Addition of dithi(ol)anylium tetrafluoroborates to α,β-unsaturated ketones

• Yu-Chieh Huang,
• An Nguyen,
• Simone Gräßle,
• Sylvia Vanderheiden,
• Nicole Jung and
• Stefan Bräse

Beilstein J. Org. Chem. 2018, 14, 515–522, doi:10.3762/bjoc.14.37

• reaction. We synthesized eight different dithi(ol)anylium TFBs 1a–d and 2a–d from commercial carbonyl chlorides, isolated them via crystallization or separation and extraction and added them to a set of eight α,β-unsaturated non-cyclic ketones (Scheme 2 and Table 1). It was shown that dithi(ol)anylium TFBs

Continuous multistep synthesis of 2-(azidomethyl)oxazoles

• Thaís A. Rossa,
• Nícolas S. Suveges,
• Marcus M. Sá,
• David Cantillo and
• C. Oliver Kappe

Beilstein J. Org. Chem. 2018, 14, 506–514, doi:10.3762/bjoc.14.36

• through a continuous addition of reagent streams, quenching, liquid–liquid extraction, or even filtration stages, thus avoiding the handling of unstable intermediates [35][36][37]. In this article we present an integrated continuous-flow procedure for the preparation of 2-(azidomethyl)oxazoles 7 starting

• % purity (HPLC). Unfortunately, the oxazoles could not be precipitated as hydrobromide salts even after cooling at −20 °C and adding petroleum ether as co-solvent. The work-up consisted in extraction with aqueous NaHCO3, evaporation of the organic phase, and purification of the residue by column

Latest development in the synthesis of ursodeoxycholic acid (UDCA): a critical review

• Fabio Tonin and
• Isabel W. C. E. Arends

Beilstein J. Org. Chem. 2018, 14, 470–483, doi:10.3762/bjoc.14.33

• extracted with organic solvents from aqueous buffers at different pHs. Then, the bile acids were separated from inorganic salts by extraction of the dry residue with absolute ethanol. The major components of the obtained mixture are the primary bile acids (CA and CDCA), secondary bile acids (DCA and LCA

• an infinitesimal change in the number of electrons [61]. The overall yield of the epimerization step is around 70% [12][15][62]. A further purification step is necessary for the preparation of free UDCA: it can be easily obtained with sequential esterification, extraction and hydrolysis (yield 91

Synthetic and semi-synthetic approaches to unprotected N-glycan oxazolines

• Antony J. Fairbanks

Beilstein J. Org. Chem. 2018, 14, 416–429, doi:10.3762/bjoc.14.30

• partially purified by acetone precipitation and extraction with 60% methanol. The crude N-glycans were found to be a rather complex mixture of compounds, the four major components of which were identified as triantennary glycans with 2 or 3 sialic acids attached as regioisomers (i.e., both α(2–6)- and α(2–3

Novel amide-functionalized chloramphenicol base bifunctional organocatalysts for enantioselective alcoholysis of meso-cyclic anhydrides

• Lingjun Xu,
• Shuwen Han,
• Linjie Yan,
• Haifeng Wang,
• Haihui Peng and
• Fener Chen

Beilstein J. Org. Chem. 2018, 14, 309–317, doi:10.3762/bjoc.14.19

• pressure and the residue was dissolved in CH2Cl2 (10 mL). The solution was successively washed with saturated Na2CO3 (2 × 5 mL), acidified with excess 2 N HCl, followed by extraction with EtOAc (3 × 10 mL). The combined organic phase were dried over Na2SO4 and concentrated to afford the corresponding

Recent advances on organic blue thermally activated delayed fluorescence (TADF) emitters for organic light-emitting diodes (OLEDs)

• Thanh-Tuân Bui,
• Fabrice Goubard,
• Malika Ibrahim-Ouali,
• Didier Gigmes and
• Frédéric Dumur

Beilstein J. Org. Chem. 2018, 14, 282–308, doi:10.3762/bjoc.14.18

Progress in copper-catalyzed trifluoromethylation

• Guan-bao Li,
• Chao Zhang,
• Chun Song and
• Yu-dao Ma

Beilstein J. Org. Chem. 2018, 14, 155–181, doi:10.3762/bjoc.14.11

• corresponding hydroxylated arene) was readily removable by extraction or column chromatography. Later, the group of Beller [42] described another example of copper-catalyzed trifluoromethylation reactions of aryl- and vinylboronic acids with CF3SO2Na as the trifluoromethyl source (Scheme 23). The

