Iodine-catalyzed electrophilic substitution of indoles: Synthesis of (un)symmetrical diindolylmethanes with a quaternary carbon center

• Thanigaimalai Pillaiyar,
• Masoud Sedaghati,
• Andhika B. Mahardhika,
• Lukas L. Wendt and
• Christa E. Müller

Beilstein J. Org. Chem. 2021, 17, 1464–1475, doi:10.3762/bjoc.17.102

• constitutive activity [41]. Compound 3e reduced the basal activity of CB1 receptors (Supporting Information File 1, Figure S2A) but not that of CB2 receptors indicating that this compound acts as an inverse agonist (EC50 0.786 ± 0.233 µM) at CB1 receptors (Supporting Information File 1, Figure S2B). This

Total synthesis of ent-pavettamine

• Memory Zimuwandeyi,
• Manuel A. Fernandes,
• Amanda L. Rousseau and
• Moira L. Bode

Beilstein J. Org. Chem. 2021, 17, 1440–1446, doi:10.3762/bjoc.17.99

• close to the OTBS center. At this point, it was crucial to conclusively characterize the unexpected product 9. Fortuitously, we were able to obtain crystals for this compound after several recrystallization attempts. The crystal structure for 9 (Figure 2) very surprisingly showed the OTBS group on the

N-tert-Butanesulfinyl imines in the asymmetric synthesis of nitrogen-containing heterocycles

• Joseane A. Mendes,
• Paulo R. R. Costa,
• Miguel Yus,
• Francisco Foubelo and
• Camilla D. Buarque

Beilstein J. Org. Chem. 2021, 17, 1096–1140, doi:10.3762/bjoc.17.86

• in the synthesis of (–)-batzelladine D 61 and (–)-13-epi-batzelladine D 62. The reaction of (SS)-58 with methyl bromoacetate in the presence on Zn and CuCl in THF, left, after removal of the sulfinyl group under acidic conditions, to β-amino ester ammonium chloride 59 in high yield. This compound was

• compound (+)-L-733,060 (140), a potent neurokinin substance P receptor antagonist. This compound displays a wide variety of biological activities, including inhibition of neurogenic inflammation, blocking of pain transmission and regulation of immune response (Scheme 38). A stereoselective synthesis of ʟ

Synthesis of multiply fluorinated N-acetyl-D-glucosamine and D-galactosamine analogs via the corresponding deoxyfluorinated glucosazide and galactosazide phenyl thioglycosides

• Vojtěch Hamala,
• Lucie Červenková Šťastná,
• Martin Kurfiřt,
• Petra Cuřínová,
• Martin Dračínský and
• Jindřich Karban

Beilstein J. Org. Chem. 2021, 17, 1086–1095, doi:10.3762/bjoc.17.85

• 1,6-anhydro derivative 10, we were able to isolate one of the side-products in sufficient purity and quantity to assign the structure of C-furanoside 20 (Scheme 2). This compound resulted from pyranose ring contraction probably caused by intramolecular displacement of the C2 azide aided by

Synthetic accesses to biguanide compounds

• Oleksandr Grytsai,
• Cyril Ronco and
• Rachid Benhida

Beilstein J. Org. Chem. 2021, 17, 1001–1040, doi:10.3762/bjoc.17.82

• of biguanides was reported for metformin (N,N-dimethylbiguanide) in 1929. The hypoglycemic activity of this compound brought real fame to biguanides [9]. The two decades following the Second World War saw the emergence of almost all famous biguanide drugs, with activity in various therapeutic fields

Application of the Meerwein reaction of 1,4-benzoquinone to a metal-free synthesis of benzofuropyridine analogues

• Rashmi Singh,
• Tomas Horsten,
• Rashmi Prakash,
• Swapan Dey and
• Wim Dehaen

Beilstein J. Org. Chem. 2021, 17, 977–982, doi:10.3762/bjoc.17.79

• expand the library of derivatives containing core structure 13, electrophilic aromatic substitution of this compound was explored (Scheme 2). Nitration of 13 using 70% nitric acid in glacial acetic acid gave the corresponding regioisomers 14 and 15 in 53% and 41% isolated yield, respectively. The 1H NMR

Enhanced target cell specificity and uptake of lipid nanoparticles using RNA aptamers and peptides

• Roslyn M. Ray,
• Anders Højgaard Hansen,
• Maria Taskova,
• Bernhard Jandl,
• Jonas Hansen,
• Citra Soemardy,
• Kevin V. Morris and
• Kira Astakhova

Beilstein J. Org. Chem. 2021, 17, 891–907, doi:10.3762/bjoc.17.75

• –transferrin increased brain delivery by 2.8-fold compared to liposomes without transferrin in a BBB model and in vivo [15] and further when loaded with the chemotherapeutic agent doxorubicin. They observed increased delivery of this compound and subsequently a significant tumor regression in mouse xenografts

