Cathodic reductive coupling of methyl cinnamate on boron-doped diamond electrodes and synthesis of new neolignan-type products

• Taiki Kojima,
• Rika Obata,
• Tsuyoshi Saito,
• Yasuaki Einaga and
• Shigeru Nishiyama

Beilstein J. Org. Chem. 2015, 11, 200–203, doi:10.3762/bjoc.11.21

• magnesium (Mg), were examined as cathodes under the optimized electrolytic conditions (Table 1, entry 11). Hydrogen evolution at the electrode was recognized when Pt and Mg electrodes were used, and the educt 1a was recovered in high yield. The GC electrode provided the coupling product 2 (34%, racemate

Formation of nanoparticles by cooperative inclusion between (S)-camptothecin-modified dextrans and β-cyclodextrin polymers

• Thorbjørn Terndrup Nielsen,
• Catherine Amiel,
• Laurent Duroux,
• Kim Lambertsen Larsen,
• Lars Wagner Städe,
• Reinhard Wimmer and
• Véronique Wintgens

Beilstein J. Org. Chem. 2015, 11, 147–154, doi:10.3762/bjoc.11.14

• EDC (982 mg, 5.02 mmol) were added and the solution was stirred at rt overnight. TLC showed complete conversion of the CPT and the solution was washed with water (3 × 100 mL), brine (100 mL) and dried over magnesium sulfate. The solution was filtered, concentrated to approx. 10 mL in vacuo and

One-pot functionalisation of N-substituted tetrahydroisoquinolines by photooxidation and tunable organometallic trapping of iminium intermediates

• Joshua P. Barham,
• Matthew P. John and
• John A. Murphy

Beilstein J. Org. Chem. 2014, 10, 2981–2988, doi:10.3762/bjoc.10.316

• BrCCl3 and its byproduct CHCl3 [22] were responsible for poor organometallic reaction profiles. Generation of radical intermediates or carbenes upon reacting Grignard reagents or magnesium salts with BrCCl3 or CHCl3 are evidenced in the literature [38][39]. Initially, we took advantage of the

Synthesis and biological evaluation of novel N-α-haloacylated homoserine lactones as quorum sensing modulators

• Michail Syrpas,
• Ewout Ruysbergh,
• Christian V. Stevens,
• Norbert De Kimpe and
• Sven Mangelinckx

Beilstein J. Org. Chem. 2014, 10, 2539–2549, doi:10.3762/bjoc.10.265

• complete clearing of the oil. The aqueous phase was removed and the yellow oil was dissolved in a saturated aq NaHCO3 solution, the medium was acidified with 5% aq H2SO4 and heated. The dense yellow oil was extracted with ethyl acetate, dried over anhydrous magnesium sulfate, filtered and evaporated under

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

• clear further in this review. An overview of different possible setups for obtaining carboxylic acids is given in Scheme 6. Electrocarboxylation reactions can either be conducted with a sacrificial anode, like magnesium or aluminum, or with an inert anode, like platinum or carbon. Most research has been

• done using a setup with a sacrificial magnesium or aluminum anode. The general mechanism of alkyne electrocarboxylation to a 1,4-dicarboxylated product is shown in Scheme 9. It is highly similar to the mechanism for electrocarboxylation of olefins. In these reactions a high selectivity for

• were conducted in a divided cell, giving only moderate yields [114][115]. A drastic increase in efficiency was obtained by employing sacrificial anodes [116], especially magnesium anodes [117][118]. The cathode material is again of great importance, with silver and platinum giving the highest

Autonomous assembly of synthetic oligonucleotides built from an expanded DNA alphabet. Total synthesis of a gene encoding kanamycin resistance

• Kristen K. Merritt,
• Kevin M. Bradley,
• Daniel Hutter,
• Mariko F. Matsuura,
• Diane J. Rowold and
• Steven A. Benner

Beilstein J. Org. Chem. 2014, 10, 2348–2360, doi:10.3762/bjoc.10.245

• nucleotide overlap with melting temperatures predicted to lie in a narrow range (44–56 °C; calculated without magnesium). OligArch also designed the sequences to have no-off target hybrids having a melting temperature greater than 25 °C, a full 20 °C below that predicted for the desired annealing pairs. Two