The synthesis of the 2,3-difluorobutan-1,4-diol diastereomers

• Robert Szpera,
• Nadia Kovalenko,
• Kalaiselvi Natarajan,
• Nina Paillard and
• Bruno Linclau

Beilstein J. Org. Chem. 2017, 13, 2883–2887, doi:10.3762/bjoc.13.280

• -butynediol (13) by LiAlH4 to give trans-1 [27] was followed by benzylation [28] and epoxidation with m-CPBA to give (±)-trans-2 [28]. When the reaction was performed on a small scale, excess m-CPBA and the byproduct 3-chlorobenzoic acid were removed by extraction with a saturated Na2S2O3 solution. However

Reactivity of bromoselenophenes in palladium-catalyzed direct arylations

• Aymen Skhiri,
• Ridha Ben Salem,
• Jean-François Soulé and
• Henri Doucet

Beilstein J. Org. Chem. 2017, 13, 2862–2868, doi:10.3762/bjoc.13.278

• to room temperature and stirred during 20 h. After addition of water, the extraction was carried out with diethyl ether. Then, the organic phase was dried over magnesium sulphate. Finally, evaporation of the solvent and purification on silica gel afforded the 5-bromo-2-arylselenophenes 15–17. Eluents

The photodecarboxylative addition of carboxylates to phthalimides as a key-step in the synthesis of biologically active 3-arylmethylene-2,3-dihydro-1H-isoindolin-1-ones

• Ommid Anamimoghadam,
• Saira Mumtaz,
• Anke Nietsch,
• Gaetano Saya,
• Cherie A. Motti,
• Jun Wang,
• Peter C. Junk,
• Ashfaq Mahmood Qureshi and
• Michael Oelgemöller

Beilstein J. Org. Chem. 2017, 13, 2833–2841, doi:10.3762/bjoc.13.275

• crystalline solids in good to excellent yields of 63–95% (Table 2, entries 1–17). In many cases, the photoproducts 3 simply precipitated during irradiation or after removal of the co-solvent acetone and could be isolated by filtration. In all other cases, the desired products 3 were obtained after extraction

• -to-Z isomerization was caused during acidic work-up or purification. When products 8a and 8j were isolated by extraction under neutral conditions, the high E-selectivity of the dehydration step was retained. After column chromatographic purification on silica gel, partial isomerization to the Z

A concise flow synthesis of indole-3-carboxylic ester and its derivatisation to an auxin mimic

• Marcus Baumann,
• Ian R. Baxendale and
• Fabien Deplante

Beilstein J. Org. Chem. 2017, 13, 2549–2560, doi:10.3762/bjoc.13.251

• ). EtOAc was promising and made extraction very easy but during the reactions small quantities of a dark red, sticky, precipitate were observed (Table 1, entry 12). This was considered problematic for processing in a meso flow reactor due to the potential for causing blockages. It was however found that

• the addition of between 10–20% v/v MeCN ensure a fully homogeneous solution and also allowed for simple aqueous extraction with good recovery (>90%). However, from the provisional results DCM stood out as the most viable solvent (Table 1, entries 7, 24 and 25) and allowed a 0.25 M solution of

One-pot three-component route for the synthesis of S-trifluoromethyl dithiocarbamates using Togni’s reagent

• Azim Ziyaei Halimehjani,
• Martin Dračínský and
• Petr Beier

Beilstein J. Org. Chem. 2017, 13, 2502–2508, doi:10.3762/bjoc.13.247

• investigated and moderate to good yields of products 4 were obtained (Scheme 2). The products were isolated from the reaction mixture by extraction with CH2Cl2 and purification was carried out by column chromatography on silica gel using CH2Cl2/n-pentane (1:9) as eluent. The structure of products was confirmed

Syntheses, structures, and stabilities of aliphatic and aromatic fluorous iodine(I) and iodine(III) compounds: the role of iodine Lewis basicity

