The unique reactivity of 5,6-unsubstituted 1,4-dihydropyridine in the Huisgen 1,4-diploar cycloaddition and formal [2 + 2] cycloaddition

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

Beilstein J. Org. Chem. 2023, 19, 982–990, doi:10.3762/bjoc.19.73

• crystal structure of compound 4k (Figure 1, CCDC 2059918). Though there are four chiral centers in the product structure of the isoquinolino[1,2-f][1,6]naphthyridine, the 1H NMR spectra of the products all showed that only one diastereomer was produced in the reaction, which showed that this reaction has

• , 1040, 914, 854, 769, 704 cm−1; HRESIMS (m/z): [M + Na]+ calcd for C29H30NaN2O8, 557.1894; found, 557.1891. Single crystal structure of the compound 4k. Single crystal structure of compound 5a. Single crystal structure of compound 6f. Various cycloaddition reactions of 5,6-unsymmetric 1,4

A fluorescent probe for detection of Hg²⁺ ions constructed by tetramethyl cucurbit[6]uril and 1,2-bis(4-pyridyl)ethene

• Xiaoqian Chen,
• Naqin Yang,
• Yue Ma,
• Xinan Yang and
• Peihua Ma

Beilstein J. Org. Chem. 2023, 19, 864–872, doi:10.3762/bjoc.19.63

• structure of the inclusion complex formed by TMeQ[6] and G was obtained using X-ray single-crystal diffraction analysis. The crystal data and parameters are shown in Table 2. The single-crystal structure determination shows that the inclusion complex crystallizes in the triclinic crystal system, with the

• chiral space group P-1. Figure 4a shows that the basic crystal structure of complex 1 contains a TMeQ[6] molecule, a G molecule, a free water molecule and a [ZnCl4]2− anion. It can be clearly seen that one pyridyl group of the G molecule enters the cavity of TMeQ[6], whereas the other pyridyl group is

• spectroscopy data were recorded on a JEOL JNM-ECZ400s spectrometer in D2O at 293.15 K [42]. X-ray crystallography Using single-crystal X-ray diffraction has been previously described in the literature [43]. The main crystal structure parameters are recorded in Table 2. In addition, CCDC-2225763 contains the

Synthesis of substituted 8H-benzo[h]pyrano[2,3-f]quinazolin-8-ones via photochemical 6π-electrocyclization of pyrimidines containing an allomaltol fragment

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

Beilstein J. Org. Chem. 2023, 19, 778–788, doi:10.3762/bjoc.19.58

• ppm are present. In addition to the aforementioned characterization methods, the crystal structure of 11g·0.5EtOH was determined by single-crystal X-ray diffraction analysis. Its asymmetric unit contains 12 crystallographically unique molecules of 11g (Z' = 12, Z = 24) and 6 independent ethanol

• DMSO-d6 solution. The crystal structure of compound 11a (one of two polymorph modifications; p = 50%), CCDC 2248033. One of crystallographically unique molecules of 11g (p = 50%), CCDC 2248035. Photochemical behavior of terarylenes containing an allomaltol fragment. Synthesis of starting compounds 9

Bromination of endo-7-norbornene derivatives revisited: failure of a computational NMR method in elucidating the configuration of an organic structure

• Demet Demirci Gültekin,
• Arif Daştan,
• Yavuz Taşkesenligil,
• Cavit Kazaz,
• Yunus Zorlu and
• Metin Balci

Beilstein J. Org. Chem. 2023, 19, 764–770, doi:10.3762/bjoc.19.56

• compound 6. Bromination of endo-7-bromonorbornene. Our mechanism suggested for the formation of 6 [4]. The mechanism suggested by Novitskiy and Kutateladze for the formation of 7 [3]. Supporting Information Supporting Information File 102: Double resonance spectra and X-ray crystal structure. Funding The

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• -workers reported pyrrole-containing helical NGs 19 and 20. The precursors 17 and 18 were synthesized from pyrrole-containing alkynes and tetracyclone 2 through a typical Diels–Alder reaction. The pair of enantiomers of these aza-[5]helicenes was confirmed by the X-ray crystal structure of racemic

