Synthesis and chemosensing properties of cinnoline-containing poly(arylene ethynylene)s

• Natalia A. Danilkina,
• Petr S. Vlasov,
• Semen M. Vodianik,
• Andrey A. Kruchinin,
• Yuri G. Vlasov and
• Irina A. Balova

Beilstein J. Org. Chem. 2015, 11, 373–384, doi:10.3762/bjoc.11.43

• ethynylene)s comprising a cinnoline core were prepared in high yields via a three-step methodology. A Richter-type cyclization of 2-ethynyl- and 2-(buta-1,3-diynyl)aryltriazenes was used for cinnoline ring formation, followed by a Sonogashira coupling for the introduction of trimethylsilylethynyl moieties

• form complexes with transition metal ions (e.g. Cu+, Cu2+, Ag+, Co2+, Ni2+) [28][29][30][31][32][33][34][35], the introduction of this structural fragments into PAEs might give rise to a new family of chemosensors. Here we describe the first synthesis of PAEs consisting of altering cinnoline, ethynyl

• or alkynyl moiety) were chosen as target structures (Figure 2). They were chosen in order to study the influence of an additional triple bond on the photochemical properties of cinnoline-containing PAEs. It should be noted that PAEs with an additional ethynyl moiety are almost unknown and only few

2-(1-Hydroxypropyn-2-yl)-1-vinylpyrroles: the first successful Favorsky ethynylation of pyrrolecarbaldehydes

• A. V. Ivanov,
• V. S. Shcherbakova,
• I. A. Ushakov,
• L. N. Sobenina,
• O. V. Petrova,
• A. I. Mikhaleva and
• B. A. Trofimov

Beilstein J. Org. Chem. 2015, 11, 228–232, doi:10.3762/bjoc.11.25

• intermediates [4]. Also, 2-(1-hydroxypropyn-2-yl)pyrroles could serve as intermediates for the synthesis of meso-ethynyl-substituted boradiazoindacene (BODIPY) dyes, which have been shown to be potential components of light-harvesting compositions [5]. Until now, 2-(1-hydroxypropyn-2-yl)pyrroles have been

Efficient deprotection of F-BODIPY derivatives: removal of BF₂ using Brønsted acids

• Mingfeng Yu,
• Joseph K.-H. Wong,
• Cyril Tang,
• Peter Turner,
• Matthew H. Todd and
• Peter J. Rutledge

Beilstein J. Org. Chem. 2015, 11, 37–41, doi:10.3762/bjoc.11.6

• was achieved by palladium-catalyzed reduction [10] followed by diazotization of the amine and subsequent substitution with azide [30]. 4-Bromobenzaldehyde (7) was readily converted to ethynyl-F-BODIPY 11 according to the literature procedures [11][31]. Azido-F-BODIPY 9 and ethynyl-F-BODIPY 11 were

• 16 by the TFA method in quantitative yield (100%). With this substrate, the HCl method required an extended reaction time (48 hours) to give 16 in excellent yield (92%). Near-quantitative (99%) conversion of azido-F-BODIPY 9 to dipyrrin 17 was achieved using both methods. Ethynyl-F-BODIPY 11 was

Copper-promoted hydration and annulation of 2-fluorophenylacetylene derivatives: from alkynes to benzo[b]furans and benzo[b]thiophenes

• Yibiao Li,
• Liang Cheng,
• Xiaohang Liu,
• Bin Li and
• Ning Sun

Beilstein J. Org. Chem. 2014, 10, 2886–2891, doi:10.3762/bjoc.10.305

• annulation of (2-(2-fluorophenyl)ethynyl)benzene (1a) to give the corresponding product 2-phenylbenzofuran (2a) by using 2 equiv KOH as a base under various conditions. In the presence of the Pd(PPh3)4 catalyst the reaction of (2-(2-fluorophenyl)ethynyl)benzene in CH3CN does not give any corresponding