• Tathagata Mukherjee,
• Soumik Biswas,
• Andreas Ehnbom,
• Subrata K. Ghosh,
• Ibrahim El-Zoghbi,
• Nattamai Bhuvanesh,
• Hassan S. Bazzi and
• John A. Gladysz

Beilstein J. Org. Chem. 2017, 13, 2486–2501, doi:10.3762/bjoc.13.246

• fluorophilicity (extraction of a CH3CN solution with perfluorohexane). An analogous procedure with Rf10I gave the higher homolog 1,3-Rf10C6H4I in 50% yield [9], and a lesser amount of what was presumed to be the dialkylation product. The analogous para diiodide 1,4-C6H4I2 gave parallel chemistry, as illustrated

Herpetopanone, a diterpene from Herpetosiphon aurantiacus discovered by isotope labeling

• Xinli Pan,
• Nicole Domin,
• Sebastian Schieferdecker,
• Hirokazu Kage,
• Martin Roth and
• Markus Nett

Beilstein J. Org. Chem. 2017, 13, 2458–2465, doi:10.3762/bjoc.13.242

• supplemented with non-labeled D-glucose. The resulting culture broth was centrifuged, and the supernatant was treated with the resin XAD-2 to adsorb the metabolites that had been secreted during the cultivation. After extraction of the adsorber resin with methanol, a preliminary fractionation was accomplished

• washed with distilled water and, subsequently, eluted with three bed volumes of methanol. The eluates were concentrated under vacuum and the resulting extracts were subjected to LCMS analysis. Production and isolation of herpetopanone The fermentation and extraction conditions were the same as described

Asymmetric synthesis of propargylamines as amino acid surrogates in peptidomimetics

• Matthias Wünsch,
• David Schröder,
• Tanja Fröhr,
• Lisa Teichmann,
• Sebastian Hedwig,
• Nils Janson,
• Clara Belu,
• Jasmin Simon,
• Shari Heidemeyer,
• Philipp Holtkamp,
• Jens Rudlof,
• Lennard Klemme,
• Alessa Hinzmann,
• Beate Neumann,
• Hans-Georg Stammler and
• Norbert Sewald

Beilstein J. Org. Chem. 2017, 13, 2428–2441, doi:10.3762/bjoc.13.240

• sulfinylimines 5. (a) Sulfinamide (S)-1, molecular sieves 4 Å, toluene. (b) 1. Dilution with H2O, 2. Extraction with DCM. (c) Addition of Ti(OiPr)4 prior to the conversion with (trimethylslyl)ethynyllithium [94]. (d) Addition of AlMe3 prior to the conversion with (trimethylsilyl)ethynyllithium. a) Possible

One-pot syntheses of blue-luminescent 4-aryl-1H-benzo[f]isoindole-1,3(2H)-diones by T3P^® activation of 3-arylpropiolic acids

• Melanie Denißen,
• Alexander Kraus,
• Guido J. Reiss and
• Thomas J. J. Müller

Beilstein J. Org. Chem. 2017, 13, 2340–2351, doi:10.3762/bjoc.13.231

• acid ( 2901–3082 cm−1). The signals at δ 12.70 and 12.98 in the 1H NMR spectrum can be assigned to the two carboxylic acid functionalities (see Supporting Information File 1). The extraction of the crude anhydrides with a saturated aqueous solution of sodium bicarbonate can be achieved uneventfully

• yield of 4a of 80%, the cyano-substituted substrate 1c furnishes a significantly lower yield of 27% (Table 4, entry 4), originating from the lower reactivity in the anhydride formation. Therefore, for accessing acceptor-substituted derivatives of 4, an intermediate extraction with bicarbonate after the

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

• yields strongly decrease when employing other aldehydes [12]. This procedure also requires a rather extensive work-up including several extraction steps and chromatography [8]. A second, more recent approach first published by Rao et al. relies on boron trifluoride as the complexing agent [13]. The

The effect of milling frequency on a mechanochemical organic reaction monitored by in situ Raman spectroscopy

