One-step route to tricyclic fused 1,2,3,4-tetrahydroisoquinoline systems via the Castagnoli–Cushman protocol

• Aleksandar Pashev,
• Nikola Burdzhiev and
• Elena Stanoeva

Beilstein J. Org. Chem. 2020, 16, 1456–1464, doi:10.3762/bjoc.16.121

• (19) with anhydrides 5–7. Reagents and conditions: xylene, inert atmosphere, 120 °C, 6 h. Reactions of 1-alkyl-3,4-dihydroisoquinolines 19 and 20 with anhydride 8. Reagents and conditions: xylene, inert atmosphere, 120 °C, 6 h. Suggested mechanism for the formation of products 25–27. NMR data and

A cyclopeptide and three oligomycin-class polyketides produced by an underexplored actinomycete of the genus Pseudosporangium

• Shun Saito,
• Kota Atsumi,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Naoya Oku,
• Md. Rokon Ul Karim,
• Hisayuki Komaki and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 1100–1110, doi:10.3762/bjoc.16.97

• experimental 1H and 13C NMR data of 1 presented a higher chemical shift similarity to those for 1b and thereby the (S)-configuration was suggested for C-2. Indeed, the DP4+ analysis [25] gave 100% probability for structure 1b and 0.0% probability for structure 1a (Table S2, Supporting Information File 2). This

• (0.48) nm; ECD (1 × 10−4 M, MeCN) λext (Δε) 217.0 (+17.3), 235.5 (−10.8) nm; IR (ATR) νmax 3328, 1722 cm−1; for 1H and 13C NMR data, see Table 1; HRESITOFMS (m/z): [M − H]− calcd for C27H27N4O6, 503.1931; found, 503.1936. Pseudosporamicin A (2): white amorphous powder; [α]D25 −23 (c 0.50, MeOH); UV

• (MeOH) λmax (log ε) 218 (4.65) nm; IR (ATR) νmax 3366, 1713, 1635 cm−1; for 1H and 13C NMR data, see Table 2; HRESITOFMS (m/z) [M − H]− calcd for C47H75O12, 831.5259; found, 831.5255. Pseudosporamicin B (3): white amorphous powder; [α]D25 −9.3 (c 0.50, MeOH); UV (MeOH) λmax (log ε) 223 (4.56) nm; IR

Bipyrrole boomerangs via Pd-mediated tandem cyclization–oxygenation. Controlling reaction selectivity and electronic properties

• Liliia Moshniaha,
• Marika Żyła-Karwowska,
• Joanna Cybińska,
• Piotr J. Chmielewski,
• Ludovic Favereau and
• Marcin Stępień

Beilstein J. Org. Chem. 2020, 16, 895–903, doi:10.3762/bjoc.16.81

• below 1 equiv (Table 1, entries 16 and 22). Structure The identity of the α-oxygenated products, cRnO, was determined on the basis of high-resolution mass spectrometry and 1H and 13C NMR data. In particular, the 1H NMR spectrum of cNMI2O revealed the absence of the pyrrolic α-H resonances, whereas the

Synthesis of C₇₀-fragment buckybowls bearing alkoxy substituents

• Yumi Yakiyama,
• Shota Hishikawa and
• Hidehiro Sakurai

Beilstein J. Org. Chem. 2020, 16, 681–690, doi:10.3762/bjoc.16.66

• depths of 5b at the specific focused carbons. Supporting Information Supporting Information File 7: CIF files of compounds 5a–c. Supporting Information File 8: 1H and 13C NMR data of 3a, 3b, 4a, 4b and 5a–c, simulated UV–vis spectra of 5a, 5b and 5c. Funding This work was supported by a Grant-in-Aid

Microwave-assisted efficient and facile synthesis of tetramic acid derivatives via a one-pot post-Ugi cascade reaction

• Yong Li,
• Zheng Huang,
• Jia Xu,
• Yong Ding,
• Dian-Yong Tang,
• Jie Lei,
• Hong-yu Li,
• Zhong-Zhu Chen and
• Zhi-Gang Xu

