London dispersion as important factor for the stabilization of (Z)-azobenzenes in the presence of hydrogen bonding

• Andreas H. Heindl,
• Raffael C. Wende and
• Hermann A. Wegner

Beilstein J. Org. Chem. 2018, 14, 1238–1243, doi:10.3762/bjoc.14.106

• -butyl methyl ether the hydrogen bonds dominate, the variation in stabilization of the different substituted azobenzenes in dimethyl sulfoxide can be rationalized by London dispersion interactions. These findings were supported by conformational analysis and DFT computations and reveal low-energy London

• ,-trimethylhexanoylamino)benzyl]azobenzene (4, Table 1, entry 1), expressed in the longest half-lives τ. However, in the highly polar solvent dimethyl sulfoxide (DMSO) all azoamides (4, 5, Table 1, entries 1 and 2) as well as the azocarbamate 6 (Table 1, entry 3) showed very similar isomerization rates. Additionally

5-Aminopyrazole as precursor in design and synthesis of fused pyrazoloazines

• Ranjana Aggarwal and
• Suresh Kumar

Beilstein J. Org. Chem. 2018, 14, 203–242, doi:10.3762/bjoc.14.15

• . (Scheme 10). Whereas the reaction in acetic acid/acetonitrile (1:5) provided 4,7-dihydro-1H-pyrazolo[3,4-b]pyridine derivatives 51, dimethyl sulfoxide/acetic acid (5:1) yielded the corresponding aromatized pyrazolo[3,4-b]pyridine derivatives 52 exclusively. In acetic acid/ethanol combination an unexpected

Photocatalytic formation of carbon–sulfur bonds

• Alexander Wimmer and
• Burkhard König

Beilstein J. Org. Chem. 2018, 14, 54–83, doi:10.3762/bjoc.14.4

• β-ketosulfoxide. No additional sacrificial substrates are needed in order to regenerate the photocatalyst or for the oxidation of the sulfenyl intermediate to the respective sulfoxide moiety. Hydrogen peroxide, which is generated as a byproduct, directly is consumed by oxidizing the sulfide to the

• sulfoxide. Different aryl thiols were reacted with aliphatic and aromatic alkenes, showing a reasonable functional group tolerance. In 2015, the group of Greaney substituted the transition metal photocatalysts by titanium dioxide (TiO2) nanoparticles (Scheme 7) [37]. Photoexcitation of electrons to the

• finally oxidized by an in situ generated superoxide radical anion to form the respective sulfoxide. In contrast, Fraile, Aleman and co-workers use the organic photocatalyst Eosin Y and propose a different mechanism for their method (Scheme 15b). Based on several quenching experiments, they suggest that

¹⁵N-Labelling and structure determination of adamantylated azolo-azines in solution

• Sergey L. Deev,
• Alexander S. Paramonov,
• Tatyana S. Shestakova,
• Igor A. Khalymbadzha,
• Oleg N. Chupakhin,
• Julia O. Subbotina,
• Oleg S. Eltsov,
• Pavel A. Slepukhin,
• Vladimir L. Rusinov,
• Alexander S. Arseniev and
• Zakhar O. Shenkarev

Beilstein J. Org. Chem. 2017, 13, 2535–2548, doi:10.3762/bjoc.13.250

• resonance assignment. The synthesized compounds were studied by NMR spectroscopy in a dimethyl sulfoxide (DMSO-d6) solution using samples with concentrations with range of 30–70 mM. The obtained 1D 15N NMR spectra are shown in Figure 2, and the 1D 1H and 13C spectra are presented as Figures S1–S18 in

Curcuminoid–BF₂ complexes: Synthesis, fluorescence and optimization of BF₂ group cleavage

• Henning Weiss,
• Jeannine Reichel,
• Helmar Görls,
• Kilian Rolf Anton Schneider,
• Mathias Micheel,
• Michael Pröhl,
• Michael Gottschaldt,
• Benjamin Dietzek and
• Wolfgang Weigand

