Using the phospha-Michael reaction for making phosphonium phenolate zwitterions

• Matthias R. Steiner,
• Max Schmallegger,
• Larissa Donner,
• Johann A. Hlina,
• Christoph Marschner,
• Judith Baumgartner and
• Christian Slugovc

Beilstein J. Org. Chem. 2024, 20, 41–51, doi:10.3762/bjoc.20.6

• = 3.9 Hz) [30]. Compared to the parent phosphine 1 (155.9 ppm, 2JPC = 19.3 Hz) [35] a pronounced down-field shift occurred upon adduct formation, which suggests a considerable contribution of a quinonic resonance structure as benzoquinones exhibit 13C NMR shifts of about 188 ppm and hydroquinones of

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

• photosynthesis. It is also noteworthy that the reduced pyridinium compounds resemble Hantzsch esters which are organic reductants commonly used in organic synthesis. Quinones and hydroquinones have also been used in RFBs. Notably, 1,4-hydroquinone and 1,4-benzoquinone were used to create membrane-less RFBs with

• (1.17 V vs SCE). This means it does not have the energy to reductively quench Ru(bpy)3 [26]. Hydroquinones are a large family of compounds with a wide range of redox potentials and only a small sample has been shown here. The NADH analogue BNAH which has been successfully regenerated using water is also

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

• -benzoquinones and p-hydroquinones or the synthesis of menadione (10). The furan derivative 34 was used as a diene and 2-iodophenyltrifluoromethanesulfonate (35) as a dienophile, in the presence of n-butyllithium, forming 10 in 55% yield (Scheme 8) [92]. In the same year, Gogin and and co-workers developed a

1,2,3,4-Tetrahydro-1,4,5,8-tetraazaanthracene revisited: properties and structural evidence of aromaticity loss

• Arnault Heynderickx,
• Sébastien Nénon,
• Olivier Siri,
• Vladimir Lokshin and
• Vladimir Khodorkovsky

Beilstein J. Org. Chem. 2019, 15, 2059–2068, doi:10.3762/bjoc.15.203

• hydroquinones or chloranilic acid as the H-bond donors (the O–H···N=C H-bonds) are known [15][16], the examples of the N–H···N=C bonds are less numerous and involve mostly aminopyrimidines and imidazoles [13][14]. Derivatives of 3 can be of special interest as flexible supramolecular synthons [14][17] owing to

Heck- and Suzuki-coupling approaches to novel hydroquinone inhibitors of calcium ATPase

• Robert J. Kempton,
• Taylor A. Kidd-Kautz,
• Soizic Laurenceau and
• Stefan Paula

Beilstein J. Org. Chem. 2019, 15, 971–975, doi:10.3762/bjoc.15.94

• convey specificity for prostate cancer cells. Keywords: calcium ATPase inhibitors; Heck- and Suzuki-coupling reactions; hydroquinones; prostate cancer; tethered amino acid; Introduction Sarco/endoplasmic reticulum calcium ATPase (SERCA) is an integral protein that resides in the membrane of the

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

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

• Qun Gothel Matthias Kock Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung, Am Handelshafen 12, 27570 Bremerhaven, Germany 10.3762/bjoc.10.52 Abstract Four new sulfated sesquiterpene hydroquinones siphonodictyals E1–E4 (1–4) and cyclosiphonodictyol A (5) were isolated from

• coralliphagum are bicyclic sesquiterpene hydroquinones. However, in the course of our investigation, three linear sesquiterpenes were isolated. From a biosynthetical point of view [11], we propose that the linear sesquiterpenes are the precursors of the bicyclic sesquiterpenes (Figure 8). Therefore

• ]. Moreover, the influence of the sulfate esters on the bioactivity has been proven by activity tests: the desulfated compounds tend to be more active [5]. Therefore, we propose that the sulfate esters act as hydroxy protecting groups. The sponges excrete the sesquiterpene hydroquinones primarily in the

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

• shorter reaction times, the Friedel–Crafts allylation intermediates are usually observed. The reaction works with ortho-, meta- and para-substituents as well as electron donating and withdrawing substituents on the phenol, and hydroquinones (Table 2). A variety of allylic alcohol substrates work well

Aromatic and heterocyclic perfluoroalkyl sulfides. Methods of preparation

• Vladimir N. Boiko

Beilstein J. Org. Chem. 2010, 6, 880–921, doi:10.3762/bjoc.6.88

• results only in the formation of a chlorohydroquinone pyridinium species [72], and neutral conditions are required in this case [69]. For the synthesis of poly(SCF3) substituted p-hydroquinones, Scribner oxidized 2,6-bis(SCF3)-4-methoxyphenol to generate 2,6-bis(SCF3)-1,4-benzoquinone. The addition of

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• this substrate in part due to the difficulties encountered during reduction of the methyl ester [124]. It is known that the treatment of quinones with mild reducing agents gives hydroquinones while strong reductants modify the quinone in a less specific manner [133][134]. 6.3. Remers. Synthesis of a