Unprecedented visible light-initiated topochemical [2 + 2] cycloaddition in a functionalized bimane dye

• Metodej Dvoracek,
• Brendan Twamley,
• Mathias O. Senge and
• Mikhail A. Filatov

Beilstein J. Org. Chem. 2025, 21, 500–509, doi:10.3762/bjoc.21.37

• in P-1 and the molecules pack in a different arrangement, where the double bonds are neither coplanar nor parallel. This product was obtained from propan-2-ol, which may have influenced the crystallization kinetics. The reactive packing mode of Cl2B is enhanced by the hydrogen bonding where the ester

Organocatalytic kinetic resolution of 1,5-dicarbonyl compounds through a retro-Michael reaction

• James Guevara-Pulido,
• Fernando González-Pérez,
• José M. Andrés and
• Rafael Pedrosa

Beilstein J. Org. Chem. 2025, 21, 473–482, doi:10.3762/bjoc.21.34

• separated using chiral resolution. This involves separating the two enantiomers by converting the racemic mixture into a pair of diastereoisomers with the help of a chiral compound. The resulting diastereoisomers can be separated based on their physical properties using crystallization, distillation, or

Beyond symmetric self-assembly and effective molarity: unlocking functional enzyme mimics with robust organic cages

• Keith G. Andrews

Beilstein J. Org. Chem. 2025, 21, 421–443, doi:10.3762/bjoc.21.30

• , although the synthesis and characterization (particularly crystallization) of low-symmetry structures remains challenging [227][231][232]. Likewise, COFs hosting chiral organocatalysts are known (Figure 6B) [226][233]. Frameworks are well-suited to hosting opposing reactive functionalities (e.g., acids and

• therefore can be subjected to automated and high-throughput crystallization studies and, with Szczypiński, Slater, Cooper and co-workers, we were able to isolate all five calculated lowest-energy conformers of cage 1 in the solid state (see crystal cavity heights marked under conformers in Figure 9A) [40

Synthesis of new condensed naphthoquinone, pyran and pyrimidine furancarboxylates

• Kirill A. Gomonov,
• Vasilii V. Pelipko,
• Igor A. Litvinov,
• Ilya A. Pilipenko,
• Anna M. Stepanova,
• Nikolai A. Lapatin,
• Ruslan I. Baichurin and
• Sergei V. Makarenko

Beilstein J. Org. Chem. 2025, 21, 340–347, doi:10.3762/bjoc.21.24

• structural analysis were obtained by crystallization from MeOH (5a), EtOH (5b), or DMFA (6b, 6c, and 7a). Single crystals of a suitable size were glued to the top of a glass fiber in a random orientation. The preliminary unit cell parameters were determined using three runs at different ω angle positions

Synthesis and characterizations of highly luminescent 5-isopropoxybenzo[rst]pentaphene

• Islam S. Marae,
• Jingyun Tan,
• Rengo Yoshioka,
• Zakaria Ziadi,
• Eugene Khaskin,
• Serhii Vasylevskyi,
• Ryota Kabe,
• Xiushang Xu and
• Akimitsu Narita

Beilstein J. Org. Chem. 2025, 21, 270–276, doi:10.3762/bjoc.21.19

• variety in crystallization, including differences in shape, length, and width, b) rod-like crystals with lengths of hundreds of nanometers, c) rod-like crystals with lengths of hundreds of micrometers, and d) longer wire. Synthesis of BPP-OiPr 3 and BPP-dione 4. Reaction conditions for the synthesis of

Synthesis, structure and π-expansion of tris(4,5-dehydro-2,3:6,7-dibenzotropone)

• Yongming Xiong,
• Xue Lin Ma,
• Shilong Su and
• Qian Miao

Beilstein J. Org. Chem. 2025, 21, 1–7, doi:10.3762/bjoc.21.1

• synthesis of 1 using a Ni-mediated Yamamoto coupling reaction and the simultaneous crystallization of its two different conformers from the same solution. Expanding the π-skeleton of 1 through a Barton–Kellogg reaction followed by a subsequent Scholl reaction resulted in a new polycyclic arene (3 in Figure

