Tosylhydrazine-promoted self-conjugate reduction–Michael/aldol reaction of 3-phenacylideneoxindoles towards dispirocyclopentanebisoxindole derivatives

• Sayan Pramanik and
• Chhanda Mukhopadhyay

Beilstein J. Org. Chem. 2022, 18, 469–478, doi:10.3762/bjoc.18.49

• (multiplet). HRMS with an ESI resource were acquired using a Waters XEVO-G2S Q TOF mass spectrometer. HPLC were recorded using an Agilent 1200 Series auto sampler HPLC system. Melting points were recorded with an open capillary on an electrical melting point apparatus and the single crystal structure of the

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

• /v, flow rate 1.0 mL/min, 254 nm, τminor = 13.0 min, τmajor = 13.9 min, 90% ee). HRMS (m/z): [M + Na]+ calcd for C17H17BrN2NaO4+, 415.0264; found, 415.0278. ORTEP diagram drawn with 30% ellipsoid probability for non-H atoms of the crystal structure of chiral compound 4a determined at 293 K. The

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

• derivatives 3a–h (1 mM) using a fluorimetric assay. DANA (2,3-dehydro-2-deoxy-N-acetylneuraminic acid) and PLP (pyridoxal phosphate) were used as positive controls at 1 mM. Crystal structure of TcTS (PDB code 1MS1 – coloured red) (A) and neuraminidase (PDB code 2VK6 – coloured green) (B) in complex with DANA

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

• , in contrast to the formation of the six-membered lactone 20. In addition, these novel compounds synthesized may be used as intermediates to design pharmacological tools. Examples of natural products containing β-amino acids. The X-ray crystal structure of 10. Solvent-corrected relative free energy

Bifunctional thiourea-catalyzed asymmetric [3 + 2] annulation reactions of 2-isothiocyanato-1-indanones with barbiturate-based olefins

• Jiang-Song Zhai and
• Da-Ming Du

Beilstein J. Org. Chem. 2022, 18, 25–36, doi:10.3762/bjoc.18.3

• scaffold. Selected examples of bioactive spirobarbiturates. The screened organocatalysts. X-ray crystal structure of 3ae (displacement ellipsoids are drawn at the 50% probability level). Known strategies and conceptual advance of this contribution. Substrate scope of 2-isothiocyanato-1-indanones. The

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

• ] and CPE was studied using single-crystal X-ray diffraction, UV–vis and 1H NMR spectroscopy, and the effects of Q[8] on the stability, in vitro release rate and antibacterial activity of CPE were investigated. Results and Discussion The host–guest interaction between Q[8] and CPE Single-crystal

• structure analysis of CPE@Q[8] The clathrate mode and crystal parameters of CPE and Q[8] were determined on a Bruker D8 Venture single-crystal diffractometer and shown in Figure 2 and Supporting Information File 1, Table S1, respectively. Figure 2A shows the interaction of CPE and Q[8] results in an

• formation of a O–H···O hydrogen bond, in which the bond distance between O20 and O5 was 2.921 Å. It can be seen that the CPE molecule is distorted at the C51 atom and the bond angle between C53–C51–N34 was 103.30°, which makes the CPE molecule fixed and enter the cavity of Q[8]. Figure 2C shows the crystal

Selective sulfonylation and isonitrilation of para-quinone methides employing TosMIC as a source of sulfonyl group or isonitrile group

• Chuanhua Qu,
• Run Huang,
• Yong Li,
• Tong Liu,
• Yuan Chen and
• Guiting Song

Beilstein J. Org. Chem. 2021, 17, 2822–2831, doi:10.3762/bjoc.17.193

• mixture was stirred at 80 °C for 10 h and monitored by TLC. Then, the reaction mixture was concentrated under reduced pressure followed by column chromatography over silica gel using petroleum/EtOAc 10:1 to ≈5:1 as eluent to afford the desired product 4. Selected bioactive compounds. Crystal structure of

Photophysical, photostability, and ROS generation properties of new trifluoromethylated quinoline-phenol Schiff bases

• Inaiá O. Rocha,
• Yuri G. Kappenberg,
• Wilian C. Rosa,
• Clarissa P. Frizzo,
• Nilo Zanatta,
• Marcos A. P. Martins,
• Isadora Tisoco,
• Bernardo A. Iglesias and
• Helio G. Bonacorso

Beilstein J. Org. Chem. 2021, 17, 2799–2811, doi:10.3762/bjoc.17.191

• the present study. ORTEP diagram of the crystal structure of (E)-2-(((2-phenyl-4-(trifluoromethyl)quinolin-6-yl)imino)methyl)phenol (3ba, CCDC 2036933). (a) Displacement ellipsoids are drawn at the 50% probability level, and circles with arbitrary radius represent the hydrogen atoms; (b) side view

