Semisynthetic derivatives of massarilactone D with cytotoxic and nematicidal activities

• Rémy B. Teponno,
• Sara R. Noumeur and
• Marc Stadler

Beilstein J. Org. Chem. 2025, 21, 607–615, doi:10.3762/bjoc.21.48

• ]. Compound 2 was obtained in 11% yield (3.50 mg, tR = 39.28 min). White powder; [α]D25 − 38.8 (c 0.0006, acetone); UV (c 0.075 mg/mL, EtOH) λmax 241 nm (3.84); 1H NMR (500 MHz, acetone-d6) δH 6.24 (dq, J = 2.1, 1.0 Hz, Ha-3''), 6.18 (dq, J = 2.2, 1.0 Hz, Ha-3'''), 6.12–6.08 (m, H-9), 5.93 (ddq, J = 15.2, 8.7

• , 1.5 Hz, H-3'), 5.92 (m, H-9), 5.85 (ddq, J = 15.3, 8.1, 1.3 Hz, H-8), 4.81 (dd, J = 7.6, 5.2 Hz, H-2), 4.38 (dd, J = 4.3, 0.9 Hz, H-4), 3.82 (dd, J = 5.1, 4.4 Hz, H-3), 1.81 (dq, J = 7.1, 1.2 Hz, 3H-4'), 1.77 (q, J = 1.2 Hz, 3H-5'), 1.76 (s, 3H-11), 1.72 (m, 3H-10); 13C NMR (125 MHz, acetone-d6) δC

• , 1.7 Hz, H-2''), 5.73 (ddq, J = 15.5, 7.7, 1.6 Hz, H-8), 5.55 (dd, J = 3.2, 1.4 Hz, H-4), 5.12 (ddt, J = 6.6, 3.3, 1.2 Hz, H-2), 4.06 (t, J = 3.2 Hz, H-3), 3.20 (s, OMe), 1.88 (dd, J = 6.9, 1.7 Hz, 3H-4''), 1.73 (ddd, J = 6.5, 1.6, 0.9 Hz, 3H-10), 1.63 (s, 3H-11); 13C NMR (125 MHz, acetone-d6) δC 174.1

The effect of neighbouring group participation and possible long range remote group participation in O-glycosylation

• Rituparna Das and
• Balaram Mukhopadhyay

Beilstein J. Org. Chem. 2025, 21, 369–406, doi:10.3762/bjoc.21.27

• . Thus, Vatèle devised a temporary protecting group named 2-(prenyloxymethyl)benzoyl (POMB, 43) which could be selectively deprotected under mild conditions by a combination of DDQ/Yb(OTf)3 keeping the other protecting groups, like acetyl, chloroacetyl, benzoyl, pivaloyl intact [125]. Owing to its ester

Recent advances in organocatalytic atroposelective reactions

• Henrich Szabados and
• Radovan Šebesta

Beilstein J. Org. Chem. 2025, 21, 55–121, doi:10.3762/bjoc.21.6

• products 89 and their subsequent oxidation with DDQ provided axially chiral quinolines 90 (Scheme 29) [53]. Good retention of the stereoinformation acquired in the first transformation, moderate to excellent yields and consistently high degrees of enantiomeric purity were achieved. The reaction could also

• be carried out in a one-pot fashion with comparable results and without significant variation from the two-step procedure. Utilization of the Povarov reaction and subsequent oxidation by DDQ was also done by Wang et al. in 2020 [54]. In situ-formed imines from anilines 91 and benzaldehydes 92 were

• subsequent oxidation with DDQ provided the respective products 127. When indoles 129 were utilized with quinone 128, no further oxidizing reagents were necessary to afford indolylquinones 130. All products were obtained with high enantiomeric ratios and moderate to good yields. A model reaction performed at

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

• trione 1 in hands, we explored the Scholl reaction and thionation reaction of it (Scheme 1b) because these reactions can potentially allow π-expansion of 1. A variety of Scholl reaction conditions, such as AlCl3/NaCl, AlCl3/CuCl2, FeCl3, and DDQ/TfOH, were tested. However, these reactions either left the

• Barton–Kellogg reaction with 8b under similar conditions gave the episulfide intermediate, which, however, could not be desulfurized with triisopropyl phosphite, trimethyl phosphite or triphenylphosphine to give the corresponding triene. The subsequent Scholl reaction of 10 with DDQ and triflic acid at

• -layer chromatography (TLC). When other typical conditions for Scholl reactions, such as FeCl3 or DDQ/CH3SO3H, were employed to treat compound 10, product 3 was not isolated. Instead, the starting material either remained unreacted or was converted to a complicated mixture of products. It is worth noting

