Selective and scalable oxygenation of heteroatoms using the elements of nature: air, water, and light

• Damiano Diprima,
• Hannes Gemoets,
• Stefano Bonciolini and
• Koen Van Aken

Beilstein J. Org. Chem. 2023, 19, 1146–1154, doi:10.3762/bjoc.19.82

• selectivity and safety. Traditional oxidants, such as Oxone, CrO3, NaIO4, or KMnO4, produce significant amounts of toxic waste, exacerbating these issues (Scheme 1A) [1]. As environmental concerns and economic factors increasingly affect chemical processes, hydrogen peroxide and oxygen (or air) are becoming

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

• compounds are insoluble in water and provides poor yields of the product in solvent-free conditions. Gullapelli et al. [92] described the Clauson–Kaas synthesis of N-arylpyrroles 79 under microwave irradiation using oxone (2KHSO5∙KHSO4∙K2SO4) as a catalyst (Scheme 38a). Many solvents (EtOH, CH3CN, THF, DMF

• , H2O, neat), reaction times (10–22 minutes), and amount of oxone were investigated in order to stabilize the best reaction conditions. Among these, CH3CN as the best solvent system, 0.09 g of oxone, and a temperature of 110 ± 10 °C were chosen as optimized reaction conditions and used for the synthesis

• of N-arylpyrroles from various amines 78 via the reaction with 2,5-dimethoxytetrahydrofuran (2). Oxone is a mild, inexpensive, nontoxic, stable, and transition-metal-free catalyst that is very easy to handle during this transformation and provided high yields of the product. The authors also proposed

Redox-active molecules as organocatalysts for selective oxidative transformations – an unperceived organocatalysis field

• Elena R. Lopat’eva,
• Igor B. Krylov,
• Dmitry A. Lapshin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2022, 18, 1672–1695, doi:10.3762/bjoc.18.179

• that hydrogen bonding is considered as one of the key factors determining the selectivity of catalyst-free sulfoxidations [68]. In such reactions, the selectivity of sulfide oxidation by oxone (sulfoxide/sulfone ratio) was controlled by the solvent nature (deeper oxidation was observed in water than in

Synthesis and HDAC inhibitory activity of pyrimidine-based hydroxamic acids

• Virginija Jakubkiene,
• Gabrielius Ernis Valiulis,
• Markus Schweipert,
• Asta Zubriene,
• Daumantas Matulis,
• Franz-Josef Meyer-Almes and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 837–844, doi:10.3762/bjoc.18.84

• -methylthiopyrimidines with m-CPBA and oxone and found that oxone gave better results, so we have chosen it for this reaction. Thus, heating compound 3 in dimethylformamide at 40 °C for 0.5 h with oxone gave compound 5 in 80% yield. In the NMR spectra of compound 5, the peaks of the methylsulfonyl group are downfield

• of compounds 3–18. Reagents and conditions: (a) ethyl 2-bromoethanoate, TBAB, TEA, 50–60 °C, 0.5 h; (b) oxone, DMF, 40 °C, 0.5 h; (c) corresponding amine, DMSO, 50–70 °C, 0.5 h; (d) H2O, DMSO, 100 °C, 0.5 h; (e) H2O, reflux, 1 h; (f) aqueous NaOH, dioxane, rt, 12 h, then, conc. HCl to pH 2; (g

DDQ in mechanochemical C–N coupling reactions

• Shyamal Kanti Bera,
• Rosalin Bhanja and
• Prasenjit Mal

Beilstein J. Org. Chem. 2022, 18, 639–646, doi:10.3762/bjoc.18.64

• reagents, but none of them gave better yields (Table 1, entries 4–7). On the other hand, oxone as an oxidant yielded product 2a with up to 43% yield (Table 1, entry 8). Similarly, we have optimized the reaction conditions for the synthesis of 2-phenylquinazolin-4(3H)-one (5a) from anthranilamide and

• the other hand, increasing the amount of DDQ to 1.2 equiv resulted in 98% yield of the product (Supporting Information File 1, Table S1, entries 1 and 3). Further studies revealed that other commonly used oxidants such as PIDA and oxone gave 30% and 61% the desired product, respectively (Supporting

Substituent effect on TADF properties of 2-modified 4,6-bis(3,6-di-tert-butyl-9-carbazolyl)-5-methylpyrimidines

• Irina Fiodorova,
• Tomas Serevičius,
• Rokas Skaisgiris,
• Saulius Juršėnas and
• Sigitas Tumkevicius

