One hundred years of benzotropone chemistry

• Arif Dastan,
• Haydar Kilic and
• Nurullah Saracoglu

Beilstein J. Org. Chem. 2018, 14, 1120–1180, doi:10.3762/bjoc.14.98

• and Brückner reported the synthesis of 7-hydroxy-2,3-benzotropones by ring-closing metathesis (Scheme 48) [173]. 7-Hydroxy-2,3-benzotropone (241) was synthesized in four steps starting from a Br/Li exchange reaction of o-bromostyrene (283) followed by the addition of aldehyde 284 to give the benzylic

Stimuli-responsive oligonucleotides in prodrug-based approaches for gene silencing

• Françoise Debart,
• Christelle Dupouy and
• Jean-Jacques Vasseur

Beilstein J. Org. Chem. 2018, 14, 436–469, doi:10.3762/bjoc.14.32

• ’-O-acetylthiomethyl-containing RNA, produces various 2’-O-alkyldithiomethyl (RSSM)-modified RNAs bearing lipophilic or polar groups through a thiol disulfide exchange reaction with alkyldisulfanyl-pyridine derivatives (Scheme 3). In a preliminary evaluation, the RSSM modifications were shown to

Recent applications of click chemistry for the functionalization of gold nanoparticles and their conversion to glyco-gold nanoparticles

• Vivek Poonthiyil,
• Thisbe K. Lindhorst,
• Vladimir B. Golovko and
• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 11–24, doi:10.3762/bjoc.14.2

• thiol end group, which is generally attached to the reducing terminus by a linker (Figure 1a) [8][14][17][18][19][20][21][22][23][24][25][26][27]. The second method is a ligand exchange reaction involving the replacement of the ligands on pre-formed AuNPs with thiol-linked carbohydrate derivatives

• reaction sequence for the synthesis of GAuNPs. Firstly, the alkyne-terminated thiol (ATT) ligand 33 was synthesized as shown in Scheme 11a (see Supporting Information File 1 for full experimental data). Next, 12 nm ATT-AuNPs were synthesized by a ligand exchange reaction of 12 nm Cit-AuNPs (themselves

Phosphonic acid: preparation and applications

• Charlotte M. Sevrain,
• Mathieu Berchel,
• Hélène Couthon and
• Paul-Alain Jaffrès

Beilstein J. Org. Chem. 2017, 13, 2186–2213, doi:10.3762/bjoc.13.219

• in situ generation of iodotrimethylsilane that result from a halogen exchange reaction [169]. This method (ClSiMe3 + NaI in acetonitrile) is currently less employed likely due to the need to remove NaI from the final phosphonic acid after the step of hydrolysis or methanolysis. It is worth noticing

Influence of the milling parameters on the nucleophilic substitution reaction of activated β-cyclodextrins

• László Jicsinszky,
• Kata Tuza,
• Giancarlo Cravotto,
• Andrea Porcheddu,
• Francesco Delogu and
• Evelina Colacino

Beilstein J. Org. Chem. 2017, 13, 1893–1899, doi:10.3762/bjoc.13.184

• poorly understood aspect of mechanochemistry. Effect of jar size on the reaction time using an equal number (30) of steel balls (ø 1 mm) for the Ts → N3 exchange reaction in glass vials at 550 min−1 sun wheel speed. Effect of ball size on the reaction time to a full conversion of Ts-β-CD: a) reactions

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

• procedure for the immobilization of carbohydrates on the nanoparticles surface [27]. The AuNPs were firstly coated with a PFPA-thiol monolayer via a ligand-exchange reaction, then carbohydrates were immobilized by means of a photocoupling reaction. Glyco-gold nanoparticles: design and structural properties

Synthesis of tetrasubstituted pyrazoles containing pyridinyl substituents

• Josef Jansa,
• Ramona Schmidt,
• Ashenafi Damtew Mamuye,
• Laura Castoldi,
• Alexander Roller,
• Vittorio Pace and
• Wolfgang Holzer

Beilstein J. Org. Chem. 2017, 13, 895–902, doi:10.3762/bjoc.13.90

• -diketones with arylhydrazines, halogenation of the resulting 1,3,5-triarylpyrazoles in the 4-position and further functionalization via Negishi cross-coupling [23][24] or halogen–lithium exchange reaction (Scheme 1). The resulting compounds amongst others seem to be interesting as potential complexing