• magnesium; using the nearest neighbor formula from http://www.clinchem.org/content/45/12/2094.long; melting temperatures in 10 mM MgCl2 are expected to be ~10 °C higher) The S:B pair was assumed to contribute to duplex stability the same as the C:G pair. Enthalpy and entropy values for nucleotide pairs in

Molecular recognition of AT-DNA sequences by the induced CD pattern of dibenzotetraaza[14]annulene (DBTAA)–adenine derivatives

• Marijana Radić Stojković,
• Marko Škugor,
• Łukasz Dudek,
• Jarosław Grolik,
• Julita Eilmes and
• Ivo Piantanida

Beilstein J. Org. Chem. 2014, 10, 2175–2185, doi:10.3762/bjoc.10.225

• , washed with water (2 × 100 mL), dried over anhydrous magnesium sulfate, concentrated to a small volume, and chromatographed on a column of silica gel with dichloromethane/methanol (20:0.5 to 20:1 v/v) as an eluent. The main orange fraction was collected and evaporated to dryness. A residue was dissolved

• was separated and washed thoroughly with water (5 × 30 mL), dried over anhydrous magnesium sulfate, concentrated to a small volume, and chromatographed on a column of silica gel with dichloromethane/methanol (10:0.6 v/v) as an eluent. The second fraction was collected from the two orange ones which

The effect of permodified cyclodextrins encapsulation on the photophysical properties of a polyfluorene with randomly distributed electron-donor and rotaxane electron-acceptor units

• Aurica Farcas,
• Ana-Maria Resmerita,
• Pierre-Henri Aubert,
• Flavian Farcas,
• Iuliana Stoica and
• Anton Airinei

Beilstein J. Org. Chem. 2014, 10, 2145–2156, doi:10.3762/bjoc.10.222

• . The organic extracts were washed with water and dried over magnesium sulfate. The DCM solution was concentrated by rotary evaporation and precipitated in hexane to remove free TMS-β-CD. The yellow polymer sample was filtered. After drying the solid was purified by Soxhlet extraction with methanol for

Photorelease of phosphates: Mild methods for protecting phosphate derivatives

• Sanjeewa N. Senadheera,
• Abraham L. Yousef and
• Richard S. Givens

Beilstein J. Org. Chem. 2014, 10, 2038–2054, doi:10.3762/bjoc.10.212

• corresponding to the photoproduct(s). At the end of the photolysis, the solution contained an orange-colored precipitate. The organic soluble components were extracted with ethyl acetate, and the organic extract was washed with water, dried over magnesium sulfate, and the solvent removed under reduced pressure

Influence of cyclodextrin on the UCST- and LCST-behavior of poly(2-methacrylamido-caprolactam)-co-(N,N-dimethylacrylamide)

• Alexander Burkhart and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 1951–1958, doi:10.3762/bjoc.10.203

• mixture is washed with brine and water. The organic phase is dried over magnesium sulfate, filtered and the solvent is evaporated under reduced pressure. A colorless solid is obtained. Mp = 125 °C; Yield: 4.7 g (23.9 mmol, 61%); FTIR (diamond), ν (cm−1): 3252 (br. NH), 2923 (s, CH), 2857 (m, CH), 1650 (s

Reaction of selected carbohydrate aldehydes with benzylmagnesium halides: benzyl versus o-tolyl rearrangement

• Maroš Bella,
• Bohumil Steiner,
• Vratislav Langer and
• Miroslav Koóš

Beilstein J. Org. Chem. 2014, 10, 1942–1950, doi:10.3762/bjoc.10.202

• unambiguously confirmed by single-crystal X-ray analysis. The formation of o-tolyl isomers 4 and 5 can be explained by the possible reaction sequence (path 1) depicted in Scheme 2. The first step involves an addition of the Grignard reagent to the saccharide aldehyde, producing a trienic magnesium alkoxide

• intermediate A (magnesium salt of 2-R-hydroxymethyl-1-methylene-1,2-dihydrobenzene, where R is the saccharide moiety) which, upon quenching with aqueous NH4Cl, affords (via an intermediate B) the corresponding o-tolyl isomer (a mixture of diastereomeric alcohols 4 and 5). A similar mechanism was proposed [24