Beilstein J. Org. Chem. 2022, 18, 497–507, doi:10.3762/bjoc.18.52

• methylsulfonyl group was necessary to perform. A suitable oxidant for this purpose appeared to be oxone [40]. Thus, the oxidation of tCbz-mPYR with oxone proceeded in DMF at 80 °C to provide the 2-methylsulfonyl derivative 3 in 92% yield. Then, treatment of compound 3 with NaCN or 4-(tert-butyl)thiophenol led to

• the formation of the 2-cyano- and 2-(4-tert-butylphenylthio) derivatives 4 and 5 in 65% and 77% yield, respectively. Finally, compound 5 in the reaction with oxone furnished 2-(4-tert-butylphenylsulfonyl) derivative 6 in reasonable 68% yield. 1H and 13C NMR spectroscopy and HRMS were employed to

• , 130.3, 131.2, 134.0, 137.8, 139.0, 144.5, 160.4, 161.7 ppm; HRMS–ESI (m/z): [M + H]+ calcd for C51H56BrN4, 803.3683; found, 803.3675. 4,6-Bis(3,6-di-tert-butyl-9H-carbazol-9-yl)-5-methyl-2-methylsulfonylpyrimidine (3). A mixture of compound tCbz-mPYR (60 mg, 0.086 mmol), oxone (133.2 mg, 0.217 mmol, 2.5

Highly stereocontrolled total synthesis of racemic codonopsinol B through isoxazolidine-4,5-diol vinylation

• Lukáš Ďurina,
• Anna Ďurinová,
• František Trejtnar,
• Ľuboš Janotka,
• Lucia Messingerová,
• Jana Doháňošová,
• Ján Moncol and
• Róbert Fischer

Beilstein J. Org. Chem. 2021, 17, 2781–2786, doi:10.3762/bjoc.17.188

• reported 2-chloropyridine reduced the product yield slightly to 60% [25]. The subsequent epoxidation of 9 with in situ-generated DMDO (a combination of oxone and NaHCO3 in acetone/water) provided isoxazolidinyl epoxide 10 in almost quantitative yield as a sole trans isomer (dr > 95:5). Finally, the acid

• rt, 16 h, 68%; (c) oxone, NaHCO3, acetone/H2O 3:2, 0 °C to rt, 80 min, 99%; (d) HCl (37 wt % in H2O), acetone/H2O 4:1, 0 °C, 30 min, 93%. Synthesis of final pyrrolidines (±)-1 and (±)-2. Reagents and conditions: (a) vinyl-MgBr, CeCl3, THF, 0 °C to rt, 16 h, 73%; (b) Zn dust, AcOH, 40 °C, 24 h, 85

A novel methodology for the efficient synthesis of 3-monohalooxindoles by acidolysis of 3-phosphate-substituted oxindoles with haloid acids

• Li Liu,
• Yue Li,
• Tiao Huang,
• Dulin Kong and
• Mingshu Wu

Beilstein J. Org. Chem. 2021, 17, 2321–2328, doi:10.3762/bjoc.17.150

• Prathima group established an expedient approach for the direct oxidative chlorination of indole-3-carboxaldehyde to 3-monochlorooxindoles using a combination of NaCl and oxone as the chlorine source and oxidant in a CH3CN/H2O 1:1 system (Scheme 1, reaction 2) [22]. Nearly at the same time, Yu and co

• -monohalooxindoles involve the direct halogenation of oxindoles with various reactive halogenating reagents, including N-chloro-N-methoxybenzenesulfonamide [24][25], ammonium halides/oxone [13], Selectfluor® [26][27], and CuBr2 (Scheme 1, reaction 4) [15]. However, these protocols each have a certain scope and

Catalyzed and uncatalyzed procedures for the syntheses of isomeric covalent multi-indolyl hetero non-metallides: an account

• Ranadeep Talukdar

Beilstein J. Org. Chem. 2021, 17, 2102–2122, doi:10.3762/bjoc.17.137

• )indole (111). As the sulfur in 111 is methyl-protected, no dimerization occurs. Oxidation of sulfur by oxone followed by repetition of the previous steps afford the diindol-3-ylsulfonium salt 114, which in the presence of a base gives product 105a. Li et al. used 2-(fluorosulfonyl)difluoroacetic acid

A comprehensive review of flow chemistry techniques tailored to the flavours and fragrances industries

• Guido Gambacorta,
• James S. Sharley and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2021, 17, 1181–1312, doi:10.3762/bjoc.17.90

Synthesis of 4-substituted azopyridine-functionalized Ni(II)-porphyrins as molecular spin switches

