Mechanochemical synthesis of small organic molecules

• Tapas Kumar Achar,
• Anima Bose and
• Prasenjit Mal

Beilstein J. Org. Chem. 2017, 13, 1907–1931, doi:10.3762/bjoc.13.186

•  11) using 2,3-dichloro-5,6-dicyanoquinone (DDQ) as an efficient oxidant [67]. Su and co-workers have also reported an asymmetric version of the CDC reaction between terminal alkynes and sp3 C–H bonds under high speed ball milling conditions [68]. Several optically active 1-alkynyl

• tetrahydroisoquinoline derivatives were synthesized using a pyridine-based chiral ligand (PyBox, Scheme 12) in the presence of DDQ (2,3-dichloro-5,6-dicyano-1,4-benzoquinone). The coupling products were isolated in fair yields with ee’s (enantiomeric excesses) up to 79%. The milling copper balls were also identified as

Synthesis of benzothiophene and indole derivatives through metal-free propargyl–allene rearrangement and allyl migration

• Jinzhong Yao,
• Yajie Xie,
• Lianpeng Zhang,
• Yujin Li and
• Hongwei Zhou

Beilstein J. Org. Chem. 2017, 13, 1866–1870, doi:10.3762/bjoc.13.181

• products in good yields (2a–k). A variety of substituents, such as p-COOEt, p-COCH3, dichloro, p-NO2, p-CF3 and p-CN were well-tolerated during the reaction, leading to 2a–f in 54–83% yield. The presence of methyl acrylate or pyridine was also well-tolerated, as exemplified in the formation of 2g,h in 48

Oxidative dehydrogenation of C–C and C–N bonds: A convenient approach to access diverse (dihydro)heteroaromatic compounds

• Santanu Hati,
• Ulrike Holzgrabe and
• Subhabrata Sen

Beilstein J. Org. Chem. 2017, 13, 1670–1692, doi:10.3762/bjoc.13.162

• -dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), KMnO4, transition metal-based oxidants and air have been extensively used to promote this transformation. o-Iodoxybenzoic acid (IBX)-mediated oxidative dehydrogenation IBX was first introduced as an oxidant (in oxidative dehydrogenation) by Nicolaou and co

Synthesis of ribavirin 2’-Me-C-nucleoside analogues

• Fanny Cosson,
• Aline Faroux,
• Jean-Pierre Baltaze,
• Jonathan Farjon,
• Régis Guillot,
• Jacques Uziel and
• Nadège Lubin-Germain

Beilstein J. Org. Chem. 2017, 13, 755–761, doi:10.3762/bjoc.13.74

• -dichloro-1,1,3,3-tetraisopropyldisiloxane (TIPDSCl2). While this reaction proceeded with a very poor yield in the case of the mixture 10a/10b (~10% yield), compound 11a was obtained in 79% yield from pure 10a (24% yield for 11b starting from 10b). Thereafter, the oxidation of 11a to the corresponding

Pd- and Cu-catalyzed approaches in the syntheses of new cholane aminoanthraquinone pincer-like ligands

• Nikolay V. Lukashev,
• Gennadii A. Grabovyi,
• Dmitry A. Erzunov,
• Alexey V. Kazantsev,
• Gennadij V. Latyshev,
• Alexei D. Averin and
• Irina P. Beletskaya.

Beilstein J. Org. Chem. 2017, 13, 564–570, doi:10.3762/bjoc.13.55

• ). Consequently, this system was used for the synthesis of bis-steroidal arylamines 5a and 5b starting from 24-aminocholanol 3a. Activated chlorinated substrates, such as 1,8- and 1,5-dichloroanthraquinones, are very promising substrates for nucleophilic substitution. For instance, 1,8-dichloro-9,10-anthraquinone

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

New approaches to organocatalysis based on C–H and C–X bonding for electrophilic substrate activation