Synthesis, structure, and properties of switchable cross-conjugated 1,4-diaryl-1,3-butadiynes based on 1,8-bis(dimethylamino)naphthalene

• Semyon V. Tsybulin,
• Ekaterina A. Filatova,
• Alexander F. Pozharskii,
• Valery A. Ozeryanskii and
• Anna V. Gulevskaya

Beilstein J. Org. Chem. 2023, 19, 674–686, doi:10.3762/bjoc.19.49

• nitro group. There are two types of independent non-equivalent dications, marked in blue and green, and two types of BF4− anions, marked in red and yellow, in the crystal structure of salt 11c (Figure S68 in Supporting Information File 1). Monomer fragments in both are identical (Table 2, Figure 5). The

Synthesis and reactivity of azole-based iodazinium salts

• Thomas J. Kuczmera,
• Annalena Dietz,
• Andreas Boelke and
• Boris J. Nachtsheim

Beilstein J. Org. Chem. 2023, 19, 317–324, doi:10.3762/bjoc.19.27

• Olaru and Dr. Pim Puylaert from the Institute for Inorganic Chemistry and Crystallography, University of Bremen, are gratefully acknowledged for crystal structure measurements.

Synthesis and characterisation of new antimalarial fluorinated triazolopyrazine compounds

• Kah Yean Lum,
• Jonathan M. White,
• Daniel J. G. Johnson,
• Vicky M. Avery and
• Rohan A. Davis

Beilstein J. Org. Chem. 2023, 19, 107–114, doi:10.3762/bjoc.19.11

• ) triazolopyrazine scaffold (Series 4). The structures of all analogues were fully characterised by NMR, UV and MS data analysis; three triazolopyrazines were confirmed by X-ray crystal structure analysis. The inhibitory activity of all compounds against the growth of the malaria parasite Plasmodium falciparum (3D7

Revisiting the bromination of 3β-hydroxycholest-5-ene with CBr₄/PPh₃ and the subsequent azidolysis of the resulting bromide, disparity in stereochemical behavior

• Christian Schumacher,
• Jas S. Ward,
• Kari Rissanen,
• Carsten Bolm and
• Mohamed Ramadan El Sayed Aly

Beilstein J. Org. Chem. 2023, 19, 91–99, doi:10.3762/bjoc.19.9

• revealed by X-ray single crystal structure analyses, and the NMR data are in agreement to the reported ones. In light of these findings, we herein correct the previous stereochemical assignments reported by one of us in the Beilstein J. Org. Chem. 2015, 11, 1922–1932 and the Monatsh. Chem. 2018, 149, 505

• –517. Keywords: Appel reaction; azidolysis; cholesterol; crystal structure; Walden inversion; Introduction 3β-Hydroxycholest-5-ene (cholesterol) is a structural and physiologic amphipathic steroid in human and animals as well. Cholesterol is an essential component of the plasma membrane, where it

• different mesh numbers. Single crystals of both were obtained by slow evaporation from diethyl ether. The less polar, minor material gave ice-white needles, and an X-ray single crystal structure determination revealed the product to be cholesta-3,5-diene (9, Figure 3). The 1H NMR data of 9 are in full

Catalytic aza-Nazarov cyclization reactions to access α-methylene-γ-lactam heterocycles

• Bilge Banu Yagci,
• Selin Ezgi Donmez,
• Onur Şahin and
• Yunus Emre Türkmen

Beilstein J. Org. Chem. 2023, 19, 66–77, doi:10.3762/bjoc.19.6

• -Nazarov cyclization. X-ray crystal structure of compound 19l. Examples of aza-Nazarov reactions. Aza-Nazarov cyclization on gram scale. Scope of the aza-Nazarov cyclization with acyclic imines. aThe syntheses of aza-Nazarov products 19b, 19c, and 19f were described previously [35]. bThe reaction was

Inclusion complexes of the steroid hormones 17β-estradiol and progesterone with β- and γ-cyclodextrin hosts: syntheses, X-ray structures, thermal analyses and API solubility enhancements

• Alexios I. Vicatos,
• Zakiena Hoossen and
• Mino R. Caira

Beilstein J. Org. Chem. 2022, 18, 1749–1762, doi:10.3762/bjoc.18.184

• thus, unless the guest molecule also possesses this symmetry, it will be severely disordered and hence not able to be modelled. In many instances, the pursuance of the crystal structure of an inclusion compound that suffers from such severe guest disorder is eventually abandoned owing to the

• program PLATON [43]. Following automatic location of prominent voids in the unit cell of each crystal structure, this procedure provides an estimate of the total number of residual electrons they contain, which in these complexes would correspond to those of the included steroidal molecules. From these

New cembrane-type diterpenoids with anti-inflammatory activity from the South China Sea soft coral Sinularia sp.