Beilstein J. Org. Chem. 2017, 13, 2264–2272, doi:10.3762/bjoc.13.223

• (yellow) and 2h (grey) in CH2Cl2. Absorbance spectra of 2b in methanol (orange), tetrahydrofuran (red), toluene (black), dichloromethane (green) and dimethyl sulfoxide (blue). Compounds 2a–h in dichloromethane solution in daylight (top) and under 365 nm irradiation (bottom). Synthesis of the curcumin

Preactivation-based chemoselective glycosylations: A powerful strategy for oligosaccharide assembly

• Weizhun Yang,
• Bo Yang,
• Sherif Ramadan and
• Xuefei Huang

Beilstein J. Org. Chem. 2017, 13, 2094–2114, doi:10.3762/bjoc.13.207

• utilized glycosyl sulfoxide donors for glycosylation of unreactive substrates such as steroid derivative 2 by the Kahne group [25]. The axial C-7 hydroxy group in 2 is sterically hindered due to unfavorable 1,3-diaxial interactions. The traditional premixed glycosylation gave only low yields (<30%) of the

• products [26]. In contrast, when glycosyl sulfoxide donor 1 was preactivated with Tf2O at −78 °C, followed by the addition of sterol 2 and 2,6-di-tert-butyl-4-methylpyridine (DTBMP) as an acid scavenger, the desired compound 3 was obtained in an excellent 86% yield (Scheme 2). While this method has not

• been applied to glycosyl sulfoxide as the acceptor for iterative glycosylation, this early example demonstrated the power of preactivation. Subsequently, a wide range of glycosyl donors have been explored. β-Glycosyl bromide-mediated iterative gycosylation of selenoglycosides Yoshida and co-workers

Intramolecular glycosylation

• Xiao G. Jia and
• Alexei V. Demchenko

Beilstein J. Org. Chem. 2017, 13, 2028–2048, doi:10.3762/bjoc.13.201

• compound 63 was then oxidized into the corresponding sulfoxide with m-CPBA. The latter was glycosidated in the presence of Tf2O to afford disaccharide 64 in complete stereoselectivity and a good yield of 61% over two steps (73% from the sulfoxide intermediate). This dimethylsilyl linker strategy was also

New electroactive asymmetrical chalcones and therefrom derived 2-amino- / 2-(1H-pyrrol-1-yl)pyrimidines, containing an N-[ω-(4-methoxyphenoxy)alkyl]carbazole fragment: synthesis, optical and electrochemical properties

• Daria G. Selivanova,
• Alexei A. Gorbunov,
• Olga A. Mayorova,
• Alexander N. Vasyanin,
• Igor V. Lunegov,
• Elena V. Shklyaeva and
• Georgii G. Abashev

Beilstein J. Org. Chem. 2017, 13, 1583–1595, doi:10.3762/bjoc.13.158

• dichloromethane (DCM), acetone (DMK), benzene, tetrahydrofuran (THF), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), but are poorly soluble in hot ethanol and not soluble in hexane. On the enlargement of the conjugated system the colour of the compounds solutions in the sunlight expectedly changes from

• and for solutions in toluene, chloroform and dimethyl sulfoxide. The solvent parameters were taken into account in the DPCM solvation model [30][31]. All geometries were initially fully optimized for energy in the ground state using the same method. Calculations of the absorption maxima values and the

• chromophores 7a,b. An additional absorption maximum was found in the longwave region of the spectra recorded for chloroform and dimethyl sulfoxide solutions of these compounds (Figure 3). The replacement of diethyl ether by chloroform causes a bathochromic shift of the longwave absorption band. Further

Phenylsilane as an effective desulfinylation reagent

• Wanda H. Midura,
• Aneta Rzewnicka and
• Jerzy A. Krysiak

Beilstein J. Org. Chem. 2017, 13, 1513–1517, doi:10.3762/bjoc.13.150

• reduction of the ester group. In both cyclopropanes the carboxylate moiety and the sulfinyl group were in vicinal relation, but in 1, formed in the reaction of vinyl phosphoryl sulfoxide with EDSA [22], the ester group was easily accessed, since the bulky phosphoryl group was also in vicinal position to the

