Preparation of an advanced intermediate for the synthesis of leustroducsins and phoslactomycins by heterocycloaddition

• Anaïs Rousseau,
• Guillaume Vincent and
• Cyrille Kouklovsky

Beilstein J. Org. Chem. 2022, 18, 1385–1395, doi:10.3762/bjoc.18.143

• conditions (1.15 equiv, 15 min) a combined 46% yield could be obtained. Higher equivalents of the oxidizing reagents or longer reaction time considerably lowered the yields. NMR analysis of products 25 and 26 showed these compounds were obtained as single diastereomers, thus indicating the complete

Make or break: the thermodynamic equilibrium of polyphosphate kinase-catalysed reactions

• Michael Keppler,
• Sandra Moser,
• Henning J. Jessen,
• Christoph Held and
• Jennifer N. Andexer

Beilstein J. Org. Chem. 2022, 18, 1278–1288, doi:10.3762/bjoc.18.134

• : Details of materials and methods and additional figures and tables. Acknowledgements We would like to thank Katharina Strack for skilful technical assistance, and Dr. Manfred Keller (University of Freiburg) for help with 31P NMR analysis of polyphosphates. Dr. Torsten Sehl (Research Centre Juelich) and

Ferrocenoyl-adenines: substituent effects on regioselective acylation

• Mateja Toma,
• Gabrijel Zubčić,
• Jasmina Lapić,
• Senka Djaković,
• Davor Šakić and
• Valerije Vrček

Beilstein J. Org. Chem. 2022, 18, 1270–1277, doi:10.3762/bjoc.18.133

• with different groups (H, Me, Bz, isopentenyl, or Boc). In 1 and 6 the N7 nitrogen atom was calculated the most nucleophilic (Table 1, values in bold), suggesting this site should be acylated predominantly. On the contrary, according to 1H NMR analysis and isolated yields, the N9-isomer was the major

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• -based materials showed similar resonances to previous work by our group on phosphorus-linked triazine networks [38]. The 31P MAS NMR of g-h-PCN showed a broad resonance centered around −8.9 ppm, with a sharp residual phosphate resonance at 0.9 ppm (Figure 3a). NMR analysis of similar materials, by our

Reductive opening of a cyclopropane ring in the Ni(II) coordination environment: a route to functionalized dehydroalanine and cysteine derivatives

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

Beilstein J. Org. Chem. 2022, 18, 1166–1176, doi:10.3762/bjoc.18.121

• Ph2N2 additive changed the relative ratio of alkene to hydrogenated derivatives in favor of the former one (see Table 1). As follows from Table 1, the azobenzene additive allows increasing the yield of the alkene complexes up to 85% suppressing formation of the hydrogenated complexes. Spectral NMR

• analysis of the reaction mixture showed that two isomeric alkenes (containing the α-β or β-γ double bond) are formed. In the isomers, two protons of the amino acid side chain create an AB system; in the α-β isomer, both protons show correlations in the HMBC spectrum with the C atoms of the COOMe groups

Radical cation Diels–Alder reactions of arylidene cycloalkanes

• Kaii Nakayama,
• Hidehiro Kamiya and
• Yohei Okada

Beilstein J. Org. Chem. 2022, 18, 1100–1106, doi:10.3762/bjoc.18.112

• ). Then, the solution was diluted with water and extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Yields were determined by 1H NMR analysis using dibromomethane as an internal standard. Silica gel column chromatography (hexane/ethyl acetate

• electrolyzed at 1.3–1.5 V vs Ag/AgCl using carbon felt electrodes (10 mm × 10 mm) in an undivided cell with stirring. Then, the solution was diluted with water and extracted with EtOAc. The combined organic layers were dried over Na2SO4, filtered, and concentrated in vacuo. Yields were determined by 1H NMR

• analysis using dibromomethane as an internal standard. Silica gel column chromatography (hexane/ethyl acetate) gave the corresponding spiro ring compound. Plausible mechanism of the radical cation Diels–Alder reaction (EDG: electron-donating group). Landscape of the radical cation Diels–Alder reaction

Electrochemical formal homocoupling of sec-alcohols

• Kosuke Yamamoto,
• Kazuhisa Arita,
• Masashi Shiota,
• Masami Kuriyama and
• Osamu Onomura

Beilstein J. Org. Chem. 2022, 18, 1062–1069, doi:10.3762/bjoc.18.108

• internal standard. bDetermined by 1H NMR analysis. Proposed mechanism. Optimization of reaction conditions.a Supporting Information Supporting Information File 116: Experimental procedure, characterization data, and copies of NMR spectra of the products. Funding This work was supported by the Japan

