Deep-blue emitting 9,10-bis(perfluorobenzyl)anthracene

• Long K. San,
• Sebastian Balser,
• Brian J. Reeves,
• Tyler T. Clikeman,
• Yu-Sheng Chen,
• Steven H. Strauss and
• Olga V. Boltalina

Beilstein J. Org. Chem. 2025, 21, 515–525, doi:10.3762/bjoc.21.39

• , dried over 4 Å molecular sieves); quinine hemisulfate salt monohydrate (Fluka); sulfuric acid (EMD Chemicals); diethyl ether anhydrous (EMD Chemicals, ACS grade); chloroform-d (CDCl3, Cambridge Isotope Labs, 99.8%); hexafluorobenzene (C6F6, Oakwood Products); deionized distilled water (purified with a

Oxidation of [3]naphthylenes to cations and dications converts local paratropicity into global diatropicity

• Abel Cárdenas,
• Zexin Jin,
• Yong Ni,
• Jishan Wu,
• Yan Xia,
• Francisco Javier Ramírez and
• Juan Casado

Beilstein J. Org. Chem. 2025, 21, 277–285, doi:10.3762/bjoc.21.20

• ] reported a stable heptacene dication in concentrated sulfuric acid, a stability attributed to the intermolecular Coulomb repulsion between the charged molecules, which prevents the dimerization of the acene. This exciting finding suggests possible modes of kinetic stabilization of oxidized species of π

Synthesis of disulfides and 3-sulfenylchromones from sodium sulfinates catalyzed by TBAI

• Zhenlei Zhang,
• Ying Wang,
• Xingxing Pan,
• Manqi Zhang,
• Wei Zhao,
• Meng Li and
• Hao Zhang

Beilstein J. Org. Chem. 2025, 21, 253–261, doi:10.3762/bjoc.21.17

• product in moderate yields, with sulfuric acid being the most effective. It is important to note that sulfuric acid is a dibasic acid. Subsequently, when the amount of HCl was increased to 2 equivalents, a significant increase in yield was observed (Table 1, entry 5). Weak acids such as acetic acid did

• salts gave relatively lower yields (Table 1, entries 20 and 21). The replacement of the catalyst with tetrabutylammonium bromide (TBAB) gave no product (Table 1, entry 22). Finally, sulfuric acid as the acidifying agent, tetrabutylammonium iodide as the catalyst, DMF as the solvent and carrying out the

Non-covalent organocatalyzed enantioselective cyclization reactions of α,β-unsaturated imines

• Sergio Torres-Oya and
• Mercedes Zurro

Beilstein J. Org. Chem. 2024, 20, 3221–3255, doi:10.3762/bjoc.20.268

• , and with bulky substituents, the reaction did not proceed. Further derivatizations of the products were carried out: firstly, the derivative 35e was reduced using NaBH3CN to obtain 36 as a single diastereomer in a good yield. Next, a hydrolysis of 36 using concentrated sulfuric acid led to the 1,2

Homogeneous continuous flow nitration of O-methylisouronium sulfate and its optimization by kinetic modeling

• Jiapeng Guo,
• Weike Su and
• An Su

Beilstein J. Org. Chem. 2024, 20, 2408–2420, doi:10.3762/bjoc.20.205

• modeling of this reaction was performed based on the theory of NO2+ attack, with the activation energy and pre-exponential factor determined. Finally, based on the response surface generated by the kinetic model, the reaction was optimized with a conversion of 87.4% under a sulfuric acid mass fraction of

• effective and non-toxic neonicotinoid insecticides, such as dinotefuran and clothianidin [2][3][4]. Currently, the industrial production of O-methyl-N-nitroisourea usually involves the nitration of O-methylisouronium sulfate (IO) with a mixture of sulfuric acid (H2SO4) and nitric acid (HNO3) in a batch

