Bis(vinylenedithio)tetrathiafulvalene analogues of BEDT-TTF

• Erdal Ertas,
• İlknur Demirtas and
• Turan Ozturk

Beilstein J. Org. Chem. 2015, 11, 403–415, doi:10.3762/bjoc.11.46

• of 52 was prepared with the acceptor 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) 53 (1:1) in dichloromethane at room temperature to investigate the optical constant and optical band gap of the complex (Scheme 8) [56]. A solution of the salt was evaporated on a quartz substrate until ≈110 nm

Electrochemical oxidation of cholesterol

• Jacek W. Morzycki and
• Andrzej Sobkowiak

Beilstein J. Org. Chem. 2015, 11, 392–402, doi:10.3762/bjoc.11.45

• , which were anodically oxidized to chlorine. The electrophilic addition of chlorine to the double bond of the investigated compounds cholesteryl acetate (1a), cholesteryl benzoate (1b), 3β-chloro-5-cholestene (1c), and 5-cholestene (1d), gave the corresponding 5α,6β-dichloro steroids in good yields (70

Cross-dehydrogenative coupling for the intermolecular C–O bond formation

• Igor B. Krylov,
• Vera A. Vil’ and
• Alexander O. Terent’ev

Beilstein J. Org. Chem. 2015, 11, 92–146, doi:10.3762/bjoc.11.13

• synthesized also from aromatic aldehydes, α,β-unsaturated aldehydes, or allylic alcohols in the presence of the DDQ (2,3-dichloro-5,6-dicyanobenzoquinone)/amberlyst-15 system in a methanol/toluene mixture under microwave irradiation [171]. Methyl, ethyl, and isopropyl benzoates were prepared from benzaldehyde

A facile synthesis of functionalized 7,8-diaza[5]helicenes through an oxidative ring-closure of 1,1’-binaphthalene-2,2’-diamines (BINAMs)

• Youhei Takeda,
• Masato Okazaki,
• Yoshiaki Maruoka and
• Satoshi Minakata

Beilstein J. Org. Chem. 2015, 11, 9–15, doi:10.3762/bjoc.11.2

• probe the influence of oxidants on the chemical yields of 2a (Table 1, entries 3–6). While the N-monochlorinated reagents N-chlorosuccinimide (NCS, entry 3) and N-chlorophthalimide (NCPh, entry 5) did not produce 2a at all, di- and tri-chlorinated oxidants 1,3-dichloro-5,5-dimethylhydantoin (DCH, entry

Palladium-catalyzed 2,5-diheteroarylation of 2,5-dibromothiophene derivatives

• Fatma Belkessam,
• Aidene Mohand,
• Jean-François Soulé,
• Abdelhamid Elias and
• Henri Doucet

Beilstein J. Org. Chem. 2014, 10, 2912–2919, doi:10.3762/bjoc.10.309

• biological and/or physical properties. For example, 2,2':5',2"-terthiophene itself is a pigment of Tagetes minuta. Some 2,2':5',2"-terthiophene derivatives such as 5,5''-dichloro-α-terthiophene also occur naturally [1]. Moreover, terthiophenes are widely used as building blocks for the synthesis of

Organic chemistry on surfaces: Direct cyclopropanation by dihalocarbene addition to vinyl terminated self-assembled monolayers (SAMs)

• Malgorzata Adamkiewicz,
• David O’Hagan and
• Georg Hähner

Beilstein J. Org. Chem. 2014, 10, 2897–2902, doi:10.3762/bjoc.10.307

• with dihalocarbenes to generate SAMs, terminated with dihalo- (fluoro, chloro, bromo) cyclopropane motifs with about 30% surface coverage. Keywords: difluoro-; dichloro-; dibromomethylenecyclopropanes; dihalocarbenes; self-assembled monolayers; surface coating; Introduction Self-assembled monolayers

• dibromo- (:CBr2), dichloro- (:CCl2) and difluoro- (:CF2) carbenes [21][22][23]. The resultant SAMs were analysed by X-ray photoelectron spectroscopy (XPS), contact angle goniometry, ellipsometry, and atomic force microscopy. Results and Discussion After exposure to carbenes the vinyl-terminated SAMs were