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• ]. Conformational analysis and self-assembling properties The 1H NMR analysis of monomer 1 in various solvents including CDCl3, CD3CN, C6D6, CD3OD, D2O, and DMSO-d6 showed two sets of resonances in proportions varying from 75:25 to 90:10 (Table 3). These two sets of signals were characterized as the backbone cis

• evaluated few segment-based coupling methods. The optimizations made with respect to the standard submonomer synthetic conditions will be useful for developing solid-phase synthesis and access longer and more diverse N-(alkylamino)peptoid oligomers in the future. NMR analysis of the synthesized oligomers 1

The stereochemical course of 2-methylisoborneol biosynthesis

• Binbin Gu,
• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 818–824, doi:10.3762/bjoc.18.82

• of both compounds was determined by small scale conversions with (S)-α-methoxy-α-trifluoromethylphenylacetyl chloride (Mosher’s acid chloride) [37] and 1H NMR analysis of the products (Figure S1 in Supporting Information File 1), showing enantiomeric purities of 85% ee for 5a and 75% ee for 5b

Complementarity of solution and solid state mechanochemical reaction conditions demonstrated by 1,2-debromination of tricyclic imides

• Petar Štrbac and
• Davor Margetić

Beilstein J. Org. Chem. 2022, 18, 746–753, doi:10.3762/bjoc.18.75

• established by 1H NMR analysis and comparison with product 10. The most indicative signals are of N-methyl groups, which are at an almost identical position for the bent isomer 38 (2.36 ppm), as in products 10 and 33 (2.38 and 2.37 ppm, respectively). The chemical shift of the NMe group in linear product 36

Identification of the new prenyltransferase Ubi-297 from marine bacteria and elucidation of its substrate specificity

• Jamshid Amiri Moghaddam,
• Huijuan Guo,
• Karsten Willing,
• Thomas Wichard and
• Christine Beemelmanns

Beilstein J. Org. Chem. 2022, 18, 722–731, doi:10.3762/bjoc.18.72

• fermentation of E. coli/pET28-297 was performed. After induction of protein expression, the precursor 8-HQA and farnesol were added to the culture and incubated overnight. MS-guided purification of cell lysate and 1H NMR analysis of the prenylated 8-HQA product confirmed the prenylation on the quinoline ring

Rapid gas–liquid reaction in flow. Continuous synthesis and production of cyclohexene oxide

• Kyoko Mandai,
• Tetsuya Yamamoto,
• Hiroki Mandai and
• Aiichiro Nagaki

Beilstein J. Org. Chem. 2022, 18, 660–668, doi:10.3762/bjoc.18.67

• pressure regulator (BPR). The reaction solution was cooled to ambient temperature in a water bath at the position right before BPR and collected in a sample vial. The solution was then immediately diluted with deuterated chloroform for 1H NMR analysis. Investigation of the temperature effect Initially, we

• against the operation time as shown in Figure 5. As demonstrated clearly, the production of cyclohexene oxide was maintained constant and high during 1-hour operation. As a result, the productivity was integrated to reach 3.7 g/h reliably, determined by 1H NMR analysis. Investigation of the equivalents of

• condenser. The reaction temperature was controlled either in a water bath or an oil bath. At a certain reaction time, 50 μL of the reaction solution was taken out using a gastight syringe and immediately diluted with deuterated chloroform for 1H NMR analysis. General procedure for epoxidation of cyclohexene

Unusual highly diastereoselective Rh(II)-catalyzed dimerization of 3-diazo-2-arylidenesuccinimides provides access to a new dibenzazulene scaffold

• Anastasia Vepreva,
• Alexander S. Bunev,
• Andrey Yu. Kudinov,
• Grigory Kantin,
• Mikhail Krasavin and
• Dmitry Dar’in

Beilstein J. Org. Chem. 2022, 18, 533–538, doi:10.3762/bjoc.18.55

• yields (Table 1, entries 2–5). In the case of N-benzyl-substituted DAS, byproduct azine 4 was detected by NMR analysis (Table 1, entry 6). The formation of these byproducts was also observed in the case of other DAS bearing alkyl groups at the nitrogen atom (Table 1, entries 10–13) as well as in the case