• ]. The reaction time and temperature were reduced from >2 h and 80 °C in industrial operation to 10 min and 65 °C in the microreactor with high conversion and selectivity. Since O-methylisouronium sulfate can be dissolved in high concentrations of sulfuric acid, it is expected to construct a homogeneous

Cage-like microstructures via sequential Ugi reactions in aqueous emulsions

• Rita S. Alqubelat,
• Yaroslava A. Menzorova and
• Maxim A. Mironov

Beilstein J. Org. Chem. 2024, 20, 2078–2083, doi:10.3762/bjoc.20.179

• emulsions. The polystyrene particles were treated with sulfuric acid to form a surface layer of sulfonated polystyrene. These particles were then used to produce Pickering emulsions, which were transformed into large-pore structures when treated with an alcohol/water mixture [12]. Another method involves

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

• 82 with concentrated sulfuric acid, cyclodehydration occurred, leading to the formation of 3-spiro[3’’’-(2’’’-phenyl-4’’’-oxo-1’’’,3’’’-thiazolidin-5’’-yl)-1’’,3’’,4’’-thiadiazolo[3’,4’-b]thiazolin]cholest-5-ene (83) in 60% yield (Scheme 24). Notably, stereochemical information at the newly formed

• reactions. To increase the molecular diversity at the morpholine ring, tertiary amines were formed by nucleophilic substitution. A final removal of the cyclic ketal group in aq sulfuric acid provided spiromorpholinone derivatives 134a–e, 136a–e, and 138 (Scheme 37). Spiromorpholinones were evaluated as

• peroxide–hydrochloric acid. A subsequent reaction of the resulting compound with simple ketones in the presence of sulfuric acid produced steroidal 1,2,4,5-tetraoxanes 170 possessing an ester functionality. The unsubstituted ketones gave a single product as expected, while those with substituted precursors

A myo-inositol dehydrogenase involved in aminocyclitol biosynthesis of hygromycin A

• Michael O. Akintubosun and
• Melanie A. Higgins

Beilstein J. Org. Chem. 2024, 20, 589–596, doi:10.3762/bjoc.20.51

• containing 3.7 mL p-anisaldehyde, 135 mL ethanol, 5 mL sulfuric acid, and 1.5 mL glacial acetic acid. Light pink spots were observed following heating at 105 °C. Kinetics assays were carried out by varying concentrations of substrate (myo-inositol or scyllo-inositol) from 1 mM to 60 mM with 1 μM Hyg17 and 10

Green and sustainable approaches for the Friedel–Crafts reaction between aldehydes and indoles

• Periklis X. Kolagkis,
• Eirini M. Galathri and
• Christoforos G. Kokotos

Beilstein J. Org. Chem. 2024, 20, 379–426, doi:10.3762/bjoc.20.36

• , such as camphorsulfonic acid (CSA) [44], diammonium hydrogen phosphate (DAHP) [45], Amberlyst 15 [46], P2O5/MeSO3H [47], p-sulfonic acid calix[4]arene [48], xanthan sulfuric acid (XSA) [49], H5PW10V2O40/pyridino-santa barbara amorphous-15 (SBA-15) [50], TiO2-SO42− [51][52], humic acid [53] or Lewis

• hydroxide. In the second step, the formed zirconium hydroxide undergoes a sulfate impregnation, utilizing sulfuric acid in the presence of polyvinylpyrrolidone (PVP) as the surfactant, to prevent particle agglomeration, leading to the formation of the desired sulfated zirconia nanoparticles after a last

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

• gradual degradation. Obviously, in our case, the activating effect of the CH2CH2 fragment in the naphthalene part of molecule 5 is insufficient against the background of the presence of two pyridine rings in its structure. In this regard, we turned to concentrated sulfuric acid as a reaction medium and

1-Butyl-3-methylimidazolium tetrafluoroborate as suitable solvent for BF₃: the case of alkyne hydration. Chemistry vs electrochemistry

