Synthesis of tryptophan-dehydrobutyrine diketopiperazine and biological activity of hangtaimycin and its co-metabolites

• Houchao Xu,
• Anne Wochele,
• Minghe Luo,
• Gregor Schnakenburg,
• Yuhui Sun,
• Heike Brötz-Oesterhelt and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2022, 18, 1159–1165, doi:10.3762/bjoc.18.120

• care, because TDD easily undergoes racemisation under basic conditions. The X-ray analysis showed an interesting dimer interaction of the enantiomers in racemic TDD through hydrogen bridges, that may support its much easier crystallisation in comparison to enantiomerically pure or enriched TDD. In fact

Facile and diastereoselective arylation of the privileged 1,4-dihydroisoquinolin-3(2H)-one scaffold

• Dmitry Dar’in,
• Grigory Kantin,
• Alexander Bunev and
• Mikhail Krasavin

Beilstein J. Org. Chem. 2022, 18, 1070–1078, doi:10.3762/bjoc.18.109

• of compound 9a, by single-crystal X-ray analysis. A curious and somewhat unexpected result was obtained when trying to employ N-formyl-N-methylaniline as an arene in the TfOH-promoted arylation of 10a. Instead of the anticipated product 9aa, 73% yield of predominantly trans-configured formate ester

• 16 was obtained and its structure was confirmed by single-crystal X-ray analysis. Presumably, the formation of ester 16 can be justified by the trapping of the carbocation intermediate 17 (vide infra) by the formamide carbonyl oxygen atom followed by hydrolysis of the iminium moiety (Scheme 4

• characterized). cCompound 14 was identified as the reaction product. Preparation of 4-diazo-3(2H)-isoquinolones 10. aConfirmed by single-crystal X-ray crystallography (see Supporting Information File 1). TfOH-promoted arylation of diazo substrates 10. aStructure confirmed by single-crystal X-ray analysis

Synthesis of novel alkynyl imidazopyridinyl selenides: copper-catalyzed tandem selenation of selenium with 2-arylimidazo[1,2-a]pyridines and terminal alkynes

• Mio Matsumura,
• Kaho Tsukada,
• Kiwa Sugimoto,
• Yuki Murata and
• Shuji Yasuike

Beilstein J. Org. Chem. 2022, 18, 863–871, doi:10.3762/bjoc.18.87

• the three components (Se powder, 1a, and 3a) in the presence of Na2CO3 at 130 °C, but unfortunately it did not proceed and gave a complex mixture (Table 1, entry 13). Single crystals suitable for X-ray analysis of 4aa were obtained by repeated recrystallization from dichloromethane/hexane as solvent

• single product, and the regiochemistry of 5-selanyltriazole 8 was confirmed by single crystal X-ray analysis (see Supporting Information File 3). The reaction performed using 10 mol % of CuI and PMDETA as catalytic system afforded only a small amount of product 8 (12%). Based on the results obtained in

Synthesis of bis-spirocyclic derivatives of 3-azabicyclo[3.1.0]hexane via cyclopropene cycloadditions to the stable azomethine ylide derived from Ruhemann's purple

• Alexander S. Filatov,
• Olesya V. Khoroshilova,
• Anna G. Larina,
• Vitali M. Boitsov and
• Alexander V. Stepakov

Beilstein J. Org. Chem. 2022, 18, 769–780, doi:10.3762/bjoc.18.77

• -hindered face of TPC (2a) is more favorable than the opposite diastereoisomer 3a' (Scheme 2). Subsequently, our hypothesis about the relative configuration of 3a was confirmed by X-ray analysis that was carried out for the related compound 3e (vide infra). Subsequently, our efforts focused on the

• underwent the cycloaddition reaction to azomethine ylide 1 to form bis-spiro 3-azabicyclo[3.1.0]hexane 3b in 78% yield (Scheme 3). Remarkably, the structure of cycloadduct 3b was additionally verified by X-ray analysis (see Supporting Information File 1, Figure S26 and Table S1). The reaction of 3-ethyl