Site-selective reactions mediated by molecular containers

• Rui Wang and
• Yang Yu

Beilstein J. Org. Chem. 2022, 18, 309–324, doi:10.3762/bjoc.18.35

• cavitand hosts were also modified with imidazolium cationic or carboxylic anionic feet [29]. Before the reaction, NMR analysis of the host–guest complex indicated that the bound guest was in yo-yo motions time-averaged between unsymmetrical J-shaped conformations and symmetrical U-shaped ones. Treatment of

Unexpected chiral vicinal tetrasubstituted diamines via borylcopper-mediated homocoupling of isatin imines

• Marco Manenti,
• Leonardo Lo Presti,
• Giorgio Molteni and
• Alessandra Silvani

Beilstein J. Org. Chem. 2022, 18, 303–308, doi:10.3762/bjoc.18.34

• optimized conditions (Table 1, entry 12) followed by flash chromatography, the unprecedented bisoxindole 2a was fully characterized by high-resolution mass spectrometry and by one- and two-dimensional NMR analysis. In particular, from HSQC, HMBC and COSY experiments all single frequencies could be safely

Anomeric 1,2,3-triazole-linked sialic acid derivatives show selective inhibition towards a bacterial neuraminidase over a trypanosome trans-sialidase

• Peterson de Andrade,
• Sanaz Ahmadipour and
• Robert A. Field

Beilstein J. Org. Chem. 2022, 18, 208–216, doi:10.3762/bjoc.18.24

• and purity (qualitative assessment based on the NMR analysis) without further purification. Enzyme inhibition assays The inhibitory activities of compounds 3a–h toward TcTS and neuraminidase were assessed by a continuous fluorimetric assay [34], which is based on the residual hydrolase activity of

Diametric calix[6]arene-based phosphine gold(I) cavitands

• Gabriele Giovanardi,
• Andrea Secchi,
• Arturo Arduini and
• Gianpiero Cera

Beilstein J. Org. Chem. 2022, 18, 190–196, doi:10.3762/bjoc.18.21

• via conventional protocols using (Me2S)AuCl. Notably, the organometallic macrocycles A,B,C(AuCl)2 could be isolated via column chromatography separation. Gold(I) catalysts were subsequently fully characterized by NMR analysis and high-resolution mass spectrometry. The conformation of the catalysts, in

• conformers, in slow exchange on the NMR timescale, was finally confirmed by variable temperature NMR analysis performed for A(AuCl)2 using tetrachloroethane-d2 as the solvent (Figure 3). Catalytic studies To probe the role of the cavity and the influence of the position of the gold(I) nuclei implanted on the

• scavenger [37]. After 4 h, NMR analysis of the crude reaction mixture revealed high conversion of the starting material with the formation of the 6-endo-dig rearranged diene 2a and the parental regioisomer 2b in a 1:1 ratio. Noteworthy, this latter is formed by an initial 5-exo-dig cyclization step (entry 1

Multi-faceted reactivity of N-fluorobenzenesulfonimide (NFSI) under mechanochemical conditions: fluorination, fluorodemethylation, sulfonylation, and amidation reactions

• José G. Hernández,
• Karen J. Ardila-Fierro,
• Dajana Barišić and
• Hervé Geneste

Beilstein J. Org. Chem. 2022, 18, 182–189, doi:10.3762/bjoc.18.20

• ). To mitigate this, the milling experiment was repeated using silica gel (SiO2) as a milling auxiliary. The use of SiO2 did not affect significantly the product composition of the reaction as determined by NMR analysis of an independent experiment milling 1c and NFSI (2.0 equiv) at 30 Hz for 3 h. This

• fluorination of arenes 1 with NFSI. (a) Product distributions and reaction conditions: Arenes 1 (0.148 mmol) were milled with NFSI (1.0–2.0 equiv) in a 2 mL Eppendorf tube with four ZrO2 milling balls (350 mg in total mass) at 25–30 Hz for 3 h. The yield of the products was determined by NMR analysis with 4

• %; (SO2Ph)2NCH3 yield = 82%. (b) Powder X-ray diffraction (PXRD) patterns measured for the reactants and simulated PXRD patterns for the published (SO2Ph)2NCH3 (CCDC ZAJBIZ) and (SO2Ph)2NH (CCDC BSULFA). (c) 1H NMR analysis of the reaction mixture of the milling of 1c and NFSI (2.0 equiv) at 30 Hz for 3 h

High-speed C–H chlorination of ethylene carbonate using a new photoflow setup

• Takayoshi Kasakado,
• Takahide Fukuyama,
• Tomohiro Nakagawa,
• Shinji Taguchi and
• Ilhyong Ryu

