Dialkyl dicyanofumarates and dicyanomaleates as versatile building blocks for synthetic organic chemistry and mechanistic studies

• Grzegorz Mlostoń and
• Heinz Heimgartner

Beilstein J. Org. Chem. 2017, 13, 2235–2251, doi:10.3762/bjoc.13.221

• [16]. However, the most efficient method for the synthesis of dialkyl dicyanomaleates Z-1 is the photochemical isomerization of the corresponding E-isomers. The reaction is performed in dichloromethane [17] and in the presence of benzophenone [18][19] or 1,4-dicyanobenzene [20] as photosensitizer. The

Regiodivergent condensation of 5-alkoxycarbonyl-1H-pyrrol-2,3-diones with cyclic ketazinones en route to spirocyclic scaffolds

• Alexey Yu. Dubovtsev,
• Maksim V. Dmitriev,
• Аndrey N. Maslivets and
• Michael Rubin

Beilstein J. Org. Chem. 2017, 13, 2179–2185, doi:10.3762/bjoc.13.218

• , which ultimately could help us to redirect the course of the reaction towards formation of spirolactones of type 20. To evaluate this idea, we prepared ketazinones 22 (crystal structure of ketazinone 22a was confirmed by X-ray crystallography (CCDC 1546065, Figure 3)), derived from benzophenone and

Glyco-gold nanoparticles: synthesis and applications

• Federica Compostella,
• Olimpia Pitirollo,
• Alessandro Silvestri and
• Laura Polito

Beilstein J. Org. Chem. 2017, 13, 1008–1021, doi:10.3762/bjoc.13.100

• and purify proteins by covalent crosslinking (Figure 5). GAuNPs were synthesized by coating the metal surface via thio-chemistry with a β-D-lactose residue (recognized by a series of lectins, i.e., PNA or Ricinus communis agglutinin) and a benzophenone moiety as photoreactive group. GAuNPs were

Benzothiadiazole oligoene fatty acids: fluorescent dyes with large Stokes shifts

• Lukas J. Patalag and
• Daniel B. Werz

Beilstein J. Org. Chem. 2016, 12, 2739–2747, doi:10.3762/bjoc.12.270

• were distilled before use unless otherwise stated. Tetrahydrofuran (THF) and diethyl ether (Et2O) were distilled from sodium/benzophenone under an argon atmosphere. Dichloromethane (CH2Cl2) and tetrachloromethane (CCl4) were distilled from CaCl2 under an argon atmosphere. All other solvents were used

Solvent-free, visible-light photocatalytic alcohol oxidations applying an organic photocatalyst

• Martin Obst and
• Burkhard König

Beilstein J. Org. Chem. 2016, 12, 2358–2363, doi:10.3762/bjoc.12.229

• (m, 4H, CH), 7.30 (m, 2H, CH); EIMS m/z: 180.0579 [M]+. Benzophenone (3b) 3b from 3a: Diphenylmethanol (73.3 mg, 0.40 mmol) and RFTA (10.9 mg, 0.020 mmol) were weighed and 74.0 mg of the mixture was used for reaction. Yield: 50%. 1H NMR (300 MHz, CDCl3) 7.83–7.79 (m, 2H, CH), 7.62–7.57 (m, 2H, CH

Synthesis and characterization of fluorinated azadipyrromethene complexes as acceptors for organic photovoltaics

• Forrest S. Etheridge,
• Roshan J. Fernando,
• Sandra Pejić,
• Matthias Zeller and
• Geneviève Sauvé

Beilstein J. Org. Chem. 2016, 12, 1925–1938, doi:10.3762/bjoc.12.182

• solvents were used as received unless otherwise specified. Xylenes and tetrahydrofuran were distilled over sodium and benzophenone, degassed and stored under nitrogen. ADP, ADPI2, WS3, BF2(WS3), and Zn(WS3)2 were synthesized and purified according to literature procedures with minor modifications [2][5][9

Biradical vs singlet oxygen photogeneration in suprofen–cholesterol systems

• Fabrizio Palumbo,
• Francisco Bosca,
• Isabel M. Morera,
• Inmaculada Andreu and
• Miguel A. Miranda

Beilstein J. Org. Chem. 2016, 12, 1196–1202, doi:10.3762/bjoc.12.115

• light. The latter involves energy transfer from the photosensitizer triplet excited state to ground state molecular oxygen [5][6]. Ketoprofen (KP) is a nonsteroidal anti-inflammatory drug that contains the benzophenone (BZP, Figure 1) chromophore and displays a n,π triplet excited state [7][8][9

