An amphiphilic pseudo[1]catenane: neutral guest-induced clouding point change

• Tomoki Ogoshi,
• Tomohiro Akutsu and
• Tada-aki Yamagishi

Beilstein J. Org. Chem. 2018, 14, 1937–1943, doi:10.3762/bjoc.14.167

• % [23]. Pillar[5]arene carrying 2 alkyne groups on the same unit (5). In a similar manner as described in [24], 5 was prepared. Under a nitrogen atmosphere, pillar[5]arene carrying one hydroquinone unit 6 [7] (Scheme 1, 417 mg, 0.230 mmol) was dissolved in acetone (10 mL). K2CO3 (159 mg, 1.15 mmol) was

Preparation of trinucleotide phosphoramidites as synthons for the synthesis of gene libraries

• Ruth Suchsland,
• Bettina Appel and
• Sabine Müller

Beilstein J. Org. Chem. 2018, 14, 397–406, doi:10.3762/bjoc.14.28

• , the disulfide tether was replaced in a following-up study with a Q-linker (hydroquinone-O,O'-diacetic acid), to be cleaved with dilute methanolic K2CO3 for the release of trimers in fully protected form. Five different trimers were assembled at 0.5 mmol scale and released form the support as described

CF₃SO₂X (X = Na, Cl) as reagents for trifluoromethylation, trifluoromethylsulfenyl-, -sulfinyl- and -sulfonylation. Part 1: Use of CF₃SO₂Na

• Hélène Guyon,
• Hélène Chachignon and
• Dominique Cahard

Beilstein J. Org. Chem. 2017, 13, 2764–2799, doi:10.3762/bjoc.13.272

• conditions tolerated a broad range of functional groups and the yields ranged from 31 to 68% (Scheme 50). During the process, the quinone was converted into hydroquinone and a regeneration process was established by passing through a cartridge of MnO2. A mechanism for this transformation was proposed as a

Vinylphosphonium and 2-aminovinylphosphonium salts – preparation and applications in organic synthesis

• Anna Kuźnik,
• Roman Mazurkiewicz and
• Beata Fryczkowska

Beilstein J. Org. Chem. 2017, 13, 2710–2738, doi:10.3762/bjoc.13.269

• of 90% (Scheme 60) [63]. Similarly, 6-hydroxy- and 7-hydroxycoumarin derivatives were obtained from hydroquinone and resorcinol, respectively (Scheme 60) [75]. The same kind of reaction with the participation of 2,4-dihydroxybenzaldehyde or 2,4-dihydroxy-3-methylbenzaldehyde was applied in 2010 by

Palladium-catalyzed Heck-type reaction of secondary trifluoromethylated alkyl bromides

• Tao Fan,
• Wei-Dong Meng and
• Xingang Zhang

Beilstein J. Org. Chem. 2017, 13, 2610–2616, doi:10.3762/bjoc.13.258

• %), Xantphos (7.5 mol %) and KOAc in DCE at 80 °C, the addition of an electron transfer scavenger 1,4-dinitrobenzene [25][26][27] dramatically diminished the yield of 3a (Table 2, entries 2 and 3), and catalytic amount of radical inhibitor hydroquinone totally shut down the reaction (Table 2, entry 4). Thus

Synthesis and application of trifluoroethoxy-substituted phthalocyanines and subphthalocyanines

• Satoru Mori and
• Norio Shibata

Beilstein J. Org. Chem. 2017, 13, 2273–2296, doi:10.3762/bjoc.13.224

• catechol, resorcinol or hydroquinone in toluene in the presence of triethylamine (Scheme 11) [131]. The synthesis of H-subPc homodimer 30 was attempted using the same method, but the target substance was obtained. This is a good example showing the high activity of the axial substitution reaction of TFEO

Rearrangements of organic peroxides and related processes

• Ivan A. Yaremenko,
• Vera A. Vil’,
• Dmitry V. Demchuk and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2016, 12, 1647–1748, doi:10.3762/bjoc.12.162