• during protonation of Ruhemann's purple. Although there was conclusive evidence of the structure of PRP (1) in the Grigg's study (proven by X-ray analysis) [27], we aimed to establish a stability order of tautomers on the basis of calculated relative values of the Gibbs free energy. Upon treatment of

Mechanochemical halogenation of unsymmetrically substituted azobenzenes

• Dajana Barišić,
• Mario Pajić,
• Ivan Halasz,
• Darko Babić and
• Manda Ćurić

Beilstein J. Org. Chem. 2022, 18, 680–687, doi:10.3762/bjoc.18.69

• % yields, respectively, as confirmed by NMR spectroscopy (Figures S82–S91 in Supporting Information File 1). Additional support for the formation of succinimide products was provided by the molecular structure of L4-III, resolved by single-crystal X-ray analysis (Figure 3 and Figure S33 and Table S1 in

A study of the photochemical behavior of terarylenes containing allomaltol and pyrazole fragments

• Constantine V. Milyutin,
• Andrey N. Komogortsev,
• Boris V. Lichitsky and
• Valeriya G. Melekhina

Beilstein J. Org. Chem. 2022, 18, 588–596, doi:10.3762/bjoc.18.61

• corresponding quinoxalines 15a–l in good yields (Scheme 5). The structure of 15a was confirmed by single-crystal X-ray diffraction (Figure 2) as a representative example. It should be noted that X-ray analysis of the final quinoxaline unambiguously proves the conversion of the allomaltol fragment into the

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

• , the formation of the spirocyclic benzoxepine was not observed. Instead, the principal product of the reaction was compound 2 (as unequivocally confirmed by the single-crystal X-ray analysis of a representative, compound 2a, see Supporting Information File 1), presumably resulting from the dimerization

• of DAS 1a in dichloromethane in the presence of Rh2(esp)2 (0.1 mol %) led to the formation of a mixture of the major product ‒ dimer 2a, and minor indene 3a (Table 1, entry 1). The target dimer was isolated in 74% yield as a single diastereomer. Its structure was reliably confirmed by X-ray analysis

• ortho-methyl substituent in the benzylidene fragment. In this case, along with conventional reaction products ‒ dimer 2r and indene 3r, unexpectedly the cyclobutane 5, a product of the formal [2 + 2] cycloaddition, was isolated in low yield (Scheme 1); its structure was confirmed by single-crystal X-ray

BINOL as a chiral element in mechanically interlocked molecules

• Matthias Krajnc and
• Jochen Niemeyer

Beilstein J. Org. Chem. 2022, 18, 508–523, doi:10.3762/bjoc.18.53

• -ray analysis revealed the presence of the expected [N–H···O] hydrogen bonds between the secondary ammonium station and the crown-ether macrocycle, but also additional [C–H···O] hydrogen bonds involving the benzylammonium methylene groups (see Figure 4). Interestingly, the presence of the directional

• -workers [46]. They reacted the amine axle 11 with the axially chiral macrocycle (rac)-12 in a mixture of dichloromethane and trifluoroacetic acid in order to generate the pseudorotaxane (rac)-13. Then, an isocyanate stopper was added for the formation of the [2]rotaxane (rac)-14 in a yield of 42%. The X

Four bioactive new steroids from the soft coral Lobophytum pauciflorum collected in South China Sea

• Di Zhang,
• Zhe Wang,
• Xiao Han,
• Xiao-Lei Li,
• Zhong-Yu Lu,
• Bei-Bei Dou,
• Wen-Ze Zhang,
• Xu-Li Tang,
• Ping-Lin Li and
• Guo-Qiang Li

Beilstein J. Org. Chem. 2022, 18, 374–380, doi:10.3762/bjoc.18.42

• particular, compound 1 also has a tetracyclic skeleton with a methyl group at C-4. The absolute configuration of 1–3 was determined by X-ray analysis. Herein, we report the isolation, structure elucidation, and bioactivities of these compounds. Results and Discussion Compound 1 was isolated as a white powder

Organocatalytic asymmetric nitroso aldol reaction of α-substituted malonamates

• Ekta Gupta,
• Narendra Kumar Vaishanv,
• Sandeep Kumar,
• Raja Krishnan Purshottam,
• Ruchir Kant and
• Kishor Mohanan