• Pavel Nagorny and
• Zhankui Sun

Beilstein J. Org. Chem. 2016, 12, 2834–2848, doi:10.3762/bjoc.12.283

• –4 M−1) between L14 or L15 and lactide in solution. The α-dichloro and α-dibromoacetanilides L14 containing electron-deficient aromatic groups (i.e., m,m’-NO2 substitution on phenyl ring) afforded the most active catalysts with the strongest N–H···O···H–CX2 interactions. Halogen bonds as alternatives

Identification, synthesis and mass spectrometry of a macrolide from the African reed frog Hyperolius cinnamomeoventris

• Markus Menke,
• Pardha Saradhi Peram,
• Iris Starnberger,
• Walter Hödl,
• Gregory F.M. Jongsma,
• David C. Blackburn,
• Mark-Oliver Rödel,
• Miguel Vences and
• Stefan Schulz

Beilstein J. Org. Chem. 2016, 12, 2731–2738, doi:10.3762/bjoc.12.269

• -trimethylphenyl)-2-imidazolidinylidene)dichloro(phenylmethylene)(tricyclohexylphosphine)ruthenium reduced the isomerization, leading to an (E/Z)-mixture of 2. Finally, the (Z)-selective Grubbs catalyst 12 furnished the best results [29][30]. This catalyst yielded only the desired product (R)-2 with a (Z

Copper-catalyzed asymmetric sp³ C–H arylation of tetrahydroisoquinoline mediated by a visible light photoredox catalyst

• Pierre Querard,
• Inna Perepichka,
• Eli Zysman-Colman and
• Chao-Jun Li

Beilstein J. Org. Chem. 2016, 12, 2636–2643, doi:10.3762/bjoc.12.260

• of THIQs with arylboronic esters via asymmetric organocatalysis methodology [25][28]. The use of chiral tartaric acid derivatives, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and high temperature (70 °C) were found to be the optimal conditions to obtain the desired arylated product with

Facile synthesis of a 3-deazaadenosine phosphoramidite for RNA solid-phase synthesis

• Elisabeth Mairhofer,
• Elisabeth Fuchs and
• Ronald Micura

Beilstein J. Org. Chem. 2016, 12, 2556–2562, doi:10.3762/bjoc.12.250

•  2) [23][24]. Treatment of the 2,6-dichloro-3-deazapurine derivative with ammonia was optimized by Bande et al. recently [25], but still required 200 °C reaction temperature and five days reaction time to afford regioselective displacement of the 2-chlorine atom and concomitant deacetylation in high

A new protocol for the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane

• Donghui Pan,
• Yanbin Wang and
• Guomin Xiao

Beilstein J. Org. Chem. 2016, 12, 2443–2449, doi:10.3762/bjoc.12.237

• precursor of parylene D, from 2,5-dichloro-p-xylene. In the first bromination step, with H2O2–HBr as a bromide source, this procedure becomes organic-waste-free and organic-solvent-free and can appropriately replace the existing bromination methods. The Winberg elimination–dimerization step, using aqueous

• prepare tetrachloroparacyclophane, but a pure polysubstituted product is difficult to obtain by electrophilic substitution without repeated crystallization or chromatographic purification [9]. Thus, we report an improved synthesis method using the Winberg dimerization of 2,5-dichloro-(4-methylbenzyl

• )trimethylammonium hydroxide without tedious purification. The important chemical 1-(bromomethyl)-2,5-dichloro-4-methylbenzene is an intermediate in the preparation of 2,5-dichloro-(4-methylbenzyl)trimethylammonium hydroxide. During our investigation of the synthesis of 4,7,12,15-tetrachloro[2.2]paracyclophane, we

Experimental and theoretical investigations into the stability of cyclic aminals

• Edgar Sawatzky,
• Antonios Drakopoulos,
• Martin Rölz,
• Christoph Sotriffer,
• Bernd Engels and
• Michael Decker