Cationic Pd(II)-catalyzed C–H activation/cross-coupling reactions at room temperature: synthetic and mechanistic studies

• Takashi Nishikata,
• Alexander R. Abela,
• Shenlin Huang and
• Bruce H. Lipshutz

Beilstein J. Org. Chem. 2016, 12, 1040–1064, doi:10.3762/bjoc.12.99

• hydroquinone as a byproduct. For the Fujiwara–Moritani coupling, addition of the palladacycle 6 to an acrylate followed by β-hydride elimination and reductive elimination of HPd+BF4− would result in a Pd(0) species unable to participate in palladacycle formation until it is oxidized by BQ to Pd2+(BF4)2

Regiodefined synthesis of brominated hydroxyanthraquinones related to proisocrinins

• Joyeeta Roy,
• Tanushree Mal,
• Supriti Jana and
• Dipakranjan Mal

Beilstein J. Org. Chem. 2016, 12, 531–536, doi:10.3762/bjoc.12.52

• cyanophthalide 12 with acceptor 36 formed hydroquinone 37, which was directly treated with bromine in DCM to give tribrominated quinone 38 in 58% yield (over two steps) (Scheme 6). The structure of bromo compound 38 was proposed on the basis of the high chemical shift (δ = 7.63 ppm) of the proton attached to the

Synthesis and reactivity of aliphatic sulfur pentafluorides from substituted (pentafluorosulfanyl)benzenes

• Norbert Vida,
• Jiří Václavík and
• Petr Beier

Beilstein J. Org. Chem. 2016, 12, 110–116, doi:10.3762/bjoc.12.12

• oxidation of aromatics. Benzoquinone 12 is a solid material with good stability at −20 °C. Several standard reactions were investigated. Reduction to hydroquinone 15 using catalytic palladium was very efficient (Scheme 5). The Diels–Alder reaction with cyclopentadiene proceeded in a high yield at ambient

Hydroquinone–pyrrole dyads with varied linkers

• Hao Huang,
• Christoffer Karlsson,
• Maria Strømme,
• Martin Sjödin and
• Adolf Gogoll

Beilstein J. Org. Chem. 2016, 12, 89–96, doi:10.3762/bjoc.12.10

• : conjugation; heterocycles; hydroquinone; linker effect; pyrrole; Introduction Quinone–pyrrole dyads have attracted interest in various applications due to the possibility of modulating the electronic interaction between the two subunits, with porphyrin–quinone dyads being well-known examples [1][2][3

• ]. Recently, we have shown the suitability of the quinone–hydroquinone redox couple (Figure 1) as the redox active and capacity carrying component in conducting redox polymers (CRPs) [4][5]. To further investigate the interaction between the molecular components in these systems, a series of compounds with

• different linkers between the pyrrole and hydroquinone subunits was designed [6]. Although it is known that N-protected pyrrole (Py) can be selectively functionalized at the β-position [7], we found the published procedures to be unsuitable for our purpose (vide infra). Therefore, we have developed improved

Total synthesis of panicein A₂

• Lili Yeung,
• Lisa I. Pilkington,
• Melissa M. Cadelis,
• Brent R. Copp and
• David Barker

Beilstein J. Org. Chem. 2015, 11, 1991–1996, doi:10.3762/bjoc.11.215

• panicein A (1), Figure 1), hydroquinone moiety (as seen in paniceins D (2), F (3) and F1 (4)) or chromenol as seen in panicein A2 (5). The first members of the panicein family were isolated by Cimino et al. in 1973 from the marine sponge Halichondria panacea [1]; members of this family have since been

Selected synthetic strategies to cyclophanes

• Sambasivarao Kotha,
• Mukesh E. Shirbhate and
• Gopalkrushna T. Waghule

Beilstein J. Org. Chem. 2015, 11, 1274–1331, doi:10.3762/bjoc.11.142

Glycoluril–tetrathiafulvalene molecular clips: on the influence of electronic and spatial properties for binding neutral accepting guests