• sulfoxide substituent. Compounds 2 and 3 were obtained by us earlier [23] in diastereomerically pure form as key intermediates in our approach to constrained phosphonic acids by the reaction of phosphoryl acrylates with (S)-dimethylsulfonium(p-tolylsulfinyl)methylide. The carboxylate moiety was geminal to

2-Methyl-2,4-pentanediol (MPD) boosts as detergent-substitute the performance of ß-barrel hybrid catalyst for phenylacetylene polymerization

• Julia Kinzel,
• Daniel F. Sauer,
• Marco Bocola,
• Marcus Arlt,
• Tayebeh Mirzaei Garakani,
• Andreas Thiel,
• Klaus Beckerle,
• Tino Polen,
• Jun Okuda and
• Ulrich Schwaneberg

Beilstein J. Org. Chem. 2017, 13, 1498–1506, doi:10.3762/bjoc.13.148

• the β-barrel membrane channel protein FhuA WT co-crystallized with the detergent n-octyl-2-hydroxyethyl sulfoxide [24]. The N-terminal cork domain (residue 1-160) blocking the channel was removed. The amino acid exchanges of the hybrid catalyst model FhuA ΔCVFtev, namely cysteine at position 545

Urea–hydrogen peroxide prompted the selective and controlled oxidation of thioglycosides into sulfoxides and sulfones

• Adesh Kumar Singh,
• Varsha Tiwari,
• Kunj Bihari Mishra,
• Surabhi Gupta and
• Jeyakumar Kandasamy

Beilstein J. Org. Chem. 2017, 13, 1139–1144, doi:10.3762/bjoc.13.113

• role in carbohydrate synthesis. Thioglycosides, glycosyl sulfoxides and sulfones have been widely used as glycosyl donors in oligosaccharide synthesis which can be activated under mild reaction conditions [5][6][7][8][9][10]. Glycosyl sulfoxide donors usually provide excellent anomeric selectivity

• controlled oxidation of thioglycosides to glycosyl sulfoxides and sulfones selectively by altering the reaction conditions. It is also observed that thioglycoside oxidation suffers from low yields, poor selectivity (i.e., sulfoxide vs sulfone), use of inconvenient reaction conditions and expensive oxidants

• as dichloromethane and acetonitrile gave a negligible amount of corresponding sulfoxide (1a) while no sulfone (1b) was detected at room temperature even after 6 hours (Table 1, entries 1 and 2). However, protic solvents such as methanol, ethanol, tert-butanol and acetic acid were found to be

From chemical metabolism to life: the origin of the genetic coding process

• Antoine Danchin

Beilstein J. Org. Chem. 2017, 13, 1119–1135, doi:10.3762/bjoc.13.111

Synthesis and enzymatic ketonization of the 5-(halo)-2-hydroxymuconates and 5-(halo)-2-hydroxy-2,4-pentadienoates

• Tyler M. M. Stack,
• William H. Johnson Jr. and
• Christian P. Whitman

Beilstein J. Org. Chem. 2017, 13, 1022–1031, doi:10.3762/bjoc.13.101

• are presented in Supporting Information File 1. Equilibrium composition mixtures of 5b–d In separate test tubes, 5b–d (4 mg) was dissolved in dimethyl sulfoxide (DMSO)-d6 (30 μL). The individual mixtures were then added to 100 mM Na2HPO4 buffer (600 μL, pH ≈9). The final pH ranged from 6.8–7.2. The Pp

Conformational study of L-methionine and L-cysteine derivatives through quantum chemical calculations and ³J_HH coupling constant analyses

• Weslley G. D. P. Silva,
• Carolyne B. Braga and
• Roberto Rittner

Beilstein J. Org. Chem. 2017, 13, 925–937, doi:10.3762/bjoc.13.94

• , and dimethyl sulfoxide), according to the Integral Equation Formalism Polarizable Continuum Model (IEF−PCM) [44]. As expected, the ωB97X-D/aug-cc-pVTZ theoretical level showed good performance for these derivatives in comparison to similar systems previously studied [12][17][19], where higher levels