Beilstein J. Org. Chem. 2016, 12, 2280–2292, doi:10.3762/bjoc.12.221

• substituents (and therefore the change in electron density at all sides), we used the data reported by Craig [36] for the aromatic site and the data reported by Topliss [37] for the side chains, respectively. A disubstituted 2,6-dichloro compound was also synthesized to study the influence of steric

• . Furthermore, the 2,6-dichloro compound 8f exhibits the same behaviour in terms of stability as the other compounds of the 8 series, even though it adheres to the equatorial minimum energy motif, both in the neutral and in the N-3 protonated form. In conclusion, a comparison of the conformational search and

Organometallic chemistry

• Bernd F. Straub,
• Rolf Gleiter,
• Claudia Meier and
• Lutz H. Gade

Beilstein J. Org. Chem. 2016, 12, 2216–2221, doi:10.3762/bjoc.12.213

• mechanism of the Dötz reaction, he found that chromacyclobutene structures were unrealistic intermediates and instead proposed vinylcarbene complexes as much more stable isomers [64][68][88]. Other research projects of his group included the synthesis of ruthenium–carbene complexes with cis-dichloro ligands

Comparing blends and blocks: Synthesis of partially fluorinated diblock polythiophene copolymers to investigate the thermal stability of optical and morphological properties

• Pierre Boufflet,
• Sebastian Wood,
• Jessica Wade,
• Zhuping Fei,
• Ji-Seon Kim and
• Martin Heeney

Beilstein J. Org. Chem. 2016, 12, 2150–2163, doi:10.3762/bjoc.12.205

• microwave vial charged with dichloro(1,3-bis(diphenylphosphino)propane)nickel (2.27 mg, 0.5 mol %) was added Grignard solution freshly prepared from 2,5-dibromo-3-octylthiophene (2.25 mL, 0.28 M in THF), and the reaction mixture was stirred at 40 °C for 1 h. GPC analysis of an aliquot quenched with methanol

• ) 7.05 (s, 1H), 2.94–2.85 (m, 1.8H), 2.85–2.77 (m, 0.9H), 1.90–1.66 (m, 3H), 1.56–1.35 (m, 15H), 1.03–0.90 (m, 4.2H); 19F NMR (376 MHz, TCE-d2, 403 K, δ) −122.94 (s). Synthesis of P3OT-b-F-P3OT 1:4 In a sealed dry 2–5 mL microwave vial charged with dichloro(1,3-bis(diphenylphosphino)propane)nickel (2.27

Rapid regio- and multi-coupling reactivity of 2,3-dibromobenzofurans with atom-economic triarylbismuths under palladium catalysis

• Maddali L. N. Rao,
• Jalindar B. Talode and
• Venneti N. Murty

Beilstein J. Org. Chem. 2016, 12, 2065–2076, doi:10.3762/bjoc.12.195

• functionalized with 5-chloro, 5,7-dichloro, 7-bromo-5-chloro and 5-bromo groups 1.3–1.6 furnished exclusive arylations at C-2 position. In these cases, the corresponding 2-aryl-3-bromobenzofuran products 2.16–2.27 were obtained in high yields (Table 2, entries 16-27). It is to be mentioned that, despite the

Economical and scalable synthesis of 6-amino-2-cyanobenzothiazole

• Jacob R. Hauser,
• Hester A. Beard,
• Mary E. Bayana,
• Katherine E. Jolley,
• Stuart L. Warriner and
• Robin S. Bon

Beilstein J. Org. Chem. 2016, 12, 2019–2025, doi:10.3762/bjoc.12.189

• alternative synthesis of ACBT that avoids the use of cyanide (Scheme 2B) [7]. This route makes use of 4,5-dichloro-1,2,3-dithiazolium chloride (Appel’s salt, 12), and variations of the procedure have enabled the synthesis of different CBT derivatives, some of which on multi-gram scale [6][7][16][17]. However