The PIFA-initiated oxidative cyclization of 2-(3-butenyl)quinazolin-4(3H)-ones – an efficient approach to 1-(hydroxymethyl)-2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-ones

• Alla I. Vaskevych,
• Nataliia O. Savinchuk,
• Ruslan I. Vaskevych,
• Eduard B. Rusanov,
• Oleksandr O. Grygorenko and
• Mykhailo V. Vovk

Beilstein J. Org. Chem. 2021, 17, 2787–2794, doi:10.3762/bjoc.17.189

• +, 217.0972; found, 217.0973. Pyrrolo[1,2-a]quinazoline derivatives – analogs of vasicinone alkaloids and their biological activity. X-ray crystal structure of compound 6f. Synthetic approaches to 2,3-dihydropyrrolo[1,2-a]quinazolin-5(1H)-one derivatives. Plausible mechanism for the formation of 6. Synthesis

Targeting active site residues and structural anchoring positions in terpene synthases

• Anwei Hou and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2021, 17, 2441–2449, doi:10.3762/bjoc.17.161

• functions as STPS and StTPS, the crystal structure of SdS [11] can be used as a template for SmTS1 to generate a Swiss homology model [20] (template pdb code 4OKM, Figure 3A). The active site residues of SdS make up a hydrophobic cavity (Figure 3B), that is structurally reflected in the SmTS1 model (Figure

• are also observed without enzyme. Swiss homology modelling of SmTS1. A) Superimposition of the SdS crystal structure (green) with the SmTS1 model (cyan). B) Active site residues of SdS. C) Active site residues of SmTS1. Active site residues that are smaller than in SdS are labelled in red. Green

Enantioselective PCCP Brønsted acid-catalyzed aminalization of aldehydes

• Martin Kamlar,
• Robert Reiberger,
• Martin Nigríni,
• Ivana Císařová and
• Jan Veselý

Beilstein J. Org. Chem. 2021, 17, 2433–2440, doi:10.3762/bjoc.17.160

• strategies employing chiral Brønsted acid catalysis. X-ray single-crystal structure of aminal 3l with the displacement ellipsoids drawn at the 30% probability level. The substrate scope of the aminalization reaction for different aldehydes. aAfter recrystallization; breaction run at 1 mmol scale. The

Efficient synthesis of polyfunctionalized carbazoles and pyrrolo[3,4-c]carbazoles via domino Diels–Alder reaction

• Ren-Jie Fang,
• Chen Yan,
• Jing Sun,
• Ying Han and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2021, 17, 2425–2432, doi:10.3762/bjoc.17.159

• crystal structure of compound 4g was determined by X-ray diffraction (Figure 4). It can be seen that the ring of pyrrolo[3,4-c]carbazole exists in a slightly twisted plane. The dihedral angles of the phenyl and the benzoyl group to the central benzene ring are 72.018° and 88.402°. To further expand the

• (CCDC 2099074), 3b (CCDC 2099075), and 4g (CCDC 2099076) have been deposited at the Cambridge Crystallographic Database Centre (http://www.ccdc.cam.ac.uk). Representative bioactive carbazole derivatives. Single crystal structure of the isomer 3a. Single crystal structure of the isomer 3b. Single crystal

• structure of the isomer 4g. Synthesis of tetrahydropyrrolo[3,4-c]carbazoles 3a and 3b. Proposed domino reaction mechanism for the formation of carbazoles 6. Synthesis of pyrrolo[3,4-c]carbazoles 4a–l.a Synthesis of the polysubstituted carbazoles 6a–n.a Supporting Information Supporting Information File 344

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

• . Crystal structure of compound 3. Colour codes: carbon = grey, mitrogen = blue, oxygen = red, hydrogen = white. Crystal structure of 1H-1,2,3-triazole compound 5c: Colour codes: carbon = grey, nitrogen = blue, oxygen = red, fluorine = yellow, hydrogen = white. Crystal structures of compound 7b. Colour

Constrained thermoresponsive polymers – new insights into fundamentals and applications

• Patricia Flemming,
• Alexander S. Münch,
• Andreas Fery and
• Petra Uhlmann

Beilstein J. Org. Chem. 2021, 17, 2123–2163, doi:10.3762/bjoc.17.138

Development of N-F fluorinating agents and their fluorinations: Historical perspective

• Teruo Umemoto,
• Yuhao Yang and
• Gerald B. Hammond

Beilstein J. Org. Chem. 2021, 17, 1752–1813, doi:10.3762/bjoc.17.123

Chemical approaches to discover the full potential of peptide nucleic acids in biomedical applications