Synthesis of fluorinated acid-functionalized, electron-rich nickel porphyrins

• Mike Brockmann,
• Jonas Lobbel,
• Lara Unterriker and
• Rainer Herges

Beilstein J. Org. Chem. 2024, 20, 2954–2958, doi:10.3762/bjoc.20.248

• porphyrins with Ni(acac)2; c) ester hydrolysis to generate the free acids 32, 33, and 34. Conditions: a) 1) 22/23/24, TFA, abs. DCM, N2, reflux, 30 min, 2) pyrrole, reflux, 2.5 h, 3) DDQ, reflux, 2 h; b) Ni(acac)2, toluene, reflux, 20 h; c) 1) LiOH, MeOH, rt, 1 h, 2) HCl. Supporting Information Supporting

N-Glycosides of indigo, indirubin, and isoindigo: blue, red, and yellow sugars and their cancerostatic activity

• Peter Langer

Beilstein J. Org. Chem. 2024, 20, 2840–2869, doi:10.3762/bjoc.20.240

• ). Dehydrogenation of the latter with DDQ afforded the anomerically pure indol-N-glycoside β-26a which upon benzylation and methylation gave products β-27a and β-27b, respectively. Iodination gave products β-28a and β-28b, however, due to the basic reaction conditions (I2, NaOH, DMF), ether rather than ester

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

• with aldehydes 8, 9, and 10 under Lindsey conditions [42] utilizing BF3·OEt2 and DDQ [43] to achieve porphyrins 4, 5, and 6, which were not isolated and instead reacted immediately. Ni(II)porphyrins 11, 12, and 13 were prepared by reacting porphyrins 4, 5, and 6 in toluene for 18 hours using Ni(II

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

• authors, the reaction proceeds via hydrogen-atom transfer (HAT) at the benzylic position, mediated by DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone). The proposed mechanism includes two possible pathways: In path A, the benzylic position undergoes HAT to form a benzyl radical, which is then oxidized by

• the DDQH• radical to generate a carbocation and DDQH−. In path B, the reaction involves direct hydride transfer to DDQ, forming DDQH− and a carbocation. In both pathways, the amine nucleophile captures the carbocation, resulting in the final amination product after losing a proton. Subsequently, DDQH

• − is protonated to produce DDQH2. The anodic oxidation of DDQH2 regenerates DDQ, which re-enters the catalytic cycle (Scheme 29). Furthermore, Qiu and coworkers disclosed a metal-free electrochemical dihydroxylation of unactivated alkenes using water as the hydroxy source under air conditions [40

Multicomponent syntheses of pyrazoles via (3 + 2)-cyclocondensation and (3 + 2)-cycloaddition key steps

• Ignaz Betcke,
• Alissa C. Götzinger,
• Maryna M. Kornet and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2024, 20, 2024–2077, doi:10.3762/bjoc.20.178

• -unsaturated ketone with hydrazine and acetic acid forms a 1-acylpyrazoline, while the chromene moiety and hydrazine form the pyrazole nucleus by ring opening/ring closing cyclocondensation. Upon oxidation with DDQ, the pyrazolylpyrazoline products can be readily converted into the corresponding bispyrazoles

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

• slight excess of diamines to sequester released HCl proved to be pivotal in achieving better yields. Oxidation with two equivalents of DDQ provided the comparator DCPQs 1a and 2a in 89% and 87% yield, respectively. The synthesis of DCPQ 3a was attempted rigorously under different conditions using

• 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

• (DART): [M + H]+ calcd for C12H4N6, 233.0570; found, 233.0574; [M + NH4]+, 250.0836; found, 250.0839. 7,8-Dimethylpyrazino[2,3-b]quinoxaline-2,3-dicarbonitrile (2a) Compound 2a was synthesized the same way as 1a using DDQ (0.581 g, 2.56 mmol), 7,8-dimethyl-5,10-dihydropyrazino[2,3-b]quinoxaline-2,3

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

• tetrabromothiophene S,S-dioxide 24 at 120–140 °C to yield the corresponding S- and Se-tribenzo[b,d,f]heteropines, 25b and 25c respectively, after oxidative aromatization mediated by DDQ. In the case of tellurepine 23d, attempts of thermally-activated Diels–Alder reaction resulted in Te-extrusion to afford

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

• activity/inactivity in amination reactions. It is known that acenaphthylenes are usually readily formed from acenaphthenes by dehydrogenation with chloranil, dichlorodicyanobenzoquinone (DDQ) or active MnO2 on reflux in toluene/xylene and other inert solvents. However, attempts to obtain acenaphthylene 8

Substituent-controlled construction of A₄B₂-hexaphyrins and A₃B-porphyrins: a mechanistic evaluation