Contribution of microreactor technology and flow chemistry to the development of green and sustainable synthesis

• Flavio Fanelli,
• Giovanna Parisi,
• Leonardo Degennaro and
• Renzo Luisi

Beilstein J. Org. Chem. 2017, 13, 520–542, doi:10.3762/bjoc.13.51

• been optimized in a green solvent such as 2-MeTHF by a precise control of the residence time, and without using cryogenic conditions (Scheme 6). In addition, many organolithiums were generated from the corresponding halo compounds by a halogen/lithium exchange reaction using hexyllithium as a more

Synthesis of 1-indanones with a broad range of biological activity

• Marika Turek,
• Dorota Szczęsna,
• Marek Koprowski and
• Piotr Bałczewski

Beilstein J. Org. Chem. 2017, 13, 451–494, doi:10.3762/bjoc.13.48

• der Eycken et al. have synthesized 1-indanone 328 by utilizing 2-methylfuran (324) as a starting compound which was converted to the Mannich adduct 325, followed by the anion exchange reaction to give ammonium hydroxide 326

Synthesis, dynamic NMR characterization and XRD studies of novel N,N’-substituted piperazines for bioorthogonal labeling

• Constantin Mamat,
• Marc Pretze,
• Matthew Gott and
• Martin Köckerling

Beilstein J. Org. Chem. 2016, 12, 2478–2489, doi:10.3762/bjoc.12.242

• . Using these methods, a synthesis procedure for both bioorthogonal 18F-building blocks [18F]4b and [18F]5b was developed from their precursors 4a and 5a, respectively (Scheme 4). For this purpose, the nitro group of 4b and 5b was replaced by [18F]fluoride in a nucleophilic aromatic exchange reaction. To

DNA functionalization by dynamic chemistry

• Zeynep Kanlidere,
• Oleg Jochim,
• Marta Cal and
• Ulf Diederichsen

Beilstein J. Org. Chem. 2016, 12, 2136–2144, doi:10.3762/bjoc.12.203

• of nucleobase monomers. In case of an amine group on the backbone, a reversible imine exchange reaction with aldehyde modified nucleobases was performed (Figure 1a). In the presence of a thiol group on the backbone, a thioester exchange reaction with thioester modified nucleobases was expected

• well as the simultaneous functionalization of DNA oligonucleotides at various positions with different kind of functional units. Template-directed dynamic chemistry assay for the attachment of modified nucleobase monomers to an abasic backbone. a) Reversible imine exchange reaction. b) Reversible

• thioester exchange reaction. Initial building blocks of a dynamic combinatorial library, a library of all possible imine products and a library of amine products after reduction. Set of aldehyde-modified nucleobases used in dynamic chemistry assay. Representative HPLC chromatograms for the mixture

The hydrolysis of geminal ethers: a kinetic appraisal of orthoesters and ketals

• Sonia L. Repetto,
• James F. Costello,
• Craig P. Butts,
• Joseph K. W. Lam and
• Norman M. Ratcliffe

Beilstein J. Org. Chem. 2016, 12, 1467–1475, doi:10.3762/bjoc.12.143

• . HRMS–ESI calculated for [M + Na]+ 169.0835, found: 169.0836. The distribution of products resulting from the exchange reaction of 6 with dl- and meso-2,3-butanediol warrants brief comment; reaction of the former affords 10 [43], whereas the latter gives C(2) epimers 11 and 14. Both GC–MS and 1H NMR

• -, respectively by 1H NMR [48]) also affords the same product ratio with 65% conversion. Performing the procedure at −10 and +20 °C does not change the product distribution; we conclude then, that the exchange reaction proceeds via equilibrium control. Computational techniques. X-ray crystal structures were

Efficient syntheses of climate relevant isoprene nitrates and (1R,5S)-(−)-myrtenol nitrate

• Sean P. Bew,
• Glyn D. Hiatt-Gipson,
• Graham P. Mills and
• Claire E. Reeves

Beilstein J. Org. Chem. 2016, 12, 1081–1095, doi:10.3762/bjoc.12.103

• monoterpene nitrate (1R,2S)-(−)-myrtenol nitrate. Keywords: atmospheric chemistry; exchange reaction; halide; isoprene nitrate; monoterpene; Introduction Understanding the chemistry of the biosphere and its interaction with the atmosphere is fundamental to Earth System science. Such is the importance of