• ][25] for the reaction of 1-naphthylmethylmagnesium chloride (10) with some aldehydes and ketones (Scheme 3). However, in this case, a trienic magnesium alkoxide intermediate E (magnesium salt of 2-hydroxymethyl-1-methylene-1,2-dihydronaphthalene, an analogue of intermediate A in Scheme 2, path 1

Streptopyridines, volatile pyridine alkaloids produced by Streptomyces sp. FORM5

• Ulrike Groenhagen,
• Michael Maczka,
• Jeroen S. Dickschat and
• Stefan Schulz

Beilstein J. Org. Chem. 2014, 10, 1421–1432, doi:10.3762/bjoc.10.146

• magnesium chloride solution, 20 g/L agar only for plates) at 28 °C for 3 days. SM-agar plates were then inoculated with 300 µL of the preculture and cultivated for 6 days at 28 °C. Then the culture was analyzed by closed-loop stripping analysis at room temperature [7]. In this system, air is continuously

Selective allylic hydroxylation of acyclic terpenoids by CYP154E1 from Thermobifida fusca YX

• Anna M. Bogazkaya,
• Clemens J. von Bühler,
• Sebastian Kriening,
• Alexandrine Busch,
• Alexander Seifert,
• Jürgen Pleiss,
• Sabine Laschat and
• Vlada B. Urlacher

Beilstein J. Org. Chem. 2014, 10, 1347–1353, doi:10.3762/bjoc.10.137

• a procedure by Fringuelli et al. [39] nerol (2) was treated with magnesium monoperoxyphthalate (MPPA) in the presence of NaOH to give 2,3-epoxynerol (6) in 77% yield together with 20% of reisolated starting material 2 (see Supporting Information File 1). According to a method by McMurry [24

• hindrance were selected. Terpene substrates (grey background) and their oxidised derivatives. a) Ac2O, pyridine, room temperature, 24 h; b) SeO2, t-BuOOH, CH2Cl2, 0 °C, 5 h; c) K2CO3, MeOH, room temperature, 2.5 h; d) MPPA, NaOH, H2O, room temperature, 5 h (MPPA = magnesium monoperoxyphthalate). a) SeO2, t

Magnesium bis(monoperoxyphthalate) hexahydrate as mild and efficient oxidant for the synthesis of selenones

• Andrea Temperini,
• Massimo Curini,
• Ornelio Rosati and
• Lucio Minuti

Beilstein J. Org. Chem. 2014, 10, 1267–1271, doi:10.3762/bjoc.10.127

• Abstract A new, efficient and mild method for the direct oxidation of selenides to selenones using magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) has been developed. Noteworthy this transformation proceeds at room temperature, employs a cheap and safety oxidant and has a broad functional group

• investigated the use of magnesium bis(monoperoxyphthalate) hexahydrate (MMPP) as a new oxidant for the straightforward conversion of selenides 1 to selenones 2 under mild experimental conditions. Magnesium bis(monoperoxyphthalate) hexahydrate is a cheap commercially available, relatively stable and easy to use

• corresponding selenone in 68% yield. It is noteworthy that the reaction byproduct magnesium phthalate is water soluble and easy to separate during work-up; acidification of the water phase and extraction with dichloromethane allows to recover the pure phthalic acid in excellent yield. This protocol was then

Amino acid motifs in natural products: synthesis of O-acylated derivatives of (2S,3S)-3-hydroxyleucine

• Oliver Ries,
• Martin Büschleb,
• Markus Granitzka,
• Dietmar Stalke and
• Christian Ducho

Beilstein J. Org. Chem. 2014, 10, 1135–1142, doi:10.3762/bjoc.10.113

• derivative with limited stability, which was immediately converted into alcohol 4 by diastereoselective Felkin–Anh type Grignard addition with isopropyl magnesium chloride (50% yield over 2 steps from 3, dr > 95:5). However, we could not confirm that the use of diethyl ether as co-solvent in the Grignard