• 1s, consistent with a CF2 group present on the surface [27]. It was anticipated that gem-dibromo-, gem-dichloro- and gem-difluorocyclopropane-terminated SAMs will be formed, following the usual transformations of these carbenes with double bonds. To add further support to this expectation, model

Superoxide chemistry revisited: synthesis of tetrachloro-substituted methylenenortricyclenes

• Basavaraj M. Budanur and
• Faiz Ahmed Khan

Beilstein J. Org. Chem. 2014, 10, 2531–2538, doi:10.3762/bjoc.10.264

• . Adducts 3k/4k containing bromine at ortho position, a relatively bulky substituent close to the reactive site, took a little longer time to afford the nortricyclene 5k. The 2,4-dichloro-substituted adduct 3l gave a good yield of the desired product 5m (78%) (Scheme 2). In order to explore this unexpected

One-pot stereoselective synthesis of α,β-differentiated diamino esters via the sequence of aminochlorination, aziridination and intermolecular S_N2 reaction

• Yiwen Xiong,
• Ping Qian,
• Chenhui Cao,
• Haibo Mei,
• Jianlin Han,
• Guigen Li and
• Yi Pan

Beilstein J. Org. Chem. 2014, 10, 1802–1807, doi:10.3762/bjoc.10.189

• directly from cinnamate esters using N,N-dichloro-p-toluenesulfonamide and benzylamine as nitrogen sources. The key transformations include a Cu-catalyzed aminohalogenation and aziridination, followed by an intermolecular SN2 nucleophilic ring opening by benzylamine. The reactions feature a wide scope of

Chemistry of polyhalogenated nitrobutadienes, 14: Efficient synthesis of functionalized (Z)-2-allylidenethiazolidin-4-ones

• Viktor A. Zapol’skii,
• Jan C. Namyslo,
• Mimoza Gjikaj and
• Dieter E. Kaufmann

Beilstein J. Org. Chem. 2014, 10, 1638–1644, doi:10.3762/bjoc.10.170

• the persubstituted allylidene side chain, the thiazolidin-4-one 15 was reacted with p-tolylthiolate. Thereby, the C(2)–Cl position of the allylidene group was selectively substituted by the reactive thiolate nucleophile, again in a SNVin-type process, to give (Z)-3-(4-tolyl)-2-(3,3-dichloro-1-nitro-2

Synthesis of zearalenone-16-β,D-glucoside and zearalenone-16-sulfate: A tale of protecting resorcylic acid lactones for regiocontrolled conjugation

• Hannes Mikula,
• Julia Weber,
• Dennis Svatunek,
• Philipp Skrinjar,
• Gerhard Adam,
• Rudolf Krska,
• Christian Hametner and
• Johannes Fröhlich

Beilstein J. Org. Chem. 2014, 10, 1129–1134, doi:10.3762/bjoc.10.112

• dry DMF after optimization in terms of base and solvent type (Scheme 4A). Königs–Knorr glucosylation of the PMB-protected mimic 15 afforded 16, which was deprotected using 2,3-dichloro-5,6-dicyano-p-benzoquinone (DDQ) for oxidative PMB cleavage and subsequent ester saponification to yield the desired

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

• ]. a) DDQ, CH2Cl2, rt, 30 min (85%); b) DMP, CH2Cl2, rt, 2 h; c) NaOCl, 2-methyl-2-butene, t-BuOH, phosphate buffer, rt, 16 h; d) TMS-CHN2, toluene/MeOH 2:3, rt, 40 min (58% over three steps); e) second generation Grubbs catalyst, crotonaldehyde, CH2Cl2, 40 °C, 120 min (88%); DDQ = 2,3-dichloro-5,6

Carbenoid-mediated nucleophilic “hydrolysis” of 2-(dichloromethylidene)-1,1,3,3-tetramethylindane with DMSO participation, affording access to one-sidedly overcrowded ketone and bromoalkene descendants^§