• Patrick A. Julien,
• Ivani Malvestiti and
• Tomislav Friščić

Beilstein J. Org. Chem. 2017, 13, 2160–2168, doi:10.3762/bjoc.13.216

• spectroscopy [30] or by a tandem technique combining these two techniques [31]. Whereas valuable mechanistic information on the course of a milling reaction can be obtained through stepwise, ex situ monitoring [32] based on periodically interrupting the milling process followed by sample extraction and

Novel approach to hydroxy-group-containing porous organic polymers from bisphenol A

• Tao Wang,
• Yan-Chao Zhao,
• Li-Min Zhang,
• Yi Cui,
• Chang-Shan Zhang and
• Bao-Hang Han

Beilstein J. Org. Chem. 2017, 13, 2131–2137, doi:10.3762/bjoc.13.211

• reaction mixture gave a solid product (denoted as PPOP-1). After cooled to room temperature, the solid was filtrated and washed with acetone, dichloromethane, and ethanol, subsequently. Further purification of the polymer was carried out by Soxhlet extraction with water, ethanol, and dichloromethane for 24

Preparation of imidazo[1,2-a]-N-heterocyclic derivatives with gem-difluorinated side chains

• Layal Hariss,
• Kamal Bou Hadir,
• Mirvat El-Masri,
• Thierry Roisnel,
• René Grée and
• Ali Hachem

Beilstein J. Org. Chem. 2017, 13, 2115–2121, doi:10.3762/bjoc.13.208

• (4 mL), then DBU (0.42 mL, 2.82 mmol, 1.5 equiv) was added and the reaction mixture was stirred at room temperature. After 2 h, 19F NMR showed 100% conversion and the reaction mixture was neutralized with a saturated solution of NH4Cl. After extraction with ethyl acetate, the organic phases were

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

• to selectively “catch” the desired tetrasaccharide 153, which was rapidly separated from non-fluorinated impurities by fluorous solid-phase extraction (F-SPE). Subsequent release of the compound from the fluorous tag and F-SPE yielded pure 153 in 61% overall yield from donor 83. One potential side

Main group mechanochemistry

• Agota A. Gečiauskaitė and
• Felipe García

Beilstein J. Org. Chem. 2017, 13, 2068–2077, doi:10.3762/bjoc.13.204

• complete eradication of solvents might not be entirely beneficial. Solvents ameliorate reactant interactions, control reaction rates, and aid heat dispersion in exothermic reactions inter alia. Needless to say, solvents are necessary for the extraction, separation, and purification of the final products

Mechanically induced oxidation of alcohols to aldehydes and ketones in ambient air: Revisiting TEMPO-assisted oxidations

• Andrea Porcheddu,
• Evelina Colacino,
• Giancarlo Cravotto,
• Francesco Delogu and
• Lidia De Luca

Beilstein J. Org. Chem. 2017, 13, 2049–2055, doi:10.3762/bjoc.13.202

• ), the full recovery of benzaldehyde was only achieved after solvent extraction. A minor modification to the synthetic protocol, involving the use of additional zirconia balls (four balls × 5 mm Ø, 7 balls × 12 mm Ø) and opening the jar (3 min) to air during the time interval between two consecutive

Are boat transition states likely to occur in Cope rearrangements? A DFT study of the biogenesis of germacranes

• José Enrique Barquera-Lozada and
• Gabriel Cuevas

Beilstein J. Org. Chem. 2017, 13, 1969–1976, doi:10.3762/bjoc.13.192

• into elemanes by heating through a Cope rearrangement. In some cases, these transformations are so favorable that it has been mentioned that the observed elemanes are only artifacts produced at the extraction [5][6][7][8]. It is known that 1,5-dienes suffer Cope rearrangements at temperatures between

18-Hydroxydolabella-3,7-diene synthase – a diterpene synthase from Chitinophaga pinensis

• Jeroen S. Dickschat,
• Jan Rinkel,
• Patrick Rabe,
• Arman Beyraghdar Kashkooli and
• Harro J. Bouwmeester

Beilstein J. Org. Chem. 2017, 13, 1770–1780, doi:10.3762/bjoc.13.171

• alcohol that can easily be isolated by extraction and column chromatography, which underpins the potential of plants, besides the recently reviewed microbial hosts for the sustainable production of diterpenes [36], as expression systems for secondary metabolite genes. The function of the investigated