• acyclic D-serinal derivatives for the addition of nucleophiles to amino acid-derived aldehydes [33][34]. However, Zhu and co-workers have pointed out that Garner’s aldehyde surprisingly furnishes the syn diastereomer as the major product from its reaction with isopropyl magnesium chloride [32], thus

• formation of 8 in moderate to good yields (Table 1, entries 4–6). Finally, when 2,2-DiMP was used as solvent with catalytic amounts of CSA in the presence of magnesium sulfate, 8 could be isolated in a very good yield of 93% (Table 1, entry 7). After TBAF-mediated cleavage of the silyl ether, the resultant

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

A new building block for DNA network formation by self-assembly and polymerase chain reaction

• Holger Bußkamp,
• Sascha Keller,
• Marta Robotta,
• Malte Drescher and
• Andreas Marx

Beilstein J. Org. Chem. 2014, 10, 1037–1046, doi:10.3762/bjoc.10.104

• denaturation studies (cf. Figure 2). The self-complementary oligonucleotides (5 μM) were annealed in 10 mM triethylammonium acetate buffer at pH 7 in the presence of sodium chloride (150 mM), sodium chloride and magnesium chloride (150 mM and 100 mM, respectively) or in the absence of salts. The solutions were

• melting in all buffers tested (data not shown). In magnesium ion-containing buffer the CG 2-mer (ODN-sc-I) shows a higher melting temperature (37.6 °C) as the ODN-sc-II 4-mer (24.3 °C). The GC-rich 4-mer ODN-sc-III shows high melting temperatures even in the presence of only sodium chloride (58.0 °C) and

• an even higher melting temperature in the presence of additional magnesium (73.0 °C). The melting temperature in presence of sodium chloride and magnesium is even higher than the respective melting temperature of the 6-mer ODN-sc-IV (50.7 °C). All in all, one can conclude that the self-assembly of GC

N-Alkylated dinitrones from isosorbide as cross-linkers for unsaturated bio-based polyesters

• Oliver Goerz and
• Helmut Ritter

Beilstein J. Org. Chem. 2014, 10, 902–909, doi:10.3762/bjoc.10.88

• product was received after drying of the organic layer over magnesium sulfate and subsequent removal of the solvent under reduced pressure. Yield: 94%. 1H NMR (300 MHz, CDCl3) δ (ppm) 6.58–6.33 (m, 2H, H2C=CH-), 6.22–6.01 (m, 2H, H2C=CH-), 5.89–5.80 (m, 2H, H2C=CH-), 5.29–5.16 (m, 2H, -CH-O-CO-), 4.87 (t

• solution and the organic layer was dried over magnesium sulfate. The pure product was obtained by evaporation of the solvent. Yield: 92%. 1H NMR (300 MHz, CDCl3) δ (ppm) 7.11–6.94 (m, H3C-HC=CH-), 5.96–5.79 (m, 1H, H3C-HC=CH-), 5.33–5.08 (m, 2H, -CH-O-CO-), 4.86 (t, 3J = 5 Hz, 1H, -CH-CH-), 4.53 (d, 3J

Structure elucidation of female-specific volatiles released by the parasitoid wasp Trichogramma turkestanica (Hymenoptera: Trichogrammatidae)

• Armin Tröger,
• Teris A. van Beek,
• Martinus E. Huigens,
• Isabel M. M. S. Silva,
• Maarten A. Posthumus and
• Wittko Francke

Beilstein J. Org. Chem. 2014, 10, 767–773, doi:10.3762/bjoc.10.72

• , 10 h; c: p-TsCl, DMAP, TEA, DCM, −20 °C to rt, 12 h; d: (3-methylbutyl)magnesium bromide, CuI, THF, −90 °C to rt, 16 h; e: TBAF, THF, rt, 14 h; f: PDC, MS 4 Å, DCM, −20 °C, 90 min; g: (3-methylbut-2-en-1-yl)triphenylphosphonium bromide, n-BuLi, THF, −40 °C to rt 16 h; h: 1) NaH, THF, −20 °C to rt, 1

Synthesis of chiral N-phosphinyl α-imino esters and their application in asymmetric synthesis of α-amino esters by reduction