Beilstein J. Org. Chem. 2020, 16, 663–669, doi:10.3762/bjoc.16.63

• Supporting Information File 250: General information, general experimental procedure, characterization data, and copies of 1H and 13C NMR spectra. Acknowledgements We would like to thank Ms H.Z. Liu for obtaining the LC–MS and NMR data. Funding The authors would like to thank the Science and Technology

Regio- and stereoselective synthesis of new ensembles of diversely functionalized 1,3-thiaselenol-2-ylmethyl selenides by a double rearrangement reaction

• Svetlana V. Amosova,
• Andrey A. Filippov,
• Nataliya A. Makhaeva,
• Alexander I. Albanov and
• Vladimir A. Potapov

Beilstein J. Org. Chem. 2020, 16, 515–523, doi:10.3762/bjoc.16.47

• ). The monitoring results are presented in Figure 1 and Table 1. The reaction was studied in the time interval from 0.25 to 6 h. Having assigned the 1H NMR data for compounds 1 and 4, we found signals of an unknown compound, which was easily identified after 0.5 h (at 46% conversion of thiaselenole 1) as

• potassium selenocyanate. The reaction pathway for the formation of compounds 4 and 5. Synthesis of new ensembles of 1,3-thiaselenol-2-ylmethyl selenides 6a–l (77Se NMR data are included). The synthesis of vinyl selenides 7a,b through nucleophilic addition of 1,3-thiaselenol-2-ylmethylselenolate anion to

• alkyl propiolates (77Se NMR data are included). One-pot synthesis of diselenide 8 from thiaselenole 1 (77Se NMR data are included). Synthesis of compounds 6a–j from diselenide 8. Results the reaction of thiaselenole 1 with KSeCN based on 1H NMR spectroscopy monitoring (Figure 1).a Supporting

Aerobic synthesis of N-sulfonylamidines mediated by N-heterocyclic carbene copper(I) catalysts

• Faïma Lazreg,
• Marie Vasseur,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2020, 16, 482–491, doi:10.3762/bjoc.16.43

• in this manner (Scheme 10). The latter was then reacted with tosyl azide. An immediate colour change resulted and based on 1H NMR data, two new species were formed. They were identified as the sulfonyltriazole and an unstable organometallic compound, presumably the triazolylcopper(I) complex C. These

Two antibacterial and PPARα/γ-agonistic unsaturated keto fatty acids from a coral-associated actinomycete of the genus Micrococcus

• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku,
• Nobuyasu Matsuura,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2020, 16, 297–304, doi:10.3762/bjoc.16.29

• correlations for 1 and 2. Spin system simulation for the C8–C9 double bond of 2. Natural keto fatty acids of various origins. PPAR activation by 1 and 2. 1H and 13C NMR data for compounds 1 and 2 in CDCl3. Supporting Information Supporting Information File 204: ESIMS-TOF, UV, IR, 1D, and 2D NMR spectra of 1

Absolute configurations of talaromycones A and B, α-diversonolic ester, and aspergillusone B from endophytic Talaromyces sp. ECN211

• Ken-ichi Nakashima,
• Junko Tomida,
• Takao Hirai,
• Yoshiaki Kawamura and
• Makoto Inoue

Beilstein J. Org. Chem. 2020, 16, 290–296, doi:10.3762/bjoc.16.28

• adduct ion peak at m/z 357.0572, attributable to the molecular formula C16H14O8Na (calcd 357.0586), suggesting that 2 had one more oxygen atom relative to 1. The 1H and 13C NMR data for 2 were substantially similar to those of 1, with the exception that 2 exhibited oxymethylene signals (δH 4.73 (2H, s

• , with thermal ellipsoids indicating 50% probability. b) Electronic circular dichroism spectrum of 5. 1H (400 MHz) and 13C (100 MHz) NMR data for 1 and 2 in CDCl3. Supporting Information Supporting Information File 265: A phytogenic tree for ECN211 and related species and NMR spectra of 1 and 2

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• crystal structure and solution-state NMR data of the coumarin 6 were studied to examine any C–F···H–C hydrogen bond interactions. DFT calculations were performed to determine the preferred conformations of the structure that might exhibit a C–F···H–C hydrogen bond. Results and Discussion Synthesis of 2