• Yoann Cotelle,
• Marie Hardouin-Lerouge,
• Stéphanie Legoupy,
• Olivier Alévêque,
• Eric Levillain and
• Piétrick Hudhomme

Beilstein J. Org. Chem. 2015, 11, 1023–1036, doi:10.3762/bjoc.11.115

• a glycoluril-based framework possessing quinone moieties for developing a Diels–Alder cycloaddition strategy. Thus compound 12 [33] was prepared in 73% yield by treatment with an excess of hydroquinone in 1,2-dichloroethane using a Friedel–Crafts alkylation as an electrophilic aromatic substitution

• onto compound 11 [34]. The hydroquinone moieties were subjected to a dehydrogenation reaction using DDQ in THF to reach desired glycolurildiquinone 13 [35] in 91% yield. The Diels–Alder cycloaddition was carried out by treatment of bis-dienophile 13 with TTF derivative 14 [36], able to give rise in

Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• examples of dimers and trimers were studied to date [36]. The O-alkylated hydroquinone scaffold was chosen as a commonly used spacer between the diethynylcinnoline units [2][3][4] that prevents the aggregation of polymer chains. An efficient modification of the Richter type cyclization [37][38] based on

• alkyl pendant groups of hydroquinone structural units matches the oligomers structure (Figure 3). The 13C NMR spectra also confirm the presence of both units in PAE molecules 10a,b. It is important to note that there are four types of Csp atom signals (A–D) in the spectrum of PAE 10a, which come from

• the oligomer chain while in the 13C NMR spectrum of PAE 10b two additional Csp signals (E, F) of ethynyl pendant group are observed (Figure 4). The splitting of H atoms (2', a') and C atoms (1'–3', a') signals of hydroquinone structural units of PAEs 10a,b in NMR spectra confirmed that the orientation

Anionic sigmatropic-electrocyclic-Chugaev cascades: accessing 12-aryl-5-(methylthiocarbonylthio)tetracenes and a related anthra[2,3-b]thiophene

• Laurence Burroughs,
• John Ritchie,
• Mkhethwa Ngwenya,
• Dilfaraz Khan,
• William Lewis and
• Simon Woodward

Beilstein J. Org. Chem. 2015, 11, 273–279, doi:10.3762/bjoc.11.31

• this compound prevents its characterisation but it is tentatively ascribed to a mixture (12, Scheme 4) of hydroquinone and its monomethylether on the basis of partial 1H NMR spectrum and ESI mass spectra. The poorly performing runs of Table 1 also show a broad isolable red band (Rf ca. 0.18, 4:1

Design and synthesis of novel bis-annulated caged polycycles via ring-closing metathesis: pushpakenediol

• Sambasivarao Kotha and
• Mirtunjay Kumar Dipak

Beilstein J. Org. Chem. 2014, 10, 2664–2670, doi:10.3762/bjoc.10.280

• using the RCM protocol. To this end, we began with the Claisen rearrangement of bis(allyloxy)benzene 15 to deliver the two possible rearranged diallylated products 16 and 17 [29][30] in equimolar ratio. When 2,5-diallyl-1,4-hydroquinone (17) was subjected to MnO2 oxidation in acetone at room temperature

• (USA). Compounds 18, 19, 20, and 21 were prepared by procedures similar to those described in [28] for analogous compounds. Preparation of 2,5-diallyl-1,4-benzoquinone (18) To a solution of 2,5-diallyl-1,4-hydroquinone (17, 1.8 g, 9.45 mmol) in acetone (50 mL) was added MnO2 in excess (8 equiv) at rt

Atherton–Todd reaction: mechanism, scope and applications

• Stéphanie S. Le Corre,
• Mathieu Berchel,
• Hélène Couthon-Gourvès,
• Jean-Pierre Haelters and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2014, 10, 1166–1196, doi:10.3762/bjoc.10.117