• Jannis Ludwig,
• Tobias Moje,
• Fynn Röhricht and
• Rainer Herges

Beilstein J. Org. Chem. 2020, 16, 2589–2597, doi:10.3762/bjoc.16.210

• Oxone™ (Wegner et al. [19][20][21], Scheme 1). Isolation of 3 was achieved, however, a one pot approach including a subsequent Baeyer–Mills reaction to yield 10 is preferred. 1-Iodo-3-nitrosobenzene (6) cannot be prepared by oxidation of the corresponding aniline because hypervalent iodine is formed [22

Synthetic approaches to bowl-shaped π-conjugated sumanene and its congeners

• Shakeel Alvi and
• Rashid Ali

Beilstein J. Org. Chem. 2020, 16, 2212–2259, doi:10.3762/bjoc.16.186

• generate the corresponding pyrazine-fused sumanene networks 169a–f and 170a–f in low-to-good yields (Scheme 44). As can be inspected from Scheme 45, oxidation of 155 and 160 with both oxone (potassium peroxymonosulfate) and H2O2 afforded the one-ring-opened product 177. Interestingly, when these compounds

• -7,7,8,8-tetracyanoquinodimethane (F4-TCNQ). On the other hand, when compounds 178 and 179 were reacted with oxidizing agents such as oxone and H2O2, selectively one benzene ring-cleaved products 180 and 181 were isolated (Scheme 46) [85]. Having the ring-opened products in hands, they were then subjected

When metal-catalyzed C–H functionalization meets visible-light photocatalysis

• Lucas Guillemard and
• Joanna Wencel-Delord

Beilstein J. Org. Chem. 2020, 16, 1754–1804, doi:10.3762/bjoc.16.147

• borylation under mild reaction conditions, thus delivering, after oxidation of the crude reaction mixture with Oxone, a large panel of the corresponding hydroxylated pyridine products. From the mechanistic point of view, this reaction is expected to differ from the previously described Ru-catalyzed meta

Fluorohydration of alkynes via I(I)/I(III) catalysis

• Jessica Neufeld,
• Constantin G. Daniliuc and
• Ryan Gilmour

Beilstein J. Org. Chem. 2020, 16, 1627–1635, doi:10.3762/bjoc.16.135

• (50% yield), ground Oxone® or N-pyridine oxide proved to be ineffective (Table 1, entries 9–11). Increasing the reaction temperature to 50 °C led to the same outcome as at ambient temperature (64% yield, Table 1, entry 12). Finally, the control reactions in the absence of catalyst, oxidant and HF

Design and synthesis of diazine-based panobinostat analogues for HDAC8 inhibition

• Sivaraman Balasubramaniam,
• Sajith Vijayan,
• Liam V. Goldman,
• Xavier A. May,
• Kyra Dodson,
• Sweta Adhikari,
• Fatima Rivas,
• Davita L. Watkins and
• Shana V. Stoddard

Beilstein J. Org. Chem. 2020, 16, 628–637, doi:10.3762/bjoc.16.59

• attempts to oxidize the methyl group at the benzylic position in starting materials 2 and 3 to provide the corresponding aldehyde compounds 13 and 14 failed, despite using rigorous reaction conditions of SeO2 or alternative strong oxidizing agents (e.g., MnO2 and oxone). Thus, we considered the critical

A toolbox of molecular photoswitches to modulate the CXCR3 chemokine receptor with light

• Xavier Gómez-Santacana,
• Sabrina M. de Munnik,
• Tamara A. M. Mocking,
• Niels J. Hauwert,
• Shanliang Sun,
• Prashanna Vijayachandran,
• Iwan J. P. de Esch,
• Henry F. Vischer,
• Maikel Wijtmans and
• Rob Leurs

Beilstein J. Org. Chem. 2019, 15, 2509–2523, doi:10.3762/bjoc.15.244

• oxidation of methyl 3-aminobenzoate (17a) using Oxone® to obtain a crude nitroso product 18a, which was used in a Mills reaction with an iodoaniline (19a–c) at 100 °C to obtain azobenzenes 20g,h in high yields and ortho-analogue 20f in a decreased yield presumably due to steric hindrance. The methyl ester

• oxidation of methyl 5-amino-2-chlorobenzoate (17c) with Oxone® to 18c, which was used in a Mills reaction with 2-iodoaniline (19a) to yield azobenzene 21. The methyl ester was selectively reduced with DIBAL-H and the resulting alcohol 24 oxidized with Dess–Martin periodinane to benzaldehyde 27. Reductive