• Marta David,
• Elisa Galli,
• Richard C. D. Brown,
• Marta Feroci,
• Fabrizio Vetica and
• Martina Bortolami

Beilstein J. Org. Chem. 2023, 19, 1966–1981, doi:10.3762/bjoc.19.147

• 1881, Kucherov identified mercury(II) salts in sulfuric acid as efficient promoters of the hydration of alkynes and this catalyst system has found applications in industrial scale synthesis [10]. However, the toxicity and the environmental issues associated with the use of mercury-based compounds have

• examples of the hydration reaction of alkynes carried out in ILs. In one case, a dicationic IL, containing sulfuric acid as catalyst, was used as reaction medium to carry out the hydration of different alkynes under mild conditions (40–60 °C, 0.5–1 h) [84]. In a second case, different Brønsted acid ionic

A novel recyclable organocatalyst for the gram-scale enantioselective synthesis of (S)-baclofen

• Gyula Dargó,
• Dóra Erdélyi,
• Balázs Molnár,
• Péter Kisszékelyi,
• Zsófia Garádi and
• József Kupai

Beilstein J. Org. Chem. 2023, 19, 1811–1824, doi:10.3762/bjoc.19.133

• . Consequently, we applied the cyclohexyl derivative of Meldrum’s acid 15, which exhibits enhanced solubility in non-polar solvents [36]. The Meldrum’s acid derivative 15 was synthesized from malonic acid and cyclohexanone using acetic anhydride and sulfuric acid as a catalyst (see Supporting Information File 1

Cyclodextrins permeabilize DPPC liposome membranes: a focus on cholesterol content, cyclodextrin type, and concentration

• Ghenwa Nasr,
• Hélène Greige-Gerges,
• Sophie Fourmentin,
• Abdelhamid Elaissari and
• Nathalie Khreich

Beilstein J. Org. Chem. 2023, 19, 1570–1579, doi:10.3762/bjoc.19.115

• sulforhodamine B were purchased from Sigma-Aldrich, USA. 4-Amino-3-hydroxy-1-naphthalene sulfonic acid was purchased from Fluka, India. Sulfuric acid was purchased from ACROS Organics, Belgium and diethyl ether was purchased from VWR-Prolabo Chemicals, Belgium. Liposomes preparation, extrusion, and purification

Secondary metabolites of Diaporthe cameroonensis, isolated from the Cameroonian medicinal plant Trema guineensis

• Bel Youssouf G. Mountessou,
• Élodie Gisèle M. Anoumedem,
• Blondelle M. Kemkuignou,
• Yasmina Marin-Felix,
• Frank Surup,
• Marc Stadler and
• Simeon F. Kouam

Beilstein J. Org. Chem. 2023, 19, 1555–1561, doi:10.3762/bjoc.19.112

• sulfuric acid before heating. LC–MS chromatograms were recorded with an UltiMate 3000 Series uHPLC (Thermo Fischer Scientific) using a C18 Acquity UPLC BEH column (2.1 × 50 mm, 1.7 µm) connected to an amazon speed ESI-Iontrap-MS (Bruker). Semi-preparative and/or preparative HPLC systems on normal and

Cyclization of 1-aryl-4,4,4-trichlorobut-2-en-1-ones into 3-trichloromethylindan-1-ones in triflic acid

• Vladislav A. Sokolov,
• Andrei A. Golushko,
• Irina A. Boyarskaya and
• Aleksander V. Vasilyev

Beilstein J. Org. Chem. 2023, 19, 1460–1470, doi:10.3762/bjoc.19.105

• Brønsted and Lewis acids were also tested for this cyclization. Thus, enones 2a and 2e were not transformed into the corresponding indanones 3 in neat sulfuric acid (H2SO4) at room temperature for 3 days. That is in accord with literature data [19], where H2SO4 was used for dehydration of hydroxy ketones 1

Clauson–Kaas pyrrole synthesis using diverse catalysts: a transition from conventional to greener approach