• Nikita Brodyagin,
• Martins Katkevics,
• Venubabu Kotikam,
• Christopher A. Ryan and
• Eriks Rozners

Beilstein J. Org. Chem. 2021, 17, 1641–1688, doi:10.3762/bjoc.17.116

• conformation (C2′-endo), base pair inclination, and helical rise resembled B-DNA [39]. The first X-ray crystal structure of a PNA–DNA–PNA triplex revealed a previously unknown helix with a wide diameter of ≈26 Å (compared to 20 Å for A-form duplex) and a wide and deep major groove (Figure 3), given the name "P

• stabilizing interactions are better aligned. The crystal structure of a self-complementary PNA–PNA duplex was very similar to the P-form helix showing a wide helix (28 Å diameter) with a very large pitch of ≈18 base pairs per turn, compared to 10 and 11 base pairs per turn for DNA and RNA, respectively, and a

• nucleobase stacking pattern similar to that of the A-form RNA [43]. Another crystal structure of a partially self-complementary PNA–PNA duplex revealed PNA’s ability to combine the P-form Watson–Crick duplex with higher order structural features, such as reversed Hoogsteen base pairing, interstrand

Breaking paracyclophane: the unexpected formation of non-symmetric disubstituted nitro[2.2]metaparacyclophanes

• Suraj Patel,
• Tyson N. Dais,
• Paul G. Plieger and
• Gareth J. Rowlands

Beilstein J. Org. Chem. 2021, 17, 1518–1526, doi:10.3762/bjoc.17.109

• cyclophane (6, Figure 3). The former is, to the best of our knowledge, the first example of a crystal structure of a non-symmetric [2.2]metaparacyclophane. The structure of the disubstituted [2.2]metaparacyclophane (5) is analogous to that of the unsubstituted [2.2]metaparacyclophane (3). The angle between

• –208 °C; Rf: 0.25 (30% EtOAc, 70% hexane). The common [2.2]cyclophanes. Crystal structure of 5. Ellipsoids are drawn at a 50% probability level [63][64][65][66]. Crystal structure of 6. Ellipsoids are drawn at a 50% probability level [63]. Crystal structure of 14. Ellipsoids are drawn at a 50

• % probability level [63]. Crystal structure of 15. Ellipsoids are drawn at a 50% probability level [63]. Possible origin of stereoselectivity. Nitration of [2.2]paracyclophane (1) and the synthesis of 4-hydroxy-5-nitro[2.2]metaparacyclophane (5) and the cyclohexadienone cyclophane 6 (average yield from more

A straightforward conversion of 1,4-quinones into polycyclic pyrazoles via [3 + 2]-cycloaddition with fluorinated nitrile imines

• Greta Utecht-Jarzyńska,
• Karolina Nagła,
• Grzegorz Mlostoń,
• Heinz Heimgartner,
• Marcin Palusiak and
• Marcin Jasiński

Beilstein J. Org. Chem. 2021, 17, 1509–1517, doi:10.3762/bjoc.17.108

• nitrile imine 7a generated from 8a. Supporting Information Supporting Information File 246: General information and experimental data of all isolated products, details of the crystal structure determination, and copies of 1H and 13C NMR spectra for all products. Funding Financial support by the

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

• stereostructures of compound cis-14aa and trans-14aa. Crystal structure of the tosylate 21. The displacement ellipsoids are drawn at the 30% probability level. Reported strategies for the synthesis of tetralin-2-ol ring systems. Designed cascade reactions to 4-substituted tetralin-2-ols. The documented synthesis

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

• pavettamine, in order to obtain the enantiomer. The final deprotection step proved particularly efficient, with two protecting groups being removed simultaneously to unveil the desired target. Structure of pavettamine 1 and its enantiomer 2. Crystal structure of compound 9. Single crystal X-ray structure of

• %; f) 95% TFA, 2.5% H2O, 2.5% triisopropylamine, rt, overnight, quantitative yield. Supporting Information Detailed experimental methods and NMR spectra for all compounds prepared and crystal structure data for compounds 4 and 9 is available as supporting information. Supporting Information File 178

Analogs of the carotane antibiotic fulvoferruginin from submerged cultures of a Thai Marasmius sp.