• determined in dichloromethane solutions using the same absorbance value (0.30) at 308 nm for each compound. A singlet oxygen quantum yield (ΦΔ) of 0.95 for perinaphthenone in dichloromethane was used as standard [22]. Chemical structure of the photosensitizing chromophores benzophenone (BZP) and 2

Synthesis and fluorosolvatochromism of 3-arylnaphtho[1,2-b]quinolizinium derivatives

• Phil M. Pithan,
• David Decker,
• Manlio Sutero Sardo,
• Giampietro Viola and
• Heiko Ihmels

Beilstein J. Org. Chem. 2016, 12, 854–862, doi:10.3762/bjoc.12.84

• obvious relationship. This behavior is in agreement with that of other donor–acceptor biaryl-type dyes, such as for example para-hetaryl-substituted benzophenone derivatives, whose emission properties were demonstrated to depend on a complex interplay of different solvent parameters [38]. Unfortunately

Opportunities and challenges for direct C–H functionalization of piperazines

• Zhishi Ye,
• Kristen E. Gettys and
• Mingji Dai

Beilstein J. Org. Chem. 2016, 12, 702–715, doi:10.3762/bjoc.12.70

• on the distal nitrogen atom is likely preventing this nitrogen from attacking the electrophile and triggers an elimination process which would yield a byproduct like 29. Of particular interest, when benzophenone (Ph2CO) was used to trap the α-lithiation product of N-Boc-N’-alkylpiperazines, in

• addition to the desired products (18, 34, and 35), a significant amount of oxidized product 36 was obtained (Figure 9). The formation of this byproduct is proposed to be a sequential single-electron oxidation of the alkyllithium intermediate by benzophenone. Again, the use of a bulky alkyl group on the

Iron complexes of tetramine ligands catalyse allylic hydroxyamination via a nitroso–ene mechanism

• David Porter,
• Belinda M.-L. Poon and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 2549–2556, doi:10.3762/bjoc.11.275

• commercially available reagents were used without purification unless otherwise specified. Solvents for extraction and chromatography were distilled before use. Solvents for reactions were freshly distilled immediately prior to use. Tetrahydrofuran (THF) was dried over sodium wire and benzophenone

Effective ascorbate-free and photolatent click reactions in water using a photoreducible copper(II)-ethylenediamine precatalyst

• Redouane Beniazza,
• Natalia Bayo,
• Florian Molton,
• Carole Duboc,
• Stéphane Massip,
• Nathan McClenaghan,
• Dominique Lastécouères and
• Jean-Marc Vincent

Beilstein J. Org. Chem. 2015, 11, 1950–1959, doi:10.3762/bjoc.11.211

• photogenerated copper(I) being very reactive. On irradiating aqueous reaction mixtures containing 1 mol % of 1 at 365 nm (TLC lamp) for 1 h, click reactions were shown to proceed to full conversion. Keywords: benzophenone photosensitizer; bioconjugation; click chemistry; copper; photoreduction; Introduction

• tren (tren = tris(2-aminoethyl)amine) ligand derivative [11][12] or the dmeda (dmeda = N,N’-dimethylethylenediamine) ligand [13][14] (Scheme 1). Irradiation at 365 nm of the benzophenone photosensitizer (n→π* electronic transition), introduced through the carboxylate counterion, mediated a highly

• molecules being most probably bound to the copper ions in aqueous solution, while in THF, the carboxylates interact more tightly with the copper ions. This is in agreement with the 1H NMR spectra of 1, which showed well resolved peaks for the benzophenone protons in D2O, while in THF-d8 broad resonances

Synthesis and structures of ruthenium–NHC complexes and their catalysis in hydrogen transfer reaction

• Chao Chen,
• Chunxin Lu,
• Qing Zheng,
• Shengliang Ni,
• Min Zhang and
• Wanzhi Chen

Beilstein J. Org. Chem. 2015, 11, 1786–1795, doi:10.3762/bjoc.11.194

• substituents (Table 2, entries 3–8) and electron-donating groups (Table 2, entries 9 and 10), and the target product could be obtained in excellent yields (90–99%). Bulkier aromatic ketone benzophenone is also tested in this reaction with 92% and 94% conversion after 3 h (Table 2, entries 11 and 12). In

A facile synthetic route to benzimidazolium salts bearing bulky aromatic N-substituents

• Gabriele Grieco,
• Olivier Blacque and
• Heinz Berke

Beilstein J. Org. Chem. 2015, 11, 1656–1666, doi:10.3762/bjoc.11.182

• standard procedures and were degassed by freeze–thaw cycles prior to use. All chemicals used were purchased from Sigma-Aldrich and used as received. The deuterated solvents were dried with sodium/benzophenone and vacuum transferred for storage in Schlenk flasks fitted with Teflon valves. 1H NMR, 13C{1H

