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

Ready access to 7,8-dihydroindolo[2,3-d][1]benzazepine-6(5H)-one scaffold and analogues via early-stage Fischer ring-closure reaction

• Irina Kuznetcova,
• Felix Bacher,
• Daniel Vegh,
• Hsiang-Yu Chuang and
• Vladimir B. Arion

Beilstein J. Org. Chem. 2022, 18, 143–151, doi:10.3762/bjoc.18.15

• methyl 4-(2-nitrophenyl)-3-oxobutanoate [36] and 1-benzyl-1-(4-bromophenyl)hydrazine in the presence of sodium acetate and sulfuric acid in glacial acetic acid affording 1b in 55% yield. It is of note that the treatment of 1b with hydrogen in the presence of Pd/C as catalyst led not only to reduction of

Chemical and chemoenzymatic routes to bridged homoarabinofuranosylpyrimidines: Bicyclic AZT analogues

• Sandeep Kumar,
• Jyotirmoy Maity,
• Banty Kumar,
• Sumit Kumar and
• Ashok K. Prasad

Beilstein J. Org. Chem. 2022, 18, 95–101, doi:10.3762/bjoc.18.10

• ]. Azidofuranoside 11 on acetolysis with acetic acid/acetic anhydride/sulfuric acid (100:10:0.1) at room temperature afforded an anomeric mixture of 1,2,5,6-tetra-O-acetyl-3-azido-3-deoxy-α,β-ᴅ-allofuranose (12a,b), which on Vorbrüggen base coupling [29] with thymine and uracil in the presence of N,O-bis

1,2-Naphthoquinone-4-sulfonic acid salts in organic synthesis

• Ruan Carlos B. Ribeiro,
• Patricia G. Ferreira,
• Amanda de A. Borges,
• Luana da S. M. Forezi,
• Fernando de Carvalho da Silva and
• Vitor F. Ferreira

Beilstein J. Org. Chem. 2022, 18, 53–69, doi:10.3762/bjoc.18.5

• -d5, and NaOD solutions in D2O. In neutral solvents, the most stable tautomer is 4-arylamino-1,2-naphthoquinone A, while in weakly basic solvents, or ethanolic sulfuric acid, B is the most stable tautomer (Scheme 3C). Reactions employing equimolecular amounts of β-NQS and primary arylamines are

• with other nitrogenous nucleophiles, such as azide ions. The reaction of 18 in the presence of sodium azide and water produces 4-azido-1,2-naphthoquinone (39) in a 52% yield. Although 39 can produce many other derivatives, few reactions have been studied. The reaction of 39 with concentrated sulfuric

• acid at room temperature produces azepinedione 40 in an 82% yield. This compound can be transformed into several 3-substituted and 4-hydroxy derivatives. However, an interesting transformation results from the treatment of 40 with hot aqueous sodium hydroxide, resulting in 2-oxoquinoline 41 in an 80

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

• methods, which provide active ingredients to prevent or reduce the effects of oxidative stress in cells. Recently, our research group reported the synthesis of 6-amino-4-(trifluoromethyl)quinolines, which were obtained through an electrophilic aromatic substitution reaction catalyzed by sulfuric acid from

• )quinolines 1a–f was synthesized via an intramolecular cyclization reaction, in which trifluoromethyl-substituted enamino ketones reacted with concentrated sulfuric acid at adequate temperature (120 °C) and time (10 hours) to furnish the desired compounds, following the method already described in the

Synthetic strategies toward 1,3-oxathiolane nucleoside analogues

• Umesh P. Aher,
• Dhananjai Srivastava,
• Girij P. Singh and
• Jayashree B. S

Beilstein J. Org. Chem. 2021, 17, 2680–2715, doi:10.3762/bjoc.17.182

• % aqueous sulfuric acid, the isopropylidene group of 13 was selectively deprotected at 70 °C in dioxane to obtain diol 14. This diol was further cleaved using lead tetraacetate, and further reduction with sodium borohydride produced compound 15. The 5'-hydroxy group of 15 was then treated with tert

α-Ketol and α-iminol rearrangements in synthetic organic and biosynthetic reactions

• Scott Benz and
• Andrew S. Murkin

Beilstein J. Org. Chem. 2021, 17, 2570–2584, doi:10.3762/bjoc.17.172

• later explored alternative Brønsted and Lewis acids that could effectively catalyze the rearrangement of symmetric α‑hydroxy aldimines [29]. A catalyst screen was performed on the model substrate 97a (97 with R = Ph; Figure 19a) using three different Brønsted acids (acetic acid, sulfuric acid, and p

• sulfuric acid, no 102 was formed, only the free alcohol (103) in 56% yield (Figure 19c). As an extension of this method, the authors demonstrated the formation of 105, an analogue of the anesthetic ketamine (106), in 83% yield using silica gel (Figure 19d) [29]. An α‑iminol rearrangement was utilized by

• gel but not the electron-deficient p-trifluoromethylphenyl derivative. c) In the presence of silica gel or montmorillonite K 10, TBS-protected 101 is converted to 102 without any side products, but when sulfuric acid is used, only the deprotected product 103 is detected. d) Silica gel-catalyzed

Phenolic constituents from twigs of Aleurites fordii and their biological activities

• Kyoung Jin Park,
• Won Se Suh,
• Da Hye Yoon,
• Chung Sub Kim,
• Sun Yeou Kim and
• Kang Ro Lee

Beilstein J. Org. Chem. 2021, 17, 2329–2339, doi:10.3762/bjoc.17.151

• spraying the samples with anisaldehyde-sulfuric acid. Plant material. Twigs of A. fordii were collected in Chungbuk Goesan, Korea in August 2012 and the plant was identified by Dr. Kang Ro Lee, Professor at Sungkyunkwan University. A voucher specimen (SKKU-NPL 1212) has been deposited in the herbarium of