Hoveyda–Grubbs catalysts with an N→Ru coordinate bond in a six-membered ring. Synthesis of stable, industrially scalable, highly efficient ruthenium metathesis catalysts and 2-vinylbenzylamine ligands as their precursors

• Kirill B. Polyanskii,
• Kseniia A. Alekseeva,
• Pavel V. Raspertov,
• Pavel A. Kumandin,
• Eugeniya V. Nikitina,
• Atash V. Gurbanov and
• Fedor I. Zubkov

Beilstein J. Org. Chem. 2019, 15, 769–779, doi:10.3762/bjoc.15.73

• catalysts 11a–c (Figure 3). In spite of the fact that we do not have the X-ray analysis for catalyst 11d, it is possible to assume that this complex should exhibit the longest coordination N→Ru bond (at least more than 2.30 Å). Interestingly, lower yields of stilbene from styrene in CH2Cl2 were obtained in

Synthesis of 2H-furo[2,3-c]pyrazole ring systems through silver(I) ion-mediated ring-closure reaction

• Vaida Milišiūnaitė,
• Rūta Paulavičiūtė,
• Eglė Arbačiauskienė,
• Vytas Martynaitis,
• Wolfgang Holzer and
• Algirdas Šačkus

Beilstein J. Org. Chem. 2019, 15, 679–684, doi:10.3762/bjoc.15.62

• −127.5 to −128.0 ppm for N-1. The structure of 4d was investigated additionally by single crystal X-ray analysis (Figure 1) [39]. The asymmetric unit of the crystal consists of two molecules 4d(A) and 4d(B) held together by the weak CH···N type hydrogen bonds C19–H···N51 (C···N = 3.470(11) Å, H···N

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

• reactions could also be carried out in water (at circa 80 °C) but with chemoselectivity favoring (Ar1Ar1Ar2)CH over (Ar1Ar2Ar3)CH. The molecular structure of a representative (Ar1Ar2Ar3)CH triad was confirmed by X-ray analysis. Model tris(heteroaryl/aryl)methylium salts were generated by reaction with DDQ

• 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

Synthesis and fluorescent properties of N(9)-alkylated 2-amino-6-triazolylpurines and 7-deazapurines

• Andrejs Šišuļins,
• Jonas Bucevičius,
• Yu-Ting Tseng,
• Irina Novosjolova,
• Kaspars Traskovskis,
• Ērika Bizdēna,
• Huan-Tsung Chang,
• Sigitas Tumkevičius and
• Māris Turks

Beilstein J. Org. Chem. 2019, 15, 474–489, doi:10.3762/bjoc.15.41

• increases with the increase of solvent polarity. Additionally, X-ray analysis of 2,6-diazidopurine 2'-deoxyribonucleoside revealed the exclusive existence of the azido tautomer in the solid state [41]. The discovered ability of the azido group to be substituted with amines at C(2) position was used for the

Annulation of 1H-pyrrole-2,3-diones by thioacetamide: an approach to 5-azaisatins

• Aleksandr I. Kobelev,
• Ekaterina E. Stepanova,
• Maksim V. Dmitriev and
• Andrey N. Maslivets

Beilstein J. Org. Chem. 2019, 15, 364–370, doi:10.3762/bjoc.15.32

• precipitates. The precipitates were isolated and analyzed. We established that they were formed by pyrrolo[3,2-c]pyridine-2,3-diones 4 (Scheme 3). The structure of compounds 4 was unequivocally confirmed by a single crystal X-ray analysis (CCDC 1877232). We assume that the formation of compounds 4 occurred

• compound 5 (Scheme 7). The structure of compound 5 was proved by X-ray analysis (CCDC 1879686). Obviously, compound 5 corresponds to an intermediate proposed in pathway b (Scheme 4) which is one more evidence to support this pathway. Unfortunately, we did not succeed to transform compound 5 in the

Reusable and highly enantioselective water-soluble Ru(II)-Amm-Pheox catalyst for intramolecular cyclopropanation of diazo compounds

• Hamada S. A. Mandour,
• Yoko Nakagawa,
• Masaya Tone,
• Hayato Inoue,
• Nansalmaa Otog,
• Ikuhide Fujisawa,
• Soda Chanthamath and
• Seiji Iwasa

Beilstein J. Org. Chem. 2019, 15, 357–363, doi:10.3762/bjoc.15.31

• Information Supporting Information File 66: Full experimental details and analytical data (reaction method, 1H NMR, 13C NMR, HPLC, X-ray analysis). Acknowledgements This work was supported by a Grant-in-Aid for Scientific Research (B) (No. 26288087) from Japan Society for the Promotion of Science. The data

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

• reported in our previous study [27]. Of these, 1a has already been synthesised by other groups [10][11] as well as our group. Particularly, Kleij et al. revealed the solid-state structure of 1a via X-ray analysis [11], but the isolation and characterisation of 1d has only been reported by our group. Herein