Grubbs–Hoveyda type catalysts bearing a dicationic N-heterocyclic carbene for biphasic olefin metathesis reactions in ionic liquids

• Maximilian Koy,
• Hagen J. Altmann,
• Benjamin Autenrieth,
• Wolfgang Frey and
• Michael R. Buchmeiser

Beilstein J. Org. Chem. 2015, 11, 1632–1638, doi:10.3762/bjoc.11.178

• , Netherlands) and were dried by using an MBraun SPS-800 solvent purification system. Hexane was purchased from VWR and distilled from sodium/benzophenone under N2. Starting materials were purchased from ABCR, Aldrich, Alfa Aesar, Fluka and TCI Europe and used without further purification. KOCMe2Et was

Deproto-metallation of N-arylated pyrroles and indoles using a mixed lithium–zinc base and regioselectivity-computed CH acidity relationship

• Mohamed Yacine Ameur Messaoud,
• Ghenia Bentabed-Ababsa,
• Madani Hedidi,
• Aïcha Derdour,
• Floris Chevallier,
• Yury S. Halauko,
• Oleg A. Ivashkevich,
• Vadim E. Matulis,
• Laurent Picot,
• Valérie Thiéry,
• Thierry Roisnel,
• Vincent Dorcet and
• Florence Mongin

Beilstein J. Org. Chem. 2015, 11, 1475–1485, doi:10.3762/bjoc.11.160

• reason [37][38][40], the corresponding N-(4-substituted phenyl)pyrroles and -indoles are rather functionalized at C3’, next to the substituent. Experimental General methods. All the reactions were performed under argon atmosphere. THF was distilled over sodium/benzophenone. ZnCl2·TMEDA was prepared as

Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

• Sambasivarao Kotha and
• Ongolu Ravikumar

Beilstein J. Org. Chem. 2015, 11, 1259–1264, doi:10.3762/bjoc.11.140

• -sensitive reagents or catalysts were performed in degassed solvents. Dry tetrahydrofuran (THF) and dry ether were obtained by distillation over sodium benzophenone ketyl freshly prior to use. Dichloromethane (DCM) and toluene were distilled over P2O5 and DMF over CaH2. Sodium sulfate was dried in an oven at

Interactions between tetrathiafulvalene units in dimeric structures – the influence of cyclic cores

• Huixin Jiang,
• Virginia Mazzanti,
• Christian R. Parker,
• Søren Lindbæk Broman,
• Jens Heide Wallberg,
• Karol Lušpai,
• Adam Brincko,
• Henrik G. Kjaergaard,
• Anders Kadziola,
• Peter Rapta,
• Ole Hammerich and
• Mogens Brøndsted Nielsen

Beilstein J. Org. Chem. 2015, 11, 930–948, doi:10.3762/bjoc.11.104

• -radiaannulenes exhibit low-energy CT absorptions. Experimental General Methods – Synthesis. Chemicals were purchased from Aldrich, Fluka, and GSF Chemicals and used as received. THF was distilled over the Na/benzophenone couple. Solvents were of HPLC grade and used as received. Thin layer chromatography (TLC

Probing multivalency in ligand–receptor-mediated adhesion of soft, biomimetic interfaces

• Stephan Schmidt,
• Hanqing Wang,
• Daniel Pussak,
• Simone Mosca and
• Laura Hartmann

Beilstein J. Org. Chem. 2015, 11, 720–729, doi:10.3762/bjoc.11.82

• -functionalized SCPs. Carboxy groups on the SCP were introduced by a radical grafting process where incubation of the PEG microgels with benzophenone and acrylic acid lead to poly(acrylic acid) grafts on the PEG backbone. Using this model system, we could already show that the mechanical flexibility of the

• (Scheme 1). It is known that benzophenone can absorb the energy of photons to excite the electron in its carbonyl group from ground state (S0) to the excited state (S1) or (S2) depending on the wavelength used. Subsequently, the excited electron can go to the triple state (T1) through intersystem crossing

• (ISC). At the T1 state, the benzophenone molecule has an excited electron which is highly reactive, and can abstract a hydrogen atom from the PEG backbone. The abstracted hydrogen atom generates a radical on the PEG-backbone and a semipinacol radical on the benzophenone carbonyl group [16]. In the