• these observations (Figure 1 and Figure 3) is that, in solution, rotation of the fluorophenyl ring (about C4–C1’) is permitted but that the average geometry of coumarin 6 has the fluorine atom closer to H5 than H3. The theoretical NMR data for twenty-four conformations of coumarin 6 were obtained from

The interaction between cucurbit[8]uril and baicalein and the effect on baicalein properties

• Xiaodong Zhang,
• Jun Xie,
• Zhiling Xu,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2020, 16, 71–77, doi:10.3762/bjoc.16.9

• concentration of BALE and the BALE–Q[8] inclusion complex. The release curves of BALE and BALE–Q[8]. Changes in the 1H NMR chemical shifts. Supporting Information Supporting Information File 305: Instrumentation, materials and methods. Supporting Information File 306: NMR data.

Synthesis of C-glycosyl phosphonate derivatives of 4-amino-4-deoxy-α-ʟ-arabinose

• Lukáš Kerner and
• Paul Kosma

Beilstein J. Org. Chem. 2020, 16, 9–14, doi:10.3762/bjoc.16.2

• and azide-to-amine conversion, compound 17 was isolated as the 4-amino-4-deoxy-ʟ-ribopyranosyl derivative. The configuration was determined from the NMR data. Position H-2 at 4.02 ppm appeared as a broad doublet with small homonuclear coupling constants, as would be expected for a manno spin system

Pigmentosins from Gibellula sp. as antibiofilm agents and a new glycosylated asperfuran from Cordyceps javanica

• Soleiman E. Helaly,
• Wilawan Kuephadungphan,
• Patima Phainuphong,
• Mahmoud A. A. Ibrahim,
• Kanoksri Tasanathai,
• Suchada Mongkolsamrit,
• Janet Jennifer Luangsa-ard,
• Souwalak Phongpaichit,
• Vatcharin Rukachaisirikul and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2968–2981, doi:10.3762/bjoc.15.293

• and HSQC NMR data revealed a similarity to compound 1 (Table 1). In addition, the presence of resonances δC (in ppm) corresponding to two carbonyl carbon atoms at 172.4 (C-1/C-1′), two methyl carbon atoms at 20.8 (C-11′) and 24.1 (C-13′), respectively, two methoxy carbon atoms at 56.5 (C-7/C-7′), two

• olefinic sp2 carbon atoms at 98.7 (C-8/C-8′) and 114.7 (C-5/C-5′), respectively, assigned to four methine units, suggested the presence of a dihydro-α-naphthopyrone moiety in 2. Comprehensive analysis of the 2D NMR data, including HSQC, COSY, and HMBC, confirmed the structure of 2 as follows: COSY

• was determined by HMBC correlations from the methoxy functions to C-7/C-7′. Nevertheless, the NMR data revealed differences in the signals of the α-pyrone moieties, suggesting the presence of two asymmetrical dihydro-α-naphthopyrone motifs in 2. C-3 showed resonances at δC 79.2 and δH 4.86, C-3′ at δC

Two new aromatic polyketides from a sponge-derived Fusarium

• Mada Triandala Sibero,
• Tao Zhou,
• Keisuke Fukaya,
• Daisuke Urabe,
• Ocky K. Karna Radjasa,
• Agus Sabdono,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2941–2947, doi:10.3762/bjoc.15.289

• chemical shifts were used for comparison. The theoretical 13C NMR data of structure a showed better agreement with the experimental 13C NMR data of 1. Specifically, the chemical shift difference between the experimental and theoretical values for the carbons spatially close to the methoxy group (C5, C6, C7

• in good accordance with those described in the literatures [19][20][21][22][23]. Karimunone A (1): red powder; UV (MeOH) λmax (log ε) 234 (3.44), 266 (3.28), 313 (3.04), 499 (2.81), 533 (2.68) nm; IR νmax 3111, 2926, 1712, 1679, 1601 cm−1; see Table 1 for 1H NMR and 13C NMR data; TOF-HRESIMS [M − H