• Dileep Kumar Singh and
• Rajesh Kumar

Beilstein J. Org. Chem. 2023, 19, 928–955, doi:10.3762/bjoc.19.71

• °C were selected as optimal reaction conditions, and used for the preparations of 19 examples of N-aryl-substittuted pyrroles in 15–94% yields (Scheme 22). In another report, Aydogan and co-workers demonstrated a silica sulfuric acid (SSA) catalyzed solvent-free Clauson–Kaas synthesis of N

• -substituted pyrrole in 60–80% yields in very short reaction times [76] (Scheme 23). To optimize the reaction conditions, several green protocols were used, among these sulfuric acid-immobilised on silica gel (SSA) catalyst under solvent-free conditions was chosen for the synthesis of these N-substituted

• -substituted pyrroles 43. Synthesis of N-substituted pyrroles 45 by using Co catalyst Co/NGr-C@SiO2-L. Zinc-catalyzed synthesis of N-arylpyrroles 47. Silica sulfuric acid-catalyzed synthesis of pyrrole derivatives 49. Bismuth nitrate-catalyzed synthesis of pyrroles 51. L-(+)-tartaric acid-choline chloride

Germacrene B – a central intermediate in sesquiterpene biosynthesis

• Houchao Xu and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2023, 19, 186–203, doi:10.3762/bjoc.19.18

• -selinene (10) (Scheme 4A) [43]. Interestingly, while racemic juniper camphor (11) is formed from 1 upon acid treatment [50], this reaction with diluted sulfuric acid in acetone results in (rac)-11 quantitatively. This observation is explained by a protonation-induced cyclisation, successive addition of

• ) Cyclisation of 1 to 9 and 10 upon treatment with alumina, B) conversion into (rac)-11 by treatment with diluted sulfuric acid in acetone, C) photochemical products from 1, and D) planar chirality of 1 and its derivative 17. Possible cyclisation reactions upon reprotonation of 1. A) Cyclisations to eudesmane

Preparation of β-cyclodextrin-based dimers with selectively methylated rims and their use for solubilization of tetracene

• Konstantin Lebedinskiy,
• Volodymyr Lobaz and
• Jindřich Jindřich

Beilstein J. Org. Chem. 2022, 18, 1596–1606, doi:10.3762/bjoc.18.170

• with Thermo Scientific Helios γ with wolfram and deuterium lamp. The wavelength range is 190–800 nm. 1H, 13C, and 2D NMR spectra were measured on Bruker Avance III HD 400 spectrometer. For TLC detection of CDs, we charred a TLC plate with 50% sulfuric acid water solution at 250 °C. UV measurements The

On drug discovery against infectious diseases and academic medicinal chemistry contributions

• Yves L. Janin

Beilstein J. Org. Chem. 2022, 18, 1355–1378, doi:10.3762/bjoc.18.141

• is what provided the content of a many chemical libraries. In fact, Louis Pasteur’s 1853 report on the sulfuric acid ring opening of cinchonine into cinchonicine/cinchotoxine as well as quinine into quinicine/quinotoxine is what eventually led to the antibacterials 8–10 depicted above [228][229][230

Cyclodextrin-based Schiff base pro-fragrances: Synthesis and release studies

• Attila Palágyi,
• Jindřich Jindřich,
• Juraj Dian and
• Sophie Fourmentin

Beilstein J. Org. Chem. 2022, 18, 1346–1354, doi:10.3762/bjoc.18.140

• temperatures up to 110 °C. For thin-layer chromatography (TLC) DC-Alufolien Kieselgel 60 F265 (Merck, Darmstadt, Germany) silica gel plates were used. Carbonization in 50% sulfuric acid was used to detect the substances. An eluent mixture propanol/water/25% aqueous ammonia/ethyl acetate 6:3:1:1 (EM1) was used

Introducing a new 7-ring fused diindenone-dithieno[3,2-b:2',3'-d]thiophene unit as a promising component for organic semiconductor materials