• Seda Cinar,
• Dilek Isik Tasgin and
• Canan Unaleroglu

Beilstein J. Org. Chem. 2023, 19, 1832–1840, doi:10.3762/bjoc.19.135

• )tripyrromethane (1, 0.090 mmol) in CH2Cl2 (1.5 mL) and the mixture was stirred at rt for 4 h. Afterwards, DDQ (0.180 mmol) was added to this solution and stirred for another 2 h. The resulting solution was eluted through a short silica gel column with EtOAc and the solvent was removed under reduced pressure. The

• stirred at rt for 4 h. Afterwards, DDQ (0.195 mmol) was added to this solution and stirred for another 2 h. The resulting solution was eluted through a short silica gel column with EtOAc and the solvent was removed under reduced pressure. The residue was purified by silica gel column chromatography (EtOAc

Tying a knot between crown ethers and porphyrins

• Maksym Matviyishyn and
• Bartosz Szyszko

Beilstein J. Org. Chem. 2023, 19, 1630–1650, doi:10.3762/bjoc.19.120

• ) complex 40-Cu formation proving that 40 acts as a colourimetric sensor. The reaction of 38 with pyrrole in the presence of BF3:Et2O resulted in 41 incorporating a single pyrrole ring [132]. The attempted oxidation with DDQ afforded fused macrocycle 42 (Scheme 11). The X-ray molecular structure of 42

Synthesis of ether lipids: natural compounds and analogues

• Marco Antônio G. B. Gomes,
• Alicia Bauduin,
• Chloé Le Roux,
• Romain Fouinneteau,
• Wilfried Berthe,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2023, 19, 1299–1369, doi:10.3762/bjoc.19.96

• cesium cation with the halogen atom and the activation of the Sn–O bond of the stannylene acetal via a pentacoordinated intermediate with the fluoride anion [110]. The acetylation of the secondary alcohol and the deprotection of the primary alcohol with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ

Non-noble metal-catalyzed cross-dehydrogenation coupling (CDC) involving ether α-C(sp³)–H to construct C–C bonds

• Hui Yu and
• Feng Xu

Beilstein J. Org. Chem. 2023, 19, 1259–1288, doi:10.3762/bjoc.19.94

• benzylic ethers occurs at room temperature in the presence of Cu(OTf)2/InCl3 as catalysts and DDQ as oxidant (Scheme 3) [51]. By this route, a series of 2-alkoxymalonate diester derivatives was synthesized through direct CDC reaction. The mechanism study showed that the first step of the catalytic cycle

• involved in the activation of DDQ by coordinating the carbonyl oxygen atom which leads to an increase in the oxidation activity of DDQ. Subsequently, Li et al. improved the above method, using a mixture of indium and copper salts as a catalyst, NHPI (N-hydroxyphthalimide) as a co-catalyst to achieve the

• attention. Todd et al. reported a method for the cross-dehydrogenation coupling of isochroman C(sp3)–H bonds with anisole C(sp2)–H bonds using CuCl as a catalyst and DDQ as an oxidant (Scheme 11) [61]. However, this method is not ideal for tolerating substrates with electron-donating substituents (such as 1

Enabling artificial photosynthesis systems with molecular recycling: A review of photo- and electrochemical methods for regenerating organic sacrificial electron donors

• Grace A. Lowe

Beilstein J. Org. Chem. 2023, 19, 1198–1215, doi:10.3762/bjoc.19.88

• reductive quenching of Ru(bpy)3 and reduction of photooxidized Ru(bpy)3. Furthermore, quinones have well-studied PCET chemistry [26]. 2,3-Dichloro-5,6-cyano-1,4,hydroquinone, the hydrogenated form of 2,3-dichloro-5,6-cyano-1,4-benzoquinone (DDQ), has the highest oxidation potential of the 3 quinone examples

• electrochemical hydrogenation methods might be more appropriate [41][42]. There is already work on electrochemical dehydrogenation of LOHCs [76][77]. In one example, DDQ was used to remove hydrogen from secondary amines by oxidizing them, followed by reoxidation of the hydrogenated DDQ at the electrode to

• establish a redox catalysis cycle [76]. In non-aqueous media DDQ has a low oxidation potential (0.14 V vs Fc/Fc+ in acetonitrile) so that DDQ could potentially reductively quench Ir(ppy)3 and Ru(bpy)3 and regenerate

New one-pot synthesis of 4-arylpyrazolo[3,4-b]pyridin-6-ones based on 5-aminopyrazoles and azlactones

• Vladislav Yu. Shuvalov,
• Ekaterina Yu. Vlasova,
• Tatyana Yu. Zheleznova and
• Alexander S. Fisyuk