• corresponding LMdiol 2d [27]. Notably, the structure of 2d was confirmed by X-ray analysis. It has been reported that reduction of the 5CC moiety with LAH gives the corresponding diol with the same stereochemical configuration at the carbon atoms as of the original 5CC moiety [28][29]. Such a reduction with LAH

Ruthenium-based olefin metathesis catalysts with monodentate unsymmetrical NHC ligands

• Veronica Paradiso,
• Chiara Costabile and
• Fabia Grisi

Beilstein J. Org. Chem. 2018, 14, 3122–3149, doi:10.3762/bjoc.14.292

• , one of the N-aryl substituents was replaced with the smaller methyl group. Complex 164 was obtained in poor yield (30%) and characterized through NOE and X-ray analysis, revealing the exclusive formation of the rotational isomer in which the N-methyl lies over the carbene unit (the syn isomer, Figure

1,8-Bis(dimethylamino)naphthyl-2-ketimines: Inside vs outside protonation

• A. S. Antonov,
• A. F. Pozharskii,
• P. M. Tolstoy,
• A. Filarowski and
• O. V. Khoroshilova

Beilstein J. Org. Chem. 2018, 14, 2940–2948, doi:10.3762/bjoc.14.273

• -arylketimines of 1,8-bis(dimethylamonio)naphthalene with a different number of methoxy groups in an aromatic substituent were investigated in solution by NMR (acetone, DMSO, MeCN), in solid state by X-ray analysis and in the gas phase by DFT calculations. Both mono- and diprotonated species were considered. It

• for 4a, while the E-form is more stable for 5a–7a. Indeed, the X-ray analysis shows that compound 6a in the solid state exists in the E-form stabilised by the N−H···O intramolecular hydrogen bond (IHB) with an ortho-OMe group (Figure 2a), while compound 4a, as it was revealed in our previous work [7

Protein–protein interactions in bacteria: a promising and challenging avenue towards the discovery of new antibiotics

• Laura Carro

Beilstein J. Org. Chem. 2018, 14, 2881–2896, doi:10.3762/bjoc.14.267

• less active than the original lead, the authors argued that it had less development issues. Finally, in order to confirm the binding mode of these new structures, the crystal structure of 39 (Kd = 83.1 μM) in complex with ZipA was solved. Excitingly, the X-ray analysis revealed that ROCS very

Molecular iodine-catalyzed one-pot multicomponent synthesis of 5-amino-4-(arylselanyl)-1H-pyrazoles

• Camila S. Pires,
• Daniela H. de Oliveira,
• Maria R. B. Pontel,
• Jean C. Kazmierczak,
• Roberta Cargnelutti,
• Diego Alves,
• Raquel G. Jacob and
• Ricardo F. Schumacher

Beilstein J. Org. Chem. 2018, 14, 2789–2798, doi:10.3762/bjoc.14.256

• -(phenylselanyl)-1H-pyrazol-5-amine was submitted to an oxidative dehydrogenative coupling to produce a diazo compound confirmed by X-ray analysis. Keywords: diaryl diselenide; diazo compound; 1H-pyrazole; molecular iodine; multicomponent reaction; Introduction Selenium-containing compounds are of great

Transition metal-free oxidative and deoxygenative C–H/C–Li cross-couplings of 2H-imidazole 1-oxides with carboranyl lithium as an efficient synthetic approach to azaheterocyclic carboranes

• Lidia A. Smyshliaeva,
• Mikhail V. Varaksin,
• Pavel A. Slepukhin,
• Oleg N. Chupakhin and
• Valery N. Charushin

Beilstein J. Org. Chem. 2018, 14, 2618–2626, doi:10.3762/bjoc.14.240

• be attributed to C-2 of the imidazole ring. The structure of imidazolyl carborane 5d has also been proved by the X-ray analysis (Figure 3). The single crystals were obtained by slow evaporation of imidazolyl carborane 5d from a mixture of CH2Cl2/heptane, 8:2. According to the XRD data, two

Synthesis of eunicellane-type bicycles embedding a 1,3-cyclohexadiene moiety

• Alex Frichert,
• Peter G. Jones and
• Thomas Lindel

Beilstein J. Org. Chem. 2018, 14, 2461–2467, doi:10.3762/bjoc.14.222

• carbon following the ethoxycarbonylation. The 3JHH coupling constant proved that the isopropyl and ethoxycarbonyl groups both assume an equatorial position in a chair conformation. We were not able to obtain an X-ray analysis of cyanohydrin 22, but of one diastereomer (30) of an analog where the OTBS was