• (5.0 equiv), EtOH, 75 °C, 2 h, 87%–quant; (c) AcOH/DCM, rt, 1–5 d, 23–73%, (d) MeI (20 equiv), DCM, rt, 6–72 h, 41–97%. Synthetic strategies for compounds 3f–h, 4e, 6b, and 6d (Y = H, F, Cl, Br). Reagents and conditions: (a) Oxone® (2.0 equiv), DCM/H2O 1:4, rt, 2 h, 91–98%; (b) AcOH, 100 °C, 16–20 h

Azologization and repurposing of a hetero-stilbene-based kinase inhibitor: towards the design of photoswitchable sirtuin inhibitors

• Christoph W. Grathwol,
• Nathalie Wössner,
• Sören Swyter,
• Adam C. Smith,
• Enrico Tapavicza,
• Robert K. Hofstetter,
• Anja Bodtke,
• Manfred Jung and
• Andreas Link

Beilstein J. Org. Chem. 2019, 15, 2170–2183, doi:10.3762/bjoc.15.214

• -[(4-fluorophenyl)diazenyl]nicotinate (10): 4-Fluoroaniline (444 mg, 4.00 mmol, 1.00 equiv) was dissolved in DCM (15 mL) and treated with a solution of oxone (4.92 g, 8.00 mmol, 2.00 equiv) in water (50 mL). The biphasic mixture was vigorously stirred until thin layer chromatography indicated complete

• ; toluene, reflux, 3 h, 76%; d) NH3, MeOH, 40 °C, 3 d, 87–95%. Photocyclization and oxidation reaction of 2b upon UV irradiation. Reagents and conditions: a) 4-fluoroaniline, oxone, HAc, 60 °C, 14 d, 42%; b) NH3, MeOH, rt, 3 d, 98%. Sirt1–3 inhibition for compounds 2a–h, 4a/4b and 8a. Percentage of E/Z

Metal-free mechanochemical oxidations in Ertalyte^® jars

• Andrea Porcheddu,
• Francesco Delogu,
• Lidia De Luca,
• Claudia Fattuoni and
• Evelina Colacino

Beilstein J. Org. Chem. 2019, 15, 1786–1794, doi:10.3762/bjoc.15.172

• compounds under very mild conditions [6][7]. Initially used in a stoichiometric amount [8], over the last 20 years it has been exploited successfully in catalytic quantities in combination with other oxidants [9]. A diverse range of co-oxidant agents (N-chlorosuccinimide, NaOCl, Oxone®, PhIO, PhICl2, PhI

• process [55]. Also, Oxone® and NH2CONH2·H2O2 appeared to fail in the oxidation of 3-phenyl-1-propanol (1a) to the corresponding aldehyde. Subsequently, we turned our attention to sodium hypochlorite (NaOCl), an inexpensive and widely used oxidizing reagent also applied as a disinfectant and household

N-(1-Phenylethyl)aziridine-2-carboxylate esters in the synthesis of biologically relevant compounds

• Iwona E. Głowacka,
• Aleksandra Trocha,
• Andrzej E. Wróblewski and
• Dorota G. Piotrowska

Beilstein J. Org. Chem. 2019, 15, 1722–1757, doi:10.3762/bjoc.15.168

• bulkiness of the tert-butyldimethylsilyloxy group in 205 three different approaches to stereoselective dihydroxylations of the C=C bond were elaborated. Thus, treatment with Oxone® gave the anti-epoxide 206 which was regioselectively opened in a boron

Recent advances on the transition-metal-catalyzed synthesis of imidazopyridines: an updated coverage

• Gagandeep Kour Reen,
• Ashok Kumar and
• Pratibha Sharma

Beilstein J. Org. Chem. 2019, 15, 1612–1704, doi:10.3762/bjoc.15.165

Mechanistic studies of an L-proline-catalyzed pyridazine formation involving a Diels–Alder reaction with inverse electron demand

• Anne Schnell,
• J. Alexander Willms,
• S. Nozinovic and
• Marianne Engeser

Beilstein J. Org. Chem. 2019, 15, 30–43, doi:10.3762/bjoc.15.3

• ; found, 326.0165; EIMS m/z (%): 326.0 (3%) [M]+•, 247.1 (4%) [M − Br]+, 116.0 (100%) [M − C7H5BrN3]+, 103.0 (36%), 76.0 (7%). TBCA preparation The synthesis of tribromoisocyanuric acid was conducted according to the procedure of de Almeida et al. [57]. A solution of OXONE® (14.29 g, 46.49 mmol, 3 equiv

DABCO- and DBU-promoted one-pot reaction of N-sulfonyl ketimines with Morita–Baylis–Hillman carbonates: a sequential approach to (2-hydroxyaryl)nicotinate derivatives