Beilstein J. Org. Chem. 2022, 18, 152–158, doi:10.3762/bjoc.18.16

• °C, temperature change rate of 5 °C/min to 250 °C, hold at this temperature for 10 min. Yields were determined by using the percentage peak area method with compensation for the relative sensitivities of each component. Product 2 and byproduct 2’ were confirmed by 1H and 13C NMR analysis (see

Tenacibactins K–M, cytotoxic siderophores from a coral-associated gliding bacterium of the genus Tenacibaculum

• Yasuhiro Igarashi,
• Yiwei Ge,
• Tao Zhou,
• Amit Raj Sharma,
• Enjuro Harunari,
• Naoya Oku and
• Agus Trianto

Beilstein J. Org. Chem. 2022, 18, 110–119, doi:10.3762/bjoc.18.12

• . The methylene carbon C35 adjacent to the hydroxamic acid group showed a smaller chemical shift (δC 28.0). The positional assignment of C34 and C35 was made by a ROESY correlation observed between H34 and 32-NH (Figure 2). To verify the structure deduced from the NMR analysis, an MS/MS analysis was

Regioselective synthesis of methyl 5-(N-Boc-cycloaminyl)-1,2-oxazole-4-carboxylates as new amino acid-like building blocks

• Jolita Bruzgulienė,
• Greta Račkauskienė,
• Aurimas Bieliauskas,
• Vaida Milišiūnaitė,
• Miglė Dagilienė,
• Gita Matulevičiūtė,
• Vytas Martynaitis,
• Sonata Krikštolaitytė,
• Frank A. Sløk and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2022, 18, 102–109, doi:10.3762/bjoc.18.11

• the corresponding reaction mixtures, they were identified using LC–MS analysis, and were immediately treated with hydroxylamine hydrochloride in an appropriate solvent to obtain the target 1,2-oxazoles 4a–h. A representative β-enamino ketoester 3a was subjected to a detailed NMR analysis (Figure 2a

The enzyme mechanism of patchoulol synthase

• Houchao Xu,
• Bernd Goldfuss,
• Gregor Schnakenburg and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 13–24, doi:10.3762/bjoc.18.2

• of Scheme 2. The site of incorporation for the deuterium uptake was evident from incubations of (3-13C)FPP and (12-13C)FPP [25] in deuterium oxide (Scheme 5B and 5C). The 13C NMR analysis of the obtained products showed slightly upfield-shifted triplets for C3 (Δδ = −0.45 ppm, J = 19.4 Hz) and C12

Efficient N-arylation of 4-chloroquinazolines en route to novel 4-anilinoquinazolines as potential anticancer agents

• Rodolfo H. V. Nishimura,
• Thiago dos Santos,
• Valter E. Murie,
• Luciana C. Furtado,
• Leticia V. Costa-Lotufo and
• Giuliano C. Clososki

Beilstein J. Org. Chem. 2021, 17, 2968–2975, doi:10.3762/bjoc.17.206

• , copies of 1H and 13C spectra and additional information of antiproliferative assay. Acknowledgements The authors acknowledge the assistance of Mrs. Izabel C. C. Turatti, Mr. José C. Tomaz and Mr. Vinicius Palaretti in the GC–MS, HRMS and NMR analysis, respectively. Funding The authors gratefully thank

DABCO-promoted photocatalytic C–H functionalization of aldehydes

• Bruno Maia da Silva Santos,
• Mariana dos Santos Dupim,
• Cauê Paula de Souza,
• Thiago Messias Cardozo and
• Fernanda Gadini Finelli

Beilstein J. Org. Chem. 2021, 17, 2959–2967, doi:10.3762/bjoc.17.205

• structure for the HAT reaction between the DABCO radical cation and isovaleraldehyde obtained at the DFT/M06-2X/cc-pVTZ level. Bond lengths and angle are presented. Aryl bromide and aldehyde scope. Isolated yields. aYield determined by 1H NMR analysis with 1,3-benzodioxole as internal standard. bAlso

A photochemical C=C cleavage process: toward access to backbone N-formyl peptides

• Haopei Wang and
• Zachary T. Ball

Beilstein J. Org. Chem. 2021, 17, 2932–2938, doi:10.3762/bjoc.17.202

• . Unfortunately, no products other than the formyl compound were isolated after photocleavage of compound 1 or 6 in acidic conditions. Instead, when irradiation of alkenyl amide 1 was conducted in acetone, crude NMR analysis indicated the appearance of product 8 as well as new peaks in the aromatic region