• ]− m/z 343.0452 (calcd for C17H11O8, 343.0459). Karimunone B (2): red powder; UV (MeOH) λmax (log ε) 244 (3.49), 277 (2.97), 324 (2.85) nm; IR νmax 3100, 1683, 1615 cm−1; see Table 3 for 1H NMR and 13C NMR data; TOF-HRESIMS [M − H]− m/z 355.0823 (calcd for C19H15O7, 355.0818). Computational procedure

Design, synthesis and investigation of water-soluble hemi-indigo photoswitches for bioapplications

• Daria V. Berdnikova

Beilstein J. Org. Chem. 2019, 15, 2822–2829, doi:10.3762/bjoc.15.275

• the phenyl ring was performed through the aldol condensation of indoxyl-3-acetate with the corresponding benzaldehydes under alkaline conditions (Scheme 1) [13]. All compounds 1a–c were obtained in good yields as pure Z-isomers as supported by the NMR data (Figures S5–S13 in Supporting Information

An improved, scalable synthesis of Notum inhibitor LP-922056 using 1-chloro-1,2-benziodoxol-3-one as a superior electrophilic chlorinating agent

• Nicky J. Willis,
• Elliott D. Bayle,
• George Papageorgiou,
• David Steadman,
• Benjamin N. Atkinson,
• William Mahy and
• Paul V. Fish

Beilstein J. Org. Chem. 2019, 15, 2790–2797, doi:10.3762/bjoc.15.271

• pharmacokinetics and profiles of amides. Supporting Information File 591: Profiles of amides. Supporting Information File 592: Raw NMR data files for compound LP-922056. Acknowledgements This work was supported by Alzheimer’s Research UK (ARUK) and The Francis Crick Institute. The ARUK UCL Drug Discovery

Skeletocutins M–Q: biologically active compounds from the fruiting bodies of the basidiomycete Skeletocutis sp. collected in Africa

• Tian Cheng,
• Clara Chepkirui,
• Cony Decock,
• Josphat C. Matasyoh and
• Marc Stadler

Beilstein J. Org. Chem. 2019, 15, 2782–2789, doi:10.3762/bjoc.15.270

• . Compound 2 (skeletocutin N, Table 1 and Figure 2) was obtained as a white solid, with the molecular formula C30H46O6 and eight degrees of unsaturation determined from HRESIMS data. The 1D and 2D NMR data for 2 revealed a similar structure to 1, with the difference being the size of the carbon chain in the

• singlet (δ = 3.37 ppm, H2-2), a quintet (δ = 1.58 ppm, H2-21), a triplet (δ = 2.45 ppm, H2-22) for three methylene groups, and a triplet for a methine unit (δ = 7.13 ppm, H-4) were observed in the 1H NMR spectrum of 3. Analysis of 1D and 2D NMR data for 3 indicated a similar structure to 1, with a

• . Peaks for m/z = 537.3058 ([M + H]+), 559.2877 ([M + Na]+), 519.2953 ([M + H − H2O])+, and 1095.5860 ([2M + Na]+) were observed in the mass spectrum. The 1D and 2D NMR data of 4 were similar to those of 3, with the difference being the presence of a tricarboxylic acid moiety instead of a dicarboxylic

Nanangenines: drimane sesquiterpenoids as the dominant metabolite cohort of a novel Australian fungus, Aspergillus nanangensis

• Heather J. Lacey,
• Cameron L. M. Gilchrist,
• Andrew Crombie,
• John A. Kalaitzis,
• Daniel Vuong,
• Peter J. Rutledge,
• Peter Turner,
• John I. Pitt,
• Ernest Lacey,
• Yit-Heng Chooi and
• Andrew M. Piggott

Beilstein J. Org. Chem. 2019, 15, 2631–2643, doi:10.3762/bjoc.15.256

• spectrum, while absorptions at 3354 and 1738 cm−1 in the IR spectrum were indicative of hydroxy and carbonyl groups, respectively. The 13C NMR data for 1 (Table 1) indicated the presence of one carbonyl carbon (δC 179.3, C-11) and two olefinic carbons (δC 128.2, C-7 and δC 131.1, C-8), accounting for two