• Rudolf Knorr,
• Thomas Menke,
• Johannes Freudenreich and
• Claudio Pires

Beilstein J. Org. Chem. 2014, 10, 307–315, doi:10.3762/bjoc.10.28

• DMSO after 16 hours at 100 °C. However, the idea that 24 might have been generated from 6 via 20 (and the dichloro alcohol 5) had to be dismissed: Although an authentic [3] sample of 5 was quickly consumed under the above conditions of hydrolyzing 6, it furnished none of 24, 23 or 10. Nevertheless, 24

New hydrogen-bonding organocatalysts: Chiral cyclophosphazanes and phosphorus amides as catalysts for asymmetric Michael additions

• Helge Klare,
• Jörg M. Neudörfl and
• Bernd Goldfuss

Beilstein J. Org. Chem. 2014, 10, 224–236, doi:10.3762/bjoc.10.18

• attempted a cis-selective synthesis of bis(amido)cyclodiphosphazanes, which also allows a more modular approach to the design of catalysts. The generation of cyclic cis-di(PIII)phosphazanes from bulky aliphatic amines is well known [38]. In most cases the dichloro derivatives can be obtained in a cis

• literature hitherto [47]. Preparation of cis-2,4-bis(((R,R)-2-(dimethylamino)cyclohexyl)amino)-1,3-diphenylcyclodiphosphazane-2,4-disulfide (14a): To a stirred solution of (R,R)-N1,N1-dimethylcyclohexane-1,2-diamine (400 mg, 2.81 mmol) in DCM (4 mL) was added a solution of 2,4-dichloro-1,3

A unified approach to the important protein kinase inhibitor balanol and a proposed analogue

• Tapan Saha,
• Ratnava Maitra and
• Shital K. Chattopadhyay

Beilstein J. Org. Chem. 2013, 9, 2910–2915, doi:10.3762/bjoc.9.327

• generation catalyst, benzylidene[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene]dichloro-(tricyclohexylphosphine)ruthenium (25). Pleasingly, the desired cycloalkene 26 was obtained in a gratifying yield of 89%. The sequential removal of the O-acetyl group leading to 27 followed by removal of the N-Boc

Halogenated volatiles from the fungus Geniculosporium and the actinomycete Streptomyces chartreusis

• Tao Wang,
• Patrick Rabe,
• Christian A. Citron and
• Jeroen S. Dickschat

Beilstein J. Org. Chem. 2013, 9, 2767–2777, doi:10.3762/bjoc.9.311

• highly complex calicheamicin 24 (Figure 7) from Micromonospora echinospora [28] that also contains an iodinated aromatic subunit. Conclusion In summary, we have presented the identification of 4-chloro-1,2-dimethoxybenzene (4b) and 1,5-dichloro-2,3-dimethoxybenzene (10b) as volatile natural products

Advancements in the mechanistic understanding of the copper-catalyzed azide–alkyne cycloaddition

• Regina Berg and
• Bernd F. Straub

Beilstein J. Org. Chem. 2013, 9, 2715–2750, doi:10.3762/bjoc.9.308

• in the following order of ligands: neocuproine < 4,7-dimethoxy-1,10-phenanthroline < bathophenanthroline < 1,10-phenanthroline < 4,7-dichloro-1,10-phenanthroline [150]. In 2006, the group of Nolan introduced a new family of monocationic copper(I) NHC-complexes of general formula [(NHC)2Cu]X (X = BF4

IBD-mediated oxidative cyclization of pyrimidinylhydrazones and concurrent Dimroth rearrangement: Synthesis of [1,2,4]triazolo[1,5-c]pyrimidine derivatives

• Caifei Tang,
• Zhiming Li and
• Quanrui Wang

Beilstein J. Org. Chem. 2013, 9, 2629–2634, doi:10.3762/bjoc.9.298

• ]. As outlined in Scheme 1, the conversion of 4,6-dihydroxypyrimidines 1 to the dichloro derivatives 2 was accomplished by refluxing in phosphorus oxychloride for 4 h in the presence of triethylamine in yields ranging from 75 to 90% [16][17]. After screening a set of conditions, 1-(6-chloropyrimidin-4