Beilstein J. Org. Chem. 2022, 18, 217–224, doi:10.3762/bjoc.18.25

• , and alkyl at the para-position of the phenyl ring and the corresponding oxyaminated products were obtained in excellent yields and good enantioselectivities (4a–f). The single crystal X-ray analysis of the product 4a established the absolute stereochemistry which was found to be S (Figure 1) [62

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

• Information File 258: General information, synthesis procedures, and spectral data. Acknowledgements The authors are grateful to Mr. S. Belyakov (Latvian Institute of Organic Synthesis, Riga, Latvia) for performing the X-ray analysis. Funding This work has been accomplished with financial support provided by

Efficient and regioselective synthesis of dihydroxy-substituted 2-aminocyclooctane-1-carboxylic acid and its bicyclic derivatives

• İlknur Polat,
• Selçuk Eşsiz,
• Uğur Bozkaya and
• Emine Salamci

Beilstein J. Org. Chem. 2022, 18, 77–85, doi:10.3762/bjoc.18.7

• resonating at 4.49, 1.53, and 2.02 ppm, respectively, in the COSY spectra of 10. The cross peak (δ 4.49 ppm) between H-6 and H-7 showed a strong correlation, which clearly supports the trans relation of the proton H-7. Furthermore, its structure was unambiguously confirmed by single crystal X-ray analysis

• reported. Supporting Information File 266: Additional experimental and computed data. Acknowledgements The authors are indebted to the Atatürk University for its support. We would also like to thank Professor Ertan Sahin for performing the X-ray analysis. Funding This study was funded by the Research Fund

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 an unexpected rearrangement this structural assignment was still erroneous, and the correct structure 3 was finally established by X-ray analysis of its chromic acid diester [6]. The patchoulol synthase (PTS) has been purified from plant leaves and shown to convert farnesyl diphosphate (FPP) into

Host–guest interaction and properties of cucurbit[8]uril with chloramphenicol

• Lin Zhang,
• Jun Zheng,
• Guangyan Luo,
• Xiaoyue Li,
• Yunqian Zhang,
• Zhu Tao and
• Qianjun Zhang

Beilstein J. Org. Chem. 2021, 17, 2832–2839, doi:10.3762/bjoc.17.194

• consistent with our single-crystal X-ray analysis of CPE@Q[8] shown in Figure 2. IR spectroscopy Figure 6 shows the IR spectra recorded for Q[8] (a), CPE (b), a physical mixture of Q[8] and CPE {n(Q[8])/n(CPE) = 1:1} (c) and the CPE@Q[8] inclusion complex (d). By comparison, spectrum (c) is a simple

Synthesis of new bile acid-fused tetrazoles using the Schmidt reaction

• Dušan Đ. Škorić,
• Olivera R. Klisurić,
• Dimitar S. Jakimov,
• Marija N. Sakač and
• János J. Csanádi

Beilstein J. Org. Chem. 2021, 17, 2611–2620, doi:10.3762/bjoc.17.174

• testing (IC50 values less than 10 μM are marked with an asterisk, while a dash denotes an IC50 value higher than 100 μM). Supporting Information Supporting Information File 348: Synthetic procedures, analytical data, X-ray analysis details, and copies of spectra. Funding The authors acknowledge the

Synthesis and antimicrobial activity of 1H-1,2,3-triazole and carboxylate analogues of metronidazole

• Satya Kumar Avula,
• Syed Raza Shah,
• Khdija Al-Hosni,
• Muhammad U. Anwar,
• Rene Csuk,
• Biswanath Das and
• Ahmed Al-Harrasi

Beilstein J. Org. Chem. 2021, 17, 2377–2384, doi:10.3762/bjoc.17.154

• were characterized by 1H NMR, 13C NMR, HRMS, and 19F NMR (5b, 5c and 5h) spectroscopy wherever applicable. The structures of compounds 3, 5c and 7b were unambiguously confirmed by single crystal X-ray analysis diffraction method. Single crystal X-ray structure analysis supported the formation of the