Trifluoromethyl-substituted tetrathiafulvalenes

• Olivier Jeannin,
• Frédéric Barrière and
• Marc Fourmigué

Beilstein J. Org. Chem. 2015, 11, 647–658, doi:10.3762/bjoc.11.73

• from Na/benzophenone. CH3CN and CH2Cl2 were distilled over P2O5 and MeOH over Mg/I2. Column chromatography was performed on silica gel. 1H, 13C and 19F NMR spectra were obtained on a Bruker Avance DRX500 spectrometer at 500.04 MHz for 1H, 470.28 MHz for 19F and 125.75 MHz for 13C. Chemical shifts were

Photocatalytic nucleophilic addition of alcohols to styrenes in Markovnikov and anti-Markovnikov orientation

• Martin Weiser,
• Sergej Hermann,
• Alexander Penner and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2015, 11, 568–575, doi:10.3762/bjoc.11.62

• °C, using a 250 mW high-power LED (λ = 530 nm) as light source while stirring. Preliminary experiments with substrate 1 revealed that formation of benzophenone was nearly completely prevented by carefully degassing the reaction mixture. A previous report of Neunteufel and Arnold considered the

Attempts to prepare an all-carbon indigoid system

• Şeref Yildizhan,
• Henning Hopf and
• Peter G. Jones

Beilstein J. Org. Chem. 2015, 11, 363–372, doi:10.3762/bjoc.11.42

• direct conjugation, whereby a third such system is excluded from interaction [3]. Typical examples are 2-vinyl-buta-1,3-diene ([3]dendralene, 3-methylene-penta-1,4-diene), benzophenone or urea. Whereas the hydrocarbon parent systems, the [n]dendralenes, have long been a neglected class of oligoenes [4

An unusually stable chlorophosphite: What makes BIFOP–Cl so robust against hydrolysis?

• Roberto Blanco Trillo,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2015, 11, 313–322, doi:10.3762/bjoc.11.36

• application as a chiral ligand to be used in, for example, Pd catalysis [13][14][15]. Experimental All reactions were carried out under an inert argon atmosphere and in heated glassware using standard Schlenk techniques. Anhydrous solvents were obtained by distillation from sodium benzophenone ketyl. The NMR

(2R,1'S,2'R)- and (2S,1'S,2'R)-3-[2-Mono(di,tri)fluoromethylcyclopropyl]alanines and their incorporation into hormaomycin analogues

• Armin de Meijere,
• Sergei I. Kozhushkov,
• Dmitrii S. Yufit,
• Christian Grosse,
• Marcel Kaiser and
• Vitaly A. Raev

Beilstein J. Org. Chem. 2014, 10, 2844–2857, doi:10.3762/bjoc.10.302

• -threonine (4) and (2S,3R)-β-methylphenylalanine (3), using the Belokon' approach with (S)- and (R)-2-[(N-benzylprolyl)amino]benzophenone [(S)- and (R)-10] as reusable chiral auxiliaries have been developed. Three new fluoromethyl analogues of the naturally occurring octadepsipeptide hormaomycin (1) with

• from (S)- and (R)-2-[(N-benzylprolyl)amino]benzophenone [(S)- and (R)-10] as reusable chiral auxiliaries with the racemic iodides 11a–c, employing the protocol of Larionov and de Meijere [7], in each case led to a mixture of diastereomeric products, which were separated by column chromatography

• corresponding (2S,1'S,2'R)- [see Scheme 3, derived from (S)-10] and (2R,1'S,2'R)-3-(2'-fluoromethylcyclopropyl)alanines [derived from (R)-10] in good to excellent yields. The chiral auxiliary was recovered as the hydrochloride of 2-[(N-benzylprolyl)amino]benzophenone (~95%). (R)-allo-Threonine (4) is

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

• nitrogen by using oven-dried glassware and syringes. THF and Et2O were distilled from sodium/benzophenone under nitrogen immediately prior to use. Dichloromethane was distilled over P2O5. TLC was performed by using (10 × 5 cm) glass plates coated with Acme’s silica gel GF254 (containing 13% calcium sulfate

Electrocarboxylation: towards sustainable and efficient synthesis of valuable carboxylic acids

• Roman Matthessen,
• Jan Fransaer,
• Koen Binnemans and
• Dirk E. De Vos

Beilstein J. Org. Chem. 2014, 10, 2484–2500, doi:10.3762/bjoc.10.260

• was first described by Wawzonek, converting benzophenone and acetophenone to benzylic acid and 2-hydroxy-2-phenylpropionic acid, respectively [79]. This offers an electrochemical route for several commercially relevant α-aryl propionic acids, used as non-steroidal anti-inflammatory drugs (NSAIDs) [80