Potent triazine-based dehydrocondensing reagents substituted by an amido group

• Munetaka Kunishima,
• Daiki Kato,
• Nobu Kimura,
• Masanori Kitamura,
• Kohei Yamada and
• Kazuhito Hioki

Beilstein J. Org. Chem. 2016, 12, 1897–1903, doi:10.3762/bjoc.12.179

• substituents (R3 = Me or Ph), and the methyl, phenyl, or hydrogen substituent was placed at R4. Tertiary amide-type compounds III–VI were prepared in one step from the well-known commercially available 2,4-dichloro-6-methoxy-1,3,5-triazine (6) [20] (Scheme 2). In contrast, attempts to prepare the secondary

Total synthesis of leopolic acid A, a natural 2,3-pyrrolidinedione with antimicrobial activity

• Atul A. Dhavan,
• Rahul D. Kaduskar,
• Loana Musso,
• Leonardo Scaglioni,
• Piera Anna Martino and
• Sabrina Dallavalle

Beilstein J. Org. Chem. 2016, 12, 1624–1628, doi:10.3762/bjoc.12.159

• cleavage with cerium ammonium nitrate (CAN) or 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ). Thus, 2,3-pyrrolidinedione 3 was obtained by the reaction of ethyl acrylate with p-methoxybenzylamine, followed by treatment with diethyl oxalate (Scheme 1) [12]. On the basis of NMR data, the compound exists as an

Methylpalladium complexes with pyrimidine-functionalized N-heterocyclic carbene ligands

• Dirk Meyer and
• Thomas Strassner

Beilstein J. Org. Chem. 2016, 12, 1557–1565, doi:10.3762/bjoc.12.150

• reported the synthesis of the imidazolium salts 1–4 and their corresponding silver complexes 5–8. The reaction with dichloro(cyclooctadiene)-palladium(II) [(COD)PdIICl2] allowed for the isolation and characterization of the [((pym)^(NHC-R))PdIICl2]-complexes [34]. For the synthesis of the corresponding

• could confirm the formation of methyl trifluoroacetate and a ‘methyl free’ Pd(II) complex. This complex showed similar NMR spectra like the bistrifluoroacetate complex 14 (Scheme 3), which was prepared by the reaction of the corresponding dichloro complex [34] with silver trifluoroacetate for comparison

• palladium dichloro complexes [(pym)^(NHC)PdII(Cl)2] [34]. As the methane activation is carried out in a mixture of trifluoroacetic acid and its anhydride, another potential intermediate could be the [((pym)^(NHC-DIPP))PdII(CH3)(CF3COO)] complex 13. Formation of methyl trifluoroacetate and the

Indenopyrans – synthesis and photoluminescence properties

• Andreea Petronela Diac,
• Ana-Maria Ţepeş,
• Albert Soran,
• Ion Grosu,
• Anamaria Terec,
• Jean Roncali and
• Elena Bogdan

Beilstein J. Org. Chem. 2016, 12, 825–834, doi:10.3762/bjoc.12.81

• obtain photoluminescent compounds with higher performance, the dehydrogenation reaction of enol-lactones 2 and 3 was performed. Adapted from a procedure previously described [38], the oxidation of the isomeric mixture 2'a/3''a and 2'c/3'c, respectively, in the presence of 2,3-dichloro-5,6-dicyano-1,4

A selective and mild glycosylation method of natural phenolic alcohols

• Mária Mastihubová and
• Monika Poláková

Beilstein J. Org. Chem. 2016, 12, 524–530, doi:10.3762/bjoc.12.51

• performed in the presence of known mild catalysts such as Ag2O [33] (method A), the less frequently used ZnO–ZnCl2 system [34] (method B) and the combination of 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) with iodine (DDQ–I2) [35] (method C). In addition ZnO–I2 (method D) was successfully applied as a

A quadruple cascade protocol for the one-pot synthesis of fully-substituted hexahydroisoindolinones from simple substrates

• Hong-Bo Zhang,
• Yong-Chun Luo,
• Xiu-Qin Hu,
• Yong-Min Liang and
• Peng-Fei Xu