• DBE and thus requiring 1 to be tricyclic. The 1H and 13C NMR data also revealed the presence of one hydroxylated quaternary carbon (C-9), two aliphatic quaternary carbons (C-4, C-10), two oxymethines (C-1, C-6), one aliphatic methine (C-5), one oxymethylene (C-12), two aliphatic methylenes (C-2, C-3

• ), three methyl groups (C-13, C-14, C-15) and three hydroxy groups (1-OH, 6-OH, 9-OH). Detailed analysis of the 2D NMR data for 1 (Table S3 in Supporting Information File 1) confirmed the presence of a drimane sesquiterpenoid lactone scaffold. A search of the literature revealed 1 to be almost identical to

1,5-Phosphonium betaines from N-triflylpropiolamides, triphenylphosphane, and active methylene compounds

• Vito A. Fiore,
• Chiara Freisler and
• Gerhard Maas

Beilstein J. Org. Chem. 2019, 15, 2603–2611, doi:10.3762/bjoc.15.253

• shift (δ = 23.53 ppm) further confirms the presence of a tetracovalent phosphorus atom (see [28]). NMR data of betaines 3 The 1H, 13C and 31P data of the P–C3–C2–C1 chain in betaines 3 are listed in Table 2. Based on the spectra of those betaines, for which the molecular geometry has been established by

• acid chlorides. Two mechanistic scenarios for the formation of betaines 3. Resonance structures describing the bonding in 1,2-oxaphospholes/1,5-betaines 8. Bond distances and torsion angles in betaines E-3a, E-3b, E-3e, and Z-3e based on XRD data.a Selected NMR data of betaines 3a. Supporting

Formation of alkyne-bridged ferrocenophanes using ring-closing alkyne metathesis on 1,1’-diacetylenic ferrocenes

• Celine Bittner,
• Dirk Bockfeld and
• Matthias Tamm

Beilstein J. Org. Chem. 2019, 15, 2534–2543, doi:10.3762/bjoc.15.246

• acetylenic sidechains show the characteristic triplet with a small coupling constant for the terminal alkyne proton at chemical shifts of 2.05 ppm and 2.01 ppm, respectively. The NMR data for the butynyl compound 1a fit the results of Suitor et al. that were published only recently [93]. From saturated DCM

• propargylic compound was synthesized as well in high yield. The NMR data fit the results of Suitor et al. that were published only recently [93]. Unfortunately, the propargylic compound could not be characterised crystallographically as it only gave an orange powder upon different crystallisation techniques

Self-assembled coordination thioether silver(I) macrocyclic complexes for homogeneous catalysis

• Zhen Cao,
• Aline Lacoudre,
• Cybille Rossy and
• Brigitte Bibal

Beilstein J. Org. Chem. 2019, 15, 2465–2472, doi:10.3762/bjoc.15.239

• diastereoisomers by coordination which had different geometries. Thereafter, the silver(I) complexes are discussed with the proposed stoichiometry from X-ray and NMR data, without accounting for stereochemistry: M2L2 for AgOTf and AgOTFA complexes (1a,b), M6L4 for AgNO3 one (1c) and M2L complex with PPh3AgOTf (1d

Sugar-derived oxazolone pseudotetrapeptide as γ-turn inducer and anion-selective transporter

• Sachin S. Burade,
• Sushil V. Pawar,
• Tanmoy Saha,
• Navanath Kumbhar,
• Amol S. Kotmale,
• Manzoor Ahmad,
• Pinaki Talukdar and
• Dilip D. Dhavale

Beilstein J. Org. Chem. 2019, 15, 2419–2427, doi:10.3762/bjoc.15.234

• presence and absence of valinomycin (1 µM) across EYPC-LUVslucigenin (D). Synthesis of linear azido ester dipeptide 5 and tetrapeptide 7. Synthesis of oxazolone pseudopeptides 1, 2a and 2b. Supporting Information Supporting Information File 200: Experimental procedures, 1H and 13C NMR data, HRMS and 2D