Synthesis and properties of oligonucleotides modified with an N-methylguanidine-bridged nucleic acid (GuNA[Me]) bearing adenine, guanine, or 5-methylcytosine nucleobases

• Naohiro Horie,
• Takao Yamaguchi,
• Shinji Kumagai and
• Satoshi Obika

Beilstein J. Org. Chem. 2021, 17, 622–629, doi:10.3762/bjoc.17.54

• )-5-(N'-Acetyl-N-methylcarbamimidoyl)-3-(N6-benzoyladenine-9-yl)-1-(4,4'-dimethoxytrityl)oxymethyl-2-oxa-5-azabicyclo[2.2.1]heptan-7-ol (2a): This compound was synthesized in a similar manner as described in reference [20]. To the mixture of compound 1a (841 mg, 1.23 mmol) and N-acetyl-S,N

• -isobutyrylguanine-9-yl)-2-oxa-5-azabicyclo[2.2.1]heptan-7-ol (2b): This compound was synthesized in a similar manner as described in reference [20]. To the mixture of compound 1b (2.15 g, 2.49 mmol) and N-acetyl-S,N'-dimethylisothiourea (402 mg, 2.75 mmol), anhydrous THF (25 mL) was added and the mixture placed in

• -diphenylcarbamoyl-N2-isobutyrylguanine-9-yl)-2-oxa-5-azabicyclo[2.2.1]heptan-7-ol (2c): This compound was synthesized in a similar manner as described in reference [20]. To the mixture of compound 1c (679 mg, 1.01 mmol) and N-acetyl-S,N'-dimethylisothiourea (194 mg, 1.33 mmol), anhydrous THF (10 mL) was added and

Breakdown of 3-(allylsulfonio)propanoates in bacteria from the Roseobacter group yields garlic oil constituents

• Anuj Kumar Chhalodia and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 569–580, doi:10.3762/bjoc.17.51

• collapses to methanethiol (MeSH) and malonyl-CoA semialdehyde (21). This compound further degrades to acetaldehyde (22) through the thioester hydrolysis and decarboxylation [27]. Feeding of (methyl-2H6)DMSP to Phaeobacter inhibens DSM 17395 and Ruegeria pomeroyi DSM 15171 resulted in the efficient uptake of

• -(diethylsulfonio)propanoate (DESP), 3-(dimethylselenio)propanoate (DMSeP; this compound is also formed naturally in Spartina alterniflora in the presence of sodium selenate [30]), and even 3-(dimethyltellurio)propanoate (DMTeP) are converted by the demethylation pathway into ethanethiol, methaneselenol, and

• standard or of mass spectra to data base spectra in our MS libraries and confirmed for most cases by comparison of the retention indices to literature data, only for the mass spectrum of 26 no data base hit was returned. Therefore, a structural suggestion for this compound was based on the observed

Identification of volatiles from six marine Celeribacter strains

• Anuj Kumar Chhalodia,
• Jan Rinkel,
• Dorota Konvalinkova,
• Jörn Petersen and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 420–430, doi:10.3762/bjoc.17.38

• into dimethyl trisulfide and S-methyl methanethiosulfonate, and revealed the origin of the methylsulfanyl group of 2-(methyldisulfanyl)benzothiazole from methionine or DMSP, while the biosynthetic origin of the benzothiazol-2-ylsulfanyl portion could not be traced. The heterocyclic moiety of this

• compound is likely of anthropogenic origin, because 2-mercaptobenzothiazole is used in the sulfur vulcanization of rubber. Also in none of the feeding experiments incorporation into ethyl (E)-3-(methylsulfanyl)acrylate could be observed, questioning its bacterial origin. Our results demonstrate that the

Unexpected rearrangements and a novel synthesis of 1,1-dichloro-1-alkenones from 1,1,1-trifluoroalkanones with aluminium trichloride

• Beatrice Lansbergen,
• Catherine S. Meister and
• Michael C. McLeod

Beilstein J. Org. Chem. 2021, 17, 404–409, doi:10.3762/bjoc.17.36

• ), a single product was isolated from the reaction that, after careful elucidation (see Supporting Information File 1), was identified as the bicycle 17. This compound could potentially arise via an initial conversion to the dichloroalkyl cation 18, followed by a ring closure and elimination of HCl to

Mesoionic tetrazolium-5-aminides: Synthesis, molecular and crystal structures, UV–vis spectra, and DFT calculations

• Vladislav A. Budevich,
• Sergei V. Voitekhovich,
• Alexander V. Zuraev,
• Vadim E. Matulis,
• Vitaly E. Matulis,
• Alexander S. Lyakhov,
• Ludmila S. Ivashkevich and
• Oleg A. Ivashkevich