• Information File 422: Experimental procedures, spectroscopical data, X-ray analysis of 30, and NMR spectra plots. Acknowledgements We thank Merck KGaA (Darmstadt, Germany) for chromatography materials. BASF Group (Ludwigshafen, Germany) and Honeywell Specialty Chemicals Seelze GmbH (Seelze, Germany) are

Microfluidic light-driven synthesis of tetracyclic molecular architectures

• Javier Mateos,
• Nicholas Meneghini,
• Marcella Bonchio,
• Nadia Marino,
• Tommaso Carofiglio,
• Xavier Companyó and
• Luca Dell’Amico

Beilstein J. Org. Chem. 2018, 14, 2418–2424, doi:10.3762/bjoc.14.219

• experiments and confirmed by X-ray analysis of a suitable single crystal (Figure 3). Noteworthy, different 2-MBPs bearing electron-donating or electron-withdrawing groups underwent the light-driven [4 + 2] cycloaddition, affording the corresponding tetracyclic products 5b–f with high dr and in good yields

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

• functionalized at the 5-position of the nucleobase with octadiynyl side chains and with azido groups at the 5’-position of the sugar moieties were synthesized. The macrocycles display freely accessible Watson–Crick recognition sites. The conformation of the 16-membered macrocycle was deduced from X-ray analysis

• new lead for a diversity of molecules. From the cyclic molecule a single crystal X-ray analysis was obtained. The sugar conformation was studied in solution and in solid state. Results and Discussion The octadiynyl derivative 1 of dC [32][33][34][35] was the starting material for the synthesis of 5

• decrease. Next, a X-ray analysis was performed from the dU macrocycle 8, which was crystallized from methanolic solution containing traces of water. Colorless needles with a melting point of 260–265 °C (decomp.) were obtained. The solid state structure of the macrocycle is displayed in Figure 2. The X- ray

Some mechanistic aspects regarding the Suzuki–Miyaura reaction between selected ortho-substituted phenylboronic acids and 3,4,5-tribromo-2,6-dimethylpyridine

• Piotr Pomarański,
• Piotr Roszkowski,
• Jan K. Maurin,
• Armand Budzianowski and
• Zbigniew Czarnocki

Beilstein J. Org. Chem. 2018, 14, 2384–2393, doi:10.3762/bjoc.14.214

• determined on the basis of HT NMR and thermal epimerisation experiments. The structure of most presented atropisomeric derivatives of 2,6-dimethylpyridine was confirmed by single-crystal X-ray analysis. Racemic chiral, differently substituted atropisomers were also examined by 1H NMR spectroscopy in the

• chromatography using a specialist high-purity grade silica gel type H (10–40 µm). The structure of (syn)-10 was also confirmed by the single-crystal X-ray analysis (see Supporting Information File 1 for details). We also carried out a series of the cross-coupling reactions using 3,4-dibromo-5-(2-methoxyphenyl

• possible by careful crystallization from methanol. The structure and configuration of the products 12–14 were established by NMR as well as the single-crystals X-ray analysis (see Supporting Information File 1 for details). The data presented in Table 4 clearly indicate that the substituent change from

Novel photochemical reactions of carbocyclic diazodiketones without elimination of nitrogen – a suitable way to N-hydrazonation of C–H-bonds

• Liudmila L. Rodina,
• Xenia V. Azarova,
• Jury J. Medvedev,
• Dmitrij V. Semenok and
• Valerij A. Nikolaev

Beilstein J. Org. Chem. 2018, 14, 2250–2258, doi:10.3762/bjoc.14.200

• ][39]. The structures of diazodiketones 1a–g were established using a standard set of spectroscopic methods (1Н and 13С NMR, IR and UV; for details, see Supporting Information File 1, Table S1) and in the case of the tricyclic diazodiketone 1с the structure was also confirmed by means of X-ray analysis

• % (Table 1, entries 1 and 3). The irradiation of tricyclic diazodiketone 1b in the presence of 1 equiv of benzophenone in THF solution led to the formation of hydrazone 2b in a yield of 32% (Table 1, entry 4), whose structure was unambiguously established by X-ray analysis (Figure 2). To increase the

• tetrahydrofuran used in the project. Molecular structure of hydrazone 2b as determined by X-ray analysis data (Olex2 plot with 50% probability level of ellipsoids). Photochemical cycloelimination of furans from hydrazones 2d,e. Different pathways of diazodiketones 1 light-induced reactions in the singlet

Synthesis of 1,4-imino-L-lyxitols modified at C-5 and their evaluation as inhibitors of GH38 α-mannosidases

• Maroš Bella,
• Sergej Šesták,
• Ján Moncoľ,
• Miroslav Koóš and
• Monika Poláková

Beilstein J. Org. Chem. 2018, 14, 2156–2162, doi:10.3762/bjoc.14.189

• absolute configuration of carbamate 20 was confirmed by single-crystal X-ray analysis (Figure 2) [36]. Basic hydrolysis of carbamate 20 with 10% NaOH in refluxing EtOH provided aminoalcohol 21 which was subsequently N-benzylated with the corresponding benzyl bromides to yield pyrrolidines 22. Final