• importance of water was confirmed by a lower yield under dry conditions (Table 1, entry 14). In the absence of CuI, we found that the reaction of (2-(2-fluorophenyl)ethynyl)benzene with KOH in DMSO at 80 °C for 4 h gave 55% yield of the annulation product (Table 1, entry 15). Next, we explored the scope and

• )ethynyl)thiophene was also successfully converted to 2-(thiophen-2-yl)benzofuran (2j) in good yields. Subsequently, the R1 substituent of the 2-fluorophenylacetylene derivatives was varied from hydrogen to other functional groups. Substituents at the ortho position of the benzyl group did not have an

Selenium halide-induced bridge formation in [2.2]paracyclophanes

• Laura G. Sarbu,
• Henning Hopf,
• Peter G. Jones and
• Lucian M. Birsa

Beilstein J. Org. Chem. 2014, 10, 2550–2555, doi:10.3762/bjoc.10.266

• substructure. The reactions have been found to be sensitive to the substitution of the ethynyl group. The formation of dienes with a zig-zag configuration is related to that observed for non-conjugated cyclic diynes of medium ring size. Keywords: acetylenes; dienes; [2.2]paracyclophane; selenium halides

• intramolecular photocyclization, yielding the corresponding ladderane isomers [9][10][11]. The ethynyl group is well known for its ability to undergo coupling reactions, making the pseudo-geminal bis(acetylene) 1 and its derivatives good candidates for building molecular scaffolding [12][13]. The reaction

• introduction of new bridges to [2.2]paracyclophanes, we decided to investigate a double addition reaction of 1 equiv of selenium dichloride to both triple bonds of 4,13-bis(ethynyl)[2.2]paracyclophane 1; a bis(vinyl)selenide bridge should result from this interaction. Thus, by reacting 1 with one equivalent of

Building complex carbon skeletons with ethynyl[2.2]paracyclophanes

• Ina Dix,
• Lidija Bondarenko,
• Peter G. Jones,
• Thomas Oeser and
• Henning Hopf

Beilstein J. Org. Chem. 2014, 10, 2013–2020, doi:10.3762/bjoc.10.209

• , Postfach 3329, D-38106 Braunschweig, Germany Organisch-Chemisches Institut der Universität Heidelberg Im Neuenheimer Feld 270, D-69120 Heidelberg, Germany, Fax: (+49) 6221-544205 10.3762/bjoc.10.209 Abstract Ethynyl[2.2]paracyclophanes are shown to be useful substrates for the preparation of complex

• ago we described the preparation of various ethynyl[2.2]paracyclophanes and suggested that these compounds could be developed into useful building blocks for the construction of larger, stereochemically complex carbon frameworks (scaffolds) [2]. This prediction is clearly becoming reality, as shown by

• Sonogashira coupling) [7]. For the smaller oligomers (dimers, trimers) the ortho-isomer with its opening angle of 60° between the ethynyl functions leads preferentially to (mono)cyclic hydrocarbons. For the meta-compound 3 we can expect both cyclic and acyclic (linear) products, and when the two ethynyl

Aryl substitution of pentacenes

• Andreas R. Waterloo,
• Anna-Chiara Sale,
• Dan Lehnherr,
• Frank Hampel and
• Rik R. Tykwinski

Beilstein J. Org. Chem. 2014, 10, 1692–1705, doi:10.3762/bjoc.10.178

• a similar range as found for pentacene-based PAH dyads 2a–c in which the pendant aryl groups are linked by an ethynyl spacer that allows electronic communication between the two arenes [18]. The range of oxidation potentials between TIPSPc, 2a–c, and 3a–k is, however, quite narrow, suggesting that

• incorporation of the ethynyl spacer in 2a–c provides for the lowest HOMO–LUMO gap of the molecules discussed here. X-ray crystallographic analysis Typically, three predominant solid-state packing patterns are found by X-ray crystallographic analysis of pentacene and its derivatives [13]: a) a herringbone

Clicked and long spaced galactosyl- and lactosylcalix[4]arenes: new multivalent galectin-3 ligands