• Soumitra Guin,
• Raman Gupta,
• Debashis Majee and
• Sampak Samanta

Beilstein J. Org. Chem. 2018, 14, 2771–2778, doi:10.3762/bjoc.14.254

• as the requirement of high temperatures or use of strong oxidants (H2O2, oxone, K2S2O8, TBHP, PIDA, NHPI etc.) that are not much compatible with functionality, precluding late-stage functionalization. Moreover, the scope of substitution on the pyridine ring is limited which in turn hampers the

The mechanochemical synthesis of quinazolin-4(3H)-ones by controlling the reactivity of IBX

• Md Toufique Alam,
• Saikat Maiti and
• Prasenjit Mal

Beilstein J. Org. Chem. 2018, 14, 2396–2403, doi:10.3762/bjoc.14.216

• ]. During the reaction with the stronger oxidant PIDA, the basicity of the amine was regulated using an externally added acid salt, NaHSO4 (Figure 2a). In Figure 2b, a comparison in the reactivities of arylamines in the presence of non-iodine-based oxidant oxone [32] and IBX (iodine-based oxidant) is shown

• . Anilines readily reacted with oxone leading to the formation of the azo derivatives [32], while their treatment with IBX led to explosive decomposition. The reactions of 2-aminobenzamide with arylaldehydes in the presence of IBX afforded quinazolin-4(3H)-ones at maximum contact of the reactants, i.e

•  1, entries 3 and 4). The reaction also took place, albeit affording the product in lower yield, with in situ-generated IBX [33], i.e., by using an IBA (2-iodobenzoic acid)–oxone combination (Table 1, entry 5). Interestingly, when silica gel [34] was used as additive during the handling of liquid

Hypervalent iodine compounds for anti-Markovnikov-type iodo-oxyimidation of vinylarenes

• Igor B. Krylov,
• Stanislav A. Paveliev,
• Mikhail A. Syroeshkin,
• Alexander A. Korlyukov,
• Pavel V. Dorovatovskii,
• Yan V. Zubavichus,
• Gennady I. Nikishin and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2018, 14, 2146–2155, doi:10.3762/bjoc.14.188

• reaction time were varied (Table 1). In general, the iodo-oxyimidation reaction is characterized by the following: The product 3aa is formed regardless what kind of hypervalent iodine compound is used (Table 1, entries 1-14) and Oxone (Table 1, entries 15 and 16) as the oxidant. The best yield of 3aa (90

• system [74], (NH4)2S2O8, and DDQ were ineffective in the studied process (Table 1, entries 17–22). A satisfactory yield of 3aa (44%) was achieved using Oxone as the oxidant (Table 1, entry 15). The addition of a catalytic amount of 2-iodobenzoic acid, which forms hypervalent iodine compounds in the

• presence of Oxone [75], did not lead to an increased yield of 3aa (Table 1, entry 16). Dichloromethane proved to be the best solvent for the reaction, as carrying out the reaction in other solvents led to a decrease in the yield of 3aa (Table 1, entries 5–7). Increasing the amount of PhI(OAc)2 from 0.6

Preparation and X-ray structure of 2-iodoxybenzenesulfonic acid (IBS) – a powerful hypervalent iodine(V) oxidant

• Irina A. Mironova,
• Pavel S. Postnikov,
• Rosa Y. Yusubova,
• Akira Yoshimura,
• Thomas Wirth,
• Viktor V. Zhdankin,
• Victor N. Nemykin and
• Mekhman S. Yusubov

Beilstein J. Org. Chem. 2018, 14, 1854–1858, doi:10.3762/bjoc.14.159

• -iodobenzenesulfonate with Oxone or sodium periodate in water is reported. The single crystal X-ray diffraction analysis reveals a complex polymeric structure consisting of three units of IBS as potassium salt and one unit of 2-iodoxybenzenesulfonic acid linked together by relatively strong I=O···I intermolecular

• to the respective carbonyl compounds with Oxone® (2KHSO5·KHSO4·K2SO4) in nitromethane, acetonitrile, or ethyl acetate [13]. Recent research has revealed the extreme activity of IBS as a catalyst in numerous other oxidations, such as: the oxidation of benzylic and alkane C–H bonds [14], the oxidation

• different approaches: direct oxidation of 2-iodobenzenesulfonic acid (2) by Oxone or hydrolysis of methyl 2-iodoxybenzenesulfate (3, Scheme 1) [18]. The hydrolysis of sulfonic ester 3 forms IBS as a mixture with methanol which is quickly oxidized by IBS in situ producing the corresponding iodine(III