data are indicative of a C2v symmetric structure of the [Cd2L]2

Stereochemical investigations on the biosynthesis of achiral (Z)-γ-bisabolene in Cryptosporangium arvum

• Jan Rinkel and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2019, 15, 789–794, doi:10.3762/bjoc.15.75

• origin in FPP. Supporting Information Experimental details of culture conditions, gene cloning, protein purification, incubation experiments, isolation of 5 and HPLC purifications, the amino acid sequence of BbS, a phylogenetic tree with the location of BbS, SDS-PAGE analysis, listed NMR data of 5

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

• indicated the existence of a trisubstituted double bond. All the above evidence suggested the laurane nature of this molecule, and literature research revealed that 1 should be an isomer of a known laurane-type terpenoid bromolaurenisol (1a) [16][17] due to their extremely similar NMR data and the same

• 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

• optically active colorless oil. The molecular formula, C15H19OBr, was deduced by HR-EIMS ion peak at m/z 294.0617, [M]+ (calcd for C15H19OBr, 294.0619). The 1H and 13C NMR data (Table 1) of 3 were found to be identical to those of laurenisol (3a), a halogenated sesquiterpenoid previously isolated from the

Influence of per-O-sulfation upon the conformational behaviour of common furanosides

• Alexey G. Gerbst,
• Vadim B. Krylov,
• Dmitry A. Argunov,
• Maksim I. Petruk,
• Arsenii S. Solovev,
• Andrey S. Dmitrenok and
• Nikolay E. Nifantiev

Beilstein J. Org. Chem. 2019, 15, 685–694, doi:10.3762/bjoc.15.63

• . Lomonosov Moscow State University, Moscow, 119991, Russia 10.3762/bjoc.15.63 Abstract The studies on the recently discovered pyranoside-into-furanoside rearrangement have led us to conformational investigations of furanosides upon their total sulfation. Experimental NMR data showed that in some cases

• ). NMR data of furanosides 1–3 and 1s–3s 1H and 13C NMR spectra of parent monosaccharides 1–3 and their per-O-sulfated derivatives 1s–3s were recorded in D2O. The signal assignment was performed using 2D COSY and HSQC. J coupling constants were measured directly from 1D 1H NMR spectra. In case of

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

• Supporting Information File 1). Assignments of the quaternary carbons including the formal carbocation centers were made by HMBC correlations. NMR data suggest that the positive charge is more effectively delocalized into the indole rings. The GIAO-NMR data show the same general trend, as evidenced by the

Syntheses and chemical properties of β-nicotinamide riboside and its analogues and derivatives

• Mikhail V. Makarov and
• Marie E. Migaud

Beilstein J. Org. Chem. 2019, 15, 401–430, doi:10.3762/bjoc.15.36

• anomeric purity were best improved with liquid SO2; the yields of 8a ( −44.7°) and 8b ( −36.8°) were 96% and 90%, respectively, with the isolated product 8b containing no α-anomer (according to 1H NMR data), as specifically emphasized by the authors. The deprotection of 8b conducted at −18 °C in cold

• synthesis may be partially explained by the fast mutarotation of 2′,3′-O-isopropylidene-D-ribofuranosylamine and its tosylate. This mutarotation is solvent-dependent. For example, according to 1H NMR data presented in the work of Cusack et al. [40], compound 23 exists essentially as the pure β-anomer in

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

• moiety had clear correlations with the double bond carbons (δc 132.8, s, αC and δc 123.3, d, βC), and the βH exhibited clear HMBC correlations with the αC and carbonyl carbon (δc 168.8, s, CO). These NMR data clearly indicate the presence of a dhThr moiety (Figure 3), and the strong NOE between the γCH3

• cichorinotoxin (Figure 1). We then determined the presence of three dhThr residues in the cichorinotoxin (Figure 6) by analyzing the NMR data; the βCH protons (olefinic protons) of the three dhThr moieties are found at δH 6.37 (q, J = 7.0 Hz), δH 6.24 (q, J = 7.0 Hz) and δH 5.89 (q, J = 7.0 Hz) in the 1H NMR