• Valentin H. K. Fell,
• Joseph Cameron,
• Alexander L. Kanibolotsky,
• Eman J. Hussien and
• Peter J. Skabara

Beilstein J. Org. Chem. 2022, 18, 944–955, doi:10.3762/bjoc.18.94

• using polyphosphoric acid [16] and sulfuric acid failed [42], therefore we tried Friedel–Crafts acylation. For that, 27 was hydrolysed to the corresponding diacid 28 with lithium hydroxide [15]. In a manner similar to [24], firstly, a ‘cold’ Friedel–Crafts acylation in dichloromethane was attempted, in

• , 21.5 h, 79% [35]. Ring closure of key intermediate 27 to achieve 29: a) Methyl 5-bromo-2-iodobenzoate, Aliquat 336®, Pd(PPh3)4, K2CO3, THF/H2O, 70 °C, 40 h, 28% [40][41]; b) polyphosphoric acid [16], 100 °C, 4.5 h, then 130 °C, overnight, 0%; c) sulfuric acid, 115 °C, 6 h, 0% [42]; d) LiOH, THF, H2O

Terpenoids from Glechoma hederacea var. longituba and their biological activities

• Dong Hyun Kim,
• Song Lim Ham,
• Zahra Khan,
• Sun Yeou Kim,
• Sang Un Choi,
• Chung Sub Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2022, 18, 555–566, doi:10.3762/bjoc.18.58

• dipping in anisaldehyde–sulfuric acid. Plant material. Aerial parts of G. hederacea var. longituba were purchased from Hongcheon, Gangwon-do, Korea, in May 2016. The plant material was identified by Kang Ro Lee. A voucher specimen of this material (SKKU-NPL-1412) has been deposited in the herbarium of the

Menadione: a platform and a target to valuable compounds synthesis

• Acácio S. de Souza,
• Ruan Carlos B. Ribeiro,
• Dora C. S. Costa,
• Fernanda P. Pauli,
• David R. Pinho,
• Matheus G. de Moraes,
• Fernando de C. da Silva,
• Luana da S. M. Forezi and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 381–419, doi:10.3762/bjoc.18.43

• dichromate as oxidizing agent in the presence of sulfuric acid, instead of acetic acid, to obtain compound 10 in 62% yield within a shorter reaction time (Table 1, entry 2) [48]. The methodology using sodium dichromate and sulfuric acid was adapted to the industrial scale production of vitamin K3 (10

• menadione (10), as was demonstrated by Minisci and co-workers [66]. In this work, the oxidation of 17 with 60% aqueous hydrogen peroxide, using bromine and sulfuric acid as catalysts, provided menadione in 90% yield (Table 2, entry 1) [66]. According to the proposed mechanism, the first step involves the

• ) triflate [123], through an adapted Thiele–Winter acetoxylation reaction. The standard procedure involved the use of acetic anhydride and sulfuric acid catalysis. However, the use of sulfuric acid, a strong acid and oxidizing agent, can produce tar in some cases. In order to get around this problem a

A resorcin[4]arene hexameric capsule as a supramolecular catalyst in elimination and isomerization reactions

• Tommaso Lorenzetto,
• Fabrizio Fabris and
• Alessandro Scarso

Beilstein J. Org. Chem. 2022, 18, 337–349, doi:10.3762/bjoc.18.38

• protonation occurred preferentially on the alkene moiety. It is worth to note that the present dehydration reaction of 1,1-diphenylethanol with 16 occurs under mild experimental conditions with respect to recent examples in the literature operating with strong Brønsted and Lewis acids like sulfuric acid [57

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

• ) and compounds were visualised by UV irradiation (λ = 254 nm) and/or dipping in ethanol/sulfuric acid (95:5 v/v) followed by heating. A Biotage SP4 flash chromatography system was used for purification of the protected sugars with normal phase silica (pre-packed SNAP Ultra cartridges). Deprotected