• Silvia Bernardi,
• Paola Fezzardi,
• Gabriele Rispoli,
• Stefania E. Sestito,
• Francesco Peri,
• Francesco Sansone and
• Alessandro Casnati

Beilstein J. Org. Chem. 2014, 10, 1672–1680, doi:10.3762/bjoc.10.175

• reaction between a 1-ethynyl-C-glycoside with a tetraazidocalix[4]arene (dipolarophile-on-the sugar strategy). It was suggested by the authors that the first intermolecular reaction, leading to a Cu-triazolide adduct, allows the copper ion to coordinate an ethynyl glycoside, thus entailing an

An economical and safe procedure to synthesize 2-hydroxy-4-pentynoic acid: A precursor towards ‘clickable’ biodegradable polylactide

• Quanxuan Zhang,
• Hong Ren and
• Gregory L. Baker

Beilstein J. Org. Chem. 2014, 10, 1365–1371, doi:10.3762/bjoc.10.139

• feasible probably due to the interruption of the ethynyl proton in the presence of organometallic reagents [29]. As discussed above, there are two important factors that should be taken into account in order to achieve a safe and economical route resulting in precursor 1: 1) a non-explosive and cheap

• source of acetylene building moiety; and 2) basic reaction conditions involving a low pKa (<24) to avoid the interruption of the ethynyl proton (pKa ~24) while introducing the acetylene moiety. Propargyl tosylate, prepared from propargyl alcohol and tosyl chloride, is a safe analogue of propargyl bromide

Synthesis, characterization and DNA interaction studies of new triptycene derivatives

• Sourav Chakraborty,
• Snehasish Mondal,
• Rina Kumari,
• Sourav Bhowmick,
• Prolay Das and
• Neeladri Das

Beilstein J. Org. Chem. 2014, 10, 1290–1298, doi:10.3762/bjoc.10.130

• reported. Using 2,6,14- or 2,7,14-triaminotriptycenes as synthons, the corresponding triazidotriptycenes were prepared in high yield. Additionally, we report the transformation of 2,6,14- or 2,7,14-triaminotriptycenes to the corresponding ethynyl-substituted triptycenes via their tribromo derivatives

• . Subsequently, derivatization of ethynyl-substituted triptycenes was studied to yield the respective propiolic acid and ethynylphosphine derivatives. Characterization of the newly functionalized triptycene derivatives and their regioisomers were carried out using FTIR and multinuclear NMR spectroscopy, mass

• ; ethynyl; pUC19 plasmid; triptycene tripod; Introduction Triptycene is the simplest member of the class of compounds called iptycenes. Structurally, iptycenes have a number of arene rings joined together to form the bridges of [2.2.2]bicyclic ring systems. In triptycene, the bicyclic ring is decorated

Metal and metal-free photocatalysts: mechanistic approach and application as photoinitiators of photopolymerization

• Jacques Lalevée,
• Sofia Telitel,
• Pu Xiao,
• Marc Lepeltier,
• Frédéric Dumur,
• Fabrice Morlet-Savary,
• Didier Gigmes and
• Jean-Pierre Fouassier

Beilstein J. Org. Chem. 2014, 10, 863–876, doi:10.3762/bjoc.10.83

• dye Vi [61][62] or an anthracene derivative (e.g. bis[(triisopropylsilyl)ethynyl]anthracene) [54][55] as PIC, Ph2I+ as eA and TTMSS as Add (see the simplified Scheme 9 based on Scheme 6). Using violanthrone-79/Ph2I+/TTMSS allowed, for the first time, the formation of an initiating cationic species

Aminofluorination of 2-alkynylanilines: a Au-catalyzed entry to fluorinated indoles

• Antonio Arcadi,
• Emanuela Pietropaolo,
• Antonello Alvino and
• Véronique Michelet

Beilstein J. Org. Chem. 2014, 10, 449–458, doi:10.3762/bjoc.10.42

• system The substrate 2-{[4-(methoxy)phenyl]ethynyl}aniline (1a) was selected as a model substrate and was subjected to various conditions in the presence of Selectfluor as the electrophilic fluorine source. The results are compiled in Table 1. When the reaction of 1a was carried out at room temperature