• Birthe Sandargo,
• Leon Kaysan,
• Rémy B. Teponno,
• Christian Richter,
• Benjarong Thongbai,
• Frank Surup and
• Marc Stadler

Beilstein J. Org. Chem. 2021, 17, 1385–1391, doi:10.3762/bjoc.17.97

• of potential pharmaceutical interest. Klein et al. obtained a crystal structure of fulvoferruginin (1) [8], as did Huneck et al. for hercynolactone [9], verifying their relative configuration. Huo et al. have further confirmed the absolute configuration of compound 1 by utilizing the CD exciton

Structural effects of meso-halogenation on porphyrins

• Keith J. Flanagan,
• Maximilian Paradiz Dominguez,
• Zoi Melissari,
• Hans-Georg Eckhardt,
• René M. Williams,
• Dáire Gibbons,
• Caroline Prior,
• Gemma M. Locke,
• Alina Meindl,
• Aoife A. Ryan and
• Mathias O. Senge

Beilstein J. Org. Chem. 2021, 17, 1149–1170, doi:10.3762/bjoc.17.88

• the crystallographic structural characteristics of 13 mesox-halo-substituted porphyrins. Data obtained from the CSD crystal structure database accompanied by data obtained from our group are discussed [25]. Furthermore, any general structural motif that appears consistent among the mesox-halo

• further exploration of the ground state geometries and concurrently frontier molecular orbitals (FMOs) and sigma-holes have been displayed. Results and Discussion Crystal structure analyses 5-Halo-substituted porphyrins First, considering the 5-halo-10,20-diphenylporphyrins (Figure 1); in this series, we

• the tolyl group breaks the high-ordered packing previously observed. The chlorine atom does not appear to have any substantial interactions present in the crystal structure. The structure of compound 5 only differs from the structure of compound 1 by the addition of a phenyl moiety. In this structure

Synthesis of functionalized imidazo[4,5-e]thiazolo[3,2-b]triazines by condensation of imidazo[4,5-e]triazinethiones with DMAD or DEAD and rearrangement to imidazo[4,5-e]thiazolo[2,3-c]triazines

• Alexei N. Izmest’ev,
• Dmitry B. Vinogradov,
• Natalya G. Kolotyrkina,
• Angelina N. Kravchenko and
• Galina A. Gazieva

Beilstein J. Org. Chem. 2021, 17, 1141–1148, doi:10.3762/bjoc.17.87

• further transformations in basic media, are continuing. Biologically active compounds having thiazolidin-4-one and thiazolo-1,2,4-triazine units. 1H NMR spectra of compounds 4h and 5h in DMSO-d6 in the region of 3.5–8.8 ppm. X-ray crystal structure of compound 5i. Regioselectivity of the cyclization of 3

• conditionsa. Supporting Information Supporting Information File 167: Experimental and analytical data. Supporting Information File 168: CIF file for compound 5i. Acknowledgements Crystal structure determination was performed in the Department of Structural Studies of the N. D. Zelinsky Institute of Organic

Beyond ribose and phosphate: Selected nucleic acid modifications for structure–function investigations and therapeutic applications

• Christopher Liczner,
• Kieran Duke,
• Gabrielle Juneau,
• Martin Egli and
• Christopher J. Wilds

Beilstein J. Org. Chem. 2021, 17, 908–931, doi:10.3762/bjoc.17.76

• nuclease-resistant probes for studying RNA–protein interactions [70]. To better elucidate the structural features of 3'-NP DNA responsible for this enhanced selective binding and stability, the Egli group determined the crystal structure of the fully modified 3'-NP DNA duplex with the sequence 5'-d

• necessary protecting groups are present on the nucleobase and sugar moieties [76][77]. Unlike the phosphodiester linkage of natural DNA, the AM1 modification is an example of a non-ionic backbone. The crystal structure of a 13-mer RNA duplex with a single central AM1 modification revealed that this

• increase in silencing activity for AM1-modified siRNAs with amide linkages at specific sites [75]. Structural insight into this observation was obtained using the crystal structure of the complex between Bacillus halodurans RNase H and the r(GAC ACC UGA UAM1UC) - d(GAA TCA GGT GTC) hybrid duplex [73

α,γ-Dioxygenated amides via tandem Brook rearrangement/radical oxygenation reactions and their application to syntheses of γ-lactams

• Mikhail K. Klychnikov,
• Radek Pohl,
• Ivana Císařová and
• Ullrich Jahn

Beilstein J. Org. Chem. 2021, 17, 688–704, doi:10.3762/bjoc.17.58

• /EtOAc 10:1 to 1:1) to give keto lactam 13. Selected alkaloids containing the pyrrolidone motif. X-ray crystal structure of the major (2R,4S)-alkoxyamine hydrochloride derived from 9j. Displacement ellipsoids at 30% probability level and a disordered CHCl3 solvent molecule is not shown for clarity. X-ray

• crystal structure of the minor cis-diastereomers of the keto lactam 13j (left) and the hydroxy lactam 12k (right). Displacement ellipsoids are drawn at the 30% probability level. A) Classical γ-lactam synthesis by atom transfer radical cyclizations; B) previously developed tandem epoxide opening/Brook