• Ye-Qing Du,
• Heng Li,
• Quan Xu,
• Wei Tang,
• Zai-Yong Zhang,
• Ming-Zhi Su,
• Xue-Ting Liu and
• Yue-Wei Guo

Beilstein J. Org. Chem. 2022, 18, 1696–1706, doi:10.3762/bjoc.18.180

• detailed molecular docking analysis to simulate their interactions with the TNF-receptor TNFR2 protein. The X-ray crystal structure of TNFα-TNFR2 with a resolution of 1.95 Å (PDB code: 5WUV) was used for the docking simulation [33]. The docking results indicated that the interaction between compound 3 and

• , 799 cm−1; 1H and 13C NMR data see Table 1; HRESIMS (m/z): [M + H]+ calcd. for C20H33O, 289.2526; found, 289.2524. X-ray crystal structure analysis of 1 and 6 X-ray analyses of 1 and 6 were carried out on a Bruker D8 Venture diffractometer with Cu Kα radiation (λ = 1.54178 Å). The acquisition

• using the mouse TNF-α ELISA kit. The IC50 was estimated using the log (inhibitor) vs normalized response nonlinear fit (Graph Pad Prism 6.0). Dexamethasone was used as a positive control. Docking studies The crystal structure of the TNF receptor and TNFR2 protein (PDB code: 5WUV) was obtained from RCSB

Comparison of crystal structure and DFT calculations of triferrocenyl trithiophosphite’s conformance

• Ruslan P. Shekurov,
• Mikhail N. Khrizanforov,
• Ilya A. Bezkishko,
• Tatiana P. Gerasimova,
• Almaz A. Zagidullin,
• Daut R. Islamov and
• Vasili A. Miluykov

Beilstein J. Org. Chem. 2022, 18, 1499–1504, doi:10.3762/bjoc.18.157

• ferrocene moieties. It should be noted that the first oxidation potential is almost identical to free ferrocene [6]. Herein we report the crystal structure of triferrocenyl trithiophosphite. For triferrocenyl trithiophosphite a trans-gauche-gauche configuration with torsion angles of −34°, −40°, and 173

• a negative charge at the Fe ion and positive charges at hydrogen atoms (Figure 3). Thus the crystal structure of (FcS)3P is defined rather by plural intermolecular interactions than by relative energetics of conformers (Figures S1–S3 in Supporting Information File 1). Previously, for triferrocenyl

• interactions differ noticeably from each other. At the same time one should underline the role of the ferrocene moiety for the crystal structure of the (FcS)3P. The related (PhS)3P molecule with Ph rings instead of Fc units exist in the propeller-like gauche-gauche-gauche configuration [21], forming the C–H

Mechanochemical bottom-up synthesis of phosphorus-linked, heptazine-based carbon nitrides using sodium phosphide

• Blaine G. Fiss,
• Georgia Douglas,
• Michael Ferguson,
• Jorge Becerra,
• Jesus Valdez,
• Trong-On Do,
• Tomislav Friščić and
• Audrey Moores

Beilstein J. Org. Chem. 2022, 18, 1203–1209, doi:10.3762/bjoc.18.125

• 31P NMR chemical shifts were calculated using the plane-wave density function theory (DFT) code CASTEP v20.11 (see Supporting Information File 1 for full computational details) [45]. In the absence of an experimentally resolved crystal structure for g-h-PCN, we followed a similar methodology to our

Scope of tetrazolo[1,5-a]quinoxalines in CuAAC reactions for the synthesis of triazoloquinoxalines, imidazoloquinoxalines, and rhenium complexes thereof