D-Fructose-based spiro-fused PHOX ligands: synthesis and application in enantioselective allylic alkylation

• Michael R. Imrich,
• Jochen Kraft,
• Cäcilia Maichle-Mössmer and
• Thomas Ziegler

Beilstein J. Org. Chem. 2018, 14, 2082–2089, doi:10.3762/bjoc.14.182

• molecular structure is shown in Figure 2, detailed crystal data and structure refinements of the X-ray analysis are given in Supporting Information File 1. The configuration at the anomeric center is β and the fructose ring adopts 5C2 conformation. To confirm that the configuration of the major product of

Water-soluble SNS cationic palladium(II) complexes and their Suzuki–Miyaura cross-coupling reactions in aqueous medium

• Alphonse Fiebor,
• Richard Tia,
• Banothile C. E. Makhubela and
• Henok H. Kinfe

Beilstein J. Org. Chem. 2018, 14, 1859–1870, doi:10.3762/bjoc.14.160

• representative X-ray crystal structure of 17d is shown in Figure 3 [38]. Single crystals suitable for X-ray analysis of complexes 17d were obtained by slow evaporation of a mixture of dichloromethane and diethyl ether at about −4 °C. Crystallographic data and structure refinement parameters for 17d are

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• -iodosylbenzenesulfonic acid as confirmed by X-ray diffraction analysis [17]. In the present work, we report the preparation and isolation of IBS (as potassium or sodium salts) and its structural study by X-ray analysis. Furthermore, we have developed a new method for the preparation of the IBS reduced form, 2

• , which probably has a noncyclic (or pseudocyclic) structure of 2-OIC6H4SO2ONa. Indeed, X-ray analysis of 2-iodosylbenzenesulfonic acid (4) indicated a cyclic structure with a I–O bond length of 2.38 Å in the benziodoxathiole ring [18], while in the anionic iodine(V) benziodoxathiole ring in aggregate 6

• impossible in the cyclic structure of 2-iodosylbenzenesulfonic acid. Conclusion In conclusion, we have reported a selective preparation of IBS (as potassium or sodium salts) and investigated its structure by X-ray analysis. Furthermore, we have developed a new method for the preparation of the reduced form

Synthesis of new tricyclic 5,6-dihydro-4H-benzo[b][1,2,4]triazolo[1,5-d][1,4]diazepine derivatives by [3⁺ + 2]-cycloaddition/rearrangement reactions

• Lin-bo Luan,
• Zi-jie Song,
• Zhi-ming Li and
• Quan-rui Wang

Beilstein J. Org. Chem. 2018, 14, 1826–1833, doi:10.3762/bjoc.14.155

• -jian Lin for structural confirmation of 10k and 13e by single-crystal X-ray analysis.

Synthesis of spirocyclic scaffolds using hypervalent iodine reagents

• Fateh V. Singh,
• Priyanka B. Kole,
• Saeesh R. Mangaonkar and
• Samata E. Shetgaonkar

Beilstein J. Org. Chem. 2018, 14, 1778–1805, doi:10.3762/bjoc.14.152

• ). Furthermore, the absolute configuration of 88 was assigned by its single crystal X-ray analysis. 3.3. Application of spirolactams in natural product synthesis In 2001, Ciufolini and co-workers [103] employed PIDA (15) as an electrophile during the synthesis of naturally occurring tricyclic azaspirane

An unusual thionyl chloride-promoted C−C bond formation to obtain 4,4'-bipyrazolones

• Gernot A. Eller,
• Gytė Vilkauskaitė,
• Algirdas Šačkus,
• Vytas Martynaitis,
• Ashenafi Damtew Mamuye,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2018, 14, 1287–1292, doi:10.3762/bjoc.14.110

• racemic mixture or the meso-form came into consideration. The single crystal X-ray analysis disclosed that the molecule of the newly obtained compound 3a consists of two pyrazolone residues, which are directly connected to each other by a single covalent carbon–carbon bond between the asymmetric sp3

• ) for performing the X-ray analysis and to one of the referees for assistance with the proposed reaction mechanism.

Novel unit B cryptophycin analogues as payloads for targeted therapy

• Eduard Figueras,
• Adina Borbély,
• Mohamed Ismail,
• Marcel Frese and
• Norbert Sewald

Beilstein J. Org. Chem. 2018, 14, 1281–1286, doi:10.3762/bjoc.14.109

• research group. Docking and modelling of cryptophycin derivatives There is no X-ray analysis of cryptophycin–tubulin complexes available to provide information on the binding site. Based on biochemical evidence, binding close to the vinca-alkaloid binding site of β-tubulin, the so called “peptide-site