• Yiwen Xiong,
• Haibo Mei,
• Lingmin Wu,
• Jianlin Han,
• Yi Pan and
• Guigen Li

Beilstein J. Org. Chem. 2014, 10, 653–659, doi:10.3762/bjoc.10.57

• phosphinyl amide 1 (Table 1). Common dehydrating reagents, like 4 Å molecular sieves and magnesium sulfate, resulted in no desired product neither at room temperature nor under reflux (Table 1, entries 1–4). Very poor chemical yields of α-imino ester 3a were detected when tetraethoxytitanium or

Synthesis of complex intermediates for the study of a dehydratase from borrelidin biosynthesis

• Frank Hahn,
• Nadine Kandziora,
• Steffen Friedrich and
• Peter F. Leadlay

Beilstein J. Org. Chem. 2014, 10, 634–640, doi:10.3762/bjoc.10.55

• presence of a methyl ester function. Amongst others, we tested Paterson’s lactate-derived benzoyl auxiliary, Evans’ magnesium-catalyzed direct aldol reaction, and an Abiko–Masamune-like aldol reaction by using a thiodesoxy variant of the norephedrine-derived auxiliary on simplified model aldehydes as well

Silver and gold-catalyzed multicomponent reactions

• Giorgio Abbiati and
• Elisabetta Rossi

Beilstein J. Org. Chem. 2014, 10, 481–513, doi:10.3762/bjoc.10.46

• catalysts for coupling arylaldehydes, piperidine and phenylacetylene in toluene at 100 °C. One year later, the same research group obtained comparable results under identical reaction conditions by using gold(0) nanoparticles stabilized by nanocristalline magnesium oxide [28]. In this work, the scope was

• G–NH2 groups under palladium/copper [61][62], copper [63][64], copper/magnesium [65], or base [66] catalysis have been reported. When tosylhydrazide (41) is used as G–NH2 component, the silver promoted MCR can afford 2-amino-1,3-disubstituted-1,2-dihydroquinolines and, when the third component (Nu

Synthesis of the B-seco limonoid core scaffold

• Hanna Bruss,
• Hannah Schuster,
• Rémi Martinez,
• Markus Kaiser,
• Andrey P. Antonchick and
• Herbert Waldmann

Beilstein J. Org. Chem. 2014, 10, 194–208, doi:10.3762/bjoc.10.15

• envisaged to be constructed by 1,2-addition, using the free β-hydroxy functionality in 63 as directing group. Several conditions with allyl boronates, stannanes, silanes, indium, magnesium bromide, cerium, zinc bromide and other reagents have been screened. Finally, the best result was achieved with

Continuous-flow Heck synthesis of 4-methoxybiphenyl and methyl 4-methoxycinnamate in supercritical carbon dioxide expanded solvent solutions

• Phei Li Lau,
• Ray W. K. Allen and
• Peter Styring

Beilstein J. Org. Chem. 2013, 9, 2886–2897, doi:10.3762/bjoc.9.325

• susceptible to decomposition. Unfortunately, an excess of phosphine reduces the reaction rate, while higher quantities of palladium result in potentially significant increased production costs [33]. Palladium on a magnesium–lanthanum mixed oxide support (Pd/MgLaO) was reported to be an efficient, thermally

• . The resulting organic mixture (top layer) was then withdrawn and dried over magnesium sulfate then analysed by gas chromatography using a Varian 3900 GC with reference to standard solutions of trans-4-methoxystilbene. Continuous flow reactions Particles of the catalyst, 2% Pd on silica, (250 mg

N,N'-(Hexane-1,6-diyl)bis(4-methyl-N-(oxiran-2-ylmethyl)benzenesulfonamide): Synthesis via cyclodextrin mediated N-alkylation in aqueous solution and further Prilezhaev epoxidation

• Julian Fischer,
• Simon Millan and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 2834–2840, doi:10.3762/bjoc.9.318

• % sodium bisulfite. Then, the organic phase was treated twice with 50 mL each of sodium hydrogen carbonate solution and stirred for 1.5 h. Subsequently, the organic phase was dried over magnesium sulfate and the solvent removed under reduced pressure to obtain 1.7 mmol (57% yield, not optimized) of 6. 1H