Olefin metathesis in air

• Lorenzo Piola,
• Fady Nahra and
• Steven P. Nolan

Beilstein J. Org. Chem. 2015, 11, 2038–2056, doi:10.3762/bjoc.11.221

• catalyst (9, Scheme 3). The reaction of RuCl2(PPh3)3-4 (3) with phenyldiazomethane (7), followed by a phosphine exchange reaction, afforded complex 9 in high yields. Complex 9 has become the most used metathesis catalyst, because of its good activity, relatively good stability to air (storage of 9 has been

New aryloxybenzylidene ruthenium chelates – synthesis, reactivity and catalytic performance in ROMP

• Patrycja Żak,
• Szymon Rogalski,
• Mariusz Majchrzak,
• Maciej Kubicki and
• Cezary Pietraszuk

Beilstein J. Org. Chem. 2015, 11, 1910–1916, doi:10.3762/bjoc.11.206

• (Scheme 1) [11]. However, in our hands to get complete transformation 5 equiv of phosphine had to be used. In a next step the complexes (4–6) were subjected to metathesis exchange reaction with 2-(prop-1-enyl)phenol (Scheme 2). The reaction was performed in the presence of an equimolar amount of the

Ruthenium indenylidene “1^st generation” olefin metathesis catalysts containing triisopropyl phosphite

• Stefano Guidone,
• Fady Nahra,
• Alexandra M. Z. Slawin and
• Catherine S. J. Cazin

Beilstein J. Org. Chem. 2015, 11, 1520–1527, doi:10.3762/bjoc.11.166

• a stoichiometric amount of triisopropyl phosphite. Complex 1 was isolated in analytically pure form in 85% yield, after recrystallization, using a simple ligand exchange reaction (Scheme 1). Similarly to the mixed NHC/phosphite species Caz-1 [25], the cis-geometry is the most thermodynamically

Consequences of the electronic tuning of latent ruthenium-based olefin metathesis catalysts on their reactivity

• Karolina Żukowska,
• Eva Pump,
• Aleksandra E. Pazio,
• Krzysztof Woźniak,
• Luigi Cavallo and
• Christian Slugovc

Beilstein J. Org. Chem. 2015, 11, 1458–1468, doi:10.3762/bjoc.11.158

• Doebner–Miller reaction and oxidation, we obtained the corresponding bromide derivative which was subsequently converted via Suzuki coupling into the carbene precursor 13. Both compounds 12 and 13 were then used in a carbene exchange reaction with compound 1 conducted in toluene at 80 °C (see Scheme 3

The synthesis of active pharmaceutical ingredients (APIs) using continuous flow chemistry

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2015, 11, 1194–1219, doi:10.3762/bjoc.11.134

• continuous synthesis of the important anticancer agent tamoxifen (132) in 2013 [106]. The synthesis starts with a halogen–lithium exchange reaction between arylbromide 133 and n-BuLi at −50 °C and the subsequent addition of the formed aryllithium species to ketone 134 at the same temperature (Scheme 23

Impact of multivalent charge presentation on peptide–nanoparticle aggregation

• Daniel Schöne,
• Boris Schade,
• Christoph Böttcher and
• Beate Koksch

Beilstein J. Org. Chem. 2015, 11, 792–803, doi:10.3762/bjoc.11.89

• exchange reaction with mercaptoundecanoic acid [38][39]. The obtained Au/MUA nanoparticles have an average diameter of 5.5 nm, as determined by TEM, and are monodisperse, as confirmed by DLS. An absorption maximum of 525 nm is observed for the Au/MUA nanoparticles in the absence of peptide, even over an

Syntheses of ¹⁵N-labeled pre-queuosine nucleobase derivatives

• Jasmin Levic and
• Ronald Micura

Beilstein J. Org. Chem. 2014, 10, 1914–1918, doi:10.3762/bjoc.10.199

• Mannich reaction using dibenzylamine–formaldehyde and 2-acylaminopyrrolo[2,3-d]pyrimidin-4(3H)-one, which resulted in the selective introduction of the dibenzylaminomethyl group [10]. The following amine exchange reaction of the dibenzylamine function in the Mannich base with ammonia resulted in the preQ1

Synthesis of ethoxy dibenzooxaphosphorin oxides through palladium-catalyzed C(sp²)–H activation/C–O formation