• shown for hydroquinone in Scheme 24 [76]. O,O-dialkyl thiophosphite was also engaged in AT reactions to produce dinucleotide designed as an anti-HIV prodrug [77]. H-phosphonothioates are intermediates considered for the synthesis of nucleotide analogues. This functional group can be used as a

New sesquiterpene hydroquinones from the Caribbean sponge Aka coralliphagum

• Qun Göthel and
• Matthias Köck

Beilstein J. Org. Chem. 2014, 10, 613–621, doi:10.3762/bjoc.10.52

• ; natural products; NMR; sesquiterpene hydroquinone; structure elucidation; Introduction Aka coralliphagum (Siphonodictyon coralliphagum) is known to have four distinct morphological forms: forma typica, f. tubulosa, f. obruta, and f. incrustans [1]. This sponge has the ability to burrow into live coral

• and C-8. The p-hydroquinone moiety was established on the basis of the 1H and 13C NMR chemical shifts as well as the HMBC correlations mentioned above, namely, H-15 → C-16, C-17, C-21; H-22 → C-16, C-20, C-21. The relative configuration was confirmed by a ROESY experiment. The observed ROESY

Continuous flow nitration in miniaturized devices

• Amol A. Kulkarni

Beilstein J. Org. Chem. 2014, 10, 405–424, doi:10.3762/bjoc.10.38

Recent applications of the divinylcyclopropane–cycloheptadiene rearrangement in organic synthesis

• Sebastian Krüger and
• Tanja Gaich

Beilstein J. Org. Chem. 2014, 10, 163–193, doi:10.3762/bjoc.10.14

• ). Davies and co-worker [91][92] investigated the formal synthesis of the sequiterpene-hydroquinone derivative frondosin B (99, see Scheme 12) [93] via an enantioselective cyclopropanation of trans-piperylene and subsequent divinylcyclopropane rearrangement, to further demonstrate the versatility of their

Halogenated volatiles from the fungus Geniculosporium and the actinomycete Streptomyces chartreusis

• Tao Wang,
• Patrick Rabe,
• Christian A. Citron and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 2767–2777, doi:10.3762/bjoc.9.311

• -dichlororesorcinol (14) provided 10h in 80% yield, and methylation of 2,3-dichlorohydroquinone (16), prepared from benzoquinone (15) by treatment with SO2Cl2 under acidic conditions, generated 10i (13% via two steps). Reduction of 2,6-dichlorobenzoquinone with ascorbic acid to the corresponding hydroquinone 18

Gold(I)-catalysed one-pot synthesis of chromans using allylic alcohols and phenols

• Eloi Coutant,
• Paul C. Young,
• Graeme Barker and
• Ai-Lan Lee

Beilstein J. Org. Chem. 2013, 9, 1797–1806, doi:10.3762/bjoc.9.209

• solvent to push the reaction to completion. Finally, to show the synthetic utility of this procedure, a hydroquinone (trimethylhydroquinone TMHQ (5l)) was also evaluated, as TMHQ is commonly used towards the synthesis of vitamin E and its analogues [17][21]. For solubility issues, dioxane is used as the

A Lewis acid-promoted Pinner reaction

• Dominik Pfaff,
• Gregor Nemecek and
• Joachim Podlech

Beilstein J. Org. Chem. 2013, 9, 1572–1577, doi:10.3762/bjoc.9.179

• . Other radical scavengers like hydroquinone had a similar effect. Reaction of hexane-1,6-diol (31) gives moderate yields of the diacylated products, where significant amounts of the monoesters were isolated (Table 2, entry 7). Alcohols with further functional groups were similarly tested, but poor yields

Expeditious, mechanochemical synthesis of BODIPY dyes

• Laramie P. Jameson and
• Sergei V. Dzyuba

Beilstein J. Org. Chem. 2013, 9, 786–790, doi:10.3762/bjoc.9.89

• be performed using the same reagents as the solution synthesis. Finally, we also experimented with isolation procedures of the crude reaction mixture and found that diluting the mixture with CH2Cl2 and subsequently washing the organic layer with saturated Na2CO3 solution (to remove the hydroquinone