• -hexyl-substituted derivative 1i. Mechanism rationale for the formation of 7. Cycloisomerization/fluorination of 2-{[4-(methoxy)phenyl]ethynyl}aniline (1a). Cycloisomerization/fluorination reaction of 2-substituted anilines. Cycloisomerization/fluorination reaction of 2-alkynyl-substituted anilines

Gold(I)-catalyzed 6-endo hydroxycyclization of 7-substituted-1,6-enynes

• Ana M. Sanjuán,
• Alberto Martínez,
• Patricia García-García,
• Manuel A. Fernández-Rodríguez and
• Roberto Sanz

Beilstein J. Org. Chem. 2013, 9, 2242–2249, doi:10.3762/bjoc.9.263

• ]. Alternatively, several o-(alkynyl)bromobenzenes [34] could be transformed into the corresponding derivatives 1 by bromine–lithium exchange and further treatment with 3,3-dimethylallyl bromide in the presence of TMEDA [23]. We selected 1-(2-(2-(3-methylbut-2-enyl)phenyl)ethynyl)benzene (1a) as model substrate

Gold-catalyzed reaction of oxabicyclic alkenes with electron-deficient terminal alkynes to produce acrylate derivatives

• Yin-wei Sun,
• Qin Xu and
• Min Shi

Beilstein J. Org. Chem. 2013, 9, 1969–1976, doi:10.3762/bjoc.9.233

• , affording the corresponding addition products in moderate yields. When using alkynyl esters as substrates, the (Z)-acrylate derivatives are obtained. Using but-3-yn-2-one (ethynyl ketone) as a substrate, the corresponding addition product is obtained with (E)-configuration. The proposed mechanism of these

One-step synthesis of pyridines and dihydropyridines in a continuous flow microwave reactor

• Mark C. Bagley,
• Vincenzo Fusillo,
• Robert L. Jenkins,
• M. Caterina Lubinu and
• Christopher Mason

Beilstein J. Org. Chem. 2013, 9, 1957–1968, doi:10.3762/bjoc.9.232

• -substituted propargyl aldehydes undergo Hantzsch dihydropyridine synthesis in preference to Bohlmann–Rahtz reaction in a very high yielding process that is readily transferred to continuous flow processing. Keywords: Bohlmann–Rahtz; continuous flow processing; ethynyl ketones; flow chemistry; Hantzsch

• recent advent of new technology for mesoscale microwave-assisted continuous flow reactions [30], we set out to establish if readily-available ethynyl carbonyl precursors were capable of delivering diverse heterocyclic targets under a continuous flow regime under microwave heating. Ley and Baxendale et al

• . [47] have demonstrated that ethynyl ketones can be generated in flow by the palladium-catalysed acylation of terminal alkynes and further transformed in a continuous process to pyrazoles by cyclocondensation with hydrazines using a commercially available conductive heating modular flow reactor. Given

AgOTf-catalyzed one-pot reactions of 2-alkynylbenzaldoximes with α,β-unsaturated carbonyl compounds

• Qiuping Ding,
• Dan Wang,
• Puying Luo,
• Meiling Liu,
• Shouzhi Pu and
• Liyun Zhou

Beilstein J. Org. Chem. 2013, 9, 1949–1956, doi:10.3762/bjoc.9.231

• products 3 in moderate to good yields. For instance, reaction of 2-((4-methoxyphenyl)ethynyl)benzaldehyde oxime (1c) with methyl methacrylate (2a) under the conditions described above gave the desired product 3j in 75% yield (Table 2, entry 1). A better yield was obtained when substrate 1e was employed in