• Seohyun Shin,
• Dongjin Kang,
• Woo Hyung Jeon and
• Phil Ho Lee

Beilstein J. Org. Chem. 2014, 10, 1220–1227, doi:10.3762/bjoc.10.120

• -(aryl)arylphosphonic acid monoethyl esters were efficiently prepared by a Suzuki reaction of 2-bromoiodoarenes with arylboronic acids, a lithium bromide exchange reaction of 2-bromobiaryls followed by diethylphosphinylation with diethyl chlorophosphate, and the C–O cleavage of diethyl 2-(aryl

• -bromophenylboronic acid (5), a lithium bromide exchange reaction of 2-bromo deuterated biphenyl 7 followed by diethylphosphinylation with diethyl chlorophosphate, and C–O cleavage of diethyl 2-(phenyl)phenylphosphonate by using L-Selectride (Scheme 6). In addition, the deuterium-labeled 2-(phenyl)phenylphosphonic

• acid monoethyl ester 1a-[D1] was obtained by the lithium bromide exchange reaction of 2‘-bromo-2-iodo-1,1‘-biphenyl (10) and the treatment of D2O, diethylphosphinylation with diethyl chlorophosphate, and C–O cleavage of diethyl 2-(phenyl)phenylphosphonate by using L-Selectride (Scheme 7). In the case

Preparation of phosphines through C–P bond formation

• Iris Wauters,
• Wouter Debrouwer and
• Christian V. Stevens

Beilstein J. Org. Chem. 2014, 10, 1064–1096, doi:10.3762/bjoc.10.106

• triarylphosphines 105a as phosphinating agents. This aryl–aryl exchange reaction was compatible with several functional groups such as ketones, aldehydes, esters, nitriles, ethers (Table 11) [192][193][194][195]. Products 106a were isolated in only moderate yields. Several P,N-biaryl ligands were prepared from the

Deoxygenative gem-difluoroolefination of carbonyl compounds with (chlorodifluoromethyl)trimethylsilane and triphenylphosphine

• Fei Wang,
• Lingchun Li,
• Chuanfa Ni and
• Jinbo Hu

Beilstein J. Org. Chem. 2014, 10, 344–351, doi:10.3762/bjoc.10.32

• TMSCF3 from fluoroform (CF3H), which paved the way for the synthetic applications of TMSCF3 [38][39]. Moreover, the preparation of TMSCF2Br either by fluoro–bromo exchange reaction of TMSCF3 [34] or by bromination of TMSCF2H [34][40] has also been disclosed. To obtain TMSCF2Cl, we tried the halogen

• exchange reaction of TMSCF2Br. When a 1:10 mixture of TMSCF2Br and TMSCl was heated in neat in the presence of 5 mol % of tetrabutylammonium chloride (TBAC) for 2 hours, 19F NMR spectroscopy analysis showed that the ratio of TMSCF2Cl to TMSCF2Br was 2.3:1, and prolonging reaction time could not improve the

• solubility of silver bromide than silver chloride in benzonitrile provides the driving force for this bromo–chloro exchange reaction. At first, the olefination of 1-naphthaldehyde (1a) or benzaldehyde (1b) by using the combination of TMSCF2Cl and PPh3 was tried. Conceiving that the chloride ion might be

Flow microreactor synthesis in organo-fluorine chemistry

• Hideki Amii,
• Aiichiro Nagaki and
• Jun-ichi Yoshida

Beilstein J. Org. Chem. 2013, 9, 2793–2802, doi:10.3762/bjoc.9.314

• or less. Pentafluorophenylmagnesium bromide (PFPMgBr) is industrially produced by means of the halogen–metal exchange reaction of ethylmagnesium bromide and bromopentafluorobenzene [71]. However, this process is a highly exothermic reaction, and therefore, the use of a slow addition technique is

An overview of the synthetic routes to the best selling drugs containing 6-membered heterocycles

• Marcus Baumann and
• Ian R. Baxendale

Beilstein J. Org. Chem. 2013, 9, 2265–2319, doi:10.3762/bjoc.9.265

• and allows for good stereochemical control. The ribose component in these drugs is either derived directly from ribose itself as in zidovudine or prepared by total synthesis as in the case of lamivudine. The oxathiolane ring in lamivudine for instance can be prepared via an acetal exchange reaction