• was acetylated under basic conditions to afford the monoacetate of cichorinotoxin (Figure 6). This basic amino acid was determined to be 2,4(α,γ)-diaminobutanoic acid (Dab-20) by detailed analyses of the NMR data. In the COSY and TOCSY spectra of the acetate, the αNH proton (δH 8.61) was correlated

First synthesis of cryptands with sucrose scaffold

• Patrycja Sokołowska,
• Michał Kowalski and
• Sławomir Jarosz

Beilstein J. Org. Chem. 2019, 15, 210–217, doi:10.3762/bjoc.15.20

• this first sucrose cryptand, suggested by HRMS analysis [m/z = 1285.6803 which corresponds to (C74H97N2O17 + H+)], was confirmed by the NMR data. In the 13C NMR spectrum of the final compound, six characteristic signals at δ ≈ 50–60 ppm were observed. They can be assigned to the methylene groups

• NMR data. In the spectrum recorded in acetone-d6, three signals at δ ≈ 60 ppm were seen. These signals were assigned (by HSQC experiments) to the benzyl groups connected to nitrogen atoms (-NCH2Ph), thus finally confirming the presence of a tripodal unit in the structure of the cryptand. Conclusion We

Unexpected loss of stereoselectivity in glycosylation reactions during the synthesis of chondroitin sulfate oligosaccharides

• Teresa Mena-Barragán,
• José L. de Paz and
• Pedro M. Nieto

Beilstein J. Org. Chem. 2019, 15, 137–144, doi:10.3762/bjoc.15.14

• deprotected derivatives in moderate to good yields. The structures of these compounds were confirmed by NMR and mass spectrometry. NMR data were in good agreement with those reported in the literature for similar CS oligosaccharides. The perfluorinated tag of acceptor 2 may strongly influence on the chemical

Systematic synthetic study of four diastereomerically distinct limonene-1,2-diols and their corresponding cyclic carbonates

• Hiroshi Morikawa,
• Jun-ichi Yamaguchi,
• Shun-ichi Sugimura,
• Masato Minamoto,
• Yuuta Gorou,
• Hisatoyo Morinaga and
• Suguru Motokucho

Beilstein J. Org. Chem. 2019, 15, 130–136, doi:10.3762/bjoc.15.13

• oxide) and conditions, the desired diastereomers were synthesised in moderate to high yields with, in most cases, high stereoselectivity. Comparison of the NMR data of the obtained diols and carbonates revealed that the four different diastereomers of each compound could be distinguished by reference to

• Sharpless AD-mix-β to afford a 2a-type main product (Scheme 1b) [22]. Hao et al. also reported the synthesis of 2a and 2d using OsO4 (Scheme 1a) [23]. However, the NMR data of 2a and 2d were not consistent with those [16] reported by Wang. Moreover, they referred to a published paper [24] for the assignment

• analysis. In particular, the NMR data for 2b and 2d exhibit rather similar values. The assignments of 1H and 13C NMR signals were found to provide a means of differentiating the respective diastereomers for the first time. These fundamental studies will contribute to the organic, bioorganic and

Thermophilic phosphoribosyltransferases Thermus thermophilus HB27 in nucleotide synthesis

• Ilja V. Fateev,
• Ekaterina V. Sinitsina,
• Aiguzel U. Bikanasova,
• Maria A. Kostromina,
• Elena S. Tuzova,
• Larisa V. Esipova,
• Tatiana I. Muravyova,
• Alexei L. Kayushin,
• Irina D. Konstantinova and
• Roman S. Esipov

Beilstein J. Org. Chem. 2018, 14, 3098–3105, doi:10.3762/bjoc.14.289

• spectrometry and NMR data. Acknowledgements The authors are grateful to Russian Science Foundation (project No. 14-50-00131) for financial support of this work.