Zinc–gold cooperative catalysis for the direct alkynylation of benzofurans

• Yifan Li and
• Jérôme Waser

Beilstein J. Org. Chem. 2013, 9, 1763–1767, doi:10.3762/bjoc.9.204

• reagent 1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one (TIPS-EBX) based on the cooperative effect between a gold catalyst and a zinc Lewis acid. High selectivity was observed for C2-alkynylation of benzofurans substituted with alkyl, aryl, halogen and ether groups. The reaction was also

• based on a cooperative effect between a gold catalyst and a zinc Lewis acid using 1-[(triisopropylsilyl)ethynyl]-1,2-benziodoxol-3(1H)-one (TIPS-EBX, 8) as reagent (Scheme 1). The reaction proceeded under mild conditions (60 °C under air) and could also be used to alkynylate the more complex polycyclic

Efficient continuous-flow synthesis of novel 1,2,3-triazole-substituted β-aminocyclohexanecarboxylic acid derivatives with gram-scale production

• Sándor B. Ötvös,
• Ádám Georgiádes,
• István M. Mándity,
• Lóránd Kiss and
• Ferenc Fülöp

Beilstein J. Org. Chem. 2013, 9, 1508–1516, doi:10.3762/bjoc.9.172

• -aminocyclohexanecarboxylates 11–14 were prepared previously by a diastereoselective epoxidation of the corresponding 2-aminocyclohexenecarboxylates, followed by a regioselective oxirane ring opening with NaN3 [68]. Three different alkynes (phenylacetylene, diethyl acetylenedicarboxylate and ethynyl ferrocene) were employed as

Synthesis, photophysical and electrochemical characterization of terpyridine-functionalized dendritic oligothiophenes and their Ru(II) complexes

• Amaresh Mishra,
• Elena Mena-Osteritz and
• Peter Bäuerle

Beilstein J. Org. Chem. 2013, 9, 866–876, doi:10.3762/bjoc.9.100

• the tpy-ethynyl type have proven to be very useful and provide a library of photoresponsive complexes derived from the basic Ru(II)-tpy type module [23][24][25][26][27]. Recently, tpy-complexes that incorporate π-conjugated thiophene or thienylene-ethynylene units became available, and the study of

• ':6',2''-terpyridine (4) [47], which was readily deprotected by CsF in methanol to give the targeted 4'-ethynyl-2,2':6',2''-terpyridine (5) (Scheme 1). Cross-coupling of ethynylated tpy building block 5 with iodinated G1-dendron 6 and G2-dendron 7 [42] under standard Sonogashira-type coupling

• package [57]. Synthesis 4'-[5,5"-Bis(trimethylsilyl)-2,2':3',2"-terthien-5'-ylethynyl]2,2':6',2"-terpyridine (8). To a degassed suspension of Pd(PPh3)2Cl2 (2.73 mg, 3.89 μmol) and CuI (0.37 mg, 1.94 μmol) in diisopropylamine (10 mL) was added 4'-ethynyl-2,2':6',2"-terpyridine (5, 50 mg, 194 μmol) and

Regio- and stereoselective carbometallation reactions of N-alkynylamides and sulfonamides

• Yury Minko,
• Morgane Pasco,
• Helena Chechik and
• Ilan Marek

Beilstein J. Org. Chem. 2013, 9, 526–532, doi:10.3762/bjoc.9.57

• organometallic species (i.e., copper) with a polar functional group in the vicinity of the reactive center should be able to reverse the regioselectivity of the carbometallation, as we have shown for the carbocupration of ethynyl carbamate (XR = OCONR2, Path C, Scheme 1) [24]. Herein we describe our results for

Microwave-assisted three-component domino reaction: Synthesis of indolodiazepinotriazoles

• Rajesh K. Arigela,
• Sudhir K. Sharma,
• Brijesh Kumar and
• Bijoy Kundu

Beilstein J. Org. Chem. 2013, 9, 401–405, doi:10.3762/bjoc.9.41

• % isolated yield, which was characterized as 2-[2-(4-methylphenyl)ethynyl]-1-(oxiran-2-ylmethyl)-1H-indole (4a, Table 1, entry 4). In contrast, use of the polar aprotic solvent DMF with high dielectric constant produced both intermediates 4a/5a as well as the annulated product 6a. Interestingly, a