Transition-metal-free one-pot synthesis of alkynyl selenides from terminal alkynes under aerobic and sustainable conditions

• Adrián A. Heredia and
• Alicia B. Peñéñory

Beilstein J. Org. Chem. 2017, 13, 910–918, doi:10.3762/bjoc.13.92

• acetonitrile or ethanol (Table 1, entries 4 and 9). Poor yields below 20% were observed by using N-methylpyrrolidone (NMP), dimethyl sulfoxide (DMSO), dioxane or toluene (Table 1, entries 5–8). Finally, product 5a was not detectable at all when performing the reaction in water. As similar yields were found

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

• similar way to synthesize 5-hydroxy substituted 1-indanone 250 by utilizing the 1,3-diene 248 and the sulfoxide 249, has been described by Danishefsky et al. [98]. As a result of the cycloaddition, 5-hydroxy-1-indanone (250) has been obtained in 68% yield (Scheme 69). Lee, Kim and Danishefsky have

Silyl-protective groups influencing the reactivity and selectivity in glycosylations

• Mikael Bols and
• Christian Marcus Pedersen

Beilstein J. Org. Chem. 2017, 13, 93–105, doi:10.3762/bjoc.13.12

• . Review One of the earliest glycosylations with a persilylated glycosyl donor was carried out by Kihlberg and Broddefalk who needed an acid-labile protective group [5]. They protected a thiocresyl glucoside with TBS groups, oxidized the sulfur to sulfoxide 1 and used the latter to glucosylate the 2-OH of

• conformational change is not needed to expel the sulfonium ion. This is not the case with the β-anomer. Selectivity is mainly controlled by sterics and hence the α-glycoside is kinetic product as the alcohol approach the oxocarbenium ion intermediate from the exo-side. Glycosylation with sulfoxide 1

Synthesis of structurally diverse 3,4-dihydropyrimidin-2(1H)-ones via sequential Biginelli and Passerini reactions

• Andreas C. Boukis,
• Baptiste Monney and
• Michael A. R. Meier

Beilstein J. Org. Chem. 2017, 13, 54–62, doi:10.3762/bjoc.13.7

• first reaction step, different 3,4-dihydropyrimidin-2(1H)-one acids were synthesized, isolated and fully characterized. These products were subsequently used in a Passerini reaction utilizing a dichloromethane/dimethyl sulfoxide solvent mixture. By variation of the components in both multicomponent

• products, however, are in most cases very poorly soluble in non-polar solvents. In our investigations, a solvent mixture of dichloromethane with a small amount of dimethyl sulfoxide (polar but aprotic) allowed the successful combination of both chemistries. All possible bifunctional components for the

• acetoacetate for the Biginelli reaction and subsequent hydrogenolytic deprotection to the corresponding acid. The Biginelli reactions were performed in dimethyl sulfoxide at 110 °C in order to remove the water formed in course of the reaction. After a simple washing procedure, the desired DHMP acids 13–18 were

Synthesis of multi-lactose-appended β-cyclodextrin and its cholesterol-lowering effects in Niemann–Pick type C disease-like HepG2 cells

• Keiichi Motoyama,
• Rena Nishiyama,
• Yuki Maeda,
• Taishi Higashi,
• Yoichi Ishitsuka,
• Yuki Kondo,
• Tetsumi Irie,
• Takumi Era and
• Hidetoshi Arima

Beilstein J. Org. Chem. 2017, 13, 10–18, doi:10.3762/bjoc.13.2

• cyanotrihydroborate in dimethyl sulfoxide (DMSO) at 90 °C for 24 h. The product yield of multi-Lac-β-CD was 25%, and no unreacted compounds were confirmed by thin-layer chromatography (TLC). The MALDI–TOF MS spectrum of multi-Lac-β-CD revealed several peaks at m/z 2804, m/z 3006, m/z 3139, m/z 3296, and m/z 3454

Versatile synthesis of end-reactive polyrotaxanes applicable to fabrication of supramolecular biomaterials