Beilstein J. Org. Chem. 2021, 17, 385–395, doi:10.3762/bjoc.17.34

• -aminide ligand in a manganese complex [29], being the only structurally characterized complex with a neutral 1,3-dialkyltetrazolium-5-aminide. Therefore, it is of interest to compare the structural data for this compound with those obtained for compound 8a to find the influence of the complexation on the

CF₃-substituted carbocations: underexploited intermediates with great potential in modern synthetic chemistry

• Anthony J. Fernandes,
• Armen Panossian,
• Bastien Michelet,
• Agnès Martin-Mingot,
• Frédéric R. Leroux and
• Sébastien Thibaudeau

Beilstein J. Org. Chem. 2021, 17, 343–378, doi:10.3762/bjoc.17.32

• observed. Similar observations have been reported by Langlois et al. [77]. In order to get some insights into the mechanism, derivative 96 was synthesized and subjected to solvolysis. However, this compound was found to be stable under the reaction conditions [52]. When primary triflate 97 was subjected to

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

• Sergey V. Norkov,
• Anton V. Cherkasov,
• Andrey S. Shavyrin,
• Maxim V. Arsenyev,
• Viacheslav A. Kuropatov and
• Vladimir K. Cherkasov

Beilstein J. Org. Chem. 2021, 17, 273–282, doi:10.3762/bjoc.17.26

• peripheral functions. o-Quinone 6c exhibits four one-electron quasi-reversible reduction waves. This compound contains of two redox-active fragments – 3,6-di-tert-butyl-o-quinonoid and 2,6-di-tert-butyl-p-quinone-methide, respectively. According to the literature data they should have very similar values of

Total synthesis of decarboxyaltenusin

• Lucas Warmuth,
• Aaron Weiß,
• Marco Reinhardt,
• Anna Meschkov,
• Ute Schepers and
• Joachim Podlech

Beilstein J. Org. Chem. 2021, 17, 224–228, doi:10.3762/bjoc.17.22

• thorough biological investigations (as have been suggested by the European Food Safety Authority, EFSA [19]), we considered it useful to supply a more straightforward synthesis of this compound, for which we here propose the obvious name decarboxyaltenusin. Results and Discussion In a retrosynthetic

• inhibitory activity against three tyrosine kinases (EGFR, VEGFR-1, and c-Met) [5]. As mentioned, it is accessible through the reduction of dehydroaltenusin with zinc powder in acetic acid with intermediate formation of altenusin [1]. Nevertheless, this route cannot be considered as a viable approach to this

• compound due to the reduced accessibility of the precursors and since no experimental details have been published for the transformation. To continue our efforts in the total synthesis of mycotoxins [8][9][10][11][12][13][14][15][16][17][18] and to provide larger amounts of the polyketide 1 sufficient for

Direct synthesis of anomeric tetrazolyl iminosugars from sugar-derived lactams

• Michał M. Więcław and
• Bartłomiej Furman

Beilstein J. Org. Chem. 2021, 17, 115–123, doi:10.3762/bjoc.17.12

• of benzoic acid at an elevated temperature yielding lactam 6 almost quantitatively. The deoxygenative reduction of this compound turned out to be challenging, as the typical procedure using LiAlH4 proved ineffective. We were able to obtain 7 using a Schwartz’s reagent-mediated amide activation

Synthesis of aryl 2-bromo-2-chloro-1,1-difluoroethyl ethers through the base-mediated reaction between phenols and halothane

• Yukiko Karuo,
• Ayaka Kametani,
• Atsushi Tarui,
• Kazuyuki Sato,
• Kentaro Kawai and
• Masaaki Omote

Beilstein J. Org. Chem. 2021, 17, 89–96, doi:10.3762/bjoc.17.9

• focused on halothane, 2-bromo-2-chloro-1,1,1-trifluoroethane, because the treatment of this compound with several bases was found to provide the highly electrophilic 2-bromo-2-chloro-1,1-difluoroethene [42][43]. Additionally, another report discussed the carbocationic character of the gem-difluorovinyl

Progress in the total synthesis of inthomycins

• Bidyut Kumar Senapati

Beilstein J. Org. Chem. 2021, 17, 58–82, doi:10.3762/bjoc.17.7

• at room temperature to give (E,E,E)-(+)-11 in 79% yield. This compound was then transformed successfully to (inthomycin C ((−)-3) in a four-step sequence (Scheme 10). The difference in Hatakeyama’s approach to inthomycin C ((–)-3) is the polarity reversal of the Stille coupling components relative to