• presents an apparently twisted central benzene ring with large torsion angles: C1–C2–C3–C4 at 19.5°, C3–C4–C5–C6 at 21.8°, and C5–C6–C1–C2 at 21.5°. The crystallization of the two conformers of 1 in different polymorphs suggests the flexibility of its polycyclic skeleton, with both its [5]helicenoid and

• HOMO level (−5.47 eV). Conclusion In conclusion, we developed a new synthesis of tris(4,5-dehydro-2,3:6,7-dibenzotropone) (1) through a Ni-mediated Yamamoto coupling reaction. Upon crystallization from the same solution in hexane, this compound yielded colorless and yellow crystal polymorphs, adopting

Efficient synthesis of fluorinated triphenylenes with enhanced arene–perfluoroarene interactions in columnar mesophases

• Yang Chen,
• Jiao He,
• Hang Lin,
• Hai-Feng Wang,
• Ping Hu,
• Bi-Qin Wang,
• Ke-Qing Zhao and
• Bertrand Donnio

Beilstein J. Org. Chem. 2024, 20, 3263–3273, doi:10.3762/bjoc.20.270

• POM observations and their room temperature behaviors (no crystallization is observed even at low temperature, except for F12). Compounds with shorter alkyl chains, F3, F4, and F5, possess almost the same clearing temperatures near 190 °C, whereas from F6 to F12, the clearing temperature gradually

Hypervalent iodine-mediated intramolecular alkene halocyclisation

• Charu Bansal,
• Oliver Ruggles,
• Albert C. Rowett and
• Alastair J. J. Lennox

Beilstein J. Org. Chem. 2024, 20, 3113–3133, doi:10.3762/bjoc.20.258

• palladium catalyst. Aminofluorination of alkenes in the synthesis of enantiomerically pure β-fluorinated piperidines. PMB = para-methoxybenzene, athe ee value was determined after Cbz group was replaced with tosyl group, bthe value in brackets corresponds to the ee value after crystallization. PG

C–C Coupling in sterically demanding porphyrin environments

• Liam Cribbin,
• Brendan Twamley,
• Nicolae Buga,
• John E. O’ Brien,
• Raphael Bühler,
• Roland A. Fischer and
• Mathias O. Senge

Beilstein J. Org. Chem. 2024, 20, 2784–2798, doi:10.3762/bjoc.20.234

• . This may also be due to crystal packing effects or the Ni(II) metal center [56][57], as well as the crystallization solvent [43]. It is not possible to ascertain whether steric effects of the β-ethyl and the anthracenyl carbons are causing the ruffling observed, and a full statistical model of a large

• from the Ni(II)...Ni(II) vector approximately perpendicular to the metals through the c-axis. Upon co-crystallization of borylated porphyrin 46 and bis(pinacolato)diboron, the accommodation of bis(pinacolato)diboron in the void of the lattice was observed (Figure 4). The crystal packing of this

Anion-dependent ion-pairing assemblies of triazatriangulenium cation that interferes with stacking structures

• Yohei Haketa,
• Takuma Matsuda and
• Hiromitsu Maeda

Beilstein J. Org. Chem. 2024, 20, 2567–2576, doi:10.3762/bjoc.20.215

• File 1). As a crystallization solvent, three CHCl3 molecules were located between the 2,6-dimethylphenyl units by forming hydrogen bonding with Cl− with C(–H)···Cl− distances of 3.36, 3.36, and 3.37 Å. A similar arrangement of the counteranions was observed for 2+-BF4− and 2+-PF6−, with the BF4− and

Evaluating the halogen bonding strength of a iodoloisoxazolium(III) salt

• Dominik L. Reinhard,
• Anna Schmidt,
• Marc Sons,
• Julian Wolf,
• Elric Engelage and
• Stefan M. Huber

Beilstein J. Org. Chem. 2024, 20, 2401–2407, doi:10.3762/bjoc.20.204

• 3Cl which resulted from crystallization of the respective cation with the abstracted chloride from the Ritter-type solvolysis of benzhydryl chloride [13]. The crystal structure of 5Br was also obtained directly from the halide-abstraction reaction (see Supporting Information File 1). These three facts

Negishi-coupling-enabled synthesis of α-heteroaryl-α-amino acid building blocks for DNA-encoded chemical library applications