Beilstein J. Org. Chem. 2023, 19, 1155–1160, doi:10.3762/bjoc.19.83

• are also low in two-stage synthesis methods. The first of them is based on the three-component condensation of aminopyrazoles, Meldrum's acid, and aromatic aldehydes, followed by the oxidation of the intermediate with DDQ [13][16][19] (method B). The second one includes the reaction of an aromatic

Photoredox catalysis harvesting multiple photon or electrochemical energies

• Mattia Lepori,
• Simon Schmid and
• Joshua P. Barham

Beilstein J. Org. Chem. 2023, 19, 1055–1145, doi:10.3762/bjoc.19.81

Aromatic C–H bond functionalization through organocatalyzed asymmetric intermolecular aza-Friedel–Crafts reaction: a recent update

• Anup Biswas

Beilstein J. Org. Chem. 2023, 19, 956–981, doi:10.3762/bjoc.19.72

• enantioselective aza-Friedel–Crafts addition. In the first step, the DDQ-promoted oxidation of 3-indolinonecarboxylate 22 generated indolenines that performed as the potential electrophiles towards indoles 4. The chiral catalyst effectively assembled the reacting partners in a chiral transition state through H

Honeycomb reactor: a promising device for streamlining aerobic oxidation under continuous-flow conditions

• Masahiro Hosoya,
• Yusuke Saito and
• Yousuke Horiuchi

Beilstein J. Org. Chem. 2023, 19, 752–763, doi:10.3762/bjoc.19.55

• Pd(OAc)2 did not dissolve in toluene even with pyridine. As a substitute for TEMPO, 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) was tried (Table 1, entries 9 and 10) [45]. Although the reactivity was improved compared with the TEMPO catalytic system in Table 1, entries 3–5, the DDQ catalytic system

Construction of hexabenzocoronene-based chiral nanographenes

• Ranran Li,
• Di Wang,
• Shengtao Li and
• Peng An

Beilstein J. Org. Chem. 2023, 19, 736–751, doi:10.3762/bjoc.19.54

• -dicyano-p-benzoquinone (DDQ) and methanesulfonic acid in dichloromethane, the helical structure 7 was obtained in a 72% yield [34]. The possible reason for this incomplete cyclization is the electronic effect of the alkoxy groups. Meanwhile, the methoxy version was also synthesized from precursor 5. The

• dibenzocyclooctyne 8 and tetracyclone 2 in a 91% yield. After a subsequent sequence of deprotection and oxidation, ketone 10 was obtained. Through the oxidative cyclodehydrogenation reaction of 10 in the presence of DDQ and trifluoromethanesulfonic acid (TfOH), a saddle-helix hybrid nanographene 11, bearing an

• Scholl reaction conditions (DDQ, H+; or FeCl3, CH3NO2), the aza-[5]helicenes 22 and 24 were obtained respectively with 60% and 23% yields [38]. It was noted that with the installation of two adjacent pyrimidines in this hexarylbenzene precursor, a fully cyclized planar NG was formed toward Scholl

Asymmetric synthesis of a stereopentade fragment toward latrunculins

• Benjamin Joyeux,
• Antoine Gamet,
• Nicolas Casaretto and
• Bastien Nay

Beilstein J. Org. Chem. 2023, 19, 428–433, doi:10.3762/bjoc.19.32

• PMB group, in presence of DDQ under anhydrous conditions [18], gratifyingly afforded acetal 25 in 74% yield, whose stereochemical assignment by NOESY NMR experiment showed the syn stereochemistry of the acetal. By deduction, it was confirmed that the asymmetric boron aldol reaction between 8 and 15

Synthetic study toward tridachiapyrone B

• Morgan Cormier,
• Florian Hernvann and
• Michaël De Paolis

Beilstein J. Org. Chem. 2022, 18, 1741–1748, doi:10.3762/bjoc.18.183

• necessary (70% yield, 2:1 dr). The desaturation of the enone compound was next examined and while exposure of 13 to oxidant (o-iodoxybenzoic acid (IBX) or 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ)) left the starting materials unchanged, treatment with NaH in the presence of oxygen to induce the

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

• application as redox-catalysts [124][125] or photoredox catalysts [30][31] for selective oxidations and also as stoichiometric oxidants [126]. Electron-withdrawing groups are used to increase oxidative properties, the most known examples are 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) [126] and 2,3,5,6

• substrates. DDQ is a popular mediator for oxidation reactions. It has been used for intramolecular dehydrogenative C–C bond formation between aromatic groups [127]. Using this method, the formation of polyaromatic systems was achieved in good yields (Scheme 26). The cross-dehydrogenative C–N coupling of

• benzylic substrates with azoles was developed [128] (Scheme 27). In the proposed mechanism DDQ participated in benzylic C–H bond cleavage. The C–N bond of the final product is formed as a result of the nucleophilic attack of azole on a benzylic cation. A two-fold molar excess of azoles was used. A