Beilstein J. Org. Chem. 2016, 12, 253–259, doi:10.3762/bjoc.12.27

• , entry 11). A heteroaromatic substrate such as thiophene could also be successfully employed to afford rac-3 with medium yield and diastereoselectivity (Table 2, entry 13). 3,4-Dichloro-substituted and 3,5-dimethoxy-substituted substrates produced the desired products in 84% and 55% yield with 20:1 and

Simple activation by acid of latent Ru-NHC-based metathesis initiators bearing 8-quinolinolate co-ligands

• Julia Wappel,
• Roland C. Fischer,
• Luigi Cavallo,
• Christian Slugovc and
• Albert Poater

Beilstein J. Org. Chem. 2016, 12, 154–165, doi:10.3762/bjoc.12.17

• -heterocyclic carbene bearing precursor complexes M31, HovII or M32 with excess of 5,7-dichloro-8-hydroxyquinoline or 5,7-dibromo-8-hydroxyquinoline in the presence of excess Cs2CO3 as the base (see Scheme 1). The silver-free method [41] resulted in any case in the formation of at least two new products (as

• outstanding solubility in nonpolar solvents such as n-pentane as well as in nonpolar substrates such as dicylopentadiene (DCPD). Both properties are desired properties for employing the compounds as initiators in solvent free polymerizations. In case of the reaction of M31 with 5,7-dichloro-8-hydroxyquinoline

• from a series of published N,O-chelating ligands [42]. The minor isolated product 1b featured two 5,7-dichloro-8-quinolinolate ligands and was identified as the OC-6-32 isomer (see Scheme 1). Complexes 1a and 1b account for 90% of the theoretical yield. In case of HovII as the starting complex again

New metathesis catalyst bearing chromanyl moieties at the N-heterocyclic carbene ligand

• Agnieszka Hryniewicka,
• Szymon Suchodolski,
• Agnieszka Wojtkielewicz,
• Jacek W. Morzycki and
• Stanisław Witkowski

Beilstein J. Org. Chem. 2015, 11, 2795–2804, doi:10.3762/bjoc.11.300

• ) ppm; HRMS (ESI): [M − Cl]+ calcd for C31H43N2O2: 475.3319, found: 475.3308. Some signals in 13C NMR spectrum are doubled (see text “Synthesis of the carbene precursor”). 1,3-Bis[(2,2,5,7,8-pentamethylchroman-6-yl)-2-imidazolidinylidene]dichloro(o-isopropoxyphenylmethylene)ruthenium (9) In a Schlenk

Versatile synthesis and biological evaluation of novel 3’-fluorinated purine nucleosides

• Hang Ren,
• Haoyun An,
• Paul J. Hatala,
• William C. Stevens Jr,
• Jingchao Tao and
• Baicheng He

Beilstein J. Org. Chem. 2015, 11, 2509–2520, doi:10.3762/bjoc.11.272

• and deprotection of 2,6-dichloropurine 42 was achieved with a saturated solution of ammonia in methanol to furnish 2-chloro-3’-deoxy-3’-fluoroadenosine (16). The 2,6-dichloro-intermediate 42 was coupled with 2-(tributylstannyl)furan catalyzed by bis(triphenylphosphine)palladium(II) chloride in DMF to

• provide monochloro-intermediate 43 (Method I, entry 16, Table 1). Monochloro-intermediates 44 and 45 were constructed by Suzuki coupling of dichloro-intermediate 42 with 3-thienylboronic acid and phenylboronic acid in toluene (Method II; entries 17 and 18, Table 1), and monochloro-intermediate 46 was

• -chlorine atom on the intermediate 42 was stable under the Stille and Suzuki reaction conditions and under ammonia deprotection conditions. However, the palladium-catalyzed cross coupling of dichloro-intermediate 42 with organostannane and organoboronic acid reagents resulted in lower yields when compared