• . The structure of metronidazide 3 was unambiguously confirmed by single crystal X-ray analysis (Figure 3). The next step was carried out by using “click” chemistry involving the 1,3-dipolar cycloaddition reaction between metronidazide 3 and alkyne derivative 4a in the presence of CuI and Hünig’s base

• + H)+ supported the structure of 1H-1,2,3-triazole compound 5c. Single crystals of 1H-1,2,3-triazole compound 5c were grown from slow evaporation of MeOH. The structure of 1H-1,2,3-triazole compound 5c was unambiguously confirmed by single crystal X-ray analysis (Figure 4). Synthesis of carboxylate

Cascade intramolecular Prins/Friedel–Crafts cyclization for the synthesis of 4-aryltetralin-2-ols and 5-aryltetrahydro-5H-benzo[7]annulen-7-ols

• Jie Zheng,
• Shuyu Meng and
• Quanrui Wang

Beilstein J. Org. Chem. 2021, 17, 1481–1489, doi:10.3762/bjoc.17.104

• configuration assignment made by NMR analysis, the sulfonate derivative 21 from 14af was prepared by reaction with tosyl chloride. For compound 21, we were able to obtain single crystals suitable for X-ray analysis and the X-ray diffraction studies on 21 confirmed undoubtedly its trans-configuration. The ORTEP

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

• that the new route doubled the overall yield to 16% for a similar number of steps. The specific optical rotation for 4 of +28.1° in acetone was comparable to that obtained previously [1]. Single crystal X-ray analysis of compound 4 (Figure 3), further confirmed the identity and stereochemistry of 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

• -tribromomethylamines 16. The structure and configuration of aziridines 15 were determined unambiguously by single crystal X-ray analysis [64]. In order to explain the experimental results, a nonchelation controlled transition state was proposed. Based on computational studies, it is known that a kind of s-cis

• determined following a single-crystal X-ray analysis (Scheme 11). The stereoselective synthesis of diastereomeric 2-chloro-2-aroylaziridines 36 and 32 was successfully accomplished through a three-component cascade coupling reaction of silyldichloromethanes 33, arylnitriles 34 and chiral N-tert

Synthesis of β-triazolylenones via metal-free desulfonylative alkylation of N-tosyl-1,2,3-triazoles

• Soumyaranjan Pati,
• Renata G. Almeida,
• Eufrânio N. da Silva Júnior and
• Irishi N. N. Namboothiri

Beilstein J. Org. Chem. 2021, 17, 762–770, doi:10.3762/bjoc.17.66

• data (IR, 1H, 13C and Mass) which were further unambiguously established by single crystal X-ray analysis of a representative compound 3e (Scheme 2 and Supporting Information File 3). Although triazole 1a reacted with cyclohexanedione 2a (vide supra), its reaction with dimedone 2d provided a complex

Effective microwave-assisted approach to 1,2,3-triazolobenzodiazepinones via tandem Ugi reaction/catalyst-free intramolecular azide–alkyne cycloaddition

• Maryna O. Mazur,
• Oleksii S. Zhelavskyi,
• Eugene M. Zviagin,
• Svitlana V. Shishkina,
• Vladimir I. Musatov,
• Maksim A. Kolosov,
• Elena H. Shvets,
• Anna Yu. Andryushchenko and
• Valentyn A. Chebanov

Beilstein J. Org. Chem. 2021, 17, 678–687, doi:10.3762/bjoc.17.57

• ). Ugi product 6aaa (first letter – isocyanide code, second letter – amine code, third – carboxylic acid code) was the first to isolate in our trials and its structure was confirmed by X-ray analysis (Figure 3) in addition to mass spectrometry, elemental analysis, 1H and 13C NMR data. Compound 6

• . Therefore, namely compound 6aaa was chosen as a model substrate for the conditions screening. It is also worth mentioning that the structure of Ugi product 6aea obtained by an alternative method in an oil bath in DCM was also confirmed by X-ray analysis (see Supporting Information File 1). In the next step

• without any catalyst (Table 1, part B, entry 8) produced a white precipitate that, according to X-ray analysis, was the target triazolobenzodiazepinone 7aaa (Figure 5). Similarly, the IAAC of the Passerini product under catalyst-free conditions was described earlier [22]. The 1H NMR analysis is less