• Matteo Gasparetto,
• Balázs Fődi and
• Gellért Sipos

Beilstein J. Org. Chem. 2024, 20, 1922–1932, doi:10.3762/bjoc.20.168

• iodine (see page 11 Supporting Information File 1), affording final concentrations between 0.35 to 0.45 M in THF. The solution can be stored in the fridge under argon for one week before being used in the Negishi reaction. With concentrations above 0.4 M we observed crystallization of ethyl (bromozinc

Enhancing structural diversity of terpenoids by multisubstrate terpene synthases

• Min Li and
• Hui Tao

Beilstein J. Org. Chem. 2024, 20, 959–972, doi:10.3762/bjoc.20.86

• . Classically, these prenyl analogs have been used as co-crystallization ligands [38], inhibitors of specific TSs [39], and tools to study the reaction mechanisms of cyclization cascades [40][41] which have been comprehensively addressed in important previous reviews [8][13]. Currently, noncanonical prenyl

Activity assays of NnlA homologs suggest the natural product N-nitroglycine is degraded by diverse bacteria

• Kara A. Strickland,
• Brenda Martinez Rodriguez,
• Ashley A. Holland,
• Shelby Wagner,
• Michelle Luna-Alva,
• David E. Graham and
• Jonathan D. Caranto

Beilstein J. Org. Chem. 2024, 20, 830–840, doi:10.3762/bjoc.20.75

• and kinetic experiments or crystallization of the active homodimer will be required to resolve the catalytic mechanism. If NnlA is specific for NNG as suggested by these results, it is worth speculating about potential functions of NNG and other nitramine natural products. Bacterial natural products

Synthesis and biological profile of 2,3-dihydro[1,3]thiazolo[4,5-b]pyridines, a novel class of acyl-ACP thioesterase inhibitors

• Jens Frackenpohl,
• David M. Barber,
• Guido Bojack,
• Birgit Bollenbach-Wahl,
• Ralf Braun,
• Rahel Getachew,
• Sabine Hohmann,
• Kwang-Yoon Ko,
• Karoline Kurowski,
• Bernd Laber,
• Rebecca L. Mattison,
• Thomas Müller,
• Anna M. Reingruber,
• Dirk Schmutzler and
• Andrea Svejda

Beilstein J. Org. Chem. 2024, 20, 540–551, doi:10.3762/bjoc.20.46

• binding affinity to enzyme targets, e.g., acyl-ACP thioesterases, belonging to the protein family of FATs, was demonstrated by using co-crystallization, fluorescence-based thermal shift assays, and chemoproteomics techniques [3]. Likewise, methiozolin (2) is a recently assigned FAT inhibitor that has

Spatial arrangements of cyclodextrin host–guest complexes in solution studied by ¹³C NMR and molecular modelling

• Konstantin Lebedinskiy,
• Ivan Barvík,
• Zdeněk Tošner,
• Ivana Císařová,
• Jindřich Jindřich and
• Radim Hrdina

Beilstein J. Org. Chem. 2024, 20, 331–335, doi:10.3762/bjoc.20.33

• crystallization of host–guest complexes and their crystallographic analysis. Keywords: anisotropy; 13C NMR; cyclodextrin; host–guest complexes; Introduction Complexation of organic and inorganic compounds with α-, β-, or γ-cyclodextrins and their derivatives [1] is an established tool used in medicine for drug

Elucidating the glycan-binding specificity and structure of Cucumis melo agglutinin, a new R-type lectin

• Jon Lundstrøm,
• Emilie Gillon,
• Valérie Chazalet,
• Nicole Kerekes,
• Antonio Di Maio,
• Ten Feizi,
• Yan Liu,
• Annabelle Varrot and
• Daniel Bojar

Beilstein J. Org. Chem. 2024, 20, 306–320, doi:10.3762/bjoc.20.31

• crystallography. We obtained several hits for the full-length protein after sparse screening using a crystallization robot at the HTX platform, EMBL, Grenoble. Pill-shaped crystals obtained under conditions of a high salt concentration, in particular ammonium sulfate (Figure S3, Supporting Information File 2

• using the free software “data entry”. The IC50 was calculated using https://www.aatbio.com/tools/ic50-calculator. X-ray crystallography All consumables for crystallization and crystal handling were purchased at Molecular Dimensions, Calibre Scientific, Rotherham, UK, unless stated otherwise. CMA1