• product in 77% isolated yield within 1 h (Table 1, entry 6). Further stirring up to 4 h at 120 °C led to the partial conversion of 4a (by ring opening of the epoxide with NaN3) into yet another intermediate 1-azido-3-{2-[2-(4-methylphenyl)ethynyl]-1H-indol-1-yl}propan-2-ol (5a, Table 1, entry 7) in 30

Efficient synthesis of phenylene-ethynylene rods and their use as rigid spacers in divalent inhibitors

• Francesca Pertici,
• Norbert Varga,
• Arnoud van Duijn,
• Matias Rey-Carrizo,
• Anna Bernardi and
• Roland J. Pieters

Beilstein J. Org. Chem. 2013, 9, 215–222, doi:10.3762/bjoc.9.25

• Figure 3 was applied to the synthesis of the two-unit spacer. In order to obtain our orthogonally protected intermediate 7, mono-iodo compound 5 was coupled with tert-butyl(ethynyl)dimethylsilane (TBDMS-acetylene, Scheme 2). From 7 the more labile TMS group was removed by using K2CO3 to give 8. This

Bioactive selaginellins from Selaginella tamariscina (Beauv.) Spring

• Chao Yang,
• Yutian Shao,
• Kang Li and
• Wujiong Xia

Beilstein J. Org. Chem. 2012, 8, 1884–1889, doi:10.3762/bjoc.8.217

• -formyl-3-((4-hydroxyphenyl)ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]cyclohexa-2,5-dien-1-one. Compound 1, 2 and 3 exhibited appreciable cytotoxic activity against cultured HeLa cells (human cervical carcinoma cells), as well as significant antioxidant activity. Keywords: antioxidant

• )ethynyl)biphenyl-2-yl)(4-hydroxyphenyl)methylene]cyclohexa-2,5-dien-1-one, named as selaginellin O. The chemical structures of selaginellin M (2), selaginellin (3) and selaginellin A (4) were identified by spectral analysis by 1D and 2D NMR spectroscopy and high-resolution MS. Their 1H and 13C NMR data

Diarylethene-modified nucleotides for switching optical properties in DNA

• Sebastian Barrois and
• Hans-Achim Wagenknecht

Beilstein J. Org. Chem. 2012, 8, 905–914, doi:10.3762/bjoc.8.103

• we have synthetically attached various chromophores, such as ethynylpyrenes [44][45], BODIPY [46], ethynyl nile red [47][48] and others, to 2’-deoxyuridines for electron transfer studies and for fluorescent probes. To gain greater insight into the counterbase selectivity, we performed PEX experiments

• the bromine was replaced by an ethynyl group. The third nucleoside 6 carries two 2’-deoxyuridine moieties and should principally allow connection of the two DNA double helices by the diarylethene linker as a covalent bridge between. The preparation of all three nucleosides 4 [30], 5 and 6 (Scheme 2

• , forms the central cyclopentane ring of diarylethene 10. Subsequently, the ethynyl linker is attached to 10 by treatment with TMS-protected acetylene in a Pd-catalyzed cross-coupling reaction. Careful evaluation of this synthetic step revealed that the best yield (43%) of the mono-ethinylated product 11

An intramolecular inverse electron demand Diels–Alder approach to annulated α-carbolines

• Zhiyuan Ma,
• Feng Ni,
• Grace H. C. Woo,
• Sie-Mun Lo,
• Philip M. Roveto,
• Scott E. Schaus and
• John K. Snyder

Beilstein J. Org. Chem. 2012, 8, 829–840, doi:10.3762/bjoc.8.93

• triazines (9, R1 = NO2, CONH2), but due to the electron withdrawing nature of the isatin substituents, subsequent sulfonylations were not successful (not shown). The intermolecular IEDDA reactions of 8a with various electron-rich dienophiles, including ethyl ethynyl ether, the enamines (E)-1-N