Amine–borane complex-initiated SF₅Cl radical addition on alkenes and alkynes

• Audrey Gilbert,
• Pauline Langowski,
• Marine Delgado,
• Laurent Chabaud,
• Mathieu Pucheault and
• Jean-François Paquin

Beilstein J. Org. Chem. 2020, 16, 3069–3077, doi:10.3762/bjoc.16.256

• substrate for our optimization, since it has been previously shown that this compound undergoes SF5Cl radical addition following Dolbier’s protocol in various solvents with high yields [51]. We started the optimization with 3 equivalents of SF5Cl, 10 mol % of the amine–borane complex, with temperatures

Pentannulation of N-heterocycles by a tandem gold-catalyzed [3,3]-rearrangement/Nazarov reaction of propargyl ester derivatives: a computational study on the crucial role of the nitrogen atom

• Giovanna Zanella,
• Martina Petrović,
• Dina Scarpi,
• Ernesto G. Occhiato and
• Enrique Gómez-Bengoa

Beilstein J. Org. Chem. 2020, 16, 3059–3068, doi:10.3762/bjoc.16.255

• was prepared via the palladium-catalyzed reduction of the corresponding phosphate 17 [54]. Iodination and Sonogashira coupling, followed by acetylation led to the formation of the desired enynyl acetate 20. This compound was treated with 5 mol % Ph3PAuCl/AgSbF6 in DCM, and after 6 h, this afforded the

Metal-free nucleophilic trifluoromethylselenolation via an iodide-mediated umpolung reactivity of trifluoromethylselenotoluenesulfonate

• Kevin Grollier,
• Alexis Taponard,
• Arnaud De Zordo-Banliat,
• Emmanuel Magnier and
• Thierry Billard

Beilstein J. Org. Chem. 2020, 16, 3032–3037, doi:10.3762/bjoc.16.252

• of iodide (from TBAI) reacts with the reagent 1a to produce the transient species CF3SeI with an inverted polarity on the selenium atom. This compound then undergoes the attack of the second equivalent of iodide to generate the CF3Se− anion with releasing of I2. Finally, the nucleophilic CF3Se− can

Controlled decomposition of SF₆ by electrochemical reduction

• Sébastien Bouvet,
• Bruce Pégot,
• Stéphane Sengmany,
• Erwan Le Gall,
• Eric Léonel,
• Anne-Marie Goncalves and
• Emmanuel Magnier

Beilstein J. Org. Chem. 2020, 16, 2948–2953, doi:10.3762/bjoc.16.244

• chemically and physiologically, it is non-flammable, has a high density and a high dielectric constant (2.5 times greater than that of air) [2][3][4][5]. These properties explain that this compound is widely used industrially as an electrical insulating gas in circuit breakers or in electrical substations [6

3-Acetoxy-fatty acid isoprenyl esters from androconia of the ithomiine butterfly Ithomia salapia

• Florian Mann,
• Daiane Szczerbowski,
• Lisa de Silva,
• Melanie McClure,
• Marianne Elias and
• Stefan Schulz

Beilstein J. Org. Chem. 2020, 16, 2776–2787, doi:10.3762/bjoc.16.228

• closely together. The number before the colon indicates the number of individuals carrying this compound, followed by the range of the relative amount. Supporting Information Supporting Information File 430: Butterfly photos, mass, IR and NMR spectra, experimental procedures and analysis of individuals

Ring-closing metathesis of prochiral oxaenediynes to racemic 4-alkenyl-2-alkynyl-3,6-dihydro-2H-pyrans

• Viola Kolaříková,
• Markéta Rybáčková,
• Martin Svoboda and
• Jaroslav Kvíčala

Beilstein J. Org. Chem. 2020, 16, 2757–2768, doi:10.3762/bjoc.16.226

• target diynol 4a was obtained in a 90% yield contaminated with up to 5% of hepta-1,2-dien-6-yn-4-ol (6a), which could not be separated at this stage; however, derivatives of this compound could be conveniently removed by column chromatography in the subsequent steps. Unfortunately, the analogous

Vicinal difluorination as a C=C surrogate: an analog of piperine with enhanced solubility, photostability, and acetylcholinesterase inhibitory activity

• Yuvixza Lizarme-Salas,
• Alexandra Daryl Ariawan,
• Ranjala Ratnayake,
• Hendrik Luesch,
• Angela Finch and
• Luke Hunter

Beilstein J. Org. Chem. 2020, 16, 2663–2670, doi:10.3762/bjoc.16.216

• carried out, and these studies have led to a diverse array of biological activities being claimed for this compound [4][5][6][7][8][9]. For example, 1 is reported to exhibit inhibitory activity towards both acetylcholinesterase (AChE) and β-secretase (BACE-1), which suggests that 1 could hold promise as a