The chemistry of isoindole natural products

• Klaus Speck and
• Thomas Magauer

Beilstein J. Org. Chem. 2013, 9, 2048–2078, doi:10.3762/bjoc.9.243

• ][125][126][127]. The approach carried out by Castedo relied on 3-hydroxysarcocapnine (147), which could either be isolated from natural sources or prepared via an Ullmann coupling of a 1-(2-bromobenzyl)-8-hydroxyisoquinoline derivative [121][125]. Oxidation of 147 with 2,3-dichloro-5,6-dicyano-1,4

Metal-free aerobic oxidations mediated by N-hydroxyphthalimide. A concise review

• Lucio Melone and
• Carlo Punta

Beilstein J. Org. Chem. 2013, 9, 1296–1310, doi:10.3762/bjoc.9.146

• acetophenone [33]. Among the different AQ derivatives that were tested, 1,4-diamino-2,3-dichloro-antraquinone (DADCAQ) was the most effective in terms of both conversion and selectivity of the ketone product. The potential of this catalytic system was proved by extending its application, in the absence of

• the oxidation of ethylbenzene [36]. In particular, aryl-tetrachloro-NHPI (TCNHPI) allowed significantly higher conversion and selectivity with respect to the NHPI/DADCAQ classical system (Scheme 13). More recently, analogous results were achieved by combining NHPI with 2,3-dichloro-5,6

Synthesis and structure of trans-bis(1,4-dimesityl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) dichloride and diacetate. Suzuki–Miyaura coupling of polybromoarenes with high catalytic turnover efficiencies

• Jeelani Basha Shaik,
• Venkatachalam Ramkumar,
• Babu Varghese and
• Sethuraman Sankararaman

Beilstein J. Org. Chem. 2013, 9, 698–704, doi:10.3762/bjoc.9.79

• polychloroarenes did not give a clean reaction, and the reactions were sluggish in comparison to polybromoarenes. In addition, unlike the polybromo derivatives, the polychloroarene derivatives of pyrene, triphenylene and [2,2]paracyclophane are not readily available. Conclusion In conclusion, the dichloro complex

• characterization of dichloro (1) and diacetate (2) complexes. Comparison of the structures of 1 and 2 with that of the corresponding (1,4-diphenyl-3-methyl-1,2,3-triazol-5-ylidene)palladium(II) complexes 3 and 4 is presented. The structures of the diacetate complexes 2 and 4 are significantly different in that 4

Polymerization of novel methacrylated anthraquinone dyes

• Christian Dollendorf,
• Susanne Katharina Kreth,
• Soo Whan Choi and
• Helmut Ritter

Beilstein J. Org. Chem. 2013, 9, 453–459, doi:10.3762/bjoc.9.48

• obtained (Scheme 1). Polymerizable green dye 2 based on anthraquinone The synthesis of the green anthraquinone based monomeric dye 2 is shown in Scheme 1, step a. 5,8-Dichloro-1,4-dihydroxyanthraquinone was first subjected to a nucleophilic substitution reaction with 2-(4-aminophenyl)ethanol to give a

• 2 compared to 5,8-dichloro-1,4-dihydroxyanthraquinone (λmax = 500 nm) is a result of the enlargement of the π-electron system as aromatic moieties are introduced. This leads to absorption at longer wavelengths (bathochromic shift). Thus, the challenge of creating a green dye is to realize selective

N-Heterocyclic carbene–palladium catalysts for the direct arylation of pyrrole derivatives with aryl chlorides

• Ismail Özdemir,
• Nevin Gürbüz,
• Nazan Kaloğlu,
• Öznur Doğan,
• Murat Kaloğlu,
• Christian Bruneau and
• Henri Doucet

Beilstein J. Org. Chem. 2013, 9, 303–312, doi:10.3762/bjoc.9.35

• ) ν(CN): 1477; Anal. calcd for C74H100N4PdBr2: C, 67.75; H, 7.68; N, 4.27; found: C, 67.72; H, 7.64; N, 4.27. cis/trans-Dichloro-bis[1-(3,5-di-tert-butylbenzyl)-3-(2,3,4,5,6-pentamethylbenzyl)benzimidazol-2-ylidene]palladium(II) (4): Yield: 0.27 g, 82%; mp 310–312 °C; 1H NMR (CDCl3, δ) 1.27, 1.29 (s