• concentrated at 5.7 or 3.5 mg/mL in 20 mM HEPES pH 8, 100 mM NaCl, and 14 mM GalNAc was subjected to crystallization screening using the robotized HTXlab platform (EMBL, Grenoble, France) with 200 nL sitting drops at 20 °C using a 1:1 ratio. Wizard I and II screen (Rigaku) and SaltRX (Hampton Research) screens

Substitution reactions in the acenaphthene analog of quino[7,8-h]quinoline and an unusual synthesis of the corresponding acenaphthylenes by tele-elimination

• Ekaterina V. Kolupaeva,
• Narek A. Dzhangiryan,
• Alexander F. Pozharskii,
• Oleg P. Demidov and
• Valery A. Ozeryanskii

Beilstein J. Org. Chem. 2024, 20, 243–253, doi:10.3762/bjoc.20.24

• this case, hydrolytic degradation of chloranil also occurred during crystallization (base 5 could act as a catalyst for such degradation), because of which yellowish needles were obtained (neither 5 nor chloranil crystallize in this form), which turned out to be the hydrochloride dihydrate of compound

• antiparallel orientation of the closely spaced cationic fragments of base 5 can be reversed to the opposite. This can be achieved with 4,6-dichlororesorcinol, a well-known molecular organizer and coordinating agent [20][21]. Thus, the joint crystallization of dipyridoacenaphthene 5 and 4,6-dichlororesorcinol

• of quinoquinolines, their planar structure, and very easy coordination to acidic and electrophilic sites (including water [15][22] or the C–H bond of chloroform [11]) almost always lead to co-crystallization. For example, there is no such crystallographic information for quinoquinoline 3 itself. In

Comparison of glycosyl donors: a supramer approach

• Anna V. Orlova,
• Nelly N. Malysheva,
• Maria V. Panova,
• Nikita M. Podvalnyy,
• Michael G. Medvedev and
• Leonid O. Kononov

Beilstein J. Org. Chem. 2024, 20, 181–192, doi:10.3762/bjoc.20.18

• . The residue was purified by silica gel column chromatography (column volume 140 mL, elution with gradient CH2Cl2 → acetone/CH2Cl2 20:80). The crude product was dissolved in acetone (3 mL) and t-BuOMe (3 mL), then petroleum ether was slowly added until crystallization commenced. The precipitate formed

Aromatic systems with two and three pyridine-2,6-dicarbazolyl-3,5-dicarbonitrile fragments as electron-transporting organic semiconductors exhibiting long-lived emissions

• Karolis Leitonas,
• Brigita Vigante,
• Dmytro Volyniuk,
• Audrius Bucinskas,
• Pavels Dimitrijevs,
• Sindija Lapcinska,
• Pavel Arsenyan and
• Juozas Vidas Grazulevicius

Beilstein J. Org. Chem. 2023, 19, 1867–1880, doi:10.3762/bjoc.19.139

• analysis (TGA) and differential scanning calorimetry (DSC), respectively. The experimental data are shown in Figure 5 and the characteristics are collected in Table 1. An amorphous character of the derivatives was identified. No endothermic (melting) or exothermic (crystallization) transitions were

• nitrogen environment. DSC allows us to investigate the enthalpy changes associated with phase transitions, crystallization, and other thermal events occurring in the samples. The choice of a nitrogen atmosphere in both TGA and DSC experiments is significant as it helps to prevent undesired reactions with

Selectivity control towards CO versus H₂ for photo-driven CO₂ reduction with a novel Co(II) catalyst

• Lisa-Lou Gracia,
• Philip Henkel,
• Olaf Fuhr and
• Claudia Bizzarri

Beilstein J. Org. Chem. 2023, 19, 1766–1775, doi:10.3762/bjoc.19.129

• ). Efforts to selectively achieve one polymorph, through differentiated crystallization processes, were unsuccessful. When analyzing the molecular structure in both crystals, the cobalt core is hexacoordinated, as expected. The two isothiocyanate ions are oriented cis to each other and trans to the

Charge carrier transport in perylene-based and pyrene-based columnar liquid crystals