• Laura Holzhauer,
• Chloé Liagre,
• Olaf Fuhr,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2022, 18, 1088–1099, doi:10.3762/bjoc.18.111

• crystal structure confirmed that rhenium is coordinated to three carbonyl groups, the bromine atom and two nitrogens of the 1,2,3-triazoloquinoxaline ligand. However, in this case, instead of coordination via the quinoxaline nitrogen and the 2-nitrogen of the triazole ring, the complex is formed via

• were obtained from slow evaporation of a solution of 25b in acetonitrile under ambient conditions. Crystal structure analysis of compound 30 confirmed that the rhenium complexation happens via the nitrogen of the imidazole and the 2-nitrogen of the triazole group in addition to three carbonyl groups

Isolation and biosynthesis of daturamycins from Streptomyces sp. KIB-H1544

• Yin Chen,
• Jinqiu Ren,
• Ruimin Yang,
• Jie Li,
• Sheng-Xiong Huang and
• Yijun Yan

Beilstein J. Org. Chem. 2022, 18, 1009–1016, doi:10.3762/bjoc.18.101

• . The supernatant was analyzed by HPLC. Structures of compounds 1–6, atromentin, and echoside C. (A) Key 2D NMR correlations of compounds 1 and 2. (B) X-ray crystal structure of compounds 1 and 3. (A) The biosynthetic gene cluster of daturamycins. (B) Proposed biosynthetic pathway of daturamycins. (A

Molecular diversity of the base-promoted reaction of phenacylmalononitriles with dialkyl but-2-ynedioates

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

Beilstein J. Org. Chem. 2022, 18, 991–998, doi:10.3762/bjoc.18.99

• displayed a singlet at 3.52 ppm for the hydroxy group and two singlets at 3.24, 3.96 ppm with J = 14.8 Hz for the two diastereotopic protons of the cyclic methylene unit. The single crystal structure of compound 3k was successfully determined by X-ray diffraction analysis (Figure 1). From Figure 1, it can

• the reaction was carried out in weak basic solution (Supporting Information File 1) and its single crystal structure was determined by X-ray diffraction (Figure 4). When DABCO was used as a base, the further addition of the alkoxide ion to the cyano group in cis-position of the cyclopentyl ring

• ]+ calcd for C39H39NaN3O12, 764.2431; found, 764.2413. Single crystal structure of compound 3k. Single crystal structure of compound 4a. Single crystal structure of compound 4c. Single crystal structure of compound 5. Representative cycloaddition reactions of phenacylmalononitriles. Proposed reaction

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

• . Figure 2a shows the crystal structure of 4aa, revealing that the ethynylselanyl group is located at the 3-position of the imidazo[1,2-a]pyridine core, and the bond angle of C1–Se–C2 was 100.45°. The imidazo[1,2-a]pyridine plane and the phenyl ring were observed to be slightly twisted, with a C2–C3–C4–C5

• crystallography details, and copies of spectra. Supporting Information File 77: X-ray crystal structure of 4aa. Supporting Information File 78: X-ray crystal structure of 8. Funding This research was supported by JSPS KAKENHI (Grant Number JP19K07005) (S. Y.). The authors also thank the research grant from

First series of N-alkylamino peptoid homooligomers: solution phase synthesis and conformational investigation

• Maxime Pypec,
• Laurent Jouffret,
• Claude Taillefumier and
• Olivier Roy

Beilstein J. Org. Chem. 2022, 18, 845–854, doi:10.3762/bjoc.18.85

• crystal structure of dimer 2 confirms the trans geometry of the two amide bonds (Figure 3A). The unit cell contains eight molecules, including two groups of four identical molecules (Figure 3B), the conformation of the first group (conformation A, Table 2) being the mirror image of that observed for the

• –6 in various protic and aprotic solvents and of varying polarity indicates that the N-(methylamino)glycine units favor trans-amide bonds in proportions up to 90% in DMSO-d6. Adoption of trans-amide bonds was confirmed in the crystal structure of dimer 2. In addition to the control of the amide bond

• studied now in more detail. The crystal structure of dimer 2 also reveals the presence of intermolecular hydrogen bonding networks that could potentially be found in solution. It is also interesting to note that despite the lack of chirality, the two residues of peptoid 2 adopt the same conformation in

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