• (Pd-Ccarbene); IR (cm−1) ν(CN): 1448; Anal. calcd for C54H60N4O4PdBr2: C, 59.21; H, 5.52; N, 5.12; found: C, 59.27; H, 5.54; N, 5.13. cis/trans-Dichloro-bis[1-(2-(2-ethoxy)phenoxyethyl)-3-(4-methylbenzyl)benzimidazol-2-ylidene] palladium(II) (6): Yield: 0.32 g, 66%; mp 235–237 °C; 1H NMR (CDCl3, δ

• ; H, 5.52; N, 5.90; found: C, 63.18; H, 5.50; N, 5.93. cis/trans-Dichloro-bis[1-(2-(2-ethoxy)phenoxyethyl)-3-(3-methoxybenzyl)benzimidazo-2-ylidene]palladium(II) (7): Yield: 0.22 g, 53%; mp 205–207 °C; 1H NMR (CDCl3, δ) 1.43, 1.45 (t, J = 7.0 Hz, 6H, NCH2CH2OC6H4(OCH2CH3)-2), 3.66, 3.75 (s, 6H

Reactions of salicylaldehyde and enolates or their equivalents: versatile synthetic routes to chromane derivatives

• Ishmael B. Masesane and
• Zelalem Yibralign Desta

Beilstein J. Org. Chem. 2012, 8, 2166–2175, doi:10.3762/bjoc.8.244

• of salicylaldehyde (5) with dimedone (18) in the presence of a catalytic amount of KF/Al2O3 (Scheme 6) [21]. The reaction is thought to proceed through a Knoevenagel condensation, a Michael addition and an intramolecular cyclization. The reaction was repeated with chloro-, bromo-, dichloro-, dibromo

• of 28% (Scheme 18) [38]. Slightly better yields (33–40%) were achieved when 5-bromo-, 5-chloro- and 3,5-dichloro-substituted salicylaldehydes were employed in the reaction. Ravichandran utilized a classical 1,4-diazabicyclo[2.2.2]octane (DABCO)-catalyzed Baylis–Hillman reaction of salicylaldehyde (5

The chemistry of bisallenes

• Henning Hopf and
• Georgios Markopoulos

Beilstein J. Org. Chem. 2012, 8, 1936–1998, doi:10.3762/bjoc.8.225

• the product, has also been employed for the preparation of the parent hydrocarbon 2 (Scheme 6). The reduction of 1,6-dichloro-2,4-butadiyne (43) in methanol with a zinc/copper couple furnished the bisallene 2, but also provided at least three other C6H6-isomers, 44–46, requiring extensive

• below). An early reference to the preparation of 3,4-dichloro-1,2,4,5-hexatetraene by Carothers and Coffman requires reinvestigation with modern spectroscopic methods [46][47]. If confirmed, it would not only describe the first preparation of a functionalized bisallene, but also the first representative

• product (Scheme 41), the reaction of 24 with either dichloro (170: R = Cl) or diphenylketene (170, R = phenyl) furnished largely the [2 + 2] cycloadducts 171. Only traces of the Diels–Alder adduct 172 are observed in this case. This example seems to be the only one in which the [2 + 4] and [2 + 2

Influence of cyclodextrin on the solubility of a classically prepared 2-vinylcyclopropane macromonomer in aqueous solution

• Helmut Ritter,
• Jia Cheng and
• Monir Tabatabai

Beilstein J. Org. Chem. 2012, 8, 1528–1535, doi:10.3762/bjoc.8.173

• (4) was synthesized following a procedure described in [32]. Diethyl 2-vinyl-1,1-cyclopropanedicarboxylate could be obtained according to [33] from sodium ethoxide, diethyl malonate and trans-1,4-dichloro-2-butene in ethanol (Scheme 2). The desired macromonomer 5 was prepared in two steps according