• Alessandro L. Alves,
• Simone V. Bernardino,
• Carlos H. Stadtlober,
• Edivandro Girotto,
• Giliandro Farias,
• Rodney M. do Nascimento,
• Sergio F. Curcio,
• Thiago Cazati,
• Marta E. R. Dotto,
• Juliana Eccher,
• Leonardo N. Furini,
• Hugo Gallardo,
• Harald Bock and
• Ivan H. Bechtold

Beilstein J. Org. Chem. 2023, 19, 1755–1765, doi:10.3762/bjoc.19.128

• 1758 cm−1 (C=O). X-ray diffraction (XRD) measurements of 1 and 2 are shown in Figure 2. The Miller indices indicate the Colhex and Colrect character of the mesophases [31]. Despite crystallization of 2, the Colrect order is partially preserved at room temperature. The Colhex lattice parameter (a

Unprecedented synthesis of a 14-membered hexaazamacrocycle

• Anastasia A. Fesenko and
• Anatoly D. Shutalev

Beilstein J. Org. Chem. 2023, 19, 1728–1740, doi:10.3762/bjoc.19.126

• with a noticeable increase in the macrocycle yield up to 41% (Table 1, entries 20 and 21). The extremely poor solubility of product 5 in most organic solvents allowed to purify it from all admixtures, including byproduct 6, by a single crystallization from boiling DMF. Thus, pure product 5 was prepared

• noteworthy that triazole 10 was the major product in dioxane (10/5/6 = 86.5:13:0.5, Table 1, entry 23). Again, macrocycle 5 was separated from this mixture by crystallization from DMF, and pyrazolyl-1,2,4-triazole 10 was isolated from the mother liquor. The structure of compound 10 was established based on

• , 3 h) followed by crystallization of the crude product from DMF. The use of compound 8 as a starting material affords the target product 5 with higher purity and yield compared with the use of imidate 4. Moreover, pyrazolopyrimidine 8 itself is much more stable than imidate 4, and its intermediate

Effects of the aldehyde-derived ring substituent on the properties of two new bioinspired trimethoxybenzoylhydrazones: methyl vs nitro groups

• Dayanne Martins,
• Roberta Lamosa,
• Talis Uelisson da Silva,
• Carolina B. P. Ligiero,
• Sérgio de Paula Machado,
• Daphne S. Cukierman and
• Nicolás A. Rey

Beilstein J. Org. Chem. 2023, 19, 1713–1727, doi:10.3762/bjoc.19.125

• beige and light-yellow solids with 78% and 44% yield, respectively. Thermal analyses between 25 and 350 °C were performed in order to verify the hydration status of the bulk. Regarding hdz-CH3, a weight loss of 9.78% from around 80 to 190 °C was observed, suggesting the presence of two crystallization

• the structures (Figure 2A) shows that spatial arrangements are nearly the same and even the crystallization water molecules were allocated in nearby sites, interacting as H-acceptors in a hydrogen bond with the respective N2H groups. In spite of these similarities, the compounds were indexed in

CO₂ complexation with cyclodextrins

• Cecilie Høgfeldt Jessen,
• Jesper Bendix,
• Theis Brock Nannestad,
• Heloisa Bordallo,
• Martin Jæger Pedersen,
• Christian Marcus Pedersen and
• Mikael Bols

Beilstein J. Org. Chem. 2023, 19, 1021–1027, doi:10.3762/bjoc.19.78

• yields was sufficient time for the crystallization, while the pressure was found less important. From the binding constant measured below and the 1:1 stoichiometry (Kg = 0.18 bar−1, Table 2) we know that 1/2 to 3/4 of the cyclodextrin is filled with CO2 at the pressures used as shown in the 5th column of

• Table 1. As CO2 is in large excess high crystal yields can be obtained even though the CD cavity is only partially filled, because more CO2 is bound in solution as crystallization proceeds. When equilibrium is reached as in entries 1–3 (Table 1) the concentration of 1·CO2 is 0.04 M which must be the

• lipophilic cyclodextrin derivative. It suggests that stronger CO2 binders can be found by improving on these two traits. Experimental Crystallization experiments. A cyclodextrin solution was prepared by dissolving 1 in Milli-Q water to the indicated concentration (Table 1) . The solution was then filtered