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

• isomerization to 2-Me-GPP and then to (R)-2-Me-LPP. Conclusively, these findings confirm Cane’s mechanistic proposal [23], while the observed conformation of 2FGPP in the crystal structure of 2MIBS may not represent the required conformation for 2-Me-GPP for the production of 1. A) Active site of 2MIBS with the

• bound substrate surrogate 2FGPP (generated with Pymol from the crystal structure, PDB code: 3V1X). B) Isomerization of 2-Me-GPP to (S)-2-Me-LPP, the hypothetical enantiomer expected for 2-Me-GPP in the same conformation as observed for 2FGPP. Structures of 2MIBS side products and spontaneous degradation

Thiophene/selenophene-based S-shaped double helicenes: regioselective synthesis and structures

• Mengjie Wang,
• Lanping Dang,
• Wan Xu,
• Zhiying Ma,
• Liuliu Shao,
• Guangxia Wang,
• Chunli Li and
• Hua Wang

Beilstein J. Org. Chem. 2022, 18, 809–817, doi:10.3762/bjoc.18.81

• packing structures of these compounds. Spectroscopic results and our previous work showed that the combination of molecular structure change and heteroatom replacement from S to Se could precisely modulate molecular energy levels. Keywords: crystal structure; double helicene; regioselective synthesis

Copper-catalyzed multicomponent reactions for the efficient synthesis of diverse spirotetrahydrocarbazoles

• Shao-Cong Zhan,
• Ren-Jie Fang,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 796–808, doi:10.3762/bjoc.18.80

• smoothly to produce the corresponding products 5h–k in high yields with high diastereoselectivity. The single crystal structure of compound 5b (CCDC 2109580) clearly indicated that the two aryl groups are in cis-position. When we did not add the dienophiles to this system, 4-methylbenzaldehyde could react

Structural basis for endoperoxide-forming oxygenases

• Takahiro Mori and
• Ikuro Abe

Beilstein J. Org. Chem. 2022, 18, 707–721, doi:10.3762/bjoc.18.71

• role in the cyclooxygenase reaction. In the crystal structure, the catalytic Tyr385 residue is located at the interface between the active regions of the peroxidase-site and cyclooxygenase-site (Figure 2) [46][47][48][49][50][51]. Furthermore, the C13 of AA is located near the catalytic residue Tyr385

• in the crystal structure, indicating that a tyrosyl radical abstracts the pro-S hydrogen atom from C13 of AA (Figure 2B and 2C) [48][52][53]. Mechanism of the cyclooxygenase reaction The enzyme reaction is initiated upon Tyr385 activation by the oxyferryl heme cation radical, which is generated

• the partially closed conformation, the substrate binding mode in the crystal structure apparently shows a different stage of the reaction. The conformational changes of the loops, especially the flipping of Glu208, would contribute to alterations of the binding mode of the substrate and the long-lived

Tri(n-butyl)phosphine-promoted domino reaction for the efficient construction of spiro[cyclohexane-1,3'-indolines] and spiro[indoline-3,2'-furan-3',3''-indolines]

• Hui Zheng,
• Ying Han,
• Jing Sun and
• Chao-Guo Yan

Beilstein J. Org. Chem. 2022, 18, 669–679, doi:10.3762/bjoc.18.68

• are summarized in Table 3. Because there are three chiral carbon atoms in the molecule, several diastereoisomers can be formed in the reaction. The spiro[cyclohexane-1,3'-indolines] 5a–e were obtained in moderate to good yields. The single crystal structure of compound 5a was determined by X-ray

• of electron-donating methyl groups in the isatins gave higher yields than electron-withdrawing groups such as chloro and fluoro substituents. The structures of the spiro compounds 8a–m were fully characterized by their IR, HRMS, 1H and 13C NMR spectra. In addition, the single crystal structure of

• , 624.1666; found, 624.1660. Single crystal structure of compound 3l. Single crystal structure of compound 3s. Single crystal structure of compound 3f’. Single crystal structure of compound 5a. Single crystal struture of compound 8a. Proposed reaction mechanism for the compounds 3 and 5. Proposed mechanism

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

• synthesized products were confirmed by X-ray diffraction. 1H NMR monitoring of the photoreaction of compound 12a under UV irradiation (365 nm) in DMSO-d6 solution. The X-ray crystal structure of compound 15a. The X-ray crystal structure of compound 15m. The X-ray crystal structure of compound 18

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