Synthesis, structural characterization, and optical properties of benzo[f]naphtho[2,3-b]phosphoindoles

• Mio Matsumura,
• Takahiro Teramoto,
• Masato Kawakubo,
• Masatoshi Kawahata,
• Yuki Murata,
• Kentaro Yamaguchi,
• Masanobu Uchiyama and
• Shuji Yasuike

Beilstein J. Org. Chem. 2021, 17, 671–677, doi:10.3762/bjoc.17.56

• ′-binaphthyl. Various derivatives, such as a phospholium salt and a borane–phosphole complex with functional groups on the phosphorus atom were synthesized using the obtained phosphole as a common starting material. Single-crystal X-ray analysis of the parent benzo[f]naphtho[2,3-b]phosphoindole revealed that

• shift for P-modified phospholes 3–7 (δ = 22.5−39.3 ppm) relative to that of the parent compound 2 (δ = −13.27 ppm). These results suggest that the electron densities of the latter were reduced in comparison to that of 2. Single crystals of 2 suitable for X-ray analysis were obtained by repeated

• ]). The sum of the bond angles around the phosphorus atom is 295.99°, and hence the phosphorus atom is sp3-hybridized and has a trigonal pyramidal geometry. X-ray analysis revealed that the packing structure of 2 had π–π-stacking, with a distance of approximately 3.427 Å between two

Amino- and polyaminophthalazin-1(2H)-ones: synthesis, coordination properties, and biological activity

• Zbigniew Malinowski,
• Emilia Fornal,
• Agata Sumara,
• Renata Kontek,
• Karol Bukowski,
• Beata Pasternak,
• Dariusz Sroczyński,
• Joachim Kusz,
• Magdalena Małecka and
• Monika Nowak

Beilstein J. Org. Chem. 2021, 17, 558–568, doi:10.3762/bjoc.17.50

• (II) complex 17 [(L3)Cu(II)Cl2] was synthesized and characterized by X-ray analysis, FTIR and vis–NIR spectroscopy (for details see Supporting Information File 2). The molecular structure of the complex 17 is shown in Figure 4 and Figure 5. The basic experimental details and selected crystallographic

Menthyl esterification allows chiral resolution for the synthesis of artificial glutamate analogs

• Kenji Morokuma,
• Shuntaro Tsukamoto,
• Kyosuke Mori,
• Kei Miyako,
• Ryuichi Sakai,
• Raku Irie and
• Masato Oikawa

Beilstein J. Org. Chem. 2021, 17, 540–550, doi:10.3762/bjoc.17.48

• ) [10][11][12]. Since 10 was obtained as crystals, the configurational analysis was thereafter confirmed by single-crystal X-ray analysis, as shown in Figure 4. The conformational differences for 10 between the results of the calculations and the analysis of the NMR data compared to the situation in the

• -crystal X-ray analysis of the (2R)-MC-27 precursor 10 (2R, Figure 4), and the analysis based on the PGME amide method [22][23] applied to the TKM-38 precursor (rac)-19 (see Supporting Information File 7). Finally, the hydrolytic removal of the menthyl, methyl, and TFA groups was attempted towards both

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

• -butyltetrazolium-5-aminide, its N,N’-ethylene-bridged bis-derivative and (1,3-di-tert-butyl-1H-tetrazol-3-ium-5-yl)(1-phenyl-1H-tetrazol-5-yl)amide by single crystal X-ray analysis. The structural and spectral features of the tetrazolium-5-aminides are discussed by using quantum-chemical calculations. Keywords

• : aminotetrazoles; DFT; mesoionic compounds; UV–vis spectra; X-ray analysis; Introduction 5-Aminotetrazoles are one of the most available and valuable tetrazole derivatives. So, due to the thermal stability and high nitrogen content the parent 5-aminotetrazole (1, Figure 1) is of practical interest as a gas

• crystal X-ray analysis. For all compounds, data collection was performed at a temperature of 100 K and the main crystal data and structure refinement details are given in Table 1. The mesoionic compounds 8a, 10, and 11a all are monoclinic, with the space groups P21/c for 8a and 10, and P21/n for 11a