• Atsushi Tamura,
• Asato Tonegawa,
• Yoshinori Arisaka and
• Nobuhiko Yui

Beilstein J. Org. Chem. 2016, 12, 2883–2892, doi:10.3762/bjoc.12.287

• assessed with size exclusion chromatography (SEC) measurements in dimethyl sulfoxide (DMSO), in which the unreacted pseudopolyrotaxanes were readily dissociated into their constituent compounds. If PRXs were produced, the peak of the PRXs would be observed at an earlier elution volume than the PEG axle

Biomimetic synthesis and HPLC–ECD analysis of the isomers of dracocephins A and B

• Viktor Ilkei,
• András Spaits,
• Anita Prechl,
• Áron Szigetvári,
• Zoltán Béni,
• Miklós Dékány,
• Csaba Szántay Jr,
• Judit Müller,
• Árpád Könczöl,
• Ádám Szappanos,
• Attila Mándi,
• Sándor Antus,
• Ana Martins,
• Attila Hunyadi,
• György Tibor Balogh,
• György Kalaus (†),
• Hedvig Bölcskei,
• László Hazai and
• Tibor Kurtán

Beilstein J. Org. Chem. 2016, 12, 2523–2534, doi:10.3762/bjoc.12.247

• -Aldrich. Water was purified with a Milli-Q system. The sample solvent was spectroscopy grade dimethyl sulfoxide (Uvasol) from Merck. Apparatus The separation of the isomeric mixtures of flavonoid alkaloids was performed with a Shimadzu chromatograph equipped with an LC-8A pump unit, SPD-M20A Photodiode

A new paradigm for designing ring construction strategies for green organic synthesis: implications for the discovery of multicomponent reactions to build molecules containing a single ring

• John Andraos

Beilstein J. Org. Chem. 2016, 12, 2420–2442, doi:10.3762/bjoc.12.236

• either of carbon monoxide [141][142][143], carbon dioxide [144], dichloromethoxymethane [145][146], or methyl methylthiomethyl sulfoxide [147][148][149] as one-carbon fragments. The only literature example of a [4 + 2] strategy applied to cyclohexanone derivatives involved reaction of but-3-en-2-one with

Efficient mechanochemical synthesis of regioselective persubstituted cyclodextrins

• Laszlo Jicsinszky,
• Marina Caporaso,
• Katia Martina,
• Emanuela Calcio Gaudino and
• Giancarlo Cravotto

Beilstein J. Org. Chem. 2016, 12, 2364–2371, doi:10.3762/bjoc.12.230

• difficult in the per-halide analogues, because of sodium azide’s poor solubility in DMF, N,N-dimethylacetamide, N-methylpyrrolidone and dimethyl sulfoxide. A solution to this problem might be found in the successive addition of sodium azide, considerably longer reaction times and/or higher temperatures

Experimental and theoretical investigations on the high-electron donor character of pyrido-annelated N-heterocyclic carbenes

• Michael Nonnenmacher,
• Dominik M. Buck and
• Doris Kunz

Beilstein J. Org. Chem. 2016, 12, 1884–1896, doi:10.3762/bjoc.12.178

• -complexes in literature, we determined the symmetric and asymmetric CO stretching modes of complex 2a in dichloromethane ( = 2082 and 2003 cm−1), dimethyl sulfoxide ( = 2064 and 1984 cm−1) and as a KBr pellet ( = 2073 and 1993 cm−1). This large medium dependence shows that it is mandatory to compare the

Towards potential nanoparticle contrast agents: Synthesis of new functionalized PEG bisphosphonates

• Souad Kachbi-Khelfallah,
• Maelle Monteil,
• Margery Cortes-Clerget,
• Evelyne Migianu-Griffoni,
• Jean-Luc Pirat,
• Olivier Gager,
• Julia Deschamp and
• Marc Lecouvey

Beilstein J. Org. Chem. 2016, 12, 1366–1371, doi:10.3762/bjoc.12.130

• a strategy in two steps via an aldehyde. Fortunately, the following two-step procedure was more effective. The alcohol derivatives 2 and 3a,b were treated with dimethyl sulfoxide, oxalyl chloride and triethylamine in dichloromethane at −55 °C. Under these classical Swern conditions, the