In water multicomponent synthesis of low-molecular-mass 4,7-dihydrotetrazolo[1,5-a]pyrimidines

• Irina G. Tkachenko,
• Sergey A. Komykhov,
• Vladimir I. Musatov,
• Svitlana V. Shishkina,
• Viktoriya V. Dyakonenko,
• Vladimir N. Shvets,
• Mikhail V. Diachkov,
• Valentyn A. Chebanov and
• Sergey M. Desenko

Beilstein J. Org. Chem. 2019, 15, 2390–2397, doi:10.3762/bjoc.15.231

• the NMR data corresponded quite well to the proposed structure 9, they did not allow the complete rejection of the isomeric structure 9' for the reaction product. The final confirmation of structures 9a–g was achieved by X-ray analysis of 9a (Figure 1). A specific behavior of acetylacetone (10) as the

Isolation and biosynthesis of an unsaturated fatty acid with unusual methylation pattern from a coral-associated bacterium Microbulbifer sp.

• Amit Raj Sharma,
• Enjuro Harunari,
• Tao Zhou,
• Agus Trianto and
• Yasuhiro Igarashi

Beilstein J. Org. Chem. 2019, 15, 2327–2332, doi:10.3762/bjoc.15.225

• unsaturation on the basis of its NMR and HR-ESI-TOFMS (m/z 181.1230 [M − H]−; calcd for C11H17O2, 181.1229) data. The UV spectrum of 1 in methanol exhibited an absorption maximum at 262 nm. The IR absorption bands at 1678 and 2800–3200 cm−1 suggested the presence of carboxyl group. The 1H and 13C NMR data of 1

• (50:50) to yield (2Z,4E)-3-methyl-2,4-decadienoic acid (1, 8.0 mg, tR 20.5 min). (2Z,4E)-3-Methyl-2,4-decadienoic acid (1): colorless amorphous solid; UV (MeOH) λmax (log ε) 262 (4.16) nm; IR (ATR) νmax 2952, 2923, 2852, 2585, 1678, 1662 cm−1; 1H and 13C NMR data, see Table 1; HR-ESI-TOFMS m/z

• of tuberculostearic acid in Mycobacterium. Possible methylation mechanism for compound 1. 1H and 13C NMR data for compound 1 in CDCl3. Incorporation of 13C-labeled precursors into 1. Supporting Information Supporting Information File 466: 1D and 2D NMR spectra of 1; 13C NMR spectra of 13C-labeled 1.

Isolation of fungi using the diffusion chamber device FIND technology

• Benjamin Libor,
• Henrik Harms,
• Stefan Kehraus,
• Ekaterina Egereva,
• Max Crüsemann and
• Gabriele M. König

Beilstein J. Org. Chem. 2019, 15, 2191–2203, doi:10.3762/bjoc.15.216

• ]+; calcd. for C15H23O3, 251.1642) implying only 5 DOU as compared to 1. 1H and 13C NMR data (Table S5, Supporting Information File 1) of 2 were similar to those of 1, except for the chemical shifts of CH2-9 (δH 1.37; δC 23.4), CH2-10 (δH 1.49, 1.73; δC 35.5), and CH3-13 (δH 1.21; δC 17.8). Additional

• and 13C NMR data see Supporting Information File 1, Table S4. Heydenoic acid B (2): yellow oil; [α]D25 −34.9 (c 0.33, MeOH); UV (MeOH) λmax (log ε): 203 (3.8), 258 (3.5) nm; CD (c 4.0 × 10−3 M, MeOH) λmax (Δ ε) 208 (0.57), 218 (0.45), 321 (−0.38); IR νmax: 3346, 2927, 1670, 1558, 1540, 1507, 1436

• , 1376, 1237, 1037, 634 cm−1; HRESI-TOF-MS m/z: [M + H]+ calcd for C15H23O3 251.1641; found, 251.1642. For 1H and 13C NMR data see Supporting Information File 1, Table S5. Agar diffusion assay Culture plates (5% sheep blood Columbia agar, BD) were overlaid with 3 mL tryptic soy soft agar, inoculated with