Gold extraction at the molecular level using α- and β-cyclodextrins

• Susana Santos Braga

Beilstein J. Org. Chem. 2025, 21, 1116–1125, doi:10.3762/bjoc.21.89

• -OES, the precipitation ability of α-CD (0.2 mmol × 2) of a solution containing gold in the presence of palladium and platinum (33 mM KAuBr4, 33 mM K2PdBr4, and saturated K2PtBr4, at ≈26 mM), with 78.3% of the gold precipitating out of solution while for the other metals there was only precipitation of

• precious metals [42]. The process of gold precipitation with cyclodextrins, bromic acid and potassium hydroxide to form the potassium bromoaurate salt was patented, with patent coverage expanding to metals like silver, platinum, palladium, and rare earths, as well as the use of other cyclodextrins, β- and

Recent total synthesis of natural products leveraging a strategy of enamide cyclization

• Chun-Yu Mi,
• Jia-Yuan Zhai and
• Xiao-Ming Zhang

Beilstein J. Org. Chem. 2025, 21, 999–1009, doi:10.3762/bjoc.21.81

• the α-position of enamide to be an active cyclization site, with the alkyne tether acting as the nucleophile. Since it is well-established that alkynes, when activated by transition metals such as gold or platinum, can also function as electrophiles, modulating the reactivity of the decahydroquinoline

Recent advances in the electrochemical synthesis of organophosphorus compounds

• Babak Kaboudin,
• Milad Behroozi,
• Sepideh Sadighi and
• Fatemeh Asgharzadeh

Beilstein J. Org. Chem. 2025, 21, 770–797, doi:10.3762/bjoc.21.61

• synthesis of various organophosphorus compounds through the formation of phosphorus–carbon, phosphorus–nitrogen, phosphorus–oxygen, phosphorus–sulfur, and phosphorus–selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, RVC, and nickel electrodes have been

• , phosphorus–sulfur, and phosphorus–selenium bonds. The impact of different electrodes is also discussed in this matter. Graphite, platinum, reticulated vitreous carbon (RVC), and nickel electrodes have been used extensively for the electrochemical synthesis of organophosphorus compounds. Review

• electrode with the reaction solution. The oxidation–reduction process complements each other, and the surface of the electrode in the reaction is critical. The material of the electrode is essential [44]. Various electrodes, including carbon (C), platinum (Pt), nickel (Ni), and reticulated vitreous carbon

Entry to 2-aminoprolines via electrochemical decarboxylative amidation of N‑acetylamino malonic acid monoesters

• Olesja Koleda,
• Janis Sadauskis,
• Darja Antonenko,
• Edvards Janis Treijs,
• Raivis Davis Steberis and
• Edgars Suna

Beilstein J. Org. Chem. 2025, 21, 630–638, doi:10.3762/bjoc.21.50

• undesired cathodic reduction. Indeed, trace amounts of 2-aminoproline derivative 6g (<4%) could be obtained by replacing SS as the cathode material with platinum that has a low overpotential for hydrogen evolution reaction [14]. To avoid the undesired cathodic reduction of the nitro group, the electrolysis

• column chromatography. Cyclic voltammetry studies CV experiments were carried out in an SVC-2 (ALS, Japan) three-electrode cell using a PalmSens4 (PalmSens). A glassy carbon disk (diameter: 1.6 mm) served as the working electrode and a platinum wire as the counter electrode. The glassy carbon disk was

Red light excitation: illuminating photocatalysis in a new spectrum

• Lucas Fortier,
• Corentin Lefebvre and
• Norbert Hoffmann

Beilstein J. Org. Chem. 2025, 21, 296–326, doi:10.3762/bjoc.21.22

• , which exploits the properties of red-light excitation while addressing the energy constraints posed by low-energy photons. Whereas multiple works addressing the upconversion phenomenon involving heavy metals like palladium, platinum [23][24] or osmium [25], grafted ruthenium complexes over ytterbium and

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

• graphite [22]. It was earlier prepared in Ar matrices [23] or via demetallation of a platinum complex of 4,5-dehydro-2,3:6,7-dibenzotropone [1]. More recently, compound 1 was prepared via Pd-catalyzed cyclotrimerization of 4-bromo-2,3:6,7-dibenzotropone (4 in Scheme 1) [22]. Herein we report an alternative

Synthesis of benzo[f]quinazoline-1,3(2H,4H)-diones

• Ruben Manuel Figueira de Abreu,
• Peter Ehlers and
• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2708–2719, doi:10.3762/bjoc.20.228

• attempt, we used platinum(II) chloride (PtCl2) as the Lewis acid and 4a as the model starting material. The reaction afforded a mixture of the desired product 5a and the starting material. Separation of both compounds proved to be difficult and, hence, optimisation was carried out as depicted in Table 1

Applications of microscopy and small angle scattering techniques for the characterisation of supramolecular gels

• Connor R. M. MacDonald and
• Emily R. Draper

Beilstein J. Org. Chem. 2024, 20, 2608–2634, doi:10.3762/bjoc.20.220

• number of structural features, but the sample preparation required can lead to significant changes in the materials morphology. EM requires many preparative steps to allow structures to be imaged including the application of an ultrathin coating of carbon, gold, or platinum. These are applied to conduct

A review of recent advances in electrochemical and photoelectrochemical late-stage functionalization classified by anodic oxidation, cathodic reduction, and paired electrolysis

• Nian Li,
• Ruzal Sitdikov,
• Ajit Prabhakar Kale,
• Joost Steverlynck,
• Bo Li and
• Magnus Rueping

Beilstein J. Org. Chem. 2024, 20, 2500–2566, doi:10.3762/bjoc.20.214

• . However, it should be noted that anodic oxidations often require electrodes with high resistance to oxidation, such as platinum electrodes, or inert electrodes with a highly developed surface, like reticulated vitreous carbon (RVC). Anodic oxidations generally involve the evolution of hydrogen (indicated

• methanol, equipped with a graphite anode and a platinum plate cathode, under a current of 10 mA at 60 °C for 3–20 hours. Several electrochemical LSF of pharmacologically active molecules were tested, including naproxen methyl ester, a derivative of aminoglutethimide, and paracetamol. The corresponding

• electrolyte, and carbon felt and platinum plate as electrodes, the intramolecular hydroamination proceeded smoothly, yielding azetidines in moderate to good yields. This method was applied to the LSF of celecoxib, zonisamide, and dansyl amide (Scheme 33a). Additionally, the allylation of aldehydes also

Harnessing the versatility of hydrazones through electrosynthetic oxidative transformations

• Aurélie Claraz

Beilstein J. Org. Chem. 2024, 20, 1988–2004, doi:10.3762/bjoc.20.175

• -derived NH-acylhydrazones to build 1,3,4-oxadiazole derivatives in good yields. The electrolysis was conducted under galvanostatic conditions in methanol using a carbon graphite anode and a platinum cathode. From a mechanistic point of view, in situ condensation of acylhydrazines 28 with α-keto acids 27

• electrolyte with potassium carbonate as a base and two platinum electrodes. Mechanistically, condensation of the two reactants formed isatin-derived acylhydrazone 37. Hydrolysis of the latter in the presence of the inorganic base gave rise to potassium carboxylate 39. Meanwhile, two consecutive SET oxidations

• -tetraethylammonium perchlorate solution under constant potential in a divided cell equipped with platinum gauze anode and nickel cathode. Such a transformation constituted a straightforward route to the corresponding fused s-triazolo perchlorates 46 in moderate to high yield. Coulometric analysis established that

Electrochemical radical cation aza-Wacker cyclizations

• Sota Adachi and
• Yohei Okada

Beilstein J. Org. Chem. 2024, 20, 1900–1905, doi:10.3762/bjoc.20.165

• ), with platinum (Pt) as a cathode. To our delight, a constant-current condition at 1 mA was productive, and the desired five-membered pyrrolidine 2 was obtained in high yield (Table 1, entry 2). During the screening of conditions, the addition of acetonitrile (CH3CN) was found to be effective, probably

Synthesis of polycyclic aromatic quinones by continuous flow electrochemical oxidation: anodic methoxylation of polycyclic aromatic phenols (PAPs)

• Hiwot M. Tiruye,
• Solon Economopoulos and
• Kåre B. Jørgensen

Beilstein J. Org. Chem. 2024, 20, 1746–1757, doi:10.3762/bjoc.20.153

• short distance between the electrodes, and easily reproduceable conditions. The electrochemical oxidation of phenols has been performed with platinum anodes [37][41], and carbon/platinum worked well for the oxidation of toluene dissolved in methanol with tetraethylammonium tosylate (Et4NOTs) as a

• the four-electron oxidation product 1,1-dimethoxynaphthalen-2(1H)-one (2). Best results were obtained with a carbon/platinum electrode pair, although stainless steel (SS) could also be used as cathode. The experiments were conducted with a 3:1 mixture of methanol/tetrahydrofuran (optimization not

• cell equipped with a platinum-coated cathode and a carbon-filled PPS (polyphenylene sulfide) micro-channel anode separated by a polyetheretherketone (PEEK) gasket [40]. Further experimental details and characterization of new compounds are given in Supporting Information File 1. General procedure A

Syntheses and medicinal chemistry of spiro heterocyclic steroids

• Laura L. Romero-Hernández,
• Ana Isabel Ahuja-Casarín,
• Penélope Merino-Montiel,
• Sara Montiel-Smith,
• José Luis Vega-Báez and
• Jesús Sandoval-Ramírez

Beilstein J. Org. Chem. 2024, 20, 1713–1745, doi:10.3762/bjoc.20.152

• their antiproliferative activity against a panel of cancer cells, in which the activity of some compounds was close to that of cis-platinum in some cell lines. It should be noted that N-propylamide derivatives showed low cytotoxicity on cancer cells. Additionally, 167c did not present cytotoxic activity

Synthesis and physical properties of tunable aryl alkyl ionic liquids based on 1-aryl-4,5-dimethylimidazolium cations

• Stefan Fritsch and
• Thomas Strassner

Beilstein J. Org. Chem. 2024, 20, 1278–1285, doi:10.3762/bjoc.20.110

• well known that the hydrogen atom at the C2 carbon atom of the imidazole core is more acidic as those in the C4/C5-position, where the methyl groups are expected to also have a significant effect on the molecular interactions. Platinum complexes using the 4,5-dimethylimidazole motif as a ligand were

• ). The setup consisted of a glassy carbon working electrode, a platinum wire counter electrode and a silver wire as reference electrode. The cutoff at which the cathodic limit Ered and the anodic limit Eox were determined was −0.1 and 0.1 mA cm−2. The electro-chemical window EEW is determined from the

Synthesis of indano[60]fullerene thioketone and its application in organic solar cells

• Yong-Chang Zhai,
• Shimon Oiwa,
• Shinobu Aoyagi,
• Shohei Ohno,
• Tsubasa Mikie,
• Jun-Zhuo Wang,
• Hirofumi Amada,
• Koki Yamanaka,
• Kazuhira Miwa,
• Naoyuki Imai,
• Takeshi Igarashi,
• Itaru Osaka and
• Yutaka Matsuo

Beilstein J. Org. Chem. 2024, 20, 1270–1277, doi:10.3762/bjoc.20.109

• supporting electrolyte at 25 °C with a scan rate of 0.05 V/s, for C60 (blue), t-Bu-FIDO (red), and t-Bu-FIDS (black). Glassy carbon, platinum wire, and Ag/Ag+ electrodes were used as the working, counter, and reference electrodes, respectively. J–V curves of BHJ OPV devices. (a) ITO/ZnO/fullerene:P3HT (1:1

Two-fold addition reaction of silylene to C₆₀: structural and electronic properties of a bis-adduct

• Masahiro Kako,
• Masato Kai,
• Masanori Yasui,
• Michio Yamada,
• Yutaka Maeda and
• Takeshi Akasaka

Beilstein J. Org. Chem. 2024, 20, 1179–1188, doi:10.3762/bjoc.20.100

• on a BAS CV50W electrochemical analyzer (BAS Inc.). The reference electrode was a saturated calomel reference electrode (SCE). The glassy carbon electrode was used as the working electrode, and a platinum wire was used as the counter electrode. All potentials are referenced to the ferrocene

Structure–property relationships in dicyanopyrazinoquinoxalines and their hydrogen-bonding-capable dihydropyrazinoquinoxalinedione derivatives

• Tural N. Akhmedov,
• Ajeet Kumar,
• Daken J. Starkenburg,
• Kyle J. Chesney,
• Khalil A. Abboud,
• Novruz G. Akhmedov,
• Jiangeng Xue and
• Ronald K. Castellano

Beilstein J. Org. Chem. 2024, 20, 1037–1052, doi:10.3762/bjoc.20.92

• 1–3 mg of sample in a 100 μL platinum pan (under nitrogen). The data was analyzed on Universal Analysis 2000 4.4A software. Synthetic procedures to access dicyanopyrazinoquinoxalines (DCPQs) 1a–6a Pyrazino[2,3-b]quinoxaline-2,3-dicarbonitrile (1a) To a 50 mL round-bottom flask was added DDQ (0.581 g

Advancements in hydrochlorination of alkenes

• Daniel S. Müller

Beilstein J. Org. Chem. 2024, 20, 787–814, doi:10.3762/bjoc.20.72

• functional group tolerance. Yang reported a hydrochlorination promoted by visible light over platinum, gold, and palladium supported on zirconia [74]. The reaction demonstrated moderate efficiency, yielding an 85:15 mixture of products 100 and 126 with low conversion (Scheme 20). The use of hydrochloric acid

Chemoenzymatic synthesis of macrocyclic peptides and polyketides via thioesterase-catalyzed macrocyclization

• Senze Qiao,
• Zhongyu Cheng and
• Fuzhuo Li

Beilstein J. Org. Chem. 2024, 20, 721–733, doi:10.3762/bjoc.20.66

• clinical trials for the treatment of non-small-cell lung cancer and platinum-resistant ovarian cancer, but was halted in phase II due to dose-limiting peripheral neuropathy and limited efficacy in vivo [80]. However, this family of depsipeptides remains of therapeutic significance and has recently been

Switchable molecular tweezers: design and applications

• Pablo Msellem,
• Maksym Dekthiarenko,
• Nihal Hadj Seyd and
• Guillaume Vives

Beilstein J. Org. Chem. 2024, 20, 504–539, doi:10.3762/bjoc.20.45

• terpyridine-bearing platinum–salphen known for their luminescence properties [41]. The closing process of the tweezers 12 was studied by NMR or UV–vis titrations with Zn2+ and other cations such as Pb2+, Fe2+, Cu2+, Eu3+, and Yb3+ indicating in all cases a 1:1 association model. The system can then be

• . Vives and co-workers reported bis(platinum–salphen)terpyridine tweezers 20 that can intercalate in the U form extended aromatic guests such as coronene and perylene [52]. The opening of the tweezers with the addition of Zn2+ released the guest demonstrating an example of negative allosteric regulation

• such Pt(II) dissymmetric tweezers could be controlled as aryl thioethers are more labile than alkyl thioethers. The addition of Cl− thus first breaks the Pt–SAr bond. Platinum-based dissymmetric tweezers were also synthetized using NHC thioether ligands that are more stable than the phosphine thioether

Ligand effects, solvent cooperation, and large kinetic solvent deuterium isotope effects in gold(I)-catalyzed intramolecular alkene hydroamination

• Ruichen Lan,
• Brock Yager,
• Yoonsun Jee,
• Cynthia S. Day and
• Amanda C. Jones

Beilstein J. Org. Chem. 2024, 20, 479–496, doi:10.3762/bjoc.20.43

• molecule of amine delivers a proton to the alkylgold intermediate (for protodeauration). In a platinum-catalyzed hydroamination, a protodemetalation pathway is supported by kinetics and reactivity studies on generated platinum alkyl intermediates [46]. In a palladium-catalyzed hydroamination, a

(E,Z)-1,1,1,4,4,4-Hexafluorobut-2-enes: hydrofluoroolefins halogenation/dehydrohalogenation cascade to reach new fluorinated allene

• Nataliia V. Kirij,
• Andrey A. Filatov,
• Yurii L. Yagupolskii,
• Sheng Peng and
• Lee Sprague

Beilstein J. Org. Chem. 2024, 20, 452–459, doi:10.3762/bjoc.20.40

• defluorosilylation product was obtained [11]. In a related study of the hydrosilylation reaction of olefins 1a,b, it was shown that, depending on the catalyst used, platinum or rhodium compounds, along with the products of the addition of silane to the double bond, the elimination of the fluorine atom occurs with

Synthesis of π-conjugated polycyclic compounds by late-stage extrusion of chalcogen fragments

• Aissam Okba,
• Pablo Simón Marqués,
• Kyohei Matsuo,
• Naoki Aratani,
• Hiroko Yamada,
• Gwénaël Rapenne and
• Claire Kammerer

Beilstein J. Org. Chem. 2024, 20, 287–305, doi:10.3762/bjoc.20.30

• naphthyl substituents carrying each an alkyne moiety on the ortho position. Ring expansion of both thiophene units in 19 was then triggered by platinum catalysis to generate the corresponding thiopyrans, and finally the bromine atoms located on the latter rings were exploited for the ring closure of the

Multi-redox indenofluorene chromophores incorporating dithiafulvene donor and ene/enediyne acceptor units

• Christina Schøttler,
• Kasper Lund-Rasmussen,
• Line Broløs,
• Philip Vinterberg,
• Ema Bazikova,
• Viktor B. R. Pedersen and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2024, 20, 59–73, doi:10.3762/bjoc.20.8

• platinum disk (diameter = 1.6 mm) or a glassy carbon disk (3 mm) was used as the working electrode. The reference electrode was separated from the solution containing the substrate by a ceramic frit. Measured potentials were referenced to ferrocene/ferrocenium (Fc/Fc+) redox couple, measured before and

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

• as a quasireference electrode, while a platinum wire served as a counter electrode to facilitate the redox reactions. For calibration purposes, the potentials were standardized using the standard ferrocene/ferrocenium (Fc/Fc+